KR20090015015A - Photomask Substrate, Photomask and Manufacturing Method Thereof - Google Patents

Abstract

[PROBLEMS] To provide a photomask substrate, a photomask, and a method of manufacturing the same, in which a fine pattern can be formed with high precision by wet etching.

In addition, the present invention includes a transparent substrate 10, a semi-transmissive layer 20 having a semi-transmissive, and a light shielding layer 33 formed on the semi-transmissive layer 20 to substantially shield irradiation light. In a photomask substrate 2, the semi-transmissive layer 20 is insoluble or poorly soluble in etching solution A than light shielding layer 33, and is soluble in etching solution B. Titanium (TiN _x : where 0 <x <1.33). On the other hand, the light shielding layer 33 is more usable with respect to the etching liquid A than the semi-transmissive layer 20, and is formed with insoluble or poorly soluble metal chromium Cr. Since the etching resistance of each layer with respect to etching liquid differs, it becomes possible to selectively etch the transflective layer 20 and the light shielding layer 33 without damaging another layer.

Description

Substrate for photomask, photomask and method for manufacturing Technical Field

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a substrate for a photomask, a photomask, and a method for manufacturing the same, having a semi-transmissive layer, and in particular, display elements and fine scattering irregularities of flat display devices such as LCDs, PDPs, and ELs, and the like. The present invention relates to a pattern forming photomask substrate, a photomask, and a method of manufacturing the same, which are used for surface modification such as antireflection plate, diffusion reflection plate with or without fine particles, microlens array, and other irregularities on the array.

With the development of liquid crystal display devices (reflective, transmissive and transflective), plasma display devices, organic electro-luminescence (EL) displays, and other flat panel display devices, the size, pattern, Various types of photomasks different from each other are used.

For example, in the formation of a liquid crystal display device, in the TFT (Thin Film Transistor) manufacturing step, depending on the manufacturing method, generally three to five photomasks for patterning are required. Moreover, also in the color filter side which is arrange | positioned facing a liquid crystal display element, the black mask formation, the color layer formation, and the photomask corresponding to a liquid crystal display element respectively are needed.

In photomasks used for forming fine patterns such as LSI, halftone masks are used for the purpose of improving pattern accuracy (for example, Patent Documents 1 to 9). The halftone mask is a photomask in which a transflective layer (halftone) is formed between the transmissive portion and the light shielding portion. This semi-transmissive layer is designed to have a film thickness such that the phase is inverted by? / 2 or shifted by? Λ / 4 in accordance with the exposure wavelength to be used. Accordingly, diffraction of light generated between adjacent patterns is prevented, and the difference in light intensity between the edge portion and the transmissive portion of the mask light shielding portion becomes clear. In addition, since moire and halation are less likely to occur, resolution can be improved. In addition, there is also a method (gray tone mask) which obtains the same effect as halftone by forming a fine continuous stripe pattern.

As a method of manufacturing such a halftone-mounted photomask, patterning is performed once by coating and exposing a resist to a photomask substrate (a photomask blank) on which a first layer (a semi-transmissive layer or a light shielding layer) is formed for the first time. The method of removing and cleaning a resist, forming a 2nd layer (shielding layer or semi-transmissive layer) again using a vacuum apparatus, etc., and then patterning the 2nd layer formed second in the photolithography process is known (for example, For example, refer patent document 3, 9). Moreover, as another manufacturing method, the method of first forming the thin film which has a homogeneous or heterogeneous multilayered structure, and then forming each pattern by dry etching is also known (for example, patent document 2, 5).

Patent Document 1: Japanese Patent Application Laid-open No. Hei 7-209849

Patent Document 2: Japanese Patent Application Laid-Open No. 9-127677

Patent Document 3: Japanese Patent Application Laid-Open No. 2001-27801

Patent Document 4: Japanese Patent Application Laid-Open No. 2001-83687

Patent Document 5: Japanese Patent Application Laid-Open No. 2001-312043

Patent Document 6: Japanese Patent Application Laid-Open No. 2003-29393

Patent Document 7: Japanese Patent Application Laid-Open No. 2003-322949

Patent Document 8: Japanese Patent Application Laid-Open No. 2004-29746

Patent Document 9: Japanese Patent Publication No. 2006-18001

Disclosure of the Invention

Problems to be Solved by the Invention

In this conventional method, after patterning the first layer formed using a vacuum apparatus or the like, it is necessary to form the second layer using a vacuum apparatus or the like and patterning again. It is necessary to perform the film-forming process using an apparatus etc. twice or more. For this reason, there existed a problem that the process required for manufacturing a photomask increased, and the manufacturing cost rose.

In addition, the pattern formation of a photomask is usually carried out by dry etching which irradiates ions to the layer on the photomask substrate by plasma or laser light, such as a reactive gas, and wet which chemically corrodes the layer with a corrosive etching liquid (chemical). There are two types of etching methods of etching (also called wet etching). Among these, the dry etching method is generally used for the pattern formation of a photomask.

However, in dry etching, there are various technical problems associated with the enlargement of the photomask and the mass production. For example, in the direct drawing process in dry etching, the drawing area increases with an increase in the size of the photomask, so that an increase in drawing time by an electron beam, a laser, or the like occurs, and it is difficult to improve the tact time of photomask manufacturing. . In addition, with the increase in the size of the photomask, facilities such as vacuum tanks and gas type switching devices need to be increased in size, resulting in an increase in burden on equipment and an increase in the cost of manufacturing the photomask. . In addition, since the number of substrates that can be processed at one time is limited, it is not suitable for mass production.

On the other hand, in wet etching, since equipment and etching liquid are generally inexpensive, and the pattern formation by etching is possible in a short time rather than dry etching, compared with dry etching, large-size photomask production, photomask production, and a short time are performed. It is suitable for the production of.

However, in the wet etching, when etching any one of the laminated layers, a part of the other layer is dissolved, or the material and the etching solution react with the material constituting the other layer at the grain boundary of the other layer. By chemically altering to a heterogeneous structure, damage may be caused to other layers, which makes it difficult to process high precision. In particular, when manufacturing a mask in which different kinds of layers are laminated, such as a halftone mask in which a phase shift layer and a light shielding layer are laminated, it is technically difficult to selectively etch only a target layer without damaging other layers.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a photomask substrate capable of forming two kinds of fine patterns on the surface of a transparent substrate in a short time and at a low cost by a wet etching method which has been difficult with conventional photomask manufacturing techniques. It is in doing it.

Another object of the present invention is to provide a photomask having two kinds of fine patterns formed in a short time and at low cost by sequentially etching the substrate for photomask by wet etching, and a manufacturing method thereof.

Means to solve the problem

According to the photomask substrate of the present invention, a transparent substrate, a first layer formed on the transparent substrate and semi-transparent to the irradiation light, and formed on the first layer to substantially shield the irradiation light A light shielding portion in which the light shielding pattern formed by the second layer is exposed on the surface, a semi-transmissive portion in which the semi-transmissive pattern formed by the first layer is exposed on the surface, and the transparent substrate. A photomask substrate capable of forming a transparent portion exposed to the surface, wherein the first layer is insoluble or poorly soluble in the first etching solution than the second layer and is soluble in the second etching solution. The second layer is solved by being more soluble in the first etching solution than the first layer and insoluble or poorly soluble in the second etching solution.

As described above, according to the photomask substrate of the present invention, the first layer is insoluble or poorly soluble in the first etching solution than the second layer, and is soluble in the second etching solution, while the second layer is first in the first layer. It is soluble in the etchant and insoluble or poorly soluble in the second etchant. Thereby, a 2nd layer can be selectively etched using a 1st etching liquid, and a 1st layer can be selectively etched using a 2nd etching liquid.

By selectively etching the first layer and the second layer with different etching solutions, two kinds of patterns, a transflective pattern and a light shielding pattern, are formed on the transparent substrate, and the light shielding portion where the light shielding pattern is exposed and the semitransmissive pattern are formed on the surface. It is possible to form three regions of the exposed semi-transmissive portion and the transparent portion in which the transparent substrate is exposed on the surface by wet etching using an etching solution.

As described above, in the photomask substrate of the present invention, the first layer and the second layer each have resistance to different etching liquids, and by using the difference in resistance, the first layer is prepared by the second etching liquid solubilizing the first layer. The two layers are hardly modified or damaged, and conversely, the first layer is hardly modified or damaged by the first etchant that solubilizes the second layer. Thereby, it becomes possible to manufacture the photomask in which the precision is high and a fine pattern was formed.

In addition, the first layer is preferably formed directly on the transparent substrate.

In general, a metal compound layer or the like is interposed between the transparent substrate and the first layer in order to improve the adhesion between them. However, by directly forming the first layer on the transparent substrate, there is no need to interpose the metal compound layer. As a result, it is possible to reduce the number of processes for forming the metal compound layer on the surface of the transparent substrate and the material therefor, thereby improving the production efficiency of the photomask substrate.

In addition, the first layer is preferably formed on the transparent substrate via a metal compound layer having a transmittance of 70% or more and less than 100%.

In this way, the first layer is formed on the transparent substrate through a metal compound layer having a transmittance of 70% or more and less than 100%, thereby improving the adhesion between the transparent substrate and the first layer with almost no reflection of light passing through the transparent substrate. In addition, it is also possible to protect the surface of the transparent substrate from damage caused by the etching solution during photomask fabrication.

At this time, the refractive index of the metal compound layer is more preferably equal to the refractive index of the substrate or lower than the refractive index of the substrate.

In addition, the first etching solution is preferably a mixed solution of cerium ammonium nitrate, perchloric acid and water.

In addition, the second etching solution is preferably a mixture of potassium hydroxide, hydrogen peroxide and water.

In addition, the first layer is preferably composed of one or two or more components selected from the group consisting of titanium, titanium nitride and titanium oxynitride as main components.

In addition, the second layer is suitably composed of one or two or more components selected from the group consisting of chromium, chromium oxide, chromium nitride and chromium nitride.

By appropriately selecting the first etching solution, the second etching solution, the first layer and the second layer in this way, the selectivity of the etching solution for each layer can be improved, and a more accurate and finer pattern can be formed.

In particular, one or two or more components selected from the group consisting of titanium, titanium nitride and titanium oxynitride are insoluble or poorly soluble in the mixed solution of cerium ammonium nitrate, perchloric acid and water as the first etching solution, potassium hydroxide, hydrogen peroxide and It is usable for the mixed liquid of water. On the other hand, one or two or more selected from the group consisting of chromium, chromium oxide, chromium nitride and chromium oxynitride are usable for a mixed solution of cerium ammonium nitrate, perchloric acid and water as the first etching solution, and potassium hydroxide, hydrogen peroxide and the second etching solution. It is insoluble or poorly soluble in the mixed solution of water.

As a result, by employing titanium or a titanium compound as the first layer and chromium or a chromium compound as the second layer, the selectivity to each etching solution can be improved, and a highly precise and fine pattern can be formed.

In particular, titanium nitride is highly resistant to chemicals such as acids and alkalis, and therefore is hardly damaged by chemicals used in etching processes such as resist removal liquids. As a result, it is possible to perform selective etching smoothly and to form a fine pattern with high accuracy.

Moreover, it is preferable that a said 2nd layer is equipped with the light shielding layer and the reflection prevention layer formed in the surface side rather than this light shielding layer.

Thus, since the 2nd layer is equipped with the antireflection layer, since an antireflection effect can be acquired and halation etc. by reflection of irradiation light at the time of mask exposure are prevented, it is preferable.

In addition, since the second layer is formed of the light shielding layer and the antireflection layer, the light shielding layer and the antireflection layer can be etched collectively, and the light shielding pattern having the antireflection layer pattern formed on the surface can be easily formed.

In this case, the anti-reflection layer is suitable as long as it is a layer composed mainly of one or two or more components selected from the group consisting of chromium oxide, chromium nitride and chromium nitride.

As described above, since the antireflection layer is formed of a layer composed mainly of one or two or more components selected from the group consisting of chromium oxide, chromium nitride and chromium nitride having low reflectance, a high antireflection effect is obtained and at the time of mask exposure. It is preferable because halation or the like due to reflection of the irradiation light is prevented.

In addition, the first layer is a layer composed mainly of one or two or more components selected from the group consisting of chromium, chromium oxide, chromium nitride and chromium nitride, and the second layer is a group consisting of titanium, titanium nitride and titan oxynitride The first etching solution is a mixture containing potassium hydroxide, hydrogen peroxide and water, and the second etching solution is a mixed solution of cerium ammonium nitrate, perchloric acid and water, by the same operation as described above. The selectivity with respect to each etching liquid improves, and it becomes possible to form a more precise and fine pattern.

Further, the first layer and the second layer are preferably formed by sputtering, ion plating or vapor deposition.

As described above, since the first layer and the second layer are manufactured by a film formation technique such as sputtering, the film thickness can be appropriately adjusted to form a photomask substrate having the desired optical characteristics. It is possible to form a photomask having characteristics. Moreover, by manufacturing by film-forming techniques, such as a sputtering method, it becomes possible to adjust physical properties, such as chemical-resistance and fastness of a photomask substrate, suitably.

According to the photomask of the present invention, a transparent substrate, a first layer formed on the transparent substrate and semi-transparent to the irradiation light, and a first layer formed on the first layer to substantially shield the irradiation light A photomask formed by a substrate for photomasks having two layers,

The first layer is insoluble or poorly soluble in the first etching solution than the second layer, and is soluble in the second etching solution, and the second layer is more soluble in the first etching solution than the first layer, Insoluble or poorly soluble in an etching solution, the photomask includes a light shielding portion on which a light shielding pattern formed by etching the second layer by the first etching solution is exposed to the surface, and the first layer is etched by the second etching solution. And a transflective portion through which the formed semitransmissive pattern is exposed on the surface, and the second layer and the first layer are etched by the first etchant and the second etchant, respectively, to form a transparent portion on which the transparent substrate is exposed. It is solved by being.

As described above, according to the photomask of the present invention, the first layer is insoluble or poorly soluble in the first etching solution than the second layer and is soluble in the second etching solution, while the second layer is the first etching solution rather than the first layer. It is soluble in water and insoluble or poorly soluble in the second etching liquid. Thereby, a 2nd layer can be selectively etched using a 1st etching liquid, and a 1st layer can be selectively etched using a 2nd etching liquid.

Then, by selectively etching the first layer and the second layer with different etching solutions, two kinds of patterns of light shielding patterns and semi-transmissive patterns are formed on the transparent substrate, and the light shielding portions where the light shielding patterns are exposed and the semi-transmissive patterns are surfaced. The three types of regions of the transflective portion exposed to the transparent portion exposed to the surface and the transparent substrate exposed to the surface are formed on the surface of the transparent substrate by wet etching using an etching solution.

Thus, according to the photomask of this invention, since the difference of the tolerance with respect to the etching liquid of a 1st layer and a 2nd layer is utilized, the 2nd layer is hardly modified or damaged by the etching liquid of a 1st layer, On the contrary, the first layer is hardly modified or damaged by the etching solution of the second layer, so that it is possible to provide a photomask having a high degree of fine pattern.

According to the above-described method for manufacturing a photomask, the above-described problem is achieved by a first resist coating step of coating a resist on a surface of the second layer and a first resist coating step by using a mask on which a first mask pattern is formed. A first exposure step of exposing the coated resist, a first resist removal step of removing an exposed portion of the resist after the first exposure step, and the second layer exposed in a region from which the resist is removed; A first etching step of etching the first etching solution to form the light shielding pattern, a first resist stripping step of peeling the resist remaining in the first resist removing step, and a second resist coating the resist on the surface again Exposure of the resist coated in the second resist coating step via a coating step and a mask having a second mask pattern formed thereon; Performing a second exposure step, a second resist removal step of removing an exposed portion of the resist after the second exposure step, and etching the first layer exposed to the region from which the resist is removed with the second etching solution. This is solved by performing a second etching step of forming the semi-transmissive pattern and a second resist peeling step of peeling the resist remaining in the second resist removing step.

Thus, according to the photomask manufacturing method of this invention, a resist is exposed using the mask in which the 1st mask pattern was formed, the exposed part of the resist was removed, the 2nd layer was etched with a 1st etching liquid, A plurality of pattern formation regions can be formed on the surface of the transparent substrate by exposing the resist with a mask on which two mask patterns are formed, removing the exposed portion of the resist, and etching the first layer with a second etching solution.

That is, by using the difference in the resistance to the etching solution of the first layer and the second layer, it is possible to form a fine pattern with high accuracy with little modification or damage by the etching solution used for etching other layers.

Effects of the Invention

According to the photomask substrate of the present invention, since the second layer can be selectively etched by the first etching liquid and the first layer by the second etching liquid, the first layer and the second layer are modified or damaged by the etching liquid of each other. It is possible to manufacture a photomask having a high degree of precision and a fine pattern formed by wet etching, which is hardly conventionally received.

In addition, according to the photomask of the present invention and a method for manufacturing the same, the first layer and the first layer can be selectively etched by the second etching solution, so that the first layer and the second layer are applied to each other's etching solution. This makes it possible to hardly modify or damage, thereby forming a photomask having a high degree of fine pattern by wet etching, which is conventionally difficult.

Therefore, according to the present invention, since the patterning can be performed by wet etching suitable for the production of large-scale photomasks or the mass production of photomasks, the photomasks can be produced in a short time and at a low cost as compared with the conventional patterning by dry etching. It becomes possible.

Brief description of the drawings

1 is a longitudinal cross-sectional view of a substrate for a photomask of one embodiment of the present invention.

2 is a longitudinal cross-sectional view of the photomask of one embodiment of the present invention.

3 is an explanatory diagram showing a step of patterning a photomask from a photomask substrate.

4 is an explanatory diagram showing a step of patterning a photomask.

It is a longitudinal cross-sectional view of the photomask board | substrate of other embodiment of this invention.

FIG. 6 is an electron microscope photograph of the end face and the plane of the photomask after the light shielding pattern is formed. FIG.

7 is an optical microscope photograph of a plane after cross pattern formation.

8 is an electron microscope photograph of the longitudinal section and the plane of the photomask after the transflective pattern is formed.

Explanation of the sign

1 ‥ Photomask

2 ‥ Photomask Substrate

1a ‥ Shading part

1b ‥ semi-permeable part

1c ‥ transparent part

10 ‥ transparent substrate

20 ‥ semi-permeable layer (first layer)

20a ‥ transflective pattern

30 ‥ Composite Layer (2nd Layer)

30a ‥ shading pattern

33 ‥ shading layer

33a ‥ Shading layer pattern

35 ‥ Antireflection layer

35a ‥ antireflection layer pattern

50 ‥ Resist

60 ‥ mask disc

70 ‥ Resist

80 ‥ mask disc

90 ‥ metal compound layer

Implement the invention  Best form for

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described with reference to drawings. In addition, the member, arrangement | positioning, order, etc. which are demonstrated below do not limit this invention, Of course, it can be variously modified according to the meaning of this invention.

1 is a longitudinal cross-sectional view of a photomask substrate of one embodiment of the present invention, FIG. 2 is a longitudinal cross-sectional view of a photomask of one embodiment of the present invention, and FIG. 3 is a step of patterning a photomask from a photomask substrate. 4 is an explanatory view showing a step of patterning a photomask, FIG. 5 is a longitudinal cross-sectional view of a photomask substrate according to another embodiment of the present invention, and FIG. 6 is a longitudinal cross section and a plane of a photomask after light shielding pattern formation. 7 shows an electron microscope photograph of the photomicrograph, and FIG. 7 shows an optical microscope photograph of the plane after the cross pattern formation, and FIG. 8 shows an electron microscope photograph of the longitudinal section and the plane of the photomask after the transflective pattern formation. In addition, in FIG. 1-5, the manufacturing process of the photomask board | substrate, photomask, and photomask is shown typically by drawing the film thickness of each layer thicker than actual thickness, in order to make understanding of invention easy.

As shown in Fig. 1, the photomask substrate (also referred to as a photomask blank) 2 of this example includes a transparent substrate 10, a semi-transmissive layer 20 formed on the surface of the transparent substrate 10, and And the light shielding layer 33 formed on the surface of the semi-transmissive layer 20. In addition, an antireflection layer 35 is formed on the surface of the light shielding layer 33. The photomask substrate 2 is a substrate on which the photomask 1 is manufactured. In the etching process and the photolithography process to be described later, the photomask substrate 2 is sequentially etched using different etching solutions. It is possible to manufacture the photomask 1 by patterning. The transflective layer 20 is corresponded to the 1st layer of this invention, and the composite layer 30 used as the light shielding layer 33 and the reflection prevention layer 35 is corresponded to the 2nd layer of this invention.

As shown in FIG. 2, the photomask 1 of this example is formed in the transparent substrate 10, the semi-transmissive pattern 20a formed in the surface of the transparent substrate 10, and the surface of the semi-transmissive pattern 20a. It is formed by the light shielding layer pattern 33a and the antireflection layer pattern 35a formed in the surface of the light shielding layer pattern 33a. The semi-transmissive pattern 20a is a pattern formed by etching the transflective layer 20 of the photomask substrate 2, and the light shielding layer pattern 33a is a pattern formed by etching the light shielding layer 33, and an antireflection layer. The pattern 35a is a pattern formed by etching the antireflection layer 35. The light shielding pattern 30a of this invention is formed by the light shielding layer pattern 33a and the reflection prevention layer pattern 35a.

The photomask 1 has a part of the light shielding portion 1a in which a part of the antireflection layer pattern 35a (that is, the light shielding pattern 30a) is exposed on the surface and a part of the semi-transmissive pattern 20a when viewed from the top surface. The transflective part 1b exposed to the surface and the transparent part 1c in which a part of the transparent substrate 10 was exposed to the surface are formed.

Transparent board (10)

Below, each member which comprises the photomask substrate 2 is demonstrated.

The transparent substrate 10 is a transparent substrate serving as a base for forming the pattern for the photomask. In the present embodiment, the transparent substrate 10 is a sufficiently polished quartz substrate. As the transparent substrate 10, materials such as natural quartz glass, synthetic quartz glass, and transparent resin film can be used. In addition, the transparent thing here means specifically, that the transmittance | permeability (Air Reference) in 350-500 nm wavelength range is contained in 80 to 95% of range.

(Transmissive layer 20)

The transflective layer 20 is formed on the surface of the transparent substrate 10. Semi-permeable layer 20 of this embodiment is a layer having a phase shifting function the transmittance at about a wavelength region having a wavelength of 350 ~ 500 ㎚ included in the range of 5 to 70%, a titanium nitride, a titanium nitride (TiN _x: Here, it forms with the material which has 0 <x <1.33) as a main component.

A film having such optical properties is possible by thinning a dielectric material based on wave optical theory, but considering the patterning property, the film is necessarily preferred from the viewpoint of selectivity to etching solution, adhesion to resist material, tact time, pattern degree, and the like. Can not. Therefore, it is preferable that the transflective layer 20 is not laminated | stacked and formed as a single layer if possible. In addition, it is also necessary to secure the optical properties with a material that is easy to pattern. In addition, from the viewpoint of photolithography, it is necessary to suppress the reflectance as low as possible, and from this point of view, a thin film having appropriate light absorption is suitable.

Examples of the material having such characteristics include oxides, nitrides, and oxynitrides of metals. In addition, also in the light shielding layer 33 mentioned later, metal oxide, nitride, oxynitride, etc. are mentioned as the constituent material. Although the basic element may be homogeneous or heterogeneous among the materials constituting the semi-transmissive layer 20 and the light shielding layer 33, a material that can be used in a conventional photomask manufacturing process or a manufacturing facility may be appropriately selected and used. .

The semi-transmissive layer 20 and the light shielding layer 33 of the present invention are characterized by being resistant to different etching liquids (insoluble or poorly soluble) and soluble.

That is, the semi-transmissive layer 20 is insoluble or poorly soluble in the etching solution A (first etching solution) than the light shielding layer 33, and is more soluble in etching solution B (second etching solution). On the other hand, the light shielding layer 33 is more soluble in the etching solution A than the semitransmissive layer 20, and insoluble or poorly soluble in the etching solution B. In this embodiment, specifically, a mixed liquid of cerium ammonium nitrate, perchloric acid and water is used as the etching solution A, and a mixed liquid of potassium hydroxide, hydrogen peroxide and water is used as the etching solution B. FIG.

In this way, the semi-transmissive layer 20 is formed by the etching solution B because the semi-transmissive layer 20 and the light shielding layer 33 are different from each other in insoluble or poorly soluble in the etching solution A, and the availability of the etching solution B is different. The light shielding layer 33 can be selectively etched by the etching solution A.

In this case, the semi-transmissive layer 20 is insoluble or poorly soluble in the etching solution A than the light shielding layer 33, so that the solubility of the semi-transmissive layer 20 in the etching solution A is substantially zero, or the light shielding layer. It means extremely lower than the solubility of (33).

In contrast, the fact that the semi-transmissive layer 20 is more soluble in the etching solution B than the light shielding layer 33 means that the solubility of the semi-transmissive layer 20 in the etching solution B is extremely higher than that of the light shielding layer 33. .

Further, even when the light shielding layer 33 is insoluble or poorly soluble in the etching solution B than the semitransmissive layer 20, the solubility of the light shielding layer 33 in the etching solution B is substantially zero, or the semitransmissive layer 20 Means extremely lower than the solubility.

In contrast, the fact that the light shielding layer 33 is more soluble in the etching solution A than the semitransmissive layer 20 means that the solubility of the light shielding layer 33 in the etching solution A is extremely higher than that of the semitransmissive layer 20. .

Specifically, in the present embodiment, when the substrate is immersed in the etching solution A for 30 ° C. for about 70 seconds (that is, the time when the light shielding layer 33 can be fully etched), the transmittance at 436 nm of the semi-transmissive layer 20 is It is ± 0.5% or less of the transmittance before immersion in the etching solution A. This indicates that even if the light shielding layer 33 can be completely etched by the etching solution A, the semitransmissive layer 20 is hardly changed (not etched) by the etching solution A. FIG.

In addition, when immersed in etching liquid B for 30 second and 120 second (that is, time which can fully etch the transflective layer 20), the optical density of the light shielding layer 33 is -0.3 or less. This indicates that the light shielding layer 33 is hardly changed (not etched) by the etching solution B even if the semi-transmissive layer 20 can be completely etched by the etching solution B. FIG.

Thus, since the solubility of the semi-transmissive layer 20 and the light shielding layer 33 in etching liquid differs, it becomes possible to selectively etch the semi-transmissive layer 20 and the light shielding layer 33 using the solubility characteristic. .

The inventors investigated the solubility of oxides, nitrides, and oxynitrides of several metals in etching solution A (a mixture of cerium ammonium nitrate, perchloric acid and water) and etching solution B (a mixture of potassium hydroxide, hydrogen peroxide, and water). Metals used are nickel, titanium, tantalum, aluminum, molybdenum and copper.

As a result, any of oxides, nitrides, and oxynitrides was soluble in the etching solution A for nickel, molybdenum, and copper, and insoluble in the etching solution B. As a result, it was found to be unsuitable for use in the selective etching with the light shielding layer 33.

In addition, as a result of investigating the oxides, nitrides, and oxynitrides of aluminum, tantalum, and titanium, it was found that the etching solution A was insoluble in all, but the titanium nitride and the titanium oxynitride were soluble in the etching solution B.

Moreover, about these compounds, the pattern formation by the etching was performed and the pattern grade was investigated individually. As a result, it was found that oxides of tantalum, nitrides, oxynitrides, oxides of aluminum, and oxides of titanium are not suitable for wet etching because patterns cannot be formed or the pattern degree is low.

From the results of the investigation, the selection of the etching solution and the patternability of the titanium nitride (TiN _x ) film having etching resistance and optical characteristics with respect to the etching solution A were examined. First, as a result of repeating the examination of the solubility and etching property of various chemicals, the titanium nitride (TiN _x ) film has an alkali (eg, potassium hydroxide (KOH)) resistance in the photolithography process, but also hydrogen peroxide (H _2). It was found that soluble in O ₂ ), a mixture of potassium hydroxide (KOH) and water, and further fine patterning is possible, that is, titanium nitride (TiN _x ) has a light shielding in addition to the properties that can be made into the desired optical properties It was found that it was resistant to the etching solution A solubilizing the layer 33 and also resistant to alkali contained in the resist removal liquid, and therefore semipermeable from the fact that it was selective with the light shielding layer 33. By selecting titanium nitride (TiN _x ) as the material of the layer 20, it was found that it had good etching characteristics.

Next, the adhesion of the transflective layer 20 to the transparent substrate 10 and the adhesion to the light shielding layer 33 were examined. The semi-transmissive layer 20 needs to be etched without securing a step or overhang between the light shielding layer 33 in the patterning process while ensuring adhesion to the transparent substrate 10. The transflective layer 20 is required to be a layer having both of these optical properties and the above-mentioned chemical resistance (etching resistance, alkali resistance, etc.).

The adhesiveness of the transflective layer 20 was tested, and the adhesiveness of the transflective layer 20 with respect to the transparent substrate 10 was evaluated. Specifically, a titanium nitride (TiN _x ) film is formed on the surface of the transparent substrate 10, and a plurality of grids are formed by inserting a cut with a cutter in a lattice shape at intervals of 1 mm to form a plurality of grids, and attaching an adhesive tape thereto. The test which peeled off was done. As a result, no peeling occurred in all grids, and it was found that the adhesion to the transparent substrate 10 was good. From this point of view, the titanium nitride (TiN _x ) film has high adhesion to the transparent substrate 10 and can be said to be suitable as a material of the semi-transmissive layer 20. In addition, since the adhesion to the transparent substrate 10 is good even when the film is directly deposited on the transparent substrate 10, the film is directly deposited on the surface of the transparent substrate 10 without having to use a layer for improving adhesion such as a metal compound layer. can do.

Thus, titanium nitride (TiN _x ) has optical characteristics, resistance to etching solution A (insoluble or poorly soluble), and solubility (soluble) in etching solution B, and also has good adhesion to the transparent substrate 10. It can be said that it is the most preferable as a material of the transflective layer 20 from a point.

(Shading Layer 33)

Next, the light shielding layer 33 is demonstrated. The light shielding layer 33 has a property of shielding almost 100% of irradiated light, and is a layer formed on the surface of the transflective layer 20. In this embodiment, the metal chromium Cr is formed so as to have a transmittance of 0.1% or less (optical concentration 3.0 or more). As the material of the light shielding layer 33, metals such as titanium, molybdenum, aluminum, nickel, and copper, as well as chromium, oxides, nitrides, and oxynitrides of these metals, and further two or more of these metals and metal compounds Alloys;

The light shielding layer 33 is more soluble in the etching solution A than the semitransmissive layer 20, and has a property of being insoluble or poorly soluble in the etching solution B. Thereby, by using the etching liquid A, it becomes possible to selectively etch only the light shielding layer 33, without etching the transflective layer 20. FIG.

(Anti-reflective layer 35)

Next, the antireflection layer 35 will be described. The antireflection layer 35 is formed on the surface of the light shielding layer 33 and is a layer for reducing the reflectance. In the present embodiment, chromium oxide (CrO _x ), which is chromium oxide, is used as a main component as the material of the antireflection layer 35, but the material of the antireflection layer 35 is not limited thereto.

In the present invention, the antireflection layer 35 has any configuration, and it is not necessary to necessarily provide the antireflection layer 35. However, when forming a fine pattern such as LSI using the photomask 1 obtained by patterning the substrate 2 for photomask, the reflection prevention layer 35 prevents reflection of the irradiation light, thereby avoiding any interference by reflected light. It is possible to lower the Arena halation.

The anti-reflection layer 35 is a wave optically thin film that obtains an anti-reflection effect by using interference of light. The material forming the antireflection layer 35 is a complex in which the refractive index (n) and the absorption (k) for the irradiated light (where the refractive index and absorption are the ratio of the speed in the vacuum of light and the phase speed in the material (in the thin film)). As a refractive index, the combination of refractive index n and absorption coefficient k generally represented by N = n-ik has the characteristic shown in Table 1 below.

The left column (refractive index) of this table shows the refractive index with respect to the irradiated light of the antireflection layer 35 with respect to the light shielding layer 33 relative (one of "low", "the same degree", "high"). In addition, the central scattering (absorption) is relative to absorption (in a range less than absorption of the light shielding layer 33) of the anti-reflection layer 35 relative to (light, medium, or many). One.).

In addition, the uranium (reflectivity) represents the relative characteristic of the reflectance, "↓" represents a low reflectance, "→" represents a medium reflectance, and "↑" represents a high reflectance. In addition, in this column, evaluation according to the height of an antireflection effect is shown by the symbol of "x", "(triangle | delta)", and "(circle)" in order from a low effect to a high order.

The following can be said from this table.

The material having less absorption for irradiated light than the light shielding layer 33 and having less absorption (for example, k value of 0.2 to 0.5) among the antireflection layer 35 has a low reflectance and high antireflection effect.

The material having less absorption for irradiated light than the light shielding layer 33, and having a moderate absorption among the antireflection layers 35 (for example, a value of k of 0.5 to 1.0) has a medium reflectance, and has an antireflection effect. Medium.

On the other hand, a material satisfying the following requirements has a low antireflection effect or almost no antireflection effect.

The material having less absorption for irradiated light than the light shielding layer 33 and having a high absorption in the antireflection layer 35 (for example, a value of k of 1.0 to 2.0) has a high reflectance and thus has a low antireflection effect.

As described above, the antireflection layer 35 is a material having less absorption than the light shielding layer 33 with respect to the wavelength to be used, and the optical film thickness nd = p × λ / 4 (where λ is the design wavelength and p is 1, n). Is a refractive index, d is a substantial film thickness.

In fact, since each of the light shielding layer 33 and the antireflection layer 35 has a wavelength dispersion of the refractive index, p is formed in the range of 0.5 to less than 1.0.

In addition, when the absorption of the antireflection layer 35 is further reduced (for example, the value of k is 0.01 to 0.1), for example, the reflectance is transferred in the ascending direction as compared with the case of k = 0.2 to 0.5. Therefore, it is necessary to adjust appropriately in accordance with the optical characteristics of the light shielding layer 33.

The antireflection layer 35 has the same etching characteristics as the light shielding layer 33. That is, the antireflection layer 35 is more soluble in the etching solution A than the semitransmissive layer 20, and has an insoluble or poorly soluble property in the etching solution B. For this reason, it becomes possible to etch only the antireflection layer 35 without etching the transflective layer 20 by using etching liquid A. FIG. In addition, since the antireflection layer 35 and the light shielding layer 33 are laminated | stacked, the antireflection layer 35 and the light shielding layer 33 can be etched collectively by using etching liquid A. FIG.

As the material of the anti-reflection layer 35, in consideration of the above-described etching characteristics and the convenience of film formation, it is preferable that the material is formed of the same material as the light shielding layer 33, but is usable with the etching solution A and with respect to the etching solution B. Other materials may be used as long as they are insoluble or poorly soluble.

Next, the manufacturing method of the photomask 1 of this invention is demonstrated.

The photomask 1 of the present invention comprises a photomask substrate 2 in which a semi-transmissive layer 20, a light shielding layer 33, and an antireflection layer 35 are sequentially laminated on the surface of the transparent substrate 10 by film formation. It is produced by forming a predetermined pattern by wet etching with respect to each layer. Examples of the film formation method include physical vapor deposition (PVD) using vacuum such as sputtering, vapor deposition, and ion plating, and vapor deposition (CVD) such as plasma CVD and thermal CVD.

In the case of film formation by sputtering, reactive sputtering can be used in addition to the usual sputtering. One of the reactive sputtering apparatuses is a device having a film formation region for sputtering a target and a reaction region for plasma treatment of the thin film after film formation with plasma of a reactive gas. The second is a conventional sputtering apparatus, which introduces a reactive gas during film formation and promotes the reaction using plasma by sputtering. Hereinafter, a film is formed by the second reactive sputtering apparatus, titanium nitride (TiN _x ) as the semi-transmissive layer 20, metal chromium (Cr) as the light shielding layer 33, and chromium oxide (CrO) as the antireflection layer 35. An example of forming a thin film of _x ) will be described.

(Film Forming Process)

First, the semitransmissive layer 20 is formed. In the film formation of the semitransmissive layer 20, metal titanium is used as a target. Before the start of film formation, the transparent substrate 10 is set in the substrate holder of the sputtering apparatus. By making the inside of the sputtering apparatus high vacuum, inert gas (Ar) and reactive gas (N ₂ ) are introduced into the target, and a voltage is applied to the sputter electrode, so that the titanium (Ti) protruding from the target is reacted with the reactive gas (N ₂ ). By reacting in the plasma, a thin film of titanium nitride (TiN _x ) is formed on the surface of the transparent substrate 10. As a result, a semi-transmissive layer 20 is formed on the surface of the transparent substrate 10 (semi-transmissive layer film forming step).

Next, the light shielding layer 33 is formed. Before film formation of the light shielding layer 33, the target is exchanged from metal titanium to metal chromium (Cr). In this state, the inside of the sputtering apparatus is again in a high vacuum state, and the target is sputtered to form a light shielding layer 33 made of metal chromium (Cr) on the surface of the semi-transmissive layer 20 (light shielding layer film forming step). .

Next, the antireflection layer 35 is formed. Since the anti-reflection layer 35 has chromium as a main component similarly to the light shielding layer 33, film formation can be performed subsequent to film formation of the light shielding layer 33 without exchanging a target.

In the same way as when forming titanium nitride, metal chromium is used as a target. After the light shielding layer 33 is formed, the target gas is applied to the sputter electrode by introducing an inert gas (Ar) and a reactive gas (O ₂ ) to the target, whereby chromium (Cr) protruding from the target is the reactive gas (O ₂ ). By reacting with the plasma, a thin film of chromium oxide (CrO _x ) is formed on the surface of the light shielding layer 33. Thereby, the antireflection layer 35 is formed on the surface of the light shielding layer 33 (reflection prevention layer film forming process).

When the antireflection layer 35 is made of a metal material different from that of the light shielding layer 33, the targets are exchanged after film formation of the light shielding layer 33 to form the antireflection layer 35.

Next, the photomask substrate 2 after film formation is cleaned by ultrasonic cleaning or the like to remove foreign substances on the surface.

Patterning process

The predetermined pattern is formed using the photolithography technique and the etching technique with respect to the photomask substrate 2 having the laminated structure thus formed. This pattern formation process (patterning process) is demonstrated with reference to FIG. 3 and FIG.

First, the photomask substrate 2 before patterning is prepared (FIG. 3 (a)). The photomask substrate 2 can be manufactured using the above-mentioned film-forming techniques, such as sputtering. Next, the resist 50 is apply | coated to the surface of the photomask substrate 2 using a method such as spin coating (FIG. 3 (b)). The resist 50 is a photosensitive polymer material which is cured by ultraviolet rays or the like. As a resist coating method, it is not limited to spin coating, For example, well-known methods, such as spray coating and roll coating, can be used. Next, the applied resist 50 is heated to a high temperature with a heater or the like and prebaked (temporarily hardened). As described above, the resist 50 is coated on the surface of the photomask substrate 2 (first resist coating step).

Next, the mask pattern is formed in the resist 50 using the mask original plate 60. The mask original plate 60 has a predetermined pattern (first mask pattern) written in advance, and is a member for transferring the pattern to the resist 50. The resist 50 is irradiated with ultraviolet light through the mask original plate 60 to be exposed (Fig. 3 (c)). This makes the surface of the resist 50 photosensitive according to a 1st mask pattern (1st exposure process).

Next, the resist 50 after exposure is immersed in a developing solution. Thereby, the area | region which was exposed to the ultraviolet-ray in the resist 50 is removed with the developing solution, and the anti-reflective layer 35 under that area | region is exposed to the surface (FIG. 3 (d)). After some of the resist 50 is removed, the remaining resist 50 is heated to a high temperature using a heater or the like to post bake (main curing). As a result, a part of the resist 50 is removed, and the same pattern as the first mask pattern is formed of the remaining resist 50 (first resist removing step).

Next, the antireflection layer 35 and the light shielding layer 33 are etched using the etching solution A (that is, the first etching solution). Etching solution A is a liquid mixture of cerium ammonium nitrate, perchloric acid, and water. The etching solution A is filled in the bath, and the antireflection layer 35 exposed after the resist removal is completely immersed in the etching solution A. In this state, etching is performed by maintaining a predetermined etching temperature. Since the anti-reflection layer 35 and the light shielding layer 33 are both usable with respect to the etching liquid A, they are etched collectively by the etching liquid A, and the same pattern as the remaining pattern of the resist 50 is formed.

On the other hand, the transflective layer 20 is insoluble or poorly soluble in the etching solution A, and thus has a role as an etching stationary layer. Thereby, even if the light shielding layer 33 is etched by the etching liquid A, the semi-transmissive layer 20 will remain as it is without being etched by the etching liquid A (FIG. 3 (e)). Thereby, the light shielding pattern 30a which becomes the light shielding layer pattern 33a and the reflection prevention layer pattern 35a is formed in the surface of the transflective layer 20 (1st etching process).

Next, the resist 50 remaining on the surface is dissolved with a release agent, and the surface is washed with pure water or the like (Fig. 3 (f)). As a result, the same pattern as the first mask pattern remains on the surface of the transparent substrate 10 (first resist stripping step).

Next, the resist 70 is apply | coated to the surface and it temporarily hardens (FIG. 4 (b)). The resist 70 may be made of the same material as that of the previous resist 50, or may be made of a material having different curing performance and the like. As a result, the resist 70 is coated on the surface (second resist coating step).

Subsequently, a mask pattern is formed in the resist 70 using the mask original plate 80. The mask original plate 80 is a member in which a predetermined pattern (second mask pattern) has been previously written in the same manner as the mask original plate 60. The resist 70 is irradiated with ultraviolet light through the mask master plate 80 to be exposed (Fig. 4 (c)). Thereby, the surface of the resist 70 is exposed to light according to the second mask pattern (second exposure step).

Next, the resist 70 after exposure is immersed in a developing solution, and the area | region which was exposed to the ultraviolet-ray among the resists 70 is removed (FIG. 4 (d)). As a result, part of the resist 70 is removed, and the same pattern as the second mask pattern is formed by the remaining resist 70 (second resist removing step).

Next, the semi-transmissive layer 20 is etched using etching liquid B (that is, a second etching liquid). Etching solution B is a mixed liquid of potassium hydroxide, hydrogen peroxide, and water. The etchant B is filled into the bath, and the semitransmissive layer 20 exposed after the resist removal is completely immersed in the etchant B. In this state, etching is performed while maintaining a predetermined etching temperature. Since the transflective layer 20 is usable with the etching liquid B, it etches by the etching liquid B, and the pattern according to the remaining pattern of the resist 70 is formed.

On the other hand, since the light shielding layer 33 and the antireflection layer 35 are both insoluble or poorly soluble in the etching solution B, the light shielding pattern 30a formed from these layers is not etched by the etching solution B (Fig. 4 (e)). . As a result, a semi-transmissive pattern 20a is formed on the surface of the transparent substrate 10 (second etching step).

Finally, the resist 70 remaining on the surface is dissolved with a release agent, and the surface is washed with pure water or the like (Fig. 4 (f)). As a result, the same pattern as the second mask pattern remains on the surface of the transparent substrate 10 (second resist stripping step).

When etching is performed by this method, as shown in FIG. 2, the part which is not exposed by the 1st mask pattern does not etch any of the transflective layer 20, the light shielding layer 33, and the antireflection layer 35, and is an antireflection layer (35) (When the anti-reflective layer 35 is not provided, the area | region (light shielding part 1a) which the light shielding layer 33 was exposed to the surface is formed. In addition, the portions exposed in the first mask pattern and not exposed in the second mask pattern are regions in which only the light shielding layer 33 and the anti-reflection layer 35 are etched and the semi-transmissive layer 20 is exposed to the surface (semi-transmissive portion ( 1b)) is formed. In addition, the exposed portions of both the first mask pattern and the second mask pattern are all etched by the transflective layer 20, the light shielding layer 33, and the anti-reflection layer 35 so that the transparent substrate 10 is exposed to the surface ( The transparent part 1c is formed.

The photomask 1 manufactured in this way can be used as a multi-tone mask used for manufacturing a TFT panel or the like. In a manufacturing process such as a TFT panel, a transfer substrate is provided so as to face the surface side (the antireflection layer 35 side) of the multi gradation mask, and the transfer light is irradiated from the transparent substrate 10 side toward the transfer substrate. When light is irradiated from the transparent substrate 10 side toward the anti-reflection layer 35 side, the irradiated light is shielded from the light shielding portion 1a, and the light of intermediate light amount (transmittance of 5 to 70%) is emitted from the semi-transmissive portion 1b. The light is transmitted through the transparent portion 1c with a transmittance of almost 100%. Accordingly, in the opposing transfer substrate, transfer is performed at three different exposure levels of the unexposed portion by the light shielding portion 1a, the semi-exposed portion by the semi-transmissive portion 1b, and the fully exposed portion by the transparent portion 1c. Is performed.

In this way, by using the photomask 1 of the present invention as a pattern transfer mask in photolithography technology, a plurality of transfer patterns having different exposure intensities can be easily formed. In addition, the variation of exposure can be further increased by changing the wavelength and intensity of the light to be irradiated.

In addition, the semi-transmissive layer 20 of this embodiment is directly coated on the transparent substrate 10. For this reason, it is not necessary to form a special layer in advance for increasing the adhesion of the transflective layer 20 on the surface of the transparent substrate 10, and the film forming process can be shortened. In addition, the transflective layer 20 has the effect | action which reduces the reflectance from the glass surface side of the light shielding layer 33 at the time of exposure. Thereby, reduction of halation with respect to irradiation light, moire phenomenon in a continuous fine stripe pattern part, etc. can be aimed at, and a pattern degree can be improved.

On the other hand, as shown in FIG. 5, the metal compound layer 90 which improves adhesiveness with the transflective layer 20 may be formed in the surface of the transparent substrate 10. FIG. In this case, the metal compound layer 90 preferably has a transmittance of 70% or more and less than 100% of the irradiation light.

The metal compound layer 90 is formed of a material that protects the surface of the transparent substrate 10 from the etching solution and has high adhesion to the semi-transmissive layer 20. Examples of such a substance include silicon oxide, aluminum oxide, titanium oxide and other metal oxides.

The metal compound layer 90 is formed on the surface of the transparent substrate 10 using a known film formation technique such as sputtering before the semitransmissive layer 20 is formed.

In addition, in description of the said embodiment, etching liquid A (mixture liquid of cerium ammonium nitrate, perchloric acid, and water) which is a 1st etching liquid, etching liquid B (mixture liquid of potassium hydroxide, hydrogen peroxide, and water) which is a 2nd etching liquid, and the 1st layer which has semipermeability (A layer mainly composed of titanium nitride), a second layer (chromium layer) that substantially shields irradiation light, and an antireflection layer (chromium oxide layer), but the material of the first layer and the material of the second layer have been described. The same effect and effect can be acquired also when the is substituted and the 1st etching liquid and the 2nd etching liquid are substituted.

That is, the first layer is composed of one or two or more components selected from the group consisting of chromium, chromium oxide, chromium nitride and chromium nitride, and the second layer is composed of titanium, titanium nitride and titanic nitride. Let it be a layer which has 1 or 2 or more components chosen as a main component. Then, a mixed solution of potassium hydroxide, hydrogen peroxide and water is used as the first etching solution, and a mixed solution of cerium ammonium nitrate, perchloric acid and water is used as the second etching solution. Also in this case, the same effect and effect as the above embodiment can be obtained.

Hereinafter, the manufacturing method of the photomask 1 using the photomask substrate 2 and the photomask substrate 2 of this invention is demonstrated, giving a specific Example.

(Example 1)

In this embodiment, each layer on the surface of the transparent substrate 10 was manufactured by a film forming method using a vacuum. Specifically, a reactive sputtering apparatus (manufactured by Cyntron Co., Ltd.) using a reactive gas such as nitrogen gas or oxygen gas was used.

In this example, a quartz substrate (transparent substrate 10) was first set in a sputtering apparatus, and reactive sputtering was performed using a commercially available metal titanium target (purity of 99.99% or more). In the sputtering step, the semi-transmissive layer 20 was formed by sputtering while introducing nitrogen gas to form nitride of titanium to form a thin film of titanium nitride (TiN _x : 0 <x <1.33). At this time, the semi-transmissive layer 20 was formed to have a transmittance of 15% at a wavelength of 436 nm.

In addition, the target at this time is not limited to the thing which used the metal titanium target like this example, The thing which bonded the sintered compact of titanium nitride may be sufficient. In addition, since the degree of nitriding varies depending on the apparatus, it may be adjusted by appropriately combining the film forming conditions.

Next, the metal titanium target was changed into a metal chromium target, and the light shielding layer 33 was formed on the surface of the transflective layer 20 so that the film thickness might be 700 kPa (70.0 nm). At this time, no reactive gas was introduced, and only metal chromium (Cr) was formed on the surface of the transflective layer 20. This light shielding layer 33 functioning as the light shielding layer is preferably sputtered at a high speed as high as possible in order to achieve an optical characteristic having an optical density OD of 3.0 or more. However, when the film thickness increases rapidly by sputtering at high speed, the stress of the chromium film forming the light shielding layer 33 increases, and therefore it is preferable to perform high vacuum and high speed sputtering in an appropriate range.

Subsequently, the target was changed into another new metal chromium target, and the antireflection layer 35 was formed to have a film thickness of 300 kPa (30.0 nm). In the sputtering process, metal chromium was converted into chromium oxide (CrO _x : 0 <x <1.5) by sputtering while introducing oxygen gas. The reflectance of chromium, which is the light shielding layer, is usually about 60%, and in order to reduce the reflectance, the film is formed with appropriate refractive index and absorption in accordance with the device.

The general reflectance at this time is 25 to 30% at the wavelength of 650 nm and at least 6 to 8% in the vicinity of 430 nm when the antireflection layer 35 is formed. By laminating 2-3 antireflection layers 35, it is possible to suppress the reflectance to an average of several percent.

Next, the photomask substrate 2 formed in the said sputtering process was taken out from the sputtering apparatus, and left to stand in the storage for 1 week. Subsequently, ultrasonic cleaning is performed on the photomask substrate 2 taken out of the storage container in each of a plurality of tanks including an alkaline detergent, a neutral detergent, and a pure water, and then placed on the entire surface of the photomask substrate 2 surface. The resist (AZ RFP-230K2 by AZ Electronic Materials) was apply | coated, and the temporary hardening was performed. In this resist coating step, the surface of the photomask substrate 2 is not surface treated with chemicals, plasma, ultraviolet light, or the like. Hereinafter, it is the same about the same process.

After resist temporary curing, exposure of 2nd stripe pattern (Ok manufacturing company jet printer: light source CHM-2000 ultra-high pressure mercury lamp exposure for 16 second), image development (Tokyo Oka Corporation PMER developer: temperature 30 degreeC, 1 minute), pattern Hardening (Yamato Scientific DX402 dry oven: 120 degreeC, 10 minutes) was performed. As the stripe pattern, two kinds of line widths of 5 m and 2 m were used. Subsequently, the light-shielding layer 33 is immersed in a mixed solution of perchloric acid, cerium ammonium nitrate, and water (perchloric acid: cerium ammonium nitrate: water = 4: 17: 70, reaction temperature: 30 ° C., etching time: 100 seconds) that is the first etching solution. By simultaneously etching the antireflection layer 35, a stripe pattern was formed to form the light shielding pattern 30a in which the light shielding layer pattern 33a and the antireflection layer pattern 35a were laminated. Next, the resist was removed with a predetermined chemical solution or the like.

Since the overetch dimension of the light shielding pattern 30a which matched the light shielding layer pattern 33a and the anti-reflective layer pattern 35a at this time was not measurable by an optical microscope, the board | substrate for photomasks after pattern formation (after removing a resist) ( 2) (hereinafter, simply referred to as "substrate") was cut in the longitudinal direction, and the cross section and the plane were observed with an electron microscope. The photographed electron microscope photograph is shown to Fig.6 (a)-(c). (A) is a cross-sectional photograph showing the cross-sectional shape of the straight pattern, an electron microscope photograph taken before the removal of the resist, (b) is a cross-sectional photograph showing a cross-sectional shape of the straight pattern, the electrons photographing the state after removing the resist The micrograph (c) is the front photograph which enlarged the edge part of a linear pattern, and is the electron microscope photograph which image | photographed the state after photoresist removal.

Among these, the cross-sectional observation results of (a) and (b) show that the semi-transmissive layer 20 and the light shielding pattern 30a are laminated on the surface of the transparent substrate 10. In addition, the result of the cross-sectional observation of (a) shows that the light shielding pattern 30a is overetched from the end of the resist toward the inside. This overetch dimension showed that it was 0.38 micrometer from the photograph of (a). Moreover, it turned out that the unevenness | corrugation generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of the front observation of (c). At this point, no change was observed in the titanium nitride (TiN _x ) film, which is the semi-transmissive layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the substrate after removing the resist was rotated 90 degrees, and the resist was applied to the entire surface to be temporarily cured. Subsequently, exposure of the first stripe pattern (Ok manufacturing company jet printer: light source CHM-2000 ultra-high pressure mercury lamp for 16 seconds), development (Tokyo Oka Co., Ltd. PMER developer: temperature 30 ° C., 1 minute), main curing ( Yamato Scientific DX402 dry oven: 120 degreeC, 10 minutes) was performed. Subsequently, a mixed solution of hydrogen peroxide, potassium hydroxide and water (hydrogen peroxide (35% aqueous solution): potassium hydroxide (30% aqueous solution): water = 16: 1: 32, reaction temperature: 30 ° C., etching time: 150 seconds), which is a second etching solution, was used. By immersing and etching the transflective layer 20, the stripe pattern used as the transflective pattern 20a was formed. As a result, the light shielding portion 1a in which the semi-transmissive pattern 20a and the light shielding pattern 30a are laminated on the surface of one transparent substrate 10, and the semi-transmissive portion 1b including only the semi-transmissive pattern 20a are provided. A cross pattern was obtained (see FIG. 7).

7 shows an example in which the patterning is performed such that the line width of the pattern is 5 占 퐉, and an example in which the patterning is performed so that the line width is 2 占 퐉 is shown. The lower straight line pattern (longitudinal straight line) of each photograph is the light shielding pattern 30a, and the straight line pattern (lateral straight line) formed under the light shielding pattern 30a is the semi-transmissive pattern 20a. An area on the grid positioned under the semi-transmissive pattern 20a is an upper surface of the transparent substrate 10.

From the photograph of FIG. 7, it turns out that each pattern has favorable linearity even if the line width is short as 2 micrometers. Therefore, according to the manufacturing method of the photomask of this invention, it turned out that it is possible to form a fine pattern with high precision.

Next, the board | substrate was cut | disconnected longitudinally and the cross section and plane were observed with the electron microscope similarly to the case where the overetch dimension was measured after formation of the light shielding pattern 30a. Electron micrographs taken are shown in Figs. 8A to 8C. (A) is a cross-sectional photograph showing the cross-sectional shape of the straight pattern, an electron microscope photograph taken before the removal of the resist, (b) is a cross-sectional photograph showing a cross-sectional shape of the straight pattern, the electrons photographing the state after removing the resist The micrograph (c) is the front photograph which enlarged the edge part of a linear pattern, and is the electron microscope photograph which image | photographed the state after photoresist removal.

Among these, it can be seen from the results of the cross-sectional observation in FIGS. 8A and 8B that the semi-transmissive pattern 20a is formed on the surface of the transparent substrate 10. In addition, it is understood from the result of the cross-sectional observation of (a) that the semi-transmissive pattern 20a is overetched from the end of the resist toward the inside. This overetch dimension showed that it was 0.37 micrometer from the photograph of (a). Moreover, from the result of the front observation of (c), it turned out that the uneven | corrugated dimension of the edge part is relatively small (0.05 micrometer or less) with respect to a straight line pattern, and sufficient linearity is maintained. Accordingly, it is considered that the linearity of the pattern is not a problem level.

Using another substrate not patterned, the optical density (OD) was measured with a Macbeth densitometer manufactured by Konishiroku Photo Co., Ltd., and the light shielding layer 33 and the antireflection layer (35) were used as an etching solution A made of a mixture of perchloric acid, cerium ammonium nitrate, and water. ), And then washed well, and the spectral transmittance, which is an optical characteristic of Hitachi Hi-Technologies, was measured with a magnetic spectrophotometer U-4000. The resultant optical density was 3.38, and the transmittance was 6.91% at 350 nm, 14.73% at 436 nm, and 18.29% at 500 nm.

By using a part of the cross pattern, the semi-transmissive pattern 20a and the light shielding pattern 30a were measured by an alky stylus surface shape measuring instrument Dectak. As a result, the film thickness of the semi-transmissive pattern 20a was 319 kPa (31.9 nm), and the film thickness of the light shielding pattern 30a was 1020 kPa (102.0 nm). When the film thickness setting of the light shielding layer pattern 33a is 700 mW and the antireflection layer pattern 35a is 300 mW (30.0 nm), the film thickness 1020 m (102.0 nm) of the light shielding pattern 30a is an error of a measuring instrument. It was confirmed that it was within the range and almost matched the target value. The results are shown in Table 2.

(Example 2)

Unlike Example 1, Example 2 is an example in which the transflective layer 20 is designed such that the transmittance of 436 nm is 20%. In this example, by adjusting the film thickness of the semi-transmissive layer 20, it is designed so that the transmittance | permeability in 436 nm of irradiation light may be set to about 20%. Conditions other than that are the same as that of Example 1.

In accordance with the same procedure as in Example 1, the light shielding layer 33 and the antireflection layer 35 were etched to form a stripe pattern serving as the light shielding pattern 30a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.37 µm. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point, no change was observed in the titanium nitride (TiN _x ) film, which is the semi-transmissive layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched in the same procedure as in Example 1, and a stripe pattern serving as the semitransmissive pattern 20a was formed. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.39 m. Moreover, it turned out that the uneven | corrugated dimension of an edge part is 0.05 micrometers or less with respect to a straight line pattern, and it is small enough.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.29, and the transmittance was 12.85% at 350 nm, 21.14% at 436 nm, and 25.53% at 500 nm.

In addition, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 260 kPa (26.0 nm) and the film thickness of the light shielding pattern 30a was 1015 kPa (101.5 nm). These results are shown in Table 2.

(Example 3)

Unlike Example 1 and 2, Example 3 is the example which designed the transflective layer 20 so that the transmittance | permeability of 436 nm may be 30%. In this example, by adjusting the film thickness of the semi-transmissive layer 20, the transmittance at 436 nm of the irradiated light is designed to be about 30%, but other conditions are the same as in Examples 1 and 2.

In accordance with the same procedure as in Example 1, the light shielding layer 33 and the antireflection layer 35 were etched to form a stripe pattern serving as the light shielding pattern 30a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.39 m. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point, no change was observed in the titanium nitride (TiN _x ) film, which is the semi-transmissive layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched in the same order as in Example 1 to form a stripe pattern that becomes the semitransmissive pattern 20a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.35 탆. Moreover, it turned out that the uneven | corrugated dimension of the edge part is sufficiently small about 0.05 micrometer or less with respect to a straight line pattern.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.22, and the transmittance was 18.79% at 350 nm, 29.67% at 436 nm, and 32.78% at 500 nm.

Moreover, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 231 kPa (23.1 nm), and the film thickness of the light shielding pattern 30a was 1005 kPa (100.5 nm). These results are shown in Table 2.

(Example 4)

Unlike Example 1-3, Example 4 is the example which designed the transflective layer 20 so that the transmittance | permeability of 436 nm may be 40%. In this example, by adjusting the film thickness of the semi-transmissive layer 20, the transmittance at 436 nm of the irradiation light is designed to be about 40%, but other conditions are the same as in Examples 1 to 3.

In accordance with the same procedure as in Example 1, the light shielding layer 33 and the antireflection layer 35 were etched to form a stripe pattern serving as the light shielding pattern 30a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.38 µm. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point, no change was observed in the titanium nitride (TiN _x ) film, which is the semi-transmissive layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched in the same order as in Example 1 to form a stripe pattern that becomes the semitransmissive pattern 20a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.38 mu m. Moreover, it turned out that the uneven | corrugated dimension of the edge part is sufficiently small about 0.05 micrometer or less with respect to a straight line pattern.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.17, and the transmittance was 28.05% at 350 nm, 39.93% at 436 nm, and 48.18% at 500 nm.

In addition, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 209 kPa (20.9 nm) and the film thickness of the light shielding pattern 30a was 1000 kPa (100.0 nm). These results are shown in Table 2.

(Example 5)

Unlike Example 1-4, Example 5 is the example which designed the transflective layer 20 so that the transmittance | permeability of 436 nm may be 50%. In this example, by adjusting the film thickness of the semi-transmissive layer 20, the transmittance at 436 nm of irradiated light is designed to be about 50%, but other conditions are the same as in Examples 1-4.

In accordance with the same procedure as in Example 1, the light shielding layer 33 and the antireflection layer 35 were etched to form a stripe pattern serving as the light shielding pattern 30a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.35 m. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point, no change was observed in the titanium nitride (TiN _x ) film, which is the semi-transmissive layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched in the same order as in Example 1 to form a stripe pattern that becomes the semitransmissive pattern 20a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.40 µm. Moreover, it turned out that the uneven | corrugated dimension of the edge part is sufficiently small about 0.05 micrometer or less with respect to a straight line pattern.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.03 and the transmittance was 40.01% at 350 nm, 52.03% at 436 nm, and 59.59% at 500 nm.

Moreover, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 153 kPa (15.3 nm), and the film thickness of the light shielding pattern 30a was 980 kPa (98.0 nm). These results are shown in Table 2.

(Example 6)

Unlike Example 1-5, Example 6 is the example which designed the transflective layer 20 so that the transmittance | permeability of 436 nm may be 60%. In this example, although the transmittance | permeability in 436 nm of irradiation light is set to about 60% by adjusting the film thickness of the semi-transmissive layer 20, other conditions are the same as that of Examples 1-5.

In accordance with the same procedure as in Example 1, the light shielding layer 33 and the antireflection layer 35 were etched to form a stripe pattern serving as the light shielding pattern 30a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.40 µm. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point, no change was observed in the titanium nitride (TiN _x ) film, which is the semi-transmissive layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched in the same order as in Example 1 to form a stripe pattern that becomes the semitransmissive pattern 20a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.39 m. Moreover, it turned out that the uneven | corrugated dimension of the edge part is sufficiently small about 0.05 micrometer or less with respect to a straight line pattern.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.13, and the transmittance was 48.06% at 350 nm, 60.52% at 436 nm, and 68.30% at 500 nm.

Moreover, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 118 kPa (11.8 nm), and the film thickness of the light shielding pattern 30a was 1010 kPa (101.0 nm). These results are shown in Table 2.

The patterning property of the light shielding pattern 30a in Examples 1-6 was 0.35-0.40 micrometer in overetch dimension, and the uneven | corrugated dimension of the edge part of a linear pattern was 0.1 micrometer or less from the observation result of an optical microscope and an electron microscope. In addition, in the semi-transmissive pattern 20a, the over-etched dimension was 0.35-0.40 micrometer, and about the linearity of a pattern edge, the uneven | corrugated dimension with respect to a straight line pattern was 0.05 micrometer or less. This uneven | corrugated dimension was small as 1/40 (0.05micrometer) with respect to the pattern width of 2 micrometers, and it was confirmed that it is a level which has no problem in linearity.

In addition, it is estimated that the linearity of pattern etch is impaired by reaction with the etching liquid in a thin film grain boundary, or lack of adhesiveness in a thin film and resist interface by patterning without surface treatment. This lack of adhesion is considered to be caused by oxidation, contamination of the surface of the thin film by leaving the substrate 2 for photomask after thin film formation, and the like.

(Example 7)

In the present embodiment, unlike Examples 1 to 6, the material of the first layer (semi-transmissive layer) and the material of the second layer (shielding layer) are replaced, and the first etching liquid (etching liquid A) and the second etching liquid ( It is an example when the etching liquid B) is substituted. In addition, the film-forming process and the patterning process are basically the same procedure as Example 1-6.

In the same manner as in Example 1, a quartz substrate (transparent substrate 10) was first set in a sputtering apparatus, and reactive sputtering was carried out using a commercially available chromium metal target (purity of 99.99 or more). In the sputtering step, the semi-transmissive layer 20 was formed by sputtering while introducing oxygen gas and nitrogen gas to form a thin film of chromium, a compound (CrON) composed of oxygen and nitrogen. At this time, the transflective layer 20 was formed into a film with a transmittance of 20% at a wavelength of 436 nm.

Next, the metal chromium target was changed into the metal titanium target, and the light shielding layer 33 was formed into a film on the surface of the transflective layer 20 so that it might be set to 700 nm (70 nm). At this time, only the titanium titanium (Ti) was formed on the surface of the transflective layer 20 without introducing a reactive gas.

Next, the target was changed to a new titanium target, and the antireflection layer 35 was formed to have a film thickness of 300 kPa (30 nm). In the sputtering step, sputtering while introducing oxygen gas and nitrogen gas forms a compound (TiON) of titanium, oxygen, and nitrogen.

The reflectance at this time is 35 to 38% at the wavelength of 650 nm and 9 to 10% at the vicinity of 430 nm when the antireflection layer 35 is formed.

Next, the photomask substrate 2 formed in the sputtering step was taken out of the sputtering apparatus and allowed to stand in the storage for 1 hour, followed by etching solution B (mixture of potassium hydroxide, hydrogen peroxide, water) in the same procedure as in Example 1. In addition, a stripe pattern formed of the light shielding pattern 30a in which the light shielding layer 33 and the antireflection layer 35 were laminated was formed.

The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.39 m. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point in time, no change was observed in the chromium oxynitride (CrON) film, which is the semi-transmissive layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched with the etching solution A (mixture of cerium ammonium nitrate, perchloric acid, and water) in the same procedure as in Example 1 to form a stripe pattern that becomes the semitransmissive pattern 20a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.38 mu m. Moreover, it turned out that the uneven | corrugated dimension of the edge part is sufficiently small about 0.1 micrometer or less with respect to a straight line pattern.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.07, and the transmittance was 7.65% at 350 nm, 18.97% at 436 nm, and 27.66% at 500 nm.

In addition, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 487 kV (48.7 nm) and the film thickness of the light shielding pattern 30a was 1000 kV (100 nm). These results are shown in Table 2.

(Example 8)

Unlike Example 7, Example 8 is an example in which the transflective layer 20 is designed such that the transmittance of 436 nm is 40%. In this example, by adjusting the film thickness of the semi-transmissive layer 20, the transmittance at 436 nm of irradiated light is designed to be about 40%, but other conditions are the same as in Example 7.

According to the same procedure as in the seventh embodiment, a stripe pattern consisting of the light shielding pattern 30a in which the light shielding layer 33 and the antireflection layer 35 were laminated was formed. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.39 m. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point in time, no change was observed in the chromium oxynitride (CrON) film, which is the transflective layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched in the same order as in Example 7 to form a stripe pattern that becomes the semitransmissive pattern 20a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.37 mu m. Moreover, it turned out that the uneven | corrugated dimension of the edge part is sufficiently small about 0.1 micrometer or less with respect to a straight line pattern.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.05 and the transmittance was 29.03% at 350 nm, 37.66% at 436 nm, and 43.48% at 500 nm.

Moreover, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 287 kPa (28.7 nm), and the film thickness of the light shielding pattern 30a was 1020 kPa (102 nm). These results are shown in Table 2.

(Example 9)

Unlike Example 7, 8, Example 9 is the example which designed the transflective layer 20 so that the transmittance | permeability of wavelength 436nm may be 60%. In this example, the transmissive layer 20 is designed to adjust the film thickness so that the transmittance of the irradiated light at a wavelength of 436 nm is about 60%, but other conditions are the same as those in Examples 7 and 8.

According to the same procedure as in Examples 7 and 8, a stripe pattern consisting of the light shielding pattern 30a in which the light shielding layer 33 and the antireflection layer 35 were laminated was formed. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 6 of Example 1 was taken, and the cross section and the plane were observed. From the results of the cross-sectional observation, it was found that the overetch dimension was 0.38 µm. Moreover, it turned out that the unevenness generate | occur | produces in the edge part of a linear pattern, and the maximum and minimum width are 0.1 micrometer or less from the result of frontal observation. At this point in time, no change was observed in the chromium oxynitride (CrON) film, which is the transflective layer 20, and it was found that it remained on the surface of the transparent substrate 10.

Next, the semitransmissive layer 20 was etched in the same procedure as in Examples 7 and 8 to form a stripe pattern serving as the semitransmissive pattern 20a. The board | substrate after formation was cut | disconnected longitudinally, the electron microscope photograph similar to FIG. 8 of Example 1 was taken, and the cross section and the plane were observed. As a result, the overetch dimension was 0.36 탆. Moreover, it turned out that the uneven | corrugated dimension of the edge part is sufficiently small about 0.1 micrometer or less with respect to a straight line pattern.

As in Example 1, the transmittance and the like were measured, and the optical concentration was 3.03 and the transmittance was 48.21% at 350 nm, 59.05% at 436 nm, and 64.98% at 500 nm.

Moreover, as a result of the film thickness measurement, the film thickness of the semitransmissive pattern 20a was 124 kPa (12.4 nm), and the film thickness of the light shielding pattern 30a was 1010 kPa (101 nm). These results are shown in Table 2.

As shown in these Examples 7-9, even when the material of the semi-transmissive layer which is a 1st layer, and the material of the light shielding layer which is a 2nd layer is substituted, and the etching liquid A which is a 1st etching liquid and the etching liquid B which is a 2nd etching liquid are substituted, The same results as in Examples 1 to 6 were obtained.

As a result, it was confirmed that not only the black matrix used in the liquid crystal display element, the color filter substrate, etc., but also as a photomask can be sufficiently used. Table 2 shows the evaluation results of Examples 1-9.

Below, a comparative example is demonstrated.

(Comparative Example 1)

Comparative Example 1 Example 1-9 unlike the transparent substrate 10 to be a chromium oxide (CrO _x) to the surface a first anti-reflection layer and a metal chromium light-shielding layer, and a chromium oxide as (Cr) (CrO _x of ) Is an example in which three layers of the second antireflection layer of () are sequentially stacked in this order. The laminated structure of this example is the same as that of the photomask generally used. That is, a general photomask often forms or sandwiches one or both of the layers disposed above and below the oxide, nitride, oxynitride, or the like depending on the degree of absorption of the light shielding layer. In the comparative example 1, the board | substrate for forming such a general photomask is employ | adopted as a comparison object with each said Example.

In Comparative Example 1, the same sputtering apparatus as in Example 1 was used, the metal titanium target of Example 1 was replaced with a metal chromium target (purity of 99.99% or more), oxygen gas was used as the reactive gas, and reactive sputtering Chromium oxide (CrO _x ) as the first antireflection layer was directly deposited on the surface of the transparent substrate 10. In addition, since oxidation degree changes with a sputtering apparatus, what is necessary is just to adjust suitably by combining film-forming conditions.

Next, the metal chromium target was changed into a new metal chromium target, and a light shielding layer of metal chromium (Cr) was formed on the surface of the first antireflection layer by sputtering. This light shielding layer has a film thickness capable of shielding almost 100% (OD> 3.0) against the irradiation light. Further, a second antireflection layer made of chromium oxide (CrO _x ) was formed on the surface of the light shielding layer successively.

Subsequently, the laminated substrate formed in the said sputtering process was taken out of the sputtering apparatus, and left to stand for one week in the storage. Subsequently, ultrasonic cleaning was performed on each of a plurality of sets of alkaline detergents, neutral detergents, and pure water on the substrate taken out from the storage, and then the same resist as in Example 1 was applied to the entire surface of the substrate to perform temporary curing. Thereafter, exposure, development, and main curing were performed using the pattern used in Example 1, and the first antireflection layer, the light shielding layer, and the second antireflection layer were prepared using a mixed solution of perchloric acid, cerium ammonium nitrate, and water as the first etching solution. It etched collectively and the stripe pattern was formed.

By observing the cross section and the plane using an electron microscope in the same manner as in Example 1, the overetch of the stripe pattern consisting of three layers at this time was evaluated. As a result, it was found from the cross-sectional observation that the overetch dimension was 0.40 µm, and from the results of the front observation, the width of the unevenness in the edge portion of the linear pattern was 0.1 µm or less.

Using other substrates without patterning, optical density (OD) and spectral reflectance, which are optical characteristics, were measured in the same manner as in Example 1 with a magnetic spectrophotometer U-4000 manufactured by Hitachi High Technologies. The resultant optical density was 3.18, and the reflectance from the substrate surface side was 7.11% at 436 nm.

Moreover, when the film thickness of the pattern which becomes a 1st anti-reflective layer, a light shielding layer, and a 2nd anti-reflective layer was measured using a part of etched stripe pattern, these total film thickness was 1280 Pa (128.0 nm). The results are shown in Table 2.

(Comparative Example 2)

In Comparative Example 2, unlike Examples 1 to 9 and Comparative Example 1, two layers of a chromium oxide (CrO _x ) layer as an antireflection layer and a metal chromium (Cr) layer as a light shielding layer are formed on the surface of the transparent substrate 10. This is an example of sequentially stacking in this order. This example is a black matrix provided on the outer periphery of each flower (for example, the outer periphery of pixels such as red, green, and blue of color filters) for the purpose of improving the display quality of liquid crystal display devices and the like. It is equipped with the structure similar to the 2-layer type photomask used for the thin film for a photomask and the photomask of several microns-several ten micron order. In the case of the black matrix, in order to reduce the reflectance from the viewing side opposite to the mask, chromium oxide (CrO _x ) as an antireflection layer is arranged on the substrate side.

In this example, chromium oxide (CrO _x ) was laminated so as to have a film thickness of 300 kPa (30.0 nm) in the same procedure as in Example 1. Subsequently, metal chromium (Cr) was deposited thereon to have a film thickness of 700 kPa (70.0 nm).

Next, exposure, development, and main curing were carried out in the same manner as in Example 1, and the chromium oxide (CrO _x ) layer and the metal chromium (Cr) layer were collectively combined using a mixed solution of perchloric acid, cerium ammonium nitrate, and water as the first etching solution. Etching was performed to form a stripe pattern.

By observing the cross section and the plane using an electron microscope in the same manner as in Example 1, the over-etch of the stripe pattern including the chromium oxide (CrO _x ) layer as the antireflection layer and the metal chromium (Cr) layer as the light shielding layer was evaluated. . As a result, it was found from the cross-sectional observation that the overetch dimension was 0.38 µm, and from the results of the front observation, the width of the unevenness in the edge portion of the linear pattern was 0.1 µm or less.

Using other substrates without patterning, optical density (OD) and spectral reflectance, which are optical characteristics, were measured in the same manner as in Example 1 with a magnetic spectrophotometer U-4000 manufactured by Hitachi High Technologies. The resultant optical density was 3.04, and the reflectance from the substrate surface side was 7.53% at 436 nm.

Moreover, when the film thickness of the pattern used as a light shielding layer and an antireflection layer was measured using a part of etched stripe pattern, these total film thickness was 980 kPa (98.0 nm). The results are shown in Table 2.

(Comparative Example 3)

In Comparative Example 3, unlike Examples 1 to 9 and Comparative Examples 1 and 2, only a chromium oxide (CrO _x ) layer is formed on the surface of the transparent substrate 10. Since the chromium oxide (CrO _x ) layer is etched with the same etching solution as the metal chromium (Cr) layer, when manufacturing a halftone mask by a conventional method, a light-shielding metal chromium (Cr) layer and semitransmissive chromium oxide (CrO _x ) The layers were being deposited individually (ie, divided into two). In Comparative Example 3, an example in which only a chromium oxide (CrO _x ) layer having only a function as a semi-transmissive layer is formed is used as a comparison target with each of the above examples.

In this example, a chromium oxide (CrO _x ) layer was formed so as to have a film thickness of 300 kPa (30.0 nm) in the same procedure as in Example 1.

Next, exposure, development, and main curing were performed in the same manner as in Example 1, and the chromium oxide (CrO _x ) layer was etched using a mixed solution of perchloric acid, cerium ammonium nitrate, and water as the first etching solution to form a stripe pattern. .

By observing the cross section and the plane using an electron microscope in the same manner as in Example 1, the overetch of the pattern of the chromium oxide (CrO _x ) layer at this time was evaluated. As a result, it was found from the cross-sectional observation that the overetch dimension was 0.38 µm, and from the results of the front observation, the width of the unevenness in the edge portion of the linear pattern was 0.1 µm or less.

Using other substrates without patterning, optical density (OD) and spectral transmittance, which are optical characteristics, were measured in the same manner as in Example 1 with a magnetic spectrophotometer U-4000 manufactured by Hitachi Hi-Technologies. The resultant optical density was 0.39, and the transmittance was 40.64% at 436 nm.

In addition, when the film thickness of the pattern was measured using a part of the etched stripe pattern, the film thickness was 290 kPa (29.0 nm). The results are shown in Table 2.

(Comparative Example 4)

In Comparative Example 4, unlike Examples 1 to 9 and Comparative Examples 1 to 3, only the metal chromium (Cr) layer is formed on the surface of the transparent substrate 10. Since metal chromium (Cr) has a high reflectance, the metal chromium Cr is used as an electrode, a mirror, or the like including wiring, and thus is a reference for comparing patternability with the embodiment.

In this example, a metal chromium (Cr) layer was formed so as to have a film thickness of 700 kPa (70.0 nm) in the same procedure as in Example 1.

Next, exposure, development, and main curing were performed in the same procedure as in Example 1, and the metal chromium (Cr) layer was etched using a mixed solution of perchloric acid, cerium ammonium nitrate, and water as the first etching solution to form a stripe pattern.

By observing the cross section and the plane using an electron microscope in the same manner as in Example 1, the over-etch of the pattern of the metal chromium (Cr) layer was evaluated at this time. As a result, it was found from the cross-sectional observation that the overetch dimension was 0.35 µm, and from the results of the frontal observation, the width of the unevenness in the edge portion of the linear pattern was 0.05 µm or less.

Using other substrates without patterning, optical density (OD) and spectral reflectance and transmittance, which are optical characteristics, were measured in the same manner as in Example 1 with a Hitachi Hi-Technologies magnetospectrophotometer U-4000. The resultant optical density was 3.02, the transmittance was 0.092% at 436 nm, and the reflectance was 59.71%.

Moreover, when the film thickness of the pattern was measured using a part of the etched stripe pattern, these total film thicknesses were 720 kPa (72.0 nm). The results are shown in Table 2.

Claims (13)

A transparent substrate, a first layer formed on the transparent substrate and semi-transparent to the irradiation light, and a second layer formed on the first layer and substantially shielding the irradiation light. A photomask substrate capable of forming a light shielding portion in which a light shielding pattern formed by the light is exposed on the surface, a semi-transmissive portion in which the semi-transmissive pattern formed by the first layer is exposed on the surface, and a transparent portion in which the transparent substrate is exposed on the surface. As The first layer is insoluble or poorly soluble in the first etching solution than the second layer, and is more soluble in the second etching solution. And said second layer is more soluble in said first etchant than said first layer and insoluble or poorly soluble in said second etchant. The substrate of claim 1, wherein the first layer is directly formed on the transparent substrate. The photomask substrate of claim 1, wherein the first layer is formed on the transparent substrate through a metal compound layer having a transmittance of 70% or more and less than 100%. The photomask substrate according to any one of claims 1 to 3, wherein the first etching solution is a mixed solution of cerium ammonium nitrate, perchloric acid, and water. The photomask substrate according to any one of claims 1 to 4, wherein the second etching solution is a mixture of potassium hydroxide, hydrogen peroxide, and water. The photomask substrate according to any one of claims 1 to 5, wherein the first layer is composed mainly of one or two or more components selected from the group consisting of titanium, titanium nitride and titan oxynitride. The photomask according to any one of claims 1 to 6, wherein the second layer is composed mainly of one or two or more components selected from the group consisting of chromium, chromium oxide, chromium nitride and chromium nitride. Substrate. The photomask substrate according to any one of claims 1 to 7, wherein the second layer includes a light shielding layer and an antireflection layer formed on the surface side of the light shielding layer. 9. The photomask substrate of claim 8, wherein the anti-reflection layer comprises at least one component selected from the group consisting of chromium oxide, chromium nitride and chromium nitride. 10. The composition of any one of claims 1 to 3, 8 and 9, wherein the first layer comprises at least one component selected from the group consisting of chromium, chromium oxide, chromium nitride and chromium nitride. It is a layer to be made, The second layer is a layer composed mainly of one or two or more components selected from the group consisting of titanium, titanium nitride and titanium oxynitride, The first etching solution is a mixture of potassium hydroxide, hydrogen peroxide and water, The second etching solution is a substrate for a photomask, characterized in that the mixture of cerium ammonium nitrate, perchloric acid and water. The substrate for a photomask according to any one of claims 1 to 10, wherein the first layer and the second layer are formed by a sputtering method, an ion plating method, or a vapor deposition method. By a photomask substrate having a transparent substrate, a first layer formed on the transparent substrate and semi-transparent to the irradiation light, and a second layer formed on the first layer to substantially shield the irradiation light. As a photomask to be formed, The first layer is insoluble or poorly soluble in the first etching solution than the second layer, and is soluble in the second etching solution, The second layer is more soluble in the first etchant than the first layer and insoluble or poorly soluble in the second etchant, The photomask has A light shielding portion on which a light shielding pattern formed by etching the second layer by the first etching solution is exposed on a surface; A semi-transmissive portion in which a semi-transmissive pattern formed by etching the first layer by the second etching solution is exposed to a surface; And the second layer and the first layer are etched by the first etchant and the second etchant to form a transparent portion on which the transparent substrate is exposed on the surface. As a method of manufacturing the photomask of claim 12, A first resist coating step of coating the resist on the surface of the second layer, A first exposure step of exposing the resist coated in the first resist coating step through a mask on which a first mask pattern is formed; A first resist removing step of removing the exposed portion of the resist after the first exposure step; A first etching process of etching the second layer exposed to the region from which the resist is removed with the first etching solution to form the light shielding pattern; A first resist stripping step of stripping the resist remaining in the first resist removing step; A second resist coating step of coating the resist on the surface again; A second exposure step of exposing the resist coated in the second resist coating step through a mask on which a second mask pattern is formed; A second resist removing step of removing the exposed portion of the resist after the second exposure step; A second etching process of etching the first layer exposed to the region from which the resist is removed with the second etching solution to form the transflective pattern; A second resist stripping step of peeling off the resist remaining in the second resist removing step is performed.

Images