KR20240004105A - Mask blank, transfer mask, method for manufacturing transfer mask, and method for manufacturing display device - Google Patents

Abstract

Provided is a mask blank with a semipermeable membrane, which can inhibit in-plane distributions of transmittance for a plurality of wavelengths in exposure light even if the transmittance for exposure light is increased and transmittance fluctuations by changes in membrane thicknesses. The mask blank comprises a light-transmissive substrate and a semipermeable membrane provided on a main surface of the light-transmissive substrate. For the semipermeable membrane, a refractive index n and an extinction coefficient k for light with wavelengths of 334 nm, and a refractive index n and an extinction coefficient k for light with wavelengths of 405 nm satisfy a relation of formula 1 and formula 2. (Formula 1) k >= 0.282 × n -0.514 (Formula 2) k <= 0.500 × n + 0.800

Description

Mask blank, transfer mask, method of manufacturing transfer mask, and method of manufacturing display device {MASK BLANK, TRANSFER MASK, METHOD FOR MANUFACTURING TRANSFER MASK, AND METHOD FOR MANUFACTURING DISPLAY DEVICE}

The present invention relates to a mask blank, a transfer mask, a method of manufacturing a transfer mask, and a method of manufacturing a display device.

In the field of masks for FPDs, attempts are being made to reduce the number of masks by using a gray tone mask (also called a multi-gradation mask) having a semi-transmissive film (the so-called half-transmissive film for a gray tone mask) (non-patent literature) One).

Here, the gray tone mask has a light blocking portion 1, a transmissive portion 2, and a gray tone portion 3 on a transparent substrate (transmissive substrate), as shown in (1) of FIG. 11. The gray tone portion 3 has a function of adjusting the amount of transmission. For example, as shown in (1) of FIG. 11, the gray tone portion 3 is an area where a semi-transmissive film (half-transmissive film) 3a' for a gray tone mask is formed. It is a formed area, and is formed for the purpose of reducing the amount of light transmitted through these areas, reducing the amount of irradiation by these areas, and controlling the reduced film thickness after development of the photoresist corresponding to these areas to a desired value. .

When a gray tone mask is mounted and used in a large exposure device using a mirror projection method or a lens method using a lens, the overall exposure amount of the exposure light passing through the gray tone portion 3 becomes insufficient, so the gray tone portion 3 The positive photoresist exposed through only becomes thinner and remains on the substrate. That is, because the resist has a difference in solubility in the developer solution in the portion corresponding to the normal light-shielding portion 1 and the portion corresponding to the gray tone portion 3 due to the difference in exposure amount, the shape of the resist after development is shown in Figure 11 ( As shown in 2), the portion 1' corresponding to the normal light blocking portion 1 is, for example, about 1 μm, and the portion 3' corresponding to the gray tone portion 3 is, for example, about 0.4 μm. to 0.5 μm, the portion corresponding to the transparent portion 2 becomes the portion 2′ without resist. Then, the first etching of the substrate to be processed is performed in the portion 2' without resist, the resist in the thin portion 3' corresponding to the gray tone portion 3 is removed by ashing, etc., and the second etching is performed in this portion. By performing this, the process equivalent to two conventional masks is performed with one mask, thereby reducing the number of masks.

In addition, in recent years, the gray tone mask has been mounted on a large exposure apparatus of a proximity exposure (projection exposure) method and is used to form a photo spacer for a color filter.

The gray tone mask shown in (1) of FIG. 11 is manufactured using, for example, the mask blank described in Patent Document 1. The mask blank described in Patent Document 1 has at least a semi-transmissive film having a function of adjusting the amount of transmission on a translucent substrate, and the semi-transparent film is radiated from an ultra-high pressure mercury lamp and has a wavelength band spanning at least the i-line to the g-line. In this case, the film is characterized in that the fluctuation range of the transmittance of the semi-transparent film is controlled to be within a range of less than 5%. As this semi-transmissive film, materials and film thicknesses such as CrN (film thickness of 20 to 250 angstroms (2 to 25 nm)) and MoSi ₄ (film thickness of 15 to 200 angstroms (1.5 to 20 nm)) are exemplified.

Japanese Patent Publication No. 2007-199700

FPD Intelligence Monthly, p.31-35, May 1999

When forming a semi-transmissive film (semi-transmissive film) having a desired transmittance using the material exemplified in Patent Document 1, the film thickness of the semi-transmissive film is controlled. However, when manufacturing a large-sized gray tone mask, a transmittance distribution due to the film thickness distribution occurs within the plane of the substrate, making it difficult to manufacture a gray tone mask with good in-plane transmittance uniformity.

Additionally, in the film formation process of the semi-transmissive film on the mask blank, since the film thickness of the semi-transmissive film is as thin as 80 nm at most, it is difficult to form the film according to the design film thickness, and a film thickness difference of approximately 10% occurs with respect to the design film thickness. There are cases where it happens. When designing a semi-permeable membrane without considering the fluctuation range of the transmittance due to the membrane thickness, as described above, when the thickness of the semi-permeable membrane deviates from the design value, the transmittance changes, and the in-plane distribution of the transmittance There was a problem that was growing.

In particular, when a gray tone mask is mounted on a large-scale exposure device of the proximity exposure method and a pattern is transferred to a transfer object, the gap between the gray tone mask and the transfer object is narrow, so foreign matter is prevented from adhering to the surface of the gray tone mask. Pellicle cannot be used.

Therefore, usually, after using the gray tone mask multiple times, chemical cleaning using an alkali or acid is performed to remove foreign substances adhering to the surface of the gray tone mask. However, a problem arises in that cleaning with the chemical solution causes a decrease in the semi-permeable membrane and changes the transmittance of the semi-permeable membrane.

Additionally, in the field of FPD masks, complex light selected from a predetermined range of wavelengths may be used as exposure light. For example, light with a wavelength of 334 nm or complex light containing h-line (405 nm) may be used as exposure light. In such a case, simply adjusting the transmittance to the desired level for one representative wavelength can suppress the in-plane distribution of the transmittance for multiple wavelengths in the exposure light and suppress the transmittance fluctuation due to film thickness fluctuation. There is a problem that it cannot be done sufficiently.

Additionally, in recent years, with the miniaturization and complexity of transfer mask patterns, the transmittance to the exposure light has been increased (for example, the transmittance of 20% or more) to enable higher resolution pattern transfer. ), the number of cases where a semi-permeable membrane is required is increasing. In addition, the requirement for in-plane uniformity of the pattern of the photosensitive film formed after exposure transfer to the photosensitive film on the transfer object is becoming more stringent, and the requirement for in-plane uniformity of transmittance for multiple wavelengths of exposure light is increasing. However, by increasing the transmittance for the exposure light, it becomes more difficult to suppress the in-plane distribution of the transmittance for a plurality of wavelengths in the exposure light and to suppress the transmittance variation due to the film thickness variation.

Therefore, the present invention relates to a mask blank for manufacturing an FPD device having at least a semi-transmissive film having a function of adjusting the transmission amount of exposure light on a translucent substrate. Even when the transmittance to exposure light is increased, the exposure light The object is to provide a mask blank having a semi-transmissive film that can suppress the in-plane distribution of the transmittance for a plurality of wavelengths and can suppress the fluctuation of the transmittance due to the film thickness fluctuation. Furthermore, the present invention can suppress the in-plane distribution of the transmittance for a plurality of wavelengths in the exposure light even when the transmittance for the exposure light is increased, and also suppress the transmittance fluctuation due to the film thickness fluctuation. The purpose is to provide a transfer mask having a semi-permeable film and a method for manufacturing the transfer mask. And the purpose of the present invention is to provide a method of manufacturing a display device using such a transfer mask.

The present invention is a means of solving the above problems and has the following structure.

(Configuration 1) A mask blank comprising a translucent substrate and a semi-transmissive film provided on the main surface of the translucent substrate,

The refractive index n and extinction coefficient k for light with a wavelength of 334 nm in the semi-transmissive film,

A mask blank characterized in that the refractive index n and extinction coefficient k for light with a wavelength of 405 nm both satisfy the relationships of (Equation 1) and (Equation 2).

(Equation 1) k≥0.282×n-0.514

(Equation 2) k≤0.500×n+0.800

(Configuration 2) The mask blank according to Configuration 1, wherein the extinction coefficient k of the semi-transmissive film for light with a wavelength of 334 nm is greater than 0.

(Configuration 3) The mask blank according to Configuration 1, wherein the refractive index n of the semi-transmissive film for light with a wavelength of 334 nm is 2.0 or more.

(Configuration 4) The mask blank according to Configuration 1, wherein the semi-transmissive film has a thickness of 30 nm or more and 70 nm or less.

(Configuration 5) The mask blank according to Configuration 1, wherein the semi-transmissive film has a transmittance of 20% or more and 60% or less to light with a wavelength of 334 nm.

(Configuration 6) The mask blank according to Configuration 1, wherein the phase difference of the semi-transmissive film with respect to light with a wavelength of 334 nm is 0 degrees or more and 120 degrees or less.

(Configuration 7) The mask according to Configuration 1, wherein the refractive index n and extinction coefficient k for light with a wavelength of 365 nm in the semi-transmissive film also satisfy the relationships of (Equation 1) and (2) above. Blank.

(Configuration 8) The mask blank according to Configuration 1, wherein the semi-transmissive film contains metal, silicon, and nitrogen.

(Configuration 9) The mask blank according to Configuration 1, wherein an etching mask film having different etching selectivity with respect to the semitransmissive film is provided on the semitransmissive film.

(Configuration 10) The mask blank according to Configuration 9, wherein the etching mask film contains chromium.

(Configuration 11) A transfer mask, characterized in that a transfer pattern is formed on the semi-transmissive film of the mask blank according to Configuration 1.

(Configuration 12) A transfer mask, wherein a transfer pattern is formed on the semi-transmissive film of the mask blank described in Configuration 9, and a pattern different from the transfer pattern is formed on the etching mask film.

(Configuration 13) A process of preparing the mask blank described in Configuration 1;

forming a resist film having a transfer pattern on the semi-transmissive film;

A process of performing wet etching using the resist film as a mask to form a transfer pattern on the semi-transmissive film.

A method of manufacturing a transfer mask characterized by having a.

(Configuration 14) A process of preparing the mask blank described in Configuration 9;

A process of forming a resist film having a transfer pattern on the etching mask film;

A step of performing wet etching using the resist film as a mask to form a transfer pattern on the etching mask film;

A process of forming a transfer pattern on the semi-transmissive film by performing wet etching using the etching mask film on which the transfer pattern is formed as a mask.

A method of manufacturing a transfer mask characterized by having a.

(Configuration 15) A process of loading the transfer mask described in Configuration 11 or 12 on a mask stage of an exposure apparatus;

A process of irradiating exposure light to the transfer mask and transferring the transfer pattern to a photosensitive film provided on a substrate for a display device.

A method of manufacturing a display device comprising:

(Configuration 16) The method of manufacturing a display device according to Configuration 15, wherein the exposure light is a composite light containing light with a wavelength of 334 nm and light with a wavelength of 405 nm.

According to the present invention, regarding a mask blank for manufacturing an FPD device having at least a semi-transmissive film having a function of adjusting the amount of transmission on a translucent substrate, even when the transmittance to the exposure light is increased, the plurality of exposure light It is possible to provide a mask blank having a semi-transmissive film that can suppress the in-plane distribution of the transmittance for the wavelength and suppress the transmittance fluctuation due to the film thickness fluctuation.

Furthermore, according to the present invention, even when the transmittance to the exposure light is increased, the in-plane distribution of the transmittance for a plurality of wavelengths in the exposure light can be suppressed, and the transmittance variation due to film thickness variation can be suppressed. A transfer mask having a semi-transmissive film pattern and a method for manufacturing the transfer mask can be provided. And, the present invention can provide a method of manufacturing a display device using such a transfer mask.

1 is a cross-sectional schematic diagram showing the film structure of a mask blank according to an embodiment of the present invention.
Figure 2 is a cross-sectional schematic diagram showing another film configuration of a mask blank according to an embodiment of the present invention.
Figure 3 is a cross-sectional schematic diagram showing the manufacturing process of the transfer mask according to the embodiment of the present invention.
Fig. 4 is a cross-sectional schematic diagram showing another manufacturing process of the transfer mask according to the embodiment of the present invention.
FIG. 5 is a diagram showing an example of the relationship between the film thickness and transmittance of a semi-transmissive film when the extinction coefficient k is changed to a predetermined refractive index n for light (h line) with a wavelength of 405 nm, derived from simulation results. am.
Fig. 6 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Example 1, derived from simulation results.
Fig. 7 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Example 2, derived from simulation results.
FIG. 8 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Comparative Example 1, derived from simulation results.
Fig. 9 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Comparative Example 2, derived from simulation results.
Figure 10 shows the relationship between the refractive index n and extinction coefficient k, which can suppress the in-plane distribution of the transmittance and the fluctuation of the transmittance due to the film thickness fluctuation, derived from simulation results, and the relationship between the in-plane distribution of the transmittance and the extinction coefficient k in Examples 1 and 2 and Comparative Examples 1 and 2. , a diagram showing the refractive index n and extinction coefficient k.
FIG. 11 is a diagram for explaining a gray tone mask having a semi-transmissive film (semi-transmissive film), where (1) is a partial plan view and (2) is a partial cross-sectional view.

First, the circumstances leading to the completion of the present invention will be explained. The present inventor has found that even when the transmittance for exposure light containing a wavelength in the ultraviolet region (hereinafter sometimes simply referred to as “exposure light”) is increased, the in-plane distribution of transmittance for a plurality of wavelengths in the exposure light An intensive study was conducted on the configuration of a mask blank having a semi-transmissive film that can suppress fluctuations in transmittance due to film thickness fluctuations as well as suppressing fluctuations in transmittance due to film thickness fluctuations.

In a mask blank including a semi-transmissive film on a translucent substrate, the refractive index n, extinction coefficient k, and film thickness of the semi-transmissive film are subject to limitations in its function as a transmittance adjustment film for exposure light containing a wavelength in the ultraviolet region. For this reason, it is necessary to control the refractive index n and extinction coefficient k of the semi-transmissive film so that they are within a predetermined range.

Here, the present inventor satisfies that the transmittance is 20% or more for light with a wavelength of 334 nm and light (h line) with a wavelength of 405 nm among exposure lights containing wavelengths in the ultraviolet region, and the An optical simulation was performed on the relationship between the refractive index n and extinction coefficient k of the semi-transmissive film in order to suppress the in-plane distribution of the transmittance for multiple wavelengths and to suppress the transmittance fluctuation due to film thickness fluctuation. This light with a wavelength of 334 nm is close to a weighted average that takes into account the intensity distribution in the wavelength range of mid-ultraviolet light, and also has a predetermined intensity (peak height) in the spectrum of a high-pressure mercury lamp, and has an effect of improving DOF (depth of focus). It is also preferably used because it is advantageous in obtaining . By satisfying these desired relationships in the light of this wavelength of 334 nm, the resolution of fine patterns can be improved. In addition, by satisfying the desired relationship between light with a wavelength of 334 nm and the h-line, if the reference wavelength for designing the transmittance of the semi-transmissive film is selected from the range of the light with a wavelength of 334 nm to the wavelength of the h-line, the transflection The film can obtain the transmittance as designed at the reference wavelength, and can suppress in-plane distribution at any wavelength ranging from light with a wavelength of 334 nm to h-line, and can suppress fluctuations in transmittance due to film thickness fluctuations. Additionally, similar effects can be expected for other wavelengths in the ultraviolet region.

In optical simulation, the refractive index n is in the range of 1.80 to 3.00 and the extinction coefficient k is in the range of 0.00 to 0.80, and the film thickness and transmittance ( and reflectance) were examined.

FIG. 5 is a diagram showing an example of the relationship between the film thickness and transmittance of a semi-transmissive film when the extinction coefficient is changed to a predetermined refractive index derived from simulation results for light (h-line) with a wavelength of 405 nm. Specifically, in Figure 5, the refractive index n is set to 2.40 and the extinction coefficient k is set to 0.10, 0.16, 0.30, 0.40, and 0.50, respectively, are shown as curves A1 to A5.

For each curve A1 to A5, it was examined whether the film thickness dependence of the transmittance was within an acceptable range (for example, whether the transmittance change was within 2% at a film thickness change of 5 nm). As a result, for curves A2 to A4, the dependence of the transmittance on film thickness was within the acceptable range, and for curves A1 and A5, it was outside the acceptable range.

Table 1 shows the relationship between film thickness and transmittance in curves A1, A3, and A5.

As shown in Table 1, in curve A3, the dependence of the transmittance on the film thickness is very good, and as shown in Figure 5, the change in the transmittance is very small in the range around the film thickness of 50 nm, and is substantially flat. had a territory. On the other hand, in curves A1 and A5, there were places where the transmittance variation exceeded 2% at a film thickness change of 5 nm, which was outside the allowable range. In addition, it can be seen that curve A2 represents the lower limit of the extinction coefficient k at which the film thickness dependence of the transmittance is within the acceptable range, and curve A4 represents the upper limit of the extinction coefficient k at which the film thickness dependence of the transmittance is within the acceptable range. there was.

Then, the values of the refractive index n and the extinction coefficient k were changed, a simulation regarding the above-mentioned transmittance was performed, and the relationship between the refractive index n and the extinction coefficient k, in which the film thickness dependence of the transmittance was within the allowable range, was summarized. In addition, a similar simulation was performed for light with a wavelength of 334 nm, and the relationship between the refractive index n and the extinction coefficient k, where the film thickness dependence of the transmittance is within the allowable range, was summarized. As a result, the refractive index n and extinction coefficient of the semi-transmissive film satisfy the transmittance of 20% or more for light with a wavelength of 334 nm and light (h line) with a wavelength of 405 nm, and the film thickness dependence of the transmittance is within the allowable range. The relational expression is as follows (see Fig. 10).

(Equation 1) k≥0.282×n-0.514

(Equation 2) k≤0.500×n+0.800

That is, the refractive index n and extinction coefficient k for light with a wavelength of 334 nm in the semitransmissive film, and the refractive index n and extinction coefficient k for light with a wavelength of 405 nm are all in the relationship of (Equation 1) and (Equation 2) When the The present inventor found out.

Equations (1) and (2) in FIG. 10 correspond to the equal sign parts of (Equation 1) and (Equation 2) described above. Additionally, in Figure 10,

Equation (3) k=0.370×n-0.590

is obtained by plotting the values of n and k, where the change in transmittance is very small with respect to the film thickness variation and has a substantially flat area.

Regarding the film thickness dependence of transmittance, the present inventor speculates as follows.

The film thickness of the semi-permeable film and the transmittance are inversely proportional (inversely proportional), and usually, as the film thickness of the semi-permeable film increases, the transmittance decreases (a graph with a downward slope on the right).

In the present invention, the phenomenon in which the change in transmittance is suppressed even when the film thickness of the semi-permeable membrane changes is that, when the film thickness changes before and after the target transmittance (set film thickness), the transmittance changes in inverse proportion to the change in film thickness. However, as the back reflectance changes, something happens to compensate for the change in transmittance. For this reason, the balance between the transmittance and the back surface reflectance is achieved, and a phenomenon occurs in which the fluctuation of the transmittance becomes gentle with respect to the variation in the film thickness, and the variation in the transmittance with respect to the variation in the film thickness becomes small.

The present invention was made as a result of the above-mentioned examination.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the following embodiment is a form for actualizing the present invention, and does not limit the present invention to its scope.

Fig. 1 is a schematic diagram showing the film structure of the mask blank 10 of this embodiment. The mask blank 10 shown in FIG. 1 includes a translucent substrate 20, a translucent film 30 formed on the translucent substrate 20, and an etching mask film 40 formed on the semitransmissive film 30. Equipped with

FIG. 2 is a schematic diagram showing the film structure of the mask blank 10 according to another embodiment. The mask blank 10 shown in FIG. 2 includes a translucent substrate 20 and a semi-transmissive film 30 formed on the translucent substrate 20.

Hereinafter, the translucent substrate 20, the semi-transmissive film 30, and the etching mask film 40 that constitute the mask blank 10 for manufacturing the display device of this embodiment will be described in detail.

<Light-transmitting substrate (20)>

The translucent substrate 20 is transparent to exposure light. The translucent substrate 20 has a transmittance of 85% or more, preferably 90% or more, for exposure light, assuming no surface reflection loss. The translucent substrate 20 is made of a material containing silicon and oxygen, and is made of glass such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.) It can be composed of materials. When the translucent substrate 20 is made of low thermal expansion glass, a change in the position of the semi-transmissive film pattern 30a due to thermal deformation of the translucent substrate 20 can be suppressed. Additionally, the translucent substrate 20 used for display devices is generally a rectangular substrate. Specifically, a translucent substrate 20 whose short side length of the main surface (the surface on which the semi-transmissive film 30 is formed) is 300 mm or more can be used. In the mask blank 10 of this embodiment, a large-sized translucent substrate 20 whose main surface has a short side length of 300 mm or more can be used. Using the mask blank 10 of the present embodiment, a transfer pattern including a fine semi-transmissive film pattern 30a having, for example, a width dimension and/or a diameter dimension of less than 2.0 μm is provided on the translucent substrate 20. A transfer mask 100 can be manufactured. By using the transfer mask 100 of this embodiment, it is possible to stably transfer a transfer pattern containing a predetermined fine pattern to a transfer object.

<Semi-permeable membrane (30)>

The semi-transmissive film 30 of the mask blank 10 for manufacturing the display device of the present embodiment (hereinafter, sometimes simply referred to as the “mask blank 10 of the present embodiment”) is composed of metal, silicon (Si), and , it is preferably made of a material containing nitrogen (N). The metal is preferably a transition metal. As transition metals, molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr), etc. are suitable, and titanium and molybdenum are particularly preferable.

The semi-permeable membrane 30 contains nitrogen. Nitrogen, a light element component, has the effect of not lowering the refractive index n and extinction coefficient k compared to oxygen, which is also a light element component. In order for the semi-transmissive film 30 to exhibit the above-mentioned effects, it is desired that the extinction coefficient k of the semi-transmissive film 30 is set to below the upper limit described later, and the refractive index n is set to be equal to or higher than the lower limit described later. Since the semi-transmissive film 30 contains nitrogen, it becomes easy to adjust the refractive index n and extinction coefficient k to a desired level. Additionally, the nitrogen content contained in the semi-permeable membrane 30 is preferably 30 atomic% or more, and more preferably 40 atomic% or more. On the other hand, the nitrogen content is preferably 60 atomic% or less, and more preferably 55 atomic% or less. By increasing the nitrogen content in the semi-transmissive film 30, excessive increase in transmittance to exposure light can be suppressed.

To the extent that the performance of the semi-permeable membrane 30 is not deteriorated, the semi-permeable membrane 30 may contain oxygen. Oxygen, a light element component, has a great effect in lowering the refractive index n and extinction coefficient k compared to nitrogen, which is also a light element component. However, if the oxygen content of the semi-permeable membrane 30 is high, there is a possibility that it may have a detrimental effect on obtaining a nearly vertical fine pattern cross section and high mask cleaning resistance. Therefore, the oxygen content of the semi-permeable membrane 30 is preferably 7 atomic% or less, and more preferably 5 atomic% or less. The semi-permeable membrane 30 may not contain oxygen.

In addition to the oxygen and nitrogen described above, the semi-permeable film 30 may contain other light element components such as carbon and helium for the purpose of reducing film stress and/or controlling the wet etching rate.

The atomic ratio of the transition metal and silicon included in the semi-permeable film 30 is preferably in the range of transition metal:silicon = 1:3 to 1:15. Within this range, the effect of suppressing a decrease in the wet etching rate during pattern formation of the semi-transmissive film 30 can be increased. Additionally, the cleaning resistance of the semi-permeable membrane 30 can be increased, making it easier to increase the transmittance. At the point of increasing the cleaning resistance of the semi-permeable film 30, it is preferable that the atomic ratio (transition metal:silicon) of the transition metal contained in the semi-permeable film 30 is in the range of 1:5 to 1:15. .

This semi-permeable membrane 30 is preferably composed of a single layer. The semi-permeable film 30 composed of a single layer is preferable because it is difficult for an interface to be formed in the semi-transmissive film 30 and the cross-sectional shape can be easily controlled. On the other hand, the semi-transmissive film 30 can be substantially regarded as a single optical layer, and may be a composition gradient film whose composition changes continuously in the thickness direction. In addition, the refractive index n and extinction coefficient k of the semi-transmissive film 30 in the case of a composition gradient film use the refractive index n and extinction coefficient k derived by considering the entire film to be an optically uniform single-layer film.

The film thickness of the semi-transmissive film 30 is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 70 nm or less from the viewpoint of the cross-sectional shape when patterned and the etching time required for patterning. . In addition, the thickness of the semi-transmissive film 30 is preferably 20 nm or more, more preferably 25 nm or more, and still more preferably 30 nm or more from the viewpoint of forming the film according to the designed film thickness.

<<Transmittance and phase difference of semi-permeable membrane 30>>

The transmittance and phase difference of the semi-transmissive film 30 with respect to the exposure light satisfy the values required for the semi-transmissive film 30. The transmittance of the semi-transmissive film 30 is preferably 20% or more and 60% or less, more preferably 25% or more and 55% or less, and even more preferably 30% or more and 50% or less, with respect to light with a wavelength of 334 nm. % or less. Unless otherwise specified, the transmittance in this specification refers to conversion based on the transmittance of the light-transmitting substrate (100%).

Additionally, the phase difference of the semi-transmissive film with respect to light with a wavelength of 334 nm is preferably 0 degrees or more and 120 degrees or less, more preferably 0 degrees or more and 90 degrees or less, and even more preferably 0 degrees or more and 60 degrees or less.

That is, when the exposure light is a composite light containing light in a wavelength range of 313 nm to 436 nm, the semi-transmissive film 30 has the above-described transmittance and phase difference with respect to light with a wavelength of 334 nm included in the wavelength range. has By having these characteristics for light of 334 nm, when composite light including i-, h-, and g-lines is used as exposure light, a similar effect is achieved with respect to the transmittance of i-, g-, or h-lines. You can expect it.

Transmittance and phase difference can be measured using a phase shift measurement device or the like.

The refractive index n and extinction coefficient k for light with a wavelength of 334 nm in the semitransmissive film 30, and the refractive index n and extinction coefficient k for light with a wavelength of 405 nm are all of (Equation 1) and (Equation 2) It is desirable that it satisfies the relationship.

(Equation 1) k≥0.282×n-0.514

(Equation 2) k≤0.500×n+0.800

In addition, it is preferable that the refractive index n and extinction coefficient k of the semi-transmissive film 30 for light (i-line) with a wavelength of 365 nm also satisfy the relationships of (Equation 1) and (Equation 2).

The extinction coefficient k of the semi-transmissive film 30 for light with a wavelength of 334 nm is preferably greater than 0, and more preferably 0.05 or more. On the other hand, the extinction coefficient k of the semi-transmissive film 30 for light with a wavelength of 334 nm is preferably 1.0 or less, and more preferably 0.8 or less.

The refractive index n of the semi-transmissive film 30 for light with a wavelength of 334 nm is preferably 2.0 or more, and more preferably 2.1 or more. On the other hand, the refractive index n of the semi-transmissive film 30 for light with a wavelength of 334 nm is preferably 3.0 or less, and more preferably 2.8 or less.

The reflectance (surface reflectance) of the semi-transmissive film 30 is 40% or less in the wavelength range of 334 nm to 405 nm, and is preferably 35% or less. The back surface reflectance of the semi-transmissive film 30 is 25% or less in the wavelength range of 334 nm to 405 nm, and is preferably 15% or less.

Surface reflectance and back surface reflectance can be measured using a spectrophotometer or the like.

The semi-transmissive film 30 can be formed by a known film forming method such as sputtering.

<Etching mask film (40)>

The mask blank 10 for manufacturing a display device of this embodiment preferably includes an etching mask film 40 having different etching selectivity with respect to the semitransmissive film 30 on the semitransmissive film 30 .

The etching mask film 40 is disposed on the upper side of the semi-transmissive film 30 and has etching resistance to the etchant that etches the semi-transmissive film 30 (etching selectivity is different from that of the semi-transmissive film 30). It is made of materials. Additionally, the etching mask film 40 may have a function of blocking the transmission of exposure light. In addition, the etching mask film 40 has a film surface reflectance such that the film surface reflectance of the semitransmissive film 30 with respect to the light incident from the semitransmissive film 30 side is 15% or less in the wavelength range of 334 nm to 405 nm. It may have a function to reduce .

The etching mask film 40 is preferably made of a chromium-based material containing chromium (Cr). The etching mask film 40 is more preferably made of a material that contains chromium and does not substantially contain silicon. Substantially containing no silicon means that the silicon content is less than 2% (however, excluding the composition gradient region at the interface between the semi-transmissive film 30 and the etching mask film 40). More specifically, chromium-based materials include chromium (Cr) or materials containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C). Additionally, examples of the chromium-based material include materials containing chromium (Cr), at least one of oxygen (O), nitrogen (N), and carbon (C), and also containing fluorine (F). For example, materials constituting the etching mask film 40 include Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF.

The etching mask film 40 can be formed by a known film forming method such as sputtering.

When the etching mask film 40 has a function of blocking the transmission of exposure light, the optical density for the exposure light in the portion where the semi-transmissive film 30 and the etching mask film 40 are stacked is preferably 3. or more, more preferably 3.5 or more, and still more preferably 4 or more. Optical density can be measured using a spectrophotometer or OD meter.

The etching mask film 40 can be a single film with a uniform composition depending on its function. Additionally, the etching mask film 40 can be made of a plurality of films with different compositions. Additionally, the etching mask film 40 can be a single film whose composition continuously changes in the thickness direction.

Additionally, the mask blank 10 of this embodiment shown in FIG. 1 includes an etching mask film 40 on the semi-transmissive film 30. The mask blank 10 of this embodiment includes a mask blank 10 having a structure including an etching mask film 40 on a semi-transmissive film 30 and a resist film on the etching mask film 40. do.

<Method for manufacturing mask blank 10>

Next, a method for manufacturing the mask blank 10 of the embodiment shown in FIG. 1 will be described. The mask blank 10 shown in FIG. 1 is manufactured by performing the following semi-transmissive film formation process and etching mask film formation process. The mask blank 10 shown in FIG. 2 is manufactured by a semi-transmissive film forming process.

Hereinafter, each process will be described in detail.

<<Semi-permeable membrane formation process>>

First, prepare a light-transmitting substrate 20. The translucent substrate 20 is made of a glass material selected from synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.) as long as it is transparent to exposure light. It can be configured.

Next, a semi-transmissive film 30 is formed on the translucent substrate 20 by sputtering.

The semi-permeable film 30 can be formed using a predetermined sputter target and in a predetermined sputter gas atmosphere. A predetermined sputter target is, for example, a metal silicide target containing metal and silicon, which are the main components of the material constituting the semi-permeable film 30, or a metal silicide target containing metal, silicon, and nitrogen as the sputter target. will be. The predetermined sputter gas atmosphere is, for example, a sputter gas atmosphere consisting of an inert gas containing at least one type selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas, or the inert gas and , a sputter gas atmosphere consisting of nitrogen gas and, in some cases, a mixed gas containing a gas selected from the group consisting of oxygen gas, carbon dioxide gas, nitrogen monoxide gas, and nitrogen dioxide gas. The formation of the semi-permeable film 30 can be performed under the condition that the gas pressure in the film formation chamber during sputtering is 0.3 Pa or more and 2.0 Pa or less, and preferably 0.43 Pa or more and 0.9 Pa or less. Side etching during pattern formation can be suppressed and a high etching rate can be achieved.

The composition and thickness of the semi-transmissive film 30 are adjusted so that the semi-transmissive film 30 has the above-described transmittance and phase difference. The composition of the semi-permeable film 30 can be controlled by the content ratio of the elements constituting the sputter target (for example, the ratio of the metal content to the silicon content), the composition and flow rate of the sputter gas, etc. The thickness of the semi-transmissive film 30 can be controlled by sputtering power, sputtering time, etc. Additionally, the semi-transmissive film 30 is preferably formed using an in-line sputtering device. When the sputtering device is an in-line sputtering device, the thickness of the semi-transmissive film 30 can be controlled also by the transfer speed of the substrate. In this way, the semi-transmissive film 30 contains metal, silicon, and nitrogen, and the refractive index n and extinction coefficient k of the semi-transmissive film 30 satisfy the desired relationship (refractive index n and extinction coefficient for light with a wavelength of 334 nm) Control is performed so that the coefficient k, the refractive index n and the extinction coefficient k for light with a wavelength of 405 nm all satisfy the relationships of the above (Equation 1) and the above (Equation 2).

<<Surface treatment process>>

When the semi-permeable film 30 contains oxygen, oxidation of the surface of the semi-permeable film 30 is performed to suppress penetration by the etching solution due to the presence of metal oxides on the surface of the semi-permeable film 30. You may perform a surface treatment process to adjust the condition. Additionally, when the semi-permeable film 30 is made of metal silicide nitride containing metal, silicon, and nitrogen, the content of transition metal oxide is small compared to the metal silicide material containing oxygen described above. Therefore, when the material of the semi-transmissive film 30 is metal silicide nitride, the above surface treatment step may or may not be performed.

Examples of the surface treatment process for adjusting the surface oxidation state of the semi-permeable membrane 30 include surface treatment with an acidic aqueous solution, surface treatment with an alkaline aqueous solution, and surface treatment with dry treatment such as ashing. You can.

In this way, the mask blank 10 of this embodiment can be obtained.

<<Etching mask film formation process>>

The mask blank 10 of this embodiment may also have an etching mask film 40. The following etching mask film formation process is further performed. Additionally, the etching mask film 40 is preferably made of a material that contains chromium and does not substantially contain silicon.

After the semi-transmissive film forming process, surface treatment to adjust the surface oxidation state of the surface of the semi-transmissive film 30 is performed as necessary, and then an etching mask film is applied on the semi-transmissive film 30 by the sputtering method. It forms (40). The etching mask film 40 is preferably formed using an in-line sputtering device. When the sputtering device is an in-line sputtering device, the thickness of the etching mask film 40 can be controlled also by the transfer speed of the translucent substrate 20.

The etching mask film 40 is formed using a sputter target containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium nitride carbide, and chromium oxynitride carbide, etc.), using an inert gas. It can be performed in a sputter gas atmosphere consisting of or a sputter gas atmosphere consisting of a mixed gas of an inert gas and an active gas. The inert gas may include, for example, at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas. The active gas may include at least one selected from the group consisting of oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon-based gas, and fluorine-based gas. Examples of hydrocarbon-based gas include methane gas, butane gas, propane gas, and styrene gas.

When the etching mask film 40 is made of a single film with a uniform composition, the above-described film forming process is performed only once without changing the composition and flow rate of the sputter gas. When the etching mask film 40 is made of a plurality of films with different compositions, the above-described film formation process is performed multiple times by changing the composition and flow rate of the sputter gas for each film formation process. When the etching mask film 40 is made of a single film whose composition changes continuously in the thickness direction, the above-described film formation process is performed only once while changing the composition and flow rate of the sputter gas with the elapsed time of the film formation process.

In this way, the mask blank 10 of this embodiment having the etching mask film 40 can be obtained.

In addition, since the mask blank 10 shown in FIG. 1 is provided with an etching mask film 40 on the semi-transmissive film 30, when manufacturing the mask blank 10, an etching mask film forming process is performed. do it In addition, when manufacturing the mask blank 10 including the etching mask film 40 on the semi-transmissive film 30 and the resist film on the etching mask film 40, etching is performed after the etching mask film forming process. A resist film is formed on the mask film 40. In addition, in the mask blank 10 shown in FIG. 2, when manufacturing the mask blank 10 including a resist film on the semi-transmissive film 30, the resist film is formed after the semi-transmissive film forming process.

In the mask blank 10 of the embodiment shown in FIG. 1, an etching mask film 40 is formed on a semi-transmissive film 30. In addition, the mask blank 10 of the embodiment shown in FIG. 2 has a semi-transmissive film 30 formed thereon. In either case, the refractive index n and extinction coefficient k of the semitransmissive film 30 satisfy the desired relationship (refractive index n and extinction coefficient k for light with a wavelength of 334 nm, and refractive index n and extinction coefficient for light with a wavelength of 405 nm Control is performed so that k both satisfies the relationships of (Equation 1) and (2) above.

The mask blank 10 of the embodiment shown in FIGS. 1 and 2 has a refractive index n and an extinction coefficient k that satisfy the desired relationship (refractive index n and extinction coefficient k for light with a wavelength of 334 nm and light with a wavelength of 405 nm). It has a semi-transmissive film 30 whose refractive index n and extinction coefficient k for light both satisfy the relationships of the above (Equation 1) and the above (Equation 2). By using the mask blank 10 of the embodiment, even when the transmittance to the exposure light is increased, the in-plane distribution of the transmittance for a plurality of wavelengths in the exposure light can be suppressed, and the A transfer mask 100 capable of transferring a semi-transmissive pattern 30a that can suppress variations in transmittance with high precision can be manufactured.

<Method of manufacturing transfer mask 100>

Next, the manufacturing method of the transfer mask 100 of this embodiment will be described. This transfer mask 100 has the same technical characteristics as the mask blank 10. Matters regarding the translucent substrate 20, semi-transmissive film 30, and etching mask film 40 in the transfer mask 100 are the same as those for the mask blank 10.

FIG. 3 is a schematic diagram showing a method of manufacturing the transfer mask 100 of this embodiment. FIG. 4 is a schematic diagram showing another manufacturing method of the transfer mask 100 of this embodiment.

<<Method of manufacturing the transfer mask 100 shown in FIG. 3>

The method of manufacturing the transfer mask 100 shown in FIG. 3 is a method of manufacturing the transfer mask 100 using the mask blank 10 shown in FIG. 1. The method of manufacturing the transfer mask 100 shown in FIG. 3 includes steps of preparing the mask blank 10 shown in FIG. 1, forming a resist film on the etching mask film 40, and forming the resist film. A process of wet etching the etching mask film 40 using the resist film pattern as a mask to form a transfer pattern (first etching mask film pattern 40a) on the semi-transmissive film 30, and etching the transfer pattern formed. There is a process of wet etching the semi-transmissive film 30 using the mask film 40 (the first etching mask film pattern 40a) as a mask to form a transfer pattern on the semi-transmissive film 30. In addition, the transfer pattern in this specification is obtained by patterning at least one optical film formed on the translucent substrate 20. The optical film can be a semi-transmissive film 30 and/or an etching mask film 40, and may further include other films (a light-shielding film, a film for suppressing reflection, a conductive film, etc.). That is, the transfer pattern may include a patterned semi-transmissive film and/or an etching mask film, and may further include other patterned films.

Specifically, the method of manufacturing the transfer mask 100 shown in FIG. 3 forms a resist film on the etching mask film 40 of the mask blank 10 shown in FIG. 1. Next, the resist film pattern 50 is formed by drawing and developing a desired pattern on the resist film (see Fig. 3(a), step of forming the first resist film pattern 50). Next, the etching mask film 40 is wet-etched using the resist film pattern 50 as a mask to form a first etching mask film pattern 40a on the transflective film 30 (see Figure 3). b) Reference, formation process of the first etching mask layer pattern 40a). Next, using the first etching mask pattern 40a as a mask, the semi-transmissive film 30 is wet-etched to form a semi-transmissive film pattern 30a on the transmissive substrate 20 (Figure 3 (c) ) Reference, formation process of the semi-transmissive film pattern (30a)). After that, a process of forming a second resist layer pattern 60 and a process of forming a second etching mask layer pattern 40b may be further included (see Figures 3 (d) and (e)).

More specifically, in the formation process of the first resist film pattern 50, a resist film is first formed on the etching mask film 40 of the mask blank 10 of this embodiment shown in FIG. 1. The resist film material used is not particularly limited. The resist film may be one that is sensitive to laser light having a wavelength selected from, for example, a wavelength range of 350 nm to 436 nm, which will be described later. Additionally, the resist film may be either positive type or negative type.

Thereafter, a desired pattern is drawn on the resist film using laser light having a wavelength selected from the wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film is the pattern formed on the semi-transmissive film 30. Patterns drawn on the resist film include line and space patterns and hole patterns.

Thereafter, the resist film is developed with a predetermined developer to form a first resist film pattern 50 on the etching mask film 40, as shown in FIG. 3(a).

<<<Formation process of the first etching mask layer pattern 40a>>>

In the forming process of the first etching mask film pattern 40a, first, the etching mask film 40 is etched using the first resist film pattern 50 as a mask to form the first etching mask film pattern 40a. . The etching mask film 40 can be formed of a chromium-based material containing chromium (Cr). The etchant for etching the etching mask film 40 is not particularly limited as long as it can selectively etch the etching mask film 40. Specifically, an etching solution containing cerium ammonium nitrate and perchloric acid can be mentioned.

Thereafter, the first resist film pattern 50 is peeled off using a resist stripper or by ashing, as shown in FIG. 3(b). In some cases, the next step of forming the transflective layer pattern 30a may be performed without peeling the first resist layer pattern 50.

<<<Formation process of semi-transmissive layer pattern 30a>>>

In the forming process of the semi-transmissive film pattern 30a, the semi-transmissive film 30 is wet-etched using the first etching mask film pattern 40a as a mask, and as shown in FIG. 3(c), the semi-transmissive film 30 is etched. A film pattern 30a is formed. Examples of the semi-transmissive film pattern 30a include a line and space pattern and a hole pattern. The etching solution for etching the semi-permeable film 30 is not particularly limited as long as it can selectively etch the semi-permeable film 30. For example, an etching liquid containing ammonium bifluoride and hydrogen peroxide, an etching liquid containing ammonium fluoride, phosphoric acid, and hydrogen peroxide, etc.

In order to improve the cross-sectional shape of the semi-transmissive film pattern 30a, wet etching is performed for a time (just etching time) longer than the time until the translucent substrate 20 is exposed in the semi-transmissive film pattern 30a. It is preferable to carry out the over-etching time). Considering the influence on the translucent substrate 20, etc., the over-etching time is preferably within the just-etching time plus 20% of the just-etching time, and is 10% of the just-etching time. It is more desirable to do it within the time added.

<<<Formation process of second resist film pattern 60>>>

In the process of forming the second resist film pattern 60, first, a resist film covering the first etching mask film pattern 40a is formed. The resist film material used is not particularly limited. For example, it may be sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Additionally, the resist film may be either positive type or negative type.

Thereafter, a desired pattern is drawn on the resist film using laser light having a wavelength selected from the wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film includes a light-shielding pattern that blocks light from the outer peripheral area of the area where the semi-transmissive film pattern 30a is formed, and a light-shielding pattern that blocks light from the central part of the semi-transmissive film pattern 30a. Additionally, the pattern drawn on the resist film may be a pattern without a light-shielding band pattern that blocks light from the central portion of the semi-transmissive film pattern 30a, depending on the transmittance of the semi-transmissive film 30 with respect to the exposure light.

Thereafter, the resist film is developed with a predetermined developer to form a second resist film pattern 60 on the first etching mask film pattern 40a, as shown in FIG. 3(d).

<<<Formation process of second etching mask pattern 40b>>>

In the process of forming the second etching mask film pattern 40b, the first etching mask film pattern 40a is etched using the second resist film pattern 60 as a mask, as shown in FIG. 3(e). , to form a second etching mask pattern 40b. The first etching mask layer pattern 40a may be formed of a chromium-based material containing chromium (Cr). The etchant for etching the first etching mask film pattern 40a is not particularly limited as long as it can selectively etch the first etching mask film pattern 40a. For example, an etching solution containing ammonium cerium nitrate and perchloric acid can be mentioned.

Thereafter, the second resist film pattern 60 is peeled off using a resist stripper or by ashing.

In this way, the transfer mask 100 can be obtained. That is, in the transfer mask 100 according to the present embodiment, a transfer pattern (semitransmissive film pattern 30a) is formed on the semi-transmissive film 30, and a pattern different from the transfer pattern is formed on the etching mask film 40. (Second etching mask film pattern 40b) is formed.

In addition, in the above description, the case where the etching mask film 40 has a function of blocking the transmission of exposure light has been explained. In the case where the etching mask film 40 simply has a hard mask function when etching the transflective film 30, in the above description, the forming process of the second resist film pattern 60 and the second etching The process of forming the mask film pattern 40b is not performed. In this case, after the forming process of the semi-transmissive layer pattern 30a, the first etching mask layer pattern 40a is peeled off to produce the transfer mask 100. That is, the transfer pattern included in the transfer mask 100 may be composed of only the semi-transmissive film pattern 30a.

According to the manufacturing method of the transfer mask 100 of this embodiment, since the mask blank 10 shown in FIG. 1 is used, even when the transmittance with respect to the exposure light is increased, a plurality of wavelengths in the exposure light are used. It is possible to form a semi-transmissive film pattern 30a that can suppress the in-plane distribution of the transmittance and suppress the fluctuation of the transmittance due to the film thickness fluctuation. Accordingly, a transfer mask 100 capable of transferring a transfer pattern including the high-precision semi-transmissive film pattern 30a with high precision can be manufactured. The transfer mask 100 manufactured in this way can respond to miniaturization of line and space patterns and/or contact holes.

<<Method of manufacturing the transfer mask 100 shown in FIG. 4>>

The method of manufacturing the transfer mask 100 shown in FIG. 4 is a method of manufacturing the transfer mask 100 using the mask blank 10 shown in FIG. 2. The manufacturing method of the transfer mask 100 shown in FIG. 4 includes the steps of preparing the mask blank 10 shown in FIG. 2, forming a resist film on the semi-transmissive film 30, and forming the resist film. There is a process of wet etching the semi-transmissive film 30 using the resist film pattern as a mask to form a transfer pattern on the semi-transmissive film 30.

Specifically, in the manufacturing method of the transfer mask 100 shown in FIG. 4, a resist film is formed on the mask blank 10. Next, the resist film pattern 50 is formed by drawing and developing a desired pattern on the resist film (FIG. 4(a), forming process of the first resist film pattern 50). Next, the semi-transmissive film 30 is wet-etched using the resist film pattern 50 as a mask to form a semi-transmissive film pattern 30a on the translucent substrate 20 (FIG. 4(b) and (c), formation process of semi-transmissive film pattern 30a).

More specifically, in the resist film pattern formation process, a resist film is first formed on the semi-transmissive film 30 of the mask blank 10 of this embodiment shown in FIG. 2. The resist film material used is the same as that described above. Additionally, if necessary, before forming the resist film, the semi-transmissive film 30 may be subjected to surface modification treatment in order to improve the adhesion between the semi-transmissive film 30 and the resist film. As described above, after forming a resist film, a desired pattern is drawn on the resist film using laser light having a wavelength selected from the wavelength range of 350 nm to 436 nm. Thereafter, the resist film is developed with a predetermined developing solution to form a resist film pattern 50 on the semi-transmissive film 30, as shown in FIG. 4(a).

<<<Formation process of semi-transmissive layer pattern 30a>>>

In the forming process of the semi-transmissive film pattern 30a, the semi-transmissive film 30 is etched using the resist film pattern as a mask to form the semi-transmissive film pattern 30a, as shown in (b) of FIG. 4. do. The etchant and over-etching time for etching the semi-transmissive film pattern 30a and the semi-transmissive film 30 are the same as those described in the embodiment shown in FIG. 3 described above.

Thereafter, the resist film pattern 50 is peeled off using a resist stripper or by ashing (FIG. 4(c)).

In this way, the transfer mask 100 can be obtained. That is, in the transfer mask 100 according to the present embodiment, a transfer pattern (semitransmissive film pattern 30a) is formed on the semitransmissive film 30. In addition, the transfer pattern of the transfer mask 100 according to the present embodiment consists only of the semi-transmissive film pattern 30a, but may further include other film patterns. Other films include, for example, a film that suppresses reflection, a conductive film, etc.

According to the manufacturing method of the transfer mask 100 of this embodiment, since the mask blank 10 shown in FIG. 2 is used, even when the transmittance with respect to the exposure light is increased, a plurality of wavelengths in the exposure light are used. It is possible to form a semi-transmissive film pattern 30a that can suppress the in-plane distribution of the transmittance and suppress the fluctuation of the transmittance due to the film thickness fluctuation. Accordingly, a transfer mask 100 capable of transferring a transfer pattern including the high-precision semi-transmissive film pattern 30a with high precision can be manufactured. The transfer mask 100 manufactured in this way can respond to miniaturization of line and space patterns and/or contact holes.

<Method of manufacturing display device>

The manufacturing method of the display device of this embodiment will be described. The method of manufacturing a display device of the present embodiment includes loading the transfer mask 100 of the present embodiment described above on a mask stage of an exposure apparatus, and applying a transfer pattern formed on the transfer mask 100 for manufacturing a display device, It has an exposure process of exposure and transfer to a resist formed on a substrate for a display device.

Specifically, the manufacturing method of the display device of the present embodiment includes a step of loading the transfer mask 100 manufactured using the above-described mask blank 10 on the mask stage of an exposure apparatus (mask loading step), It includes a process (exposure process) of irradiating exposure light onto the transfer mask 100 and exposing and transferring the transfer pattern onto a photosensitive film (resist film) provided on a display device substrate. Hereinafter, each process will be described in detail.

<<Loading process>>

In the loading process, the transfer mask 100 of this embodiment is loaded on the mask stage of the exposure apparatus. Here, the transfer mask 100 is arranged to face the resist film formed on the display device substrate through the projection optical system of the exposure device.

<<Pattern transfer process>>

In the pattern transfer process, exposure light is irradiated to the transfer mask 100 to transfer the transfer pattern including the semi-transmissive layer pattern 30a to the resist film formed on the substrate for the display device. Exposure light is composite light containing light of a plurality of wavelengths selected from the wavelength range of 313 nm to 436 nm. For example, the exposure light is preferably a composite light containing at least one of light with a wavelength of 334 nm, i-line, h-line, and g-line, and more preferably, it is a composite light including light with a wavelength of 334 nm and h-line. do. By using composite light as the exposure light, the intensity of the exposure light can be increased and throughput can be improved. Therefore, the manufacturing cost of the display device can be lowered.

According to the display device manufacturing method of this embodiment, a high-precision display device with high resolution and fine line and space patterns and/or contact holes can be manufactured.

[Example]

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these.

(Example 1)

To manufacture the mask blank 10 of Example 1, first, a synthetic quartz glass substrate of size 1214 (1220 mm x 1400 mm) was prepared as the light-transmitting substrate 20.

Thereafter, the synthetic quartz glass substrate was placed on a tray (not shown) with its main surface facing downward and loaded into the chamber of the in-line sputtering device.

In order to form the semi-transmissive film 30 on the main surface of the transparent substrate 20, first, a mixed gas consisting of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced into the first chamber. Then, using a first sputter target containing titanium and silicon (titanium:silicon=14:86), titanium silicide containing titanium, silicon, and nitrogen is deposited on the main surface of the translucent substrate 20 by reactive sputtering. nitrides were deposited. The film thickness of the semi-transmissive film 30 was set to 50 nm so that the transmittance of the semi-transmissive film 30 to the i line (365 nm) was 58%. In this way, a semi-transmissive film 30 with a film thickness of 50 nm made of titanium silicide nitride was formed.

Next, the translucent substrate 20 provided with the semi-transmissive film 30 was brought into the second chamber, and a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced into the second chamber. Then, chromium nitride (CrN) containing chromium and nitrogen was formed on the semi-permeable film 30 by reactive sputtering using a second sputter target made of chromium. Next, with the inside of the third chamber at a predetermined vacuum level, a mixed gas of argon (Ar) gas and methane (CH ₄ ) gas is introduced, and a third sputter target made of chromium is used to perform reactive sputtering. Chromium carbide (CrC) containing chromium and carbon was formed on CrN. Finally, with the fourth chamber at a predetermined vacuum level, a mixed gas of argon (Ar) gas and methane (CH ₄ ) gas and a mixed gas of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas are introduced. And, using the fourth sputter target made of chromium, chromium carboxynitride (CrCON) containing chromium, carbon, oxygen, and nitrogen was formed on CrC by reactive sputtering. As described above, an etching mask film 40 having a stacked structure of a CrN layer, a CrC layer, and a CrCON layer was formed on the semi-transmissive film 30.

In this way, the mask blank 10 in which the semi-transmissive film 30 and the etching mask film 40 were formed on the translucent substrate 20 was obtained.

Another semi-transmissive film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film formation conditions as in Example 1 above. For this semi-transmissive film, the refractive index n and extinction coefficient k for light with a wavelength of 334 nm, i-line (365 nm) and h-line (405 nm) were measured. The refractive index n of light with a wavelength of 334 nm was 2.18, and the extinction coefficient k was 0.21. The refractive index n at the i line (365 nm) was 2.19, and the extinction coefficient k was 0.17. Additionally, the refractive index n at the h line (405 nm) was 2.20, and the extinction coefficient k was 0.12.

Figure 10 shows the relationship between the refractive index n and extinction coefficient k, which can suppress the in-plane distribution of the transmittance and the fluctuation of the transmittance due to the film thickness fluctuation, derived from simulation results, and the relationship between the in-plane distribution of the transmittance and the extinction coefficient k in Examples 1 and 2 and Comparative Examples 1 and 2. , a diagram showing the refractive index n and extinction coefficient k. As shown in FIG. 10, the semitransmissive film 30 of Example 1 has a refractive index n and extinction coefficient k in light with a wavelength of 334 nm, a refractive index n and extinction coefficient k in the i-line (365 nm), and , both the refractive index n and extinction coefficient k at the h line (405 nm) were within the range specified in (Equation 1) and (Equation 2) mentioned above.

Next, based on the refractive index n and extinction coefficient k of the semi-transmissive film 30 of Example 1, the transmittance of the semi-transmissive film 30 to the i line (365 nm) is set to 58%. In contrast, a simulation of the transmittance, phase difference, and reflectance of the semi-transmissive film 30 when the film thickness of the semi-transmissive film 30 was changed was performed.

Fig. 6 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Example 1, derived from simulation results. As shown in FIG. 6, the semi-transmissive film 30 of Example 1 has a thickness of 39 nm to 39 nm, with respect to the set film thickness at which the transmittance of the semi-transmissive film 30 to the i line (365 nm) is 58%. Over the range of 60 nm (the range of Δd in Figure 6), the film thickness dependence of the transmittance for light with a wavelength of 334 nm, the film thickness dependence of the transmittance for the i line (365 nm), and the film thickness dependence for the h line (405 nm). It was found that the film thickness dependence of the transmittance was all within the acceptable range (within 2% change in transmittance at a change in film thickness of 5 nm).

<Measurement of transmittance and phase difference>

With respect to the surface of the semi-transmissive film 30 of the mask blank 10 of Example 1, the transmittance and phase difference at the i line (365 nm) were measured using MPM-100 manufactured by Lasertec. To measure the transmittance and phase difference of the semi-transmissive film 30, a thin film-equipped substrate in which another semi-transmissive film was deposited on the main surface of the above-described synthetic quartz glass substrate was used (hereafter, Example 2 and Comparative Examples 1 and 2) The same applies to ). As a result, the transmittance of the semi-transmissive film 30 at the i line (365 nm) in Example 1 was 58%, and the phase difference was 55 degrees.

In addition, at 11 x 11 measurement points in the reference plane, the transmittance was measured for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm), and the transmittance fluctuation was within 1% for all. , were all within the acceptable range.

In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (acoustic ammonia (APM), 30°C, 5 minutes) six times to determine the change in transmittance due to variation in the film thickness of the semi-permeable membrane 30. was evaluated. As a result, before the alkaline cleaning treatment, the fluctuations in transmittance for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm) were all within 1% and within the acceptable range. Additionally, this evaluation was performed on the semitransmissive film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film formation conditions. From the above results, the semi-transmissive film 30 of Example 1 is capable of suppressing the in-plane distribution of the transmittance for multiple wavelengths in the exposure light, and has a very small change in the transmittance due to the film thickness fluctuation. It can be called a permeable membrane 30.

<Transfer mask 100 and manufacturing method thereof>

A transfer mask 100 was manufactured using the mask blank 10 of Example 1 manufactured as described above. First, a photoresist film was applied onto the etching mask film 40 of the mask blank 10 using a resist coating device.

Afterwards, a heating/cooling process was performed to form a photoresist film.

After that, the photoresist film was drawn using a laser drawing device, and through a development/rinsing process, a resist film pattern with a hole pattern having a hole diameter of 1.5 μm was formed on the etching mask film 40.

Thereafter, using the resist film pattern as a mask, the etching mask film 40 was wet etched with a chromium etching solution containing cerium ammonium nitrate and perchloric acid to form the first etching mask film pattern 40a.

Thereafter, using the first etching mask film pattern 40a as a mask, the semi-transmissive film 30 is wet-etched with a titanium silicide etching solution obtained by diluting a mixture of ammonium bifluoride and hydrogen peroxide with pure water, thereby forming a semi-transmissive film pattern ( 30a) was formed.

After that, the resist film pattern was peeled off.

After that, a photoresist film was applied using a resist coating device to cover the first etching mask film pattern 40a.

Afterwards, a heating/cooling process was performed to form a photoresist film.

Thereafter, the photoresist film is drawn using a laser drawing device, and through a development/rinsing process, a second resist film pattern 60 for forming a light-shielding zone is formed on the first etching mask film pattern 40a. did.

Thereafter, using the second resist film pattern 60 as a mask, the first etching mask film pattern 40a formed in the transfer pattern formation area is wet-etched using a chromium etching solution containing cerium ammonium nitrate and perchloric acid. did.

Afterwards, the second resist film pattern 60 was peeled off.

In this way, on the translucent substrate 20, the semi-transmissive film pattern 30a with a hole diameter of 1.5 μm, the semi-transmissive film pattern 30a, and the etching mask film pattern 40b are stacked in the transfer pattern formation area. The transfer mask 100 of Example 1, in which a light-shielding band consisting of a structure was formed, was obtained.

The transfer mask 100 of Example 1 obtained as described above can suppress the in-plane distribution of the transmittance for a plurality of wavelengths in the exposure light even when the transmittance for the exposure light is increased. Since it is manufactured using the mask blank 10 having a semi-transmissive film 30 that can suppress the change in transmittance due to the change in film thickness, the transmittance adjustment effect can be improved by increasing the transmittance for the exposure light. The transfer mask 100 has a semi-transmissive film pattern 30a that can suppress the in-plane distribution of the transmittance for a plurality of wavelengths and can suppress the fluctuation of the transmittance due to the film thickness fluctuation. .

From the above, when the transfer mask 100 of Example 1 is set on the mask stage of an exposure apparatus and exposed and transferred to a resist film on a substrate for a display device, a transfer pattern containing a fine pattern of less than 2.0 μm is obtained. It can be said that it is possible to transcribe with high precision.

(Example 2)

The mask blank 10 of Example 2 was manufactured in the same manner as the mask blank 10 of Example 1, except that the semi-transmissive film 30 was formed as follows.

The method of forming the semi-permeable membrane 30 of Example 2 is as follows.

In order to form the semi-transmissive film 30 on the main surface of the transparent substrate 20, first, a mixed gas consisting of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced into the first chamber. Then, using a first sputter target containing titanium and silicon (titanium:silicon=19:81), titanium silicide containing titanium, silicon, and nitrogen is deposited on the main surface of the translucent substrate 20 by reactive sputtering. nitrides were deposited. The film thickness of the semi-transmissive film 30 was set to 50 nm so that the transmittance of the semi-transmissive film 30 to the i line (365 nm) was 44%. In this way, a semi-transmissive film 30 with a film thickness of 50 nm made of titanium silicide nitride was formed.

After that, as in Example 1, an etching mask film 40 was formed.

Another semi-transmissive film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film formation conditions as in Example 2 above. For this semi-transmissive film, the refractive index n and extinction coefficient k for light with a wavelength of 334 nm, i-line (365 nm) and h-line (405 nm) were measured. The refractive index n of light with a wavelength of 334 nm was 2.39, and the extinction coefficient k was 0.36. The refractive index n at the i line (365 nm) was 2.42, and the extinction coefficient k was 0.31. Additionally, the refractive index n at the h line (405 nm) was 2.44, and the extinction coefficient k was 0.22.

As shown in FIG. 10, the semitransmissive film 30 of Example 2 has a refractive index n and extinction coefficient k in light with a wavelength of 334 nm, a refractive index n and extinction coefficient k in the i-line (365 nm), and , both the refractive index n and extinction coefficient k at the h line (405 nm) were within the range specified in (Equation 1) and (Equation 2) mentioned above.

Next, based on the refractive index n and extinction coefficient k of the semi-transmissive film 30 of Example 2, the transmittance of the semi-transmissive film 30 to the i line (365 nm) is set to 44%. In contrast, a simulation of the transmittance, phase difference, and reflectance of the semi-transmissive film 30 when the film thickness of the semi-transmissive film 30 was changed was performed.

Fig. 7 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Example 2, derived from simulation results. As shown in FIG. 7, the semi-transmissive film 30 of Example 2 has a thickness of 38 nm to 38 nm, with respect to the set film thickness at which the transmittance of the semi-transmissive film 30 to the i line (365 nm) is 44%. Over the range of 62 nm (range of Δd in Fig. 7), the film thickness dependence of the transmittance for light with a wavelength of 334 nm, the film thickness dependence of the transmittance for the i line (365 nm), and the film thickness dependence for the h line (405 nm). It was found that the film thickness dependence of the transmittance was all within the acceptable range (within 2% change in transmittance at a change in film thickness of 5 nm).

<Measurement of transmittance and phase difference>

With respect to the surface of the semi-transmissive film 30 of the mask blank 10 of Example 2, the transmittance and phase difference at the i line (365 nm) were measured using MPM-100 manufactured by Lasertec. As a result, the transmittance of the semi-transmissive film 30 at the i line (365 nm) in Example 2 was 44%, and the phase difference was 64 degrees.

In addition, at 11 x 11 measurement points in the reference plane, the transmittance was measured for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm), and the transmittance fluctuation was within 1% for all. , were all within the acceptable range.

In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (acoustic ammonia (APM), 30°C, 5 minutes) six times to determine the change in transmittance due to variation in the film thickness of the semi-permeable membrane 30. was evaluated. As a result, before the alkaline cleaning treatment, the fluctuations in transmittance for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm) were all within 1% and within the acceptable range. Additionally, this evaluation was performed on the semitransmissive film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film formation conditions. From the above results, the semi-transmissive film 30 of Example 2 is capable of suppressing the in-plane distribution of the transmittance for multiple wavelengths in the exposure light, and has a very small change in the transmittance due to the film thickness fluctuation. It can be called a permeable membrane 30.

<Transfer mask 100 and manufacturing method thereof>

Using the mask blank 10 of Example 2 manufactured as described above, a transfer mask 100 was manufactured in the same procedure as Example 1, and a transfer pattern was formed on the translucent substrate 20. The transfer mask 100 of Example 2 is formed in an area with a semi-transmissive film pattern 30a having a hole diameter of 1.5 ㎛, and a light-shielding zone made of a stacked structure of the semi-transmissive film pattern 30a and the etching mask pattern 40b. got it

The transfer mask 100 of Example 2 obtained as described above can increase the transmittance adjustment effect by increasing the transmittance to the exposure light, and suppress the in-plane distribution of the transmittance for a plurality of wavelengths in the exposure light. In addition, since it was manufactured using a mask blank 10 having a semi-transmissive film 30 that can suppress fluctuations in transmittance due to film thickness fluctuations, the transmittance to the exposure light can be increased to increase the transmittance adjustment effect. A transfer mask ( 100).

From the above, when the transfer mask 100 of Example 2 is set on the mask stage of an exposure apparatus and exposed and transferred to a resist film on a substrate for a display device, a transfer pattern containing a fine pattern of less than 2.0 μm is obtained. It can be said that it is possible to transcribe with high precision.

(Comparative Example 1)

The mask blank 10 of Comparative Example 1 was manufactured in the same manner as the mask blank 10 of Example 1, except that the semi-transmissive film 30 was formed as follows.

The method of forming the semi-permeable membrane 30 of Comparative Example 1 is as follows.

In order to form the semi-transmissive film 30 on the main surface of the transparent substrate 20, first, a mixed gas consisting of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced into the first chamber. Then, using a first sputter target containing molybdenum and silicon (molybdenum:silicon = 20:80), molybdenum silicide containing molybdenum, silicon, and nitrogen is deposited on the main surface of the translucent substrate 20 by reactive sputtering. nitrides were deposited. The film thickness of the semi-transmissive film 30 was set to 5 nm so that the transmittance of the semi-transmissive film 30 to the i-line (365 nm) was 46%. In this way, a semi-transmissive film 30 with a film thickness of 5 nm made of molybdenum silicide nitride was formed.

After that, as in Example 1, an etching mask film 40 was formed.

Another semi-transmissive film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film formation conditions as in Comparative Example 1 above. For this semi-transmissive film, the refractive index n and extinction coefficient k for light with a wavelength of 334 nm, i-line (365 nm) and h-line (405 nm) were measured. The refractive index n of light with a wavelength of 334 nm was 3.40, and the extinction coefficient k was 1.90. The refractive index n at the i line (365 nm) was 3.50, and the extinction coefficient k was 1.81. Additionally, the refractive index n at the h line (405 nm) was 3.60, and the extinction coefficient k was 1.61.

The semitransmissive film 30 of Comparative Example 1 has a refractive index n and extinction coefficient k in light with a wavelength of 334 nm, a refractive index n and extinction coefficient k in the i line (365 nm), and a refractive index n and extinction coefficient k in the h line (405 nm). Both the refractive index n and the extinction coefficient k were outside the range specified in the above-mentioned (Equation 1) and (Equation 2) shown in FIG. 10 (shown because they are outside the range of the refractive index n and extinction coefficient k in FIG. 10 do not).

Next, based on the refractive index n and extinction coefficient k of the semi-transmissive film 30 of Comparative Example 1, the transmittance of the semi-transmissive film 30 to the i line (365 nm) is set to 46%. In contrast, a simulation of the transmittance, phase difference, and reflectance of the semi-transmissive film 30 when the film thickness of the semi-transmissive film 30 was changed was performed.

FIG. 8 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Comparative Example 1, derived from simulation results. As shown in FIG. 8, the semi-transmissive film 30 of Comparative Example 1 has a transmittance of 5 nm to 5 nm with respect to the set film thickness at which the transmittance of the semi-transmissive film 30 to the i line (365 nm) is 46%. Transmittance variation can be allowed only in the range of 6 nm (the range of Δd in Figure 8), so the film thickness dependence of the transmittance for the i line (365 nm) is within the allowable range (transmittance variation within 2% at a film thickness change of 5 nm). It was found that this did not work. In addition, it was found that the film thickness dependence of the transmittance for light with a wavelength of 334 nm and h-line (405 nm) was not within the acceptable range (transmittance change within 2% at a film thickness change of 5 nm).

<Measurement of transmittance and phase difference>

With respect to the surface of the semi-transmissive film 30 of the mask blank 10 of Comparative Example 1, the transmittance and phase difference at the i line (365 nm) were measured using MPM-100 manufactured by Lasertec. As a result, in Comparative Example 1, the transmittance of the semi-transmissive film 30 at the i line (365 nm) was 46%, and the phase difference was 12 degrees.

In addition, at 11 x 11 measurement points in the reference plane, the transmittance was measured for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm), and the transmittance variation was 1% for any of them. It was greatly exceeded and was all outside the allowable range.

In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (acoustic ammonia (APM), 30°C, 5 minutes) six times to determine the change in transmittance due to variation in the film thickness of the semi-permeable membrane 30. was evaluated. As a result, before the alkaline cleaning treatment, the fluctuations in transmittance for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm) all greatly exceeded 1% and were outside the allowable range. Additionally, this evaluation was performed on the semitransmissive film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film formation conditions. From the above results, the semi-transmissive film 30 of Comparative Example 1 cannot suppress the in-plane distribution of the transmittance for multiple wavelengths in the exposure light, and is a semi-transmissive film ( 30).

<Transfer mask 100 and manufacturing method thereof>

Using the mask blank 10 of Comparative Example 1 manufactured as described above, a transfer mask 100 was manufactured in the same procedure as Example 1, and a transfer pattern was formed on the translucent substrate 20. Transfer mask 100 of Comparative Example 1 having a semi-transmissive film pattern 30a with a hole diameter of 1.5 ㎛ in the area, and a light-shielding zone made of a stacked structure of the semi-transmissive film pattern 30a and the etching mask pattern 40b. got it

The transfer mask 100 of Comparative Example 1 obtained as described above uses a mask blank 10 that has poor transmittance uniformity within the substrate surface and has a large change in transmittance due to changes in the film thickness of the semi-transmissive film 30. Therefore, when the transfer mask 100 is repeatedly cleaned and the film thickness of the semi-transmissive film pattern 30a decreases, the change in transmittance of the semi-transmissive film pattern 30a is large, causing the display device to be damaged. In the case of manufacturing, a CD error in pattern transfer due to the transfer mask 100 occurs.

(Comparative Example 2)

The mask blank 10 of Comparative Example 2 was manufactured in the same manner as the mask blank 10 of Example 1, except that the semi-transmissive film 30 was formed as follows.

The method of forming the semi-permeable membrane 30 of Comparative Example 2 is as follows.

In order to form the semi-transmissive film 30 on the main surface of the transparent substrate 20, first, a mixed gas consisting of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced into the first chamber. Then, using a first sputter target containing chromium and silicon (chromium:silicon=80:20), chromium silicide containing chromium, silicon, and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering. nitrides were deposited. The film thickness of the semi-transmissive film 30 was set to 5 nm so that the transmittance of the semi-transmissive film 30 to the i-line (365 nm) was 46%. In this way, a semi-transmissive film 30 with a film thickness of 5 nm made of molybdenum silicide nitride was formed.

After that, as in Example 1, an etching mask film 40 was formed.

Another semi-transmissive film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film formation conditions as in Comparative Example 2 above. For this semi-transmissive film, the refractive index n and extinction coefficient k were measured for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm). The refractive index n of light with a wavelength of 334 nm was 2.41, and the extinction coefficient k was 2.65. The refractive index n at the i line (365 nm) was 2.45, and the extinction coefficient k was 2.81. Additionally, the refractive index n at the h line (405 nm) was 2.55, and the extinction coefficient k was 3.00.

The semitransmissive film 30 of Comparative Example 2 had a refractive index n and extinction coefficient k in light with a wavelength of 334 nm, a refractive index n and extinction coefficient k in the i line (365 nm), and a refractive index n and extinction coefficient k in the h line (405 nm). Both the refractive index n and the extinction coefficient k were outside the range specified in the above-mentioned (Equation 1) and (Equation 2) shown in FIG. 10 (shown because they are outside the range of the refractive index n and extinction coefficient k in FIG. 10 do not).

Next, based on the refractive index n and extinction coefficient k of the semi-transmissive film 30 of Comparative Example 2, the transmittance of the semi-transmissive film 30 to the i line (365 nm) is set to 46%. In contrast, a simulation of the transmittance, phase difference, and reflectance of the semi-transmissive film 30 when the film thickness of the semi-transmissive film 30 was changed was performed.

Fig. 9 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transmissive film in Comparative Example 2, derived from simulation results. As shown in FIG. 9, the semi-transmissive film 30 of Comparative Example 2 has a transmittance of 4 nm to 4 nm with respect to the set film thickness at which the transmittance of the semi-transmissive film 30 to the i-line (365 nm) is 46%. Transmittance variation can be allowed only in the range of 5 nm (the range of Δd in Figure 9), so the film thickness dependence of the transmittance for the i line (365 nm) is within the allowable range (transmittance variation within 2% at a film thickness change of 5 nm). It was found that this did not work. In addition, it was found that the film thickness dependence of the transmittance for light with a wavelength of 334 nm and h-line (405 nm) was not within the acceptable range (transmittance change within 2% at a film thickness change of 5 nm).

<Measurement of transmittance and phase difference>

With respect to the surface of the semi-transmissive film 30 of the mask blank 10 of Comparative Example 2, the transmittance and phase difference at the i line (365 nm) were measured using MPM-100 manufactured by Lasertec. As a result, in Comparative Example 2, the transmittance of the semi-transmissive film 30 at the i-line (365 nm) was 46%, and the phase difference was 3 degrees.

In addition, at 11 x 11 measurement points in the reference plane, the transmittance was measured for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm), and the transmittance variation was 1% for any of them. It was greatly exceeded and was all outside the allowable range.

In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (acoustic ammonia (APM), 30°C, 5 minutes) six times to determine the change in transmittance due to variation in the film thickness of the semi-permeable membrane 30. was evaluated. As a result, before the alkaline cleaning treatment, the fluctuations in transmittance for light with a wavelength of 334 nm, i-line (365 nm), and h-line (405 nm) all greatly exceeded 1% and were outside the allowable range. Additionally, this evaluation was performed on the semitransmissive film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film formation conditions. From the above results, the semi-transmissive film 30 of Comparative Example 2 cannot suppress the in-plane distribution of the transmittance for multiple wavelengths in the exposure light, and is a semi-transmissive film ( 30).

<Transfer mask 100 and manufacturing method thereof>

Using the mask blank 10 of Comparative Example 2 manufactured as described above, a transfer mask 100 was manufactured in the same procedure as Example 1, and a transfer pattern was formed on the translucent substrate 20. Transfer mask 100 of Comparative Example 2 having a semi-transmissive film pattern 30a with a hole diameter of 1.5 ㎛ in the area, and a light-shielding zone composed of a stacked structure of the semi-transmissive film pattern 30a and the etching mask pattern 40b. got it

The transfer mask 100 of Comparative Example 2 obtained as described above uses a mask blank 10 that has poor transmittance uniformity within the substrate surface and has a large change in transmittance due to changes in the film thickness of the semi-transmissive film 30. Therefore, when the transfer mask 100 is repeatedly cleaned and the film thickness of the semi-transmissive film pattern 30a decreases, the change in transmittance of the semi-transmissive film pattern 30a is large, causing the display device to be damaged. In the case of manufacturing, a CD error in pattern transfer due to the transfer mask 100 occurs.

In the above-described embodiment, examples of the transfer mask 100 for manufacturing a display device and the mask blank 10 for manufacturing the transfer mask 100 for manufacturing a display device have been described, but the present invention is not limited to this. The mask blank 10 and/or the transfer mask 100 of the present invention can also be applied to semiconductor device manufacturing, MEMS manufacturing, and printed circuit board manufacturing.

In addition, in the above-described embodiment, an example in which the size of the translucent substrate 20 is 1214 size (1220 mm x 1400 mm x 13 mm) has been described, but it is not limited to this. In the case of the mask blank 10 for display device manufacturing, a large size translucent substrate 20 is used, and the size of the translucent substrate 20 is such that the length of one side of the main surface is 300 mm or more. The size of the translucent substrate 20 used for the mask blank 10 for manufacturing a display device is, for example, 330 mm x 450 mm or more and 2280 mm x 3130 mm or less.

In addition, in the case of the mask blank 10 for semiconductor device manufacturing, MEMS manufacturing, and printed circuit board manufacturing, a small size translucent substrate 20 is used, and the size of the translucent substrate 20 is such that the length of one side is 9. less than an inch The size of the translucent substrate 20 used for the mask blank 10 for the above purpose is, for example, 63.1 mm x 63.1 mm or more and 228.6 mm x 228.6 mm or less. Usually, as the translucent substrate 20 for the transfer mask 100 for semiconductor device manufacturing and MEMS manufacturing, size 6025 (152 mm × 152 mm) or size 5009 (126.6 mm × 126.6 mm) is used. Additionally, usually, as the translucent substrate 20 for the transfer mask 100 for manufacturing a printed circuit board, size 7012 (177.4 mm x 177.4 mm) or size 9012 (228.6 mm x 228.6 mm) is used.

10: Mask blank
20: Translucent substrate
30: semi-permeable membrane
30a: Semipermeable membrane pattern (transfer pattern)
40: Etching mask film
40a: First etching mask pattern (transfer pattern)
40b: second etching mask pattern
50: first resist film pattern
60: Second resist film pattern
100: Transfer mask

Claims (16)

A mask blank comprising a translucent substrate and a semi-transmissive film provided on the main surface of the translucent substrate,
The refractive index n and extinction coefficient k for light with a wavelength of 334 nm in the semi-transmissive film,
A mask blank characterized in that the refractive index n and extinction coefficient k for light with a wavelength of 405 nm both satisfy the relationships of (Equation 1) and (Equation 2).
(Equation 1) k≥0.282×n-0.514
(Equation 2) k≤0.500×n+0.800 According to paragraph 1,
A mask blank, wherein the extinction coefficient k of the semi-transmissive film for light with a wavelength of 334 nm is greater than 0. According to paragraph 1,
A mask blank, characterized in that the refractive index n of the semi-transmissive film for light with a wavelength of 334 nm is 2.0 or more. According to paragraph 1,
A mask blank, characterized in that the thickness of the semi-transmissive film is 30 nm or more and 70 nm or less. According to paragraph 1,
A mask blank, wherein the semi-transmissive film has a transmittance of 20% or more and 60% or less to light with a wavelength of 334 nm. According to paragraph 1,
A mask blank, characterized in that the phase difference of the semi-transmissive film with respect to light with a wavelength of 334 nm is 0 degrees or more and 120 degrees or less. According to paragraph 1,
A mask blank, wherein the refractive index n and extinction coefficient k of the semi-transmissive film for light with a wavelength of 365 nm also satisfy the relationships of (Equation 1) and (2). According to paragraph 1,
A mask blank characterized in that the semi-permeable film contains metal, silicon, and nitrogen. According to paragraph 1,
A mask blank comprising an etching mask film having different etching selectivity with respect to the semi-transmissive film on the semi-transmissive film. According to clause 9,
A mask blank characterized in that the etching mask film contains chromium. A transfer mask, wherein a transfer pattern is formed on the semi-transmissive film of the mask blank according to claim 1. A transfer mask, wherein a transfer pattern is formed on the semi-transmissive film of the mask blank according to claim 9, and a pattern different from the transfer pattern is formed on the etching mask film. A process of preparing the mask blank according to claim 1,
forming a resist film having a transfer pattern on the semi-transmissive film;
A process of performing wet etching using the resist film as a mask to form a transfer pattern on the semi-transmissive film.
A method of manufacturing a transfer mask characterized by having a. A process of preparing the mask blank described in paragraph 9,
A process of forming a resist film having a transfer pattern on the etching mask film;
A step of performing wet etching using the resist film as a mask to form a transfer pattern on the etching mask film;
A process of forming a transfer pattern on the semi-transmissive film by performing wet etching using the etching mask film on which the transfer pattern is formed as a mask.
A method of manufacturing a transfer mask characterized by having a. A step of loading the transfer mask according to claim 11 or 12 on a mask stage of an exposure apparatus;
A process of irradiating exposure light to the transfer mask and transferring the transfer pattern to a photosensitive film provided on a substrate for a display device.
A method of manufacturing a display device comprising: According to clause 15,
A method of manufacturing a display device, wherein the exposure light is a composite light containing light with a wavelength of 334 nm and light with a wavelength of 405 nm.

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