JP2006053342A - Phase shift mask manufacturing method and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a phase shift mask including a chromeless transmission type phase shifter or an edge enhancement type phase shifter engraved with a quartz substrate with high controllability, high accuracy and high quality.
A quartz substrate 1 is etched using a light shielding pattern made of a chromium pattern 32 as a mask, and then a second resist film 22 is deposited using a positive resist, and the coverage with respect to the entire mask area is 70%. A second resist pattern 221 and a dummy pattern 222 that do not exceed the second resist pattern 221 are formed, and the light shielding film pattern 31 is selectively dry-etched using the second resist pattern 221 as a mask. The dummy pattern 222 is configured to be peeled off.
[Selection] Figure 1

Description

  The present invention relates to a method for manufacturing a phase shift mask, and more particularly to a method for manufacturing a reticle mask to which the function of a phase shift mask is applied.

  In recent years, with high integration of semiconductor devices and large chips, masks, particularly reticle masks, require fine and high-precision processing. Correspondingly, there is a phase shift mask as one of the means exceeding the limits of ordinary lithography.

  Various systems have been proposed for the configuration and manufacturing method of the phase shift mask. For example, the edge emphasis method has a configuration in which a phase shifter is arranged around the light shielding film pattern. Here, the phase shifter is a transparent film whose phase is inverted when exposed light is transmitted, and can improve the pattern contrast (see, for example, Patent Document 1).

  The halftone method is a method in which an edge-enhancing function is provided by providing the light-shielding film itself with translucency and also having a function of inverting the phase. The configuration is simpler than the edge enhancement method, and it has become practical.

  The Levenson method is a method in which phase shifters are alternately arranged in the light-transmitting portions of the repetitive pattern, and the separation resolution is improved by the interference between transmitted light between the phase-shifter arranging portion and the non-placed portion. The mainstream of the current phase shift mask method is the halftone method and the Levenson method.

  By the way, a method called shifter light shielding or shifter edge light shielding is generally called a chromeless method or a transmission type phase shift mask. This method is a method in which a pattern is formed only on a phase shifter on a transparent substrate, and a pattern is formed on a wafer only by the phase inversion effect of the phase shifter. In particular, it is used when a fine line width such as a logic gate is required (see, for example, Patent Document 2).

  Device patterns constituting semiconductor devices are becoming more and more complex, and there is a demand for a mask in which an edge enhancement method and a chromeless method are mixedly mounted.

  FIG. 7 shows a conventional chromeless mask manufacturing method (part 1), and FIG. 8 shows a conventional chromeless mask manufacturing method (part 2). FIG. 7A shows a mask blank. That is, the light shielding film 3 made of a metal film or a metal oxide film is formed on the quartz substrate 1 having high dimensional stability. Here, a metal chromium film is most commonly used for the light shielding film 3, and therefore, the light shielding film 3 is expressed as a chromium pattern 32. The first resist film 21 is formed on the chromium pattern 32.

  Next, in FIG. 7B, a pattern is drawn on the first resist film 21 with an electron beam or laser light, and development is performed to obtain a first resist pattern 211.

  Next, in FIG. 7C, using the first resist pattern 211 as a mask, the chromium pattern 32 is etched by a dry etching method or a wet etching method to obtain a first chromium pattern 321. In recent years, in order to create a pattern with high accuracy, drawing with an electron beam and etching by a dry etching method have become mainstream.

  Next, in FIG. 7D, the quartz substrate 1 is etched by a dry etching method using the first chromium pattern 321 and the first resist pattern 211 as a mask. The degree of this etching is the depth at which the phase of the wavelength of light when performing wafer exposure is reversed. Thus, the quartz step pattern 10 is formed on the quartz substrate 1. The quartz step pattern 10 is also called a phase shifter.

  Next, in FIG. 7E, the first resist pattern 211 is removed.

  Next, in FIG. 8F, a third resist film 23 is formed.

  Next, in FIG. 8G, when the third resist film 23 is drawn with an electron beam in the next step, the conductive film 4 is formed to prevent charge-up. The conductive film 4 is not necessary when drawing is performed using a laser beam.

  Next, in FIG. 8H, overlay drawing of the third resist film 23 is performed with an electron beam. This drawing is performed so that the third resist film 23 remains except for the device pattern portion to be chromeless, and the third resist pattern 231 is formed by removing and developing the conductive film 4.

  Next, in FIG. 8I, the first chromium pattern 321 is etched by a wet etching method using the third resist pattern 231 as a mask to obtain a second chromium pattern 322.

  Finally, in FIG. 8J, the third resist pattern 231 is removed, and a chromeless transmission type phase shift mask 102 is obtained.

By the way, in recent years, due to the demand from devices, there has been a demand to mount a chromeless type and an edge-enhanced type phase shift pattern in one mask in addition to a normal light shielding film pattern.
JP-A-8-297358 Japanese Patent No. 3301557

  FIG. 9 shows a conventional method for forming an edge-enhanced phase shift pattern. FIG. 9A is an enlarged view of a part of the first chrome pattern 321 of FIG. 8H in the conventional chromeless mask manufacturing method (part 2) of FIG. 1, a quartz step pattern 10 is formed, and a first chromium pattern 321 is formed thereon.

  In FIG. 9B, the conductive film 4 is formed after the second resist film 22 using a positive resist is formed by the same process as in FIGS. 8F and 8G.

  Next, in FIG. 9C, overlay drawing of the second resist film 22 and removal of the conductive film 4 are performed with an electron beam, and development is further performed to obtain a second resist pattern 221. The second resist pattern 221 is a pattern having a narrower pattern width than the first chrome pattern 321 on the first chrome pattern 321 in order to obtain an edge-enhanced phase shift mask structure.

  Next, in FIG. 9D, using the second resist pattern 221 as a mask, a part of the first chrome pattern 321 is removed by wet etching to obtain the second chrome pattern 322 and at the same time, an edge-enhanced phase shift. A mask 101 is obtained.

  However, since this forming method uses wet etching, the etching bias of the second chromium pattern 322 is larger than that of the second resist pattern 221. Therefore, the dimensional controllability of the second chrome pattern 322 is not good.

  FIG. 10 shows another conventional method for forming an edge-enhanced phase shift pattern, in which dry etching is used to increase the dimensional accuracy of the second chromium pattern 322.

  FIG. 10A is a view similar to FIG. 9C. The first chrome pattern is formed by performing overlay drawing of the second resist film 22 and removal of the conductive film 4 with an electron beam, and further developing. A second resist pattern 221 is obtained on 321.

  Next, in FIG. 10B, the second chromium pattern 322 can be accurately formed by etching the first chromium pattern 321 by dry etching using the second resist pattern 221 as a mask.

  Next, FIG. 10C is obtained by removing the second resist pattern 221, and an edge-enhanced phase shift mask 101 using the quartz step pattern 10 formed by steps of the quartz substrate 1 as a phase shifter is obtained. The quartz step pattern 10 is originally a pattern itself formed in the step of FIG.

  However, the quartz substrate 1 is damaged by dry etching. For this reason, the quartz step pattern 10 of the quartz substrate 1 serving as the phase shifter shown in FIG. 10B is damaged. Then, there arises a problem that the depth of the step formed with accuracy is changed so that the phase is inverted at the wafer exposure wavelength formed in the step of FIG.

  In other words, in a phase shift mask in which an edge-enhanced phase shift mask and a chromeless transmission type phase shift mask are mixedly mounted, a fatal problem that is incompatible in the manufacturing process occurs in which the phase difference fluctuates.

  FIG. 11 is an explanatory diagram of the fluctuation of the phase difference and shows how much the fluctuation of the phase difference actually occurs.

  In FIG. 11A, the step size L1 indicates the original quartz step formed on the quartz substrate 1 in the step of FIG. 7D. When the quartz step is formed by wet etching, no damage occurs as shown in FIG. 11B. Therefore, this step size: L1 becomes the phase shift amount of the phase shifter as it is.

  Next, the step size L2 indicates the shift amount of the edge-enhanced phase shifter after being damaged by dry etching.

  Next, the step dimension L3 was caused by damage that was caused when the etched quartz substrate 1 shown in FIG. 10 was subjected to dry etching on the portion masked with the second resist pattern 221 and the exposed portion. It is a step.

  Next, the step dimension L4 is overetched after the portion exposed by using the second resist pattern 221 of the first chrome pattern 321 shown in FIG. 10A as a mask is removed without excess or deficiency by dry etching. It is a level difference caused by being damaged. Here, over-etching is a process necessary for forming the first chrome pattern 321 with high accuracy and cannot be omitted.

  Note that the ratio of the total pattern area of the pattern corresponding to the first chrome pattern 321 in FIG. 10C before the phase shifter formation of this mask pattern to the entire mask area is 13%, and the aperture ratio is 87. %Met. The aperture ratio of the second resist pattern 221 serving as a mask when etching the first chromium pattern 321 after the phase shifter was formed by dry etching was 7%.

  The etching conditions used were optimized for the 90 nm device mask chrome etching conditions.

・ Pressure: 8mTorr
・ Power: RIE 65W / ICP 750W
Process gas: Cl2 / O2 / He = 48/15/22 sccm
・ Over etching: 150%
A sample was formed under the above dry etching conditions.

Each of the step dimensions L1, L2, and L3 in FIG. 11 was measured with a phase difference measuring device using an ArF laser light source having a wavelength of 193 nm. The phase differences corresponding to the step dimensions L1, L2, L3, and L4 were as follows: If P1, P2, P3, and P4,
Step size: Phase difference due to L1: P1 = 180.5 °
Step size: Phase difference due to L2: P2 = 183.2 °
Step size: Phase difference due to L3: P3 = 17.3 °
Step size: Phase difference due to L4: P4 = P3- (P2-P1) = 14.6 °.

  That is, in FIG. 7D, the phase difference due to the step dimension L1 originally intended by the quartz step pattern 10 formed by dry etching of the quartz substrate 1 forms the second chromium pattern 322 of FIG. Therefore, the phase difference fluctuates by the dry etching performed, and the variation amount of the phase difference is ΔP = P2−P1 = P3−P4 = 2.7 °.

  This fluctuation amount: ΔP is the same as that in FIG. 10A, the etched quartz substrate 1 in FIG. 10A until the first chromium pattern 321 is completely etched by the dry etching in FIG. 10B. This corresponds to the amount of damage incurred during the etching of chromium in FIG.

  That is, when overetching is performed after just etching in which the first chrome pattern 321 is completely etched and the quartz substrate 1 is exposed, the step dimensions L3 and L4 are damaged by the same amount. Maintained. This is why there is a difference in the final values of the phase differences P3 and P4 due to the step size L3 and L4, respectively.

  In addition, in consideration of errors due to process variations that occur during dry etching of the quartz substrate 1 shown in FIG. 7D, the phase shift mask described below will require a phase shift mask with the amount of phase difference variation described here. Therefore, a mask that satisfies the phase difference accuracy cannot be stably supplied.

  Therefore, it is necessary to reduce damage to the quartz substrate 1 during the just etching of the first chrome pattern 321 as much as possible.

  Further, when the actual overetching amount is calculated from the above phase difference, it becomes 540%, and the just etching time during dry etching of the first chromium pattern 321 becomes shorter than that of a normal chromium light shielding mask.

  For example, when the first chrome pattern 321 of this mask is etched under the above-described etching conditions, the aperture ratio of the resist used as a mask during dry etching when forming a chrome pattern in a normal chrome light shielding mask manufacturing process If the aperture ratio of the second resist pattern 221 is about the same, the amount of damage to the quartz substrate 1 due to overetching is about 4.5 ° in terms of the phase difference of the ArF laser wavelength. However, in this mask, there is also 14.6 °, and when etching by dry etching using a resist pattern having a low aperture ratio as a mask on a high aperture ratio mask such as the present mask, There was a problem that just etching was greatly shifted.

  Therefore, in the present invention, in a phase shift mask in which a chromium-less mask engraved with a quartz substrate as a phase shifter and an edge-enhanced phase shift mask are mixed, damage to the quartz substrate that occurs during etching of a chromium light-shielding film is reduced. An object of the present invention is to provide a method of manufacturing a phase shift mask.

  The above-described problem is that, in claim 1, a light shielding film pattern, a transmissive phase shift pattern having an optical phase inversion effect, and a phase shifter having an optical phase inversion effect around the light shielding pattern are formed on a transparent substrate. A method of manufacturing a phase shift mask including an arranged edge-enhanced phase shift pattern, comprising: forming a light shielding film on a transparent substrate; and applying a first resist film on the light shielding film Forming a resist pattern, etching the light-shielding film using the first resist pattern as a mask to form a light-shielding film pattern, and masking the first resist pattern and the light-shielding film pattern The step of etching the transparent substrate, the step of peeling off the first resist pattern, and applying a second resist film using a positive resist, A step of forming a second resist pattern and a dummy pattern whose coverage with respect to the product does not exceed 70%, a step of selectively dry-etching the light-shielding film pattern using the second resist pattern as a mask, This is solved by a method for manufacturing a phase shift mask configured to include a step of peeling the second resist pattern and the dummy pattern.

  In other words, the quartz substrate is etched using the first resist pattern and the light shielding film pattern as a mask to form a transmission type phase shift pattern, and then the second resist pattern is formed with a positive resist. In addition, a dummy pattern is also formed so that the mask coverage does not exceed 70%.

  Then, when the edge-enhanced phase shift pattern is formed by dry etching the light shielding film pattern, damage to the exposed quartz substrate due to dry etching can be suppressed. As a result, the amount of fluctuation of the phase shifter can be reduced.

  Next, in claim 2, an edge enhancement type in which a light shielding pattern, a transmission phase shift pattern having an optical phase inversion effect, and a phase shifter having an optical phase inversion effect are arranged around the light shielding pattern on a transparent substrate. A method of manufacturing a phase shift mask including a phase shift pattern, the step of forming a light shielding film on a transparent substrate, and forming a first resist film on the light shielding film to form a first resist pattern Etching the light-shielding film using the first resist pattern as a mask to form a light-shielding film pattern, and using the first resist pattern and the light-shielding film pattern as a mask, Etching, removing the first resist pattern, applying a third resist film using a negative resist, and forming a third resist pattern And a phase shift mask configured to include a step of selectively dry-etching the light-shielding film pattern using the third resist pattern as a mask, and a step of removing the second resist pattern. It is solved by the manufacturing method.

  That is, the third resist pattern is provided so as to be limited to the area of the light shielding film pattern by the negative resist. As a result, the mask coverage covered with the third resist pattern can be minimized, so that damage to the transparent substrate due to dry etching of the light shielding film to form the edge-enhanced phase shift mask can be suppressed. .

  Next, according to a third aspect of the present invention, there is provided a solution to the phase shift mask manufacturing method according to the first or third aspect, wherein the transparent substrate is a quartz substrate and the light shielding film is made of chromium.

  That is, since the phase shift mask is also used as a reticle mask, the transparent substrate needs to have excellent specifications for light and heat. Therefore, a quartz substrate is used. The light-shielding film is provided with a chromium film deposited by sputtering or vapor deposition having excellent specifications and light-shielding properties.

  Next, a fourth aspect of the present invention is solved by a semiconductor device configured to be manufactured using the phase shift mask manufactured by the method of manufacturing the phase shift mask according to the first or third aspect.

  According to the present invention, when manufacturing a phase shift mask in which a light shielding pattern, a transmission phase shift pattern, and an edge enhancement phase shift pattern are mixed on a transparent substrate, the edge enhancement phase shift pattern is formed. It is possible to suppress damage to the quartz substrate due to the dry etching performed in this step.

  Therefore, it is particularly effective in improving the efficiency in the manufacturing process of the semiconductor device using the phase shift mask as a reticle mask.

It is a positive resist that is masked when an edge-enhanced phase shift mask is formed by etching a light shielding film made of chromium. When dry etching is performed after forming a dummy mask so that the coverage does not exceed 70%, chromium-free The transmission type phase shift mask and the ordinary light shielding mask can be mixed with high accuracy.
[Example 1]
FIG. 1 is an explanatory diagram of one pattern of the first embodiment, FIG. 2 is an explanatory diagram of another pattern of the first embodiment, FIG. 3 is an explanatory diagram of an example of a dummy pattern, and FIG. It is explanatory drawing of an example.

  In FIG. 1, a phase shift mask 100 formed by FIG. 1 has a configuration in which an edge-enhanced phase shift mask 101 and a chromeless transmission type phase shift mask 102 are mixed, and the process shown in FIG. These have gone through the process of the front | former stage of the conventional phase shift mask manufacturing process shown to FIG. 7 (A)-(E).

  That is, in FIG. 1A, after engraving the quartz substrate 1 to a depth at which the phase is inverted at the wafer exposure wavelength, a second resist film 22 made of a positive resist is deposited, and then the second resist film 22 is applied. 1 shows a configuration in which a conductive film 4 is deposited. A chromium pattern 32 as a light shielding film 3 is deposited on the surface of the quartz substrate 1 that is not engraved. The conductive film 4 is provided in order to prevent the surface of the second resist film 22 from being charged up during electron beam drawing.

  Next, overlay drawing with an electron beam (not shown) is performed so that the second resist pattern 221 remains in a portion where the edge enhancement type phase shift function is to be formed with the chrome pattern 32. In addition, drawing is performed so that a plurality of dummy patterns 222 remain on the quartz substrate 1 etched in the process of FIG.

  Next, dry etching is performed using the second resist pattern 221 and the dummy pattern 222 as a mask, and the second resist pattern 221 and the dummy pattern 222 are removed, as shown in FIG. The phase shift mask 100 in which the emphasis type phase shift mask 101 and the transmission type phase shift mask 102 are mixed is obtained.

  In FIG. 2, the phase shift mask 100 formed by FIG. 2 has a configuration in which three types of masks, that is, a transmission type phase shift mask 102, a chromeless edge-enhanced phase shift mask 101, and a normal light shielding mask 103 are mixed. Thus, the process shown in FIG. 2A is performed through the conventional phase shift mask manufacturing process shown in FIGS.

  That is, in FIG. 2A, after engraving the quartz substrate 1 to a depth at which the phase is inverted at the wafer exposure wavelength, the second resist film 22 made of a positive resist is deposited, and then the second resist film 22 is applied. 1 shows a configuration in which the conductive film 4 is deposited. A chromium pattern 32 as a light shielding film 3 is deposited on the surface of the quartz substrate 1 that is not engraved. As in FIG. 1, the conductive film 4 is provided to prevent the surface of the second resist film 22 from being charged up during electron beam drawing.

  Next, overlay drawing with an electron beam (not shown) is performed, and the second resist pattern 221 is left in a portion where the edge-enhanced phase shift function is to be configured by the chrome pattern 32. Further, the second resist pattern 221 is removed to expose the chrome pattern 32 at a portion where a chromeless transmission type phase shift mask is desired. Further, the chrome pattern 32 is completely covered with the second resist pattern 221 in a portion that is desired to be a normal light shielding mask. In addition, drawing is performed so that a plurality of dummy patterns 222 remain on the quartz substrate 1 etched in the process of FIG.

  Next, dry etching is performed using the second resist pattern 221 and the dummy pattern 222 as a mask. After that, if the second resist pattern 221 and the dummy pattern 222 are removed, the edge-enhanced phase shift mask 101, the transmission type phase shift mask 102, and the light shielding mask 103 3 are formed as shown in FIG. A phase shift mask 100 in which various types of masks are mixed is obtained.

  In FIG. 3, a chrome pattern 32 is provided on the quartz substrate 1, and a second resist pattern 221 is provided at a central portion at a portion constituting the edge-enhanced phase shift mask 101, and a chromeless transmission type phase is provided. The chrome pattern 32 is exposed at a portion constituting the shift mask 102. Then, a dummy pattern 222 is formed by the second resist film 22 in a portion carved by etching of the quartz substrate 1. Here, the second resist film 22 has a configuration in which, for example, a 3 μm × 3 μm square is removed to form the dummy pattern 222.

  In FIG. 4, similarly to FIG. 3, a chrome pattern 32 is provided on the quartz substrate 1, and a second resist pattern 221 is provided in a central portion at a portion constituting the edge-emphasized phase shift mask 101. The chrome pattern 32 is exposed at a portion constituting the chromeless transmission type phase shift mask 102. Then, a dummy pattern 222 is formed by the second resist film 22 in a portion carved by etching of the quartz substrate 1. Here, the second resist film 22 has a configuration in which, for example, 3 μm × 3 μm squares are arranged in a lattice pattern to form the dummy pattern 222.

The dummy pattern 222 indicates the coverage ratio of the resist film, here the second resist film 22 with respect to the mask, or the opening ratio of the mask, and if the coverage area can be grasped, it is not necessary to strictly control the shape and dimensional accuracy, An aperture ratio of at least 30% is desirable.
[Example 2]
FIG. 5 is an explanatory diagram of one pattern of the second embodiment, and FIG. 6 is an explanatory diagram of another pattern of the second embodiment.

  In FIG. 5, the phase shift mask 100 formed in FIG. 5 has a configuration in which an edge-enhanced phase shift mask 101 and a chromeless transmission type phase shift mask 102 are mixed, and the process shown in FIG. These have gone through the process of the front | former stage of the conventional phase shift mask manufacturing process shown to FIG. 7 (A)-(E).

  That is, in FIG. 5A, after engraving the quartz substrate 1 to a depth at which the phase is inverted at the wafer exposure wavelength, the third resist film 23 made of a negative resist is deposited, and then the third resist film 23 is deposited. 1 shows a configuration in which the conductive film 4 is deposited. The conductive film 4 is provided to prevent the surface of the third resist film 23 from being charged up during electron beam drawing.

  FIG. 5B shows that the third resist pattern 231 is drawn on the chromium pattern 32 by electron beam drawing so that the third resist pattern 231 remains only on the portion to be formed in an edge-enhanced type, and then the conductive film is removed and developed. It has been processed.

  Next, after the chrome pattern 32 is dry-etched and the third resist pattern 231 is removed, an edge-enhanced phase shift mask 101 and a chromeless transmissive phase shift mask 102 are obtained as shown in FIG. A mixed phase shift mask 100 is obtained.

  6, the phase shift mask 100 configured in FIG. 6 includes a mixture of three types of masks: an edge-enhanced phase shift mask 101, a chromeless transmission type phase shift mask 102, and a normal light shielding mask 103. It is. Further, the process shown in FIG. 6A is a process that precedes the conventional phase shift mask manufacturing process shown in FIGS. 7A to 7E.

  That is, in FIG. 6A, after engraving the quartz substrate 1 to a depth at which the phase is inverted at the wafer exposure wavelength, a third resist film 23 made of a negative resist is deposited, and then the third resist film 23 is applied. 1 shows a configuration in which a conductive film 4 is deposited. A chromium pattern 32 as a light shielding film 3 is deposited on the surface of the quartz substrate 1 that is not engraved. The conductive film 4 is provided in order to prevent the surface of the third resist film 23 from being charged up during electron beam drawing.

  Next, overlay drawing with an electron beam (not shown) is performed, and a third resist pattern 231 is left at a portion where the edge-enhanced phase shift mask is to be formed with the chromium pattern 32. Further, a portion where a normal light shielding mask is desired is completely covered with the third resist pattern 231. Further, the third resist pattern 231 is completely removed to expose the chrome pattern 32 at a portion where a chromeless transmission type phase shift mask is to be formed.

  Next, dry etching is performed using the third resist pattern 231 as a mask. Thereafter, if the third resist pattern 231 is removed, as shown in FIG. 6C, three types of masks of the edge-enhanced phase shift mask 101, the transmission type phase shift mask 102, and the light shielding mask 103 are mixed. Thus obtained phase shift mask 100 is obtained.

  By the way, in [Embodiment 2], when a phase shift mask is formed, a step is provided on a quartz substrate as a phase shifter, and then a chromium film is dry-etched to form an edge-enhanced phase shifter. If the aperture ratio of the entire resist pattern mask is increased as much as possible, damage due to dry etching of the quartz substrate can be reduced. Experimental results to prove this fact are shown below.

  That is, a sample in which an SOG film is formed as a shifter material on a chrome substrate is prepared, an aperture ratio: 100%, that is, a sample in which no resist is applied on the SGO film, a resist film is formed on the SGO film, and a small opening Two samples with an aperture ratio of 0.01% in which several tens of patterns were formed were used.

  In order to compare the amount of damage with respect to the aperture ratio during chrome etching, the dry etching rate is slightly different between the quartz substrate and the SOG film. A dry etching process was performed.

As a result, the amount of decrease in the thickness of the SOG film when using a 90 nm device mask optimized under the chrome etching conditions is as follows:
・ Aperture ratio: 1.7% at 100% (damage of 1.8 ° in terms of ArF wavelength phase difference)
-Aperture ratio: 0.01%, 14 nm (14.7 ° damage in terms of ArF wavelength phase difference)
Thus, when the aperture ratio was 100% and the aperture ratio was 0.01%, the difference in film thickness reduction was about 8 times.

  That is, when an SOG film is used as the shifter material, the amount of damage corresponding to P3 = 17.3 ° due to the step size L3 shown in FIG. 11A is an ArF wavelength at an aperture ratio of 0.01%. Although it is 14.7 °, it becomes 1.8 ° at an aperture ratio of 100%, which is about 1/8.

  Further, in [Embodiment 1], when a phase shift mask is formed, a step is provided on a quartz substrate as a phase shifter, and then a chromium film is dry-etched to form an edge-enhanced phase shifter. If the aperture ratio of the entire resist pattern mask is increased as much as possible, damage due to dry etching of the quartz substrate can be reduced.

  In other words, as described above, when a positive resist is used for the second resist film that is masked to etch the chromium film, the film is coated on the etched quartz substrate as shown in FIG. If a dummy pattern in which the opening pattern group shown in FIGS. 3 and 4 is formed is disposed on the resist film thus deposited, the aperture ratio of the entire mask can be increased.

  Even when a positive resist is used, the resist pattern shown in FIG. 5B can be formed. However, since the amount of electron beam coverage increases, the accuracy of the resist pattern at the edge enhancement portion deteriorates, which is not practical.

  A phase shift mask having a configuration in which three types of masks, ie, a chromeless transmission type phase shifter, an edge enhancement type phase shifter, and a normal light shielding mask manufactured according to the first or second embodiment are mixed, is a semiconductor as a reticle mask. It can be used in the manufacturing process of the device.

  According to the method of manufacturing a phase shift mask of the present invention, it is possible to manufacture three types of masks, that is, a chromeless transmission type phase shifter, an edge enhancement type phase shifter, and a normal light shielding mask, with high accuracy and high quality. it can. Therefore, it contributes particularly to the efficiency of the manufacturing process of the semiconductor device.

It is explanatory drawing of one pattern of a 1st Example. It is explanatory drawing of the other pattern of a 1st Example. It is explanatory drawing of an example of a dummy pattern. It is explanatory drawing of the other example of a dummy pattern. It is explanatory drawing of one pattern of a 2nd Example. It is explanatory drawing of the other pattern of a 2nd Example. It is the manufacturing method (the 1) of the conventional chromeless mask. It is the manufacturing method (the 2) of the conventional chromeless mask. This is a conventional method for forming an edge-enhanced phase shift pattern. It is another formation method of the conventional edge emphasis type phase shift pattern. It is explanatory drawing of the fluctuation | variation of a phase difference.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Quartz substrate 21 1st resist film 22 2nd resist film 23 3rd resist film 211 1st resist pattern 221 2nd resist pattern 222 Dummy pattern 231 3rd resist pattern 3 Light-shielding film (chromium film)
31 Light shielding film pattern 32 Chrome pattern 4 Conductive film 100 Phase shift mask 101 Edge-enhanced phase shift mask 102 Transmission type phase shift mask 103 Light shielding mask

Claims (4)

Including a light shielding film pattern, a transmissive phase shift pattern having an optical phase inversion effect, and an edge-enhanced phase shift pattern in which a phase shifter having an optical phase inversion effect is disposed around the light shielding pattern on a transparent substrate A method of manufacturing a phase shift mask, comprising:
Forming a light shielding film on a transparent substrate;
Depositing a first resist film on the light-shielding film to form a first resist pattern;
Etching the light-shielding film using the first resist pattern as a mask to form a light-shielding film pattern;
Etching the transparent substrate using the first resist pattern and the light shielding film pattern as a mask;
Removing the first resist pattern;
Applying a second resist film using a positive resist, and forming a second resist pattern and a dummy pattern whose coverage with respect to the entire mask area does not exceed 70%;
Selectively etching the light-shielding film pattern using the second resist pattern as a mask;
And a step of stripping the second resist pattern and the dummy pattern. Phase including a light shielding pattern, a transmissive phase shift pattern having an optical phase inversion effect, and an edge-enhanced phase shift pattern in which a phase shifter having an optical phase inversion effect is disposed around the light shielding pattern on a transparent substrate A manufacturing method of a shift mask,
Forming a light shielding film on a transparent substrate;
Forming a first resist film on the light-shielding film to form a first resist pattern;
Etching the light shielding film using the first resist pattern as a mask to form a light shielding film pattern;
Etching the transparent substrate using the first resist pattern and the light-shielding film pattern as a mask;
Removing the first resist pattern;
Applying a third resist film using a negative resist to form a third resist pattern;
Selectively etching the light-shielding film pattern using the third resist pattern as a mask;
And a step of stripping the second resist pattern. The method of manufacturing a phase shift mask according to claim 1, wherein the transparent substrate is a quartz substrate. It manufactures using the phase shift mask manufactured by the manufacturing method of the phase shift mask of Claim 1 or 2. The semiconductor device characterized by the above-mentioned.

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