TWI847949B - Photomask blank, method of manufacturing photomask, and method of manufacturing display device - Google Patents

Abstract

Provided is a photomask blank in which a transfer pattern having a good cross-sectional shape can be formed and in which over-etching time can be shortened in forming the transfer pattern on a thin film for pattern formation by wet etching. A photomask blank has a thin film for pattern formation on a transparent substrate, the photomask blank is an original form for forming a photomask having a transfer pattern on a transparent substrate by wet-etching the thin film for pattern formation, the thin film for pattern formation contains a transition metal and silicon, and the thin film for pattern formation has a columnar structure.

Description

Photomask substrate, photomask manufacturing method, and display device manufacturing method

The present invention relates to a photomask substrate, a method for manufacturing the photomask substrate, a method for manufacturing a photomask, and a display device.

In recent years, in display devices such as FPD (Flat Panel Display) represented by LCD (Liquid Crystal Display), high-definition and high-speed display have developed rapidly along with large screens and wide viewing angles. One of the elements required for high-definition and high-speed display is the production of electronic circuit patterns such as components or wiring with fine and high dimensional accuracy. Photolithography is mostly used in the patterning of electronic circuits for display devices. Therefore, a photomask such as a phase shift mask or a binary mask is required for the manufacture of display devices with fine and high-precision patterns.

For example, Patent Document 1 discloses a phase reversal mask substrate having a phase reversal film on a transparent substrate. In the mask substrate, the phase reversal film has a reflectivity of less than 35% and a transmittance of 1% to 40% for exposure light of a composite wavelength including i-line (365 nm), h-line (405 nm), and g-line (436 nm), and includes a multilayer film of more than 2 layers in a manner that a gradient of a pattern profile is formed rapidly when forming a pattern. The multilayer film contains a metal silicide compound containing at least one light element substance including oxygen (O), nitrogen (N), and carbon (C), and the metal silicide compound is formed by injecting a reactive gas containing the light element substance and an inert gas at a ratio of 0.5:9.5 to 4:6. Furthermore, Patent Document 2 discloses a phase-shift mask substrate, which comprises: a transparent substrate; a light semi-transmissive film having the property of changing the phase of the exposure light and comprising a metal silicide material; and an etching mask film comprising a chromium material. In the phase-shift mask substrate, a composition gradient region is formed at the interface between the light semi-transmissive film and the etching mask film. In the composition gradient region, the ratio of the component that slows down the wet etching speed of the light semi-transmissive film increases toward the depth direction. Moreover, the oxygen content in the composition gradient region is less than 10 atomic %. [Prior Technical Document] [Patent Document]

[Patent Document 1] Korean registered patent No. 1801101 [Patent Document 2] Japanese patent No. 6101646

[The problem the invention is trying to solve]

As a phase shift mask used in the production of high-precision (1000 ppi or more) panels in recent years, in order to achieve high-resolution pattern transfer, a phase shift mask with a fine phase shift film pattern with an aperture of less than 6 μm and a line width of less than 4 μm is required as a phase shift mask. Specifically, a phase shift mask with a fine phase shift film pattern with an aperture of 1.5 μm is required. In addition, in order to achieve higher-resolution pattern transfer, a phase shift mask base with a phase shift film with a transmittance of more than 15% for exposure light and a phase shift mask with a phase shift film pattern with a transmittance of more than 15% for exposure light are required. Furthermore, in terms of the washability (chemical properties) of a phase shift mask base or a phase shift mask, a phase shift mask base having a phase shift film or a phase shift film pattern having washability and in which the change in optical properties caused by the film reduction or surface composition change is suppressed, and a phase shift mask having a phase shift film pattern having washability are required. In order to meet the requirements for the transmittance of the exposure light and the requirements for washing resistance, it is more effective to increase the ratio of silicon in the atomic ratio of metal to silicon in the metal silicide compound (metal silicide-based material) constituting the phase shift film, but there are the following problems: the wet etching speed is greatly slowed down (the wet etching time is prolonged), and the wet etching liquid damages the substrate, and the transmittance of the transparent substrate is reduced. In addition, in a binary mask substrate having a light-shielding film containing transition metal and silicon, there is also a requirement for washing resistance when a light-shielding pattern is formed on the light-shielding film by wet etching, resulting in the same problem as above.

Therefore, the present invention is completed to solve the above-mentioned problem. The purpose of the present invention is to provide a photomask base, a method for manufacturing a photomask base, a method for manufacturing a photomask, and a method for manufacturing a display device. When the photomask base forms a transfer pattern on a pattern-forming thin film such as a phase shift film or a light-shielding film containing transition metal and silicon by wet etching, the wet etching time can be shortened, thereby forming a transfer pattern with a good cross-sectional shape. [Technical means for solving the problem]

The inventors of the present invention have conducted intensive research on countermeasures for solving these problems. First, the atomic ratio of transition metal to silicon in the pattern-forming thin film is set to a material of transition metal:silicon of 1:3 or more, and in order to shorten the wet etching time of the wet etching solution in the pattern-forming thin film, the oxygen contained in the sputtering gas introduced into the film-forming chamber is adjusted so that the pattern-forming thin film contains a large amount of oxygen (O), and the pattern-forming thin film is formed. As a result, although the wet etching speed for forming the transfer pattern is increased, the refractive index of the phase shift film in the phase shift mask base to the exposure light is reduced, thereby resulting in a thicker film thickness required to obtain the desired phase difference (for example, 180 ^° ). In addition, the extinction coefficient of the light-shielding film in the binary mask base to the exposure light decreases, so the film thickness required to obtain the required light-shielding performance (for example, optical density (OD) of 3 or more) becomes thicker. The thickening of the film thickness of the pattern-forming film is disadvantageous in the pattern formation of wet etching, and the effect of shortening the wet etching time is limited due to the thickening of the film thickness. On the other hand, if the atomic ratio of the transition metal to silicon is set to the above-mentioned (transition metal: silicon = 1:3 or more), it has the advantage of improving the washing resistance of the pattern-forming film, so in this regard, it is not good to deviate from the above-mentioned composition ratio of the transition metal to silicon.

Therefore, the inventors changed their ideas and studied how to adjust the pressure of the sputtering gas in the film forming chamber to change the film structure. When forming a pattern-forming thin film on a substrate, the sputtering gas pressure in the film forming chamber is usually set to 0.1-0.5 Pa. However, the inventors dared to make the sputtering gas pressure greater than 0.5 Pa to form a pattern-forming thin film. Furthermore, it was found that when the pattern-forming thin film is formed at a sputtering pressure of 0.7 Pa to 3.0 Pa, preferably at a sputtering gas pressure of 0.8 Pa to 3.0 Pa, not only does it have better properties as a thin film, but also when a transfer pattern is formed on the pattern-forming thin film by wet etching, the etching time can be greatly shortened, and a transfer pattern with a good cross-sectional shape can be formed. Moreover, the pattern-forming thin film formed in this way has a columnar structure that has not been seen in a conventional pattern-forming thin film. The present invention is completed as a result of the above-mentioned intensive research, and has the following structure.

(Constitution 1) A photomask base characterized in that: It has a pattern-forming film on a transparent substrate, and The photomask base is used to form a photomask having a transfer pattern on the transparent substrate by wet etching on the pattern-forming film, The pattern-forming film contains transition metal and silicon, The pattern-forming film has a columnar structure.

(Constitution 2) A photomask substrate as described in constitution 1, wherein the pattern forming film is For an image obtained by observing the cross section of the photomask substrate at a magnification of 80,000 times with a scanning electron microscope, an area including the center portion in the thickness direction of the pattern forming film is captured with image data of 64 pixels in the vertical direction and 256 pixels in the horizontal direction, and in the spatial frequency spectrum distribution obtained by Fourier transforming the image data, there is a spatial frequency spectrum having a signal intensity of 1.0% or more relative to the maximum signal intensity corresponding to the origin of the spatial frequency. (Configuration 3) A photomask substrate as described in Configuration 2, wherein the pattern forming film is such that the signal having a signal strength of 1.0% or more is at a spatial frequency that is 2.0% or more away from the origin of the spatial frequency when the maximum spatial frequency is set to 100%.

(Configuration 4) A mask substrate as described in any one of Configurations 1 to 3, wherein the atomic ratio of the transition metal and the silicon contained in the pattern forming thin film is transition metal:silicon=1:3 or more and 1:15 or less.

(Constitution 5) A mask substrate as described in any one of constitutions 1 to 4, wherein the pattern-forming film contains at least nitrogen or oxygen. (Constitution 6) A mask substrate as described in constitution 5, wherein the pattern-forming film contains nitrogen, and the atomic ratio of the transition metal to the silicon contained in the pattern-forming film is transition metal: silicon = 1:3 or more and 1:15 or less, and The indentation hardness of the pattern-forming film derived by the nanoindentation method is 18 GPa or more and 23 GPa or less. (Constitution 7) A mask substrate as described in constitution 6, wherein the nitrogen content is 35 atomic % or more and 60 atomic % or less. (Constitution 8) A mask substrate as described in any one of constitutions 1 to 7, wherein the transition metal is molybdenum.

(Configuration 9) A mask substrate as described in any one of Configurations 1 to 8, wherein the above-mentioned pattern-forming film is a phase shift film having optical properties such that the transmittance of the representative wavelength of the exposure light is greater than 1% and less than 80% and the phase difference is greater than 160° and less than 200°.

(Configuration 10) A photomask base as described in any one of Configurations 1 to 9, wherein an etching mask film having an etching selectivity different from that of the pattern forming film is provided on the pattern forming film. (Configuration 11) A photomask base as described in Configuration 10, wherein the etching mask film comprises a material containing chromium and substantially containing no silicon.

(Construction 12) A method for manufacturing a photomask base, characterized in that: a pattern-forming thin film containing transition metal and silicon is formed on a transparent substrate by sputtering. The pattern-forming thin film is formed in a film-forming chamber using a transition metal silicide target containing transition metal and silicon, and the sputtering gas pressure in the film-forming chamber supplied with sputtering gas is 0.7 Pa or more and 3.0 Pa or less.

(Configuration 13) A method for manufacturing a mask substrate as described in Configuration 12, wherein the atomic ratio of the transition metal to silicon in the transition metal silicide target is transition metal:silicon=1:3 or more and 1:15 or less.

(Configuration 14) A method for manufacturing a photomask base as described in Configuration 12 or 13, wherein a sputtering target including a material having an etching selectivity different from that of the pattern forming film is used on the pattern forming film to form an etching mask film. (Configuration 15) A method for manufacturing a photomask base as described in Configuration 14, wherein the pattern forming film and the etching mask film are formed using an inline sputtering device.

(Constitution 16) A method for manufacturing a photomask, characterized by comprising the following steps: Preparing a photomask base as described in any one of constitutions 1 to 9, or a photomask base manufactured by a method for manufacturing a photomask base as described in constitution 12 or 13; and Forming a photoresist film on the above-mentioned pattern-forming film, using the photoresist film pattern formed by the above-mentioned photoresist film as a mask, wet-etching the above-mentioned pattern-forming film to form a transfer pattern on the above-mentioned transparent substrate.

(Constitution 17) A method for manufacturing a photomask, characterized by comprising the following steps: Preparing a photomask base as described in constitution 10 or 11, or a photomask base manufactured by a method for manufacturing a photomask base as described in constitution 14 or 15; Forming a photoresist film on the etching mask film, wet-etching the etching mask film using the photoresist film pattern formed by the photoresist film as a mask, and forming an etching mask film pattern on the pattern forming film; and Using the etching mask film pattern as a mask, wet-etching the pattern forming film to form a transfer pattern on the transparent substrate. (Construction 18) A method for manufacturing a display device, characterized in that it includes an exposure step, wherein the photomask obtained by the photomask manufacturing method described in construction 16 or 17 is placed on a mask stage of an exposure device, and the transfer pattern formed on the photomask is exposed and transferred to a photoresist formed on a display device substrate.

Furthermore, the inventors have studied the effect of adjusting the pressure of the sputtering gas in the film-forming chamber to change the film structure, and have discovered the following other structures. As described above, the inventors dared to make the sputtering gas pressure greater than 0.5 Pa to form a film for pattern formation. Moreover, it was found that when the film for pattern formation is formed at a sputtering gas pressure of 0.7 Pa or more, the etching time can be greatly shortened, and a transfer pattern with a good cross-sectional shape can be formed, and the surface roughness of the transparent substrate can be suppressed. On the other hand, it can be seen that if the sputtering gas pressure during film formation is excessively increased, sufficient wash resistance cannot be obtained in the film for pattern formation. The inventors of the present invention have conducted intensive research and found that by forming a pattern-forming film with a sputtering gas pressure of 0.7 Pa or more and 2.4 Pa or less, not only can the film have better characteristics as a pattern-forming film, but also can form a transfer pattern with a good cross-sectional shape, and can suppress the surface roughness of the transparent substrate and improve the washing resistance of the pattern-forming film. In addition, the inventors of the present invention have further explored the physical indicators of the pattern-forming film with such excellent characteristics. As a result, it was found that the indentation hardness of the pattern-forming film is correlated with the wet etching rate. Further research was conducted on this point, and it was found that if the indentation hardness derived by the nanoindentation method is 18 GPa or more and 23 GPa or less, it not only has better properties as a pattern-forming film, but also can form a transfer pattern with a good cross-sectional shape when forming a transfer pattern on the pattern-forming film by wet etching, can suppress the surface roughness of the transparent substrate, and can improve the washing resistance of the pattern-forming film.

(Other components 1) A photomask base, characterized in that: it has a pattern-forming film on a transparent substrate, the photomask base is used to form a master plate of a photomask having a transfer pattern on the transparent substrate by wet etching on the pattern-forming film, the pattern-forming film contains transition metal, silicon and nitrogen, and the atomic ratio of the transition metal to the silicon contained in the pattern-forming film is transition metal: silicon = 1:3 or more and 1:15 or less, the indentation hardness of the pattern-forming film derived by nano-indentation method is 18 GPa or more and 23 GPa or less.

(Other composition 2) A photomask base as described in other composition 1, wherein the transition metal is molybdenum. (Other composition 3) A photomask base as described in other composition 1 or 2, wherein the nitrogen content is greater than 35 atomic % and less than 60 atomic %.

(Other configuration 4) A mask substrate as described in any one of other configurations 1 to 3, wherein the above-mentioned pattern-forming film is a phase shift film having optical properties such that the transmittance of the representative wavelength of the exposure light is greater than 1% and less than 80% and the phase difference is greater than 160° and less than 200°.

(Other configuration 5) A photomask base as described in any one of other configurations 1 to 4, wherein an etching mask film having an etching selectivity different from that of the pattern forming film is provided on the above-mentioned pattern forming film. (Other configuration 6) A photomask base as described in other configuration 5, wherein the above-mentioned etching mask film comprises a material containing chromium and substantially containing no silicon.

(Other configuration 7) A method for manufacturing a photomask, characterized by comprising the following steps: Preparing a photomask base as described in any one of other configurations 1 to 4; and Forming a photoresist film on the above-mentioned pattern-forming film, using the photoresist film pattern formed by the above-mentioned photoresist film as a mask, wet-etching the above-mentioned pattern-forming film to form a transfer pattern on the above-mentioned transparent substrate. (Other configuration 8) A method for manufacturing a photomask, characterized by comprising the following steps: Preparing a photomask substrate as described in other configuration 5 or 6; Forming a photoresist film on the etching mask film, using the photoresist film pattern formed by the photoresist film as a mask, wet-etching the etching mask film to form an etching mask film pattern on the pattern-forming film; and Using the etching mask film pattern as a mask, wet-etching the pattern-forming film to form a transfer pattern on the transparent substrate. (Other configuration 9) A method for manufacturing a display device, characterized in that it includes an exposure step, wherein a mask obtained by the method for manufacturing a mask as described in other configuration 7 or 8 is placed on a mask stage of an exposure device, and the transfer pattern formed on the mask is exposed and transferred to a photoresist formed on a display device substrate. [Effect of the invention]

According to the photomask base or the method for manufacturing the photomask base of the present invention, the following photomask base can be obtained. When the required fine transfer pattern is formed on the transfer pattern film by wet etching, even if the pattern forming film is made into a silicon-rich metal silicide compound from the viewpoint of wash resistance, the transmittance of the transparent substrate will not decrease due to the damage of the wet etching solution to the substrate, and a transfer pattern with a good cross-sectional shape can be formed within a shorter etching time. Furthermore, according to the other configurations of the photomask base of the present invention, the following photomask base can be obtained, which can form a transfer pattern with a good cross-sectional shape when the required fine transfer pattern is formed on the transfer pattern film by wet etching, and can suppress the surface roughness of the transparent substrate and improve the washing resistance of the transfer pattern film.

Furthermore, according to the manufacturing method of the photomask of the present invention, the photomask is manufactured using the above-mentioned photomask base. Therefore, even when the film for pattern formation is made into a silicon-rich metal silicide compound from the viewpoint of washability, the transmittance of the transparent substrate will not decrease due to damage to the substrate by the wet etching solution, and a photomask with a transfer pattern with good transfer accuracy can be manufactured. The photomask can cope with the miniaturization of line gap patterns or contact holes. Furthermore, according to the manufacturing method of the photomask of other structures of the present invention, a photomask can be manufactured that can form a transfer pattern with a good cross-sectional shape, can suppress the surface roughness of the transparent substrate, and can improve the washability of the film for the transfer pattern.

Furthermore, according to the manufacturing method of the display device of the present invention, a display device is manufactured using a mask manufactured using the above-mentioned mask substrate or a mask obtained by the above-mentioned mask manufacturing method. Therefore, a display device having a fine line gap pattern or contact hole can be manufactured.

Implementation form 1.2. In implementation forms 1 and 2, a phase shift mask substrate is described. The phase shift mask substrate of implementation form 1 is used to set an etching mask film pattern having a desired pattern formed on an etching mask film as a mask, and to form a master of a phase shift mask having a phase shift film pattern on a transparent substrate by wet etching on the phase shift film. In addition, the phase shift mask substrate of implementation form 2 is used to set a photoresist film pattern having a desired pattern formed on a photoresist film as a mask, and to form a master of a phase shift film having a phase shift film pattern on a transparent substrate by wet etching on the phase shift film.

FIG. 1 is a schematic diagram showing the film structure of the phase shift mask substrate 10 of the embodiment 1. The phase shift mask substrate 10 shown in FIG. 1 has a transparent substrate 20, a phase shift film 30 formed on the transparent substrate 20, and an etching mask film 40 formed on the phase shift film 30. FIG. 2 is a schematic diagram showing the film structure of the phase shift mask substrate 10 of the embodiment 2. The phase shift mask substrate 10 shown in FIG. 2 has a transparent substrate 20 and a phase shift film 30 formed on the transparent substrate 20. The transparent substrate 20, the phase shift film 30, and the etching mask film 40 constituting the phase shift mask substrate 10 of the embodiments 1 and 2 are described below.

The transparent substrate 20 is transparent to the exposure light. When the transparent substrate 20 is set to have no surface reflection loss, the exposure light has a transmittance of 85% or more, preferably a transmittance of 90% or more. The transparent substrate 20 includes a material containing silicon and oxygen, and may include glass materials such as synthetic quartz glass, quartz glass, aluminum silicate glass, sodium calcium glass, and low thermal expansion glass ( _SiO2 - _TiO2 glass, etc.). When the transparent substrate 20 includes low thermal expansion glass, the position change of the phase shift film pattern caused by the thermal deformation of the transparent substrate 20 can be suppressed. In addition, the transparent substrate 20 used for display device purposes usually uses a rectangular substrate and the length of the short side of the transparent substrate is 300 mm or more. The present invention is a phase shift mask substrate that can provide a phase shift mask that can stably transfer a fine phase shift film pattern, for example, less than 2.0 μm, formed on a transparent substrate even if the short side length of the transparent substrate is large and is greater than 300 mm.

The phase shift film 30 includes a transition metal silicide material containing a transition metal and silicon. As the transition metal, molybdenum (Mo), tungsten (W), titanium (Ti), zirconium (Zr), etc. are preferred, and in particular, molybdenum (Mo) is further preferred. In addition, the phase shift film 30 preferably contains at least nitrogen or oxygen. In the above-mentioned transition metal silicide material, oxygen as a light element component has an effect of reducing the extinction coefficient compared with nitrogen as a light element component. Therefore, the content of other light element components (nitrogen, etc.) used to obtain the required transmittance can be reduced, and the reflectivity of the front and back surfaces of the phase shift film 30 can also be effectively reduced. Furthermore, in the above-mentioned transition metal silicide material, nitrogen as a light element component has the effect of not lowering the refractive index compared to oxygen as a light element component, so the film thickness used to obtain the desired phase difference can be made thinner. Furthermore, the total content of light element components containing oxygen and nitrogen contained in the phase shift film 30 is preferably 40 atomic % or more. Further, it is preferably 40 atomic % or more and 70 atomic % or less, and ideally 50 atomic % or more and 65 atomic % or less. Furthermore, when oxygen is contained in the phase shift film 30, in terms of defect quality and chemical resistance, it is ideal that the oxygen content exceeds 0 atomic % and is 40 atomic % or less. As transition metal silicide materials, for example, transition metal silicide nitrides, transition metal silicide oxides, transition metal silicide oxynitrides, and transition metal silicide oxynitride carbides can be listed. Furthermore, if the transition metal silicide material is a molybdenum silicide material (MoSi material), a zirconium silicide material (ZrSi material), or a molybdenum zirconium silicide material (MoZrSi material), it is preferred in that an excellent pattern cross-sectional shape can be easily obtained by wet etching, and the molybdenum silicide material (MoSi material) is particularly preferred. In addition to the above-mentioned oxygen and nitrogen, the phase shift film 30 may also contain other light element components such as carbon or helium for the purpose of reducing film stress or controlling the wet etching rate. The phase shift film 30 has the function of adjusting the reflectivity of light incident from the transparent substrate 20 side (hereinafter, sometimes referred to as back reflectivity) and the function of adjusting the transmittance and phase difference of the exposure light. The phase shift film 30 can be formed by sputtering.

The phase shift film 30 preferably has a columnar structure. The columnar structure can be confirmed by cross-sectional SEM observation of the phase shift film 30. That is, the columnar structure in the present invention refers to a state in which particles of a transition metal silicide compound containing a transition metal and silicon constituting the phase shift film 30 extend in the film thickness direction of the phase shift film 30 (the direction of the above-mentioned particle deposition). Furthermore, in the present case, particles whose length in the film thickness direction is longer than their length in the perpendicular direction are defined as columnar particles. That is, the phase shift film 30 is formed by columnar particles extending in the film thickness direction throughout the surface of the transparent substrate 20. In addition, the phase shift film 30 also forms a sparse portion (hereinafter sometimes referred to as a "sparse portion") having a density relatively lower than that of the columnar particles by adjusting the film forming conditions (sputtering pressure, etc.). Furthermore, in order to effectively suppress side corrosion during wet etching and improve the cross-sectional shape of the pattern, as a preferred form of the columnar structure of the phase shift film 30, it is preferred that columnar particles extending in the film thickness direction are irregularly formed in the film thickness direction. Furthermore, it is preferred that the columnar particles of the phase shift film 30 are in a state where the lengths in the film thickness direction are inconsistent. Moreover, the sparse portion of the phase shift film 30 is preferably formed continuously in the film thickness direction. Furthermore, the sparse portion of the phase shift film 30 is preferably formed intermittently in a direction perpendicular to the film thickness direction. As a preferred form of the columnar structure of the phase shift film 30, an index obtained by Fourier transforming the image obtained by the above-mentioned cross-sectional SEM observation can be used to represent it in the following manner. That is, the columnar structure of the phase shift film 30 is preferably in the following state, that is, for an image obtained by cross-sectional SEM observation on a cross section of the phase shift mask substrate at a magnification of 80,000 times, an area including the center portion in the thickness direction of the phase shift film 30 is captured with image data of 64 pixels in length by 256 pixels in width, and a spatial frequency spectrum obtained by Fourier transforming the image data has a signal intensity of 1.0% or more relative to the maximum signal intensity corresponding to the origin of the spatial frequency. By making the phase shift film 30 into the columnar structure described above, when wet etching is performed using a wet etching liquid, the wet etching liquid easily penetrates in the film thickness direction of the phase shift film 30, so that the wet etching speed becomes faster, thereby significantly shortening the wet etching time. Therefore, even if the phase shift film 30 is a silicon-rich metal silicide compound, the transmittance of the transparent substrate does not decrease due to damage to the substrate by the wet etching liquid. In addition, the phase shift film 30 has a columnar structure extending in the film thickness direction, so side etching during wet etching is suppressed, and the cross-sectional shape of the pattern also becomes good.

In addition, the phase shift film 30 preferably has a signal having an intensity signal of 1.0% or more relative to the maximum signal intensity of the spatial frequency spectrum distribution obtained by Fourier transform, and is located at a spatial frequency of 2.0% or more away from the origin of the spatial frequency when the maximum spatial frequency is set to 100%. The signal having an intensity signal of 1.0% or more relative to the maximum signal intensity being 2.0% or more away indicates that a spatial frequency component higher than a certain level is included. That is, it indicates that the phase shift film 30 is in a state of a fine columnar structure, and the farther the spatial frequency is from the origin, the smaller the line edge roughness of the phase shift film pattern 30a formed by wet etching on the phase shift film 30 is, and therefore it is preferred.

The indentation hardness of the phase shift film 30 is preferably 18 GPa or more and 23 GPa or less. The indentation hardness is measured using the principle of the nanoindentation method established in accordance with ISO14577. By setting the indentation hardness of the phase shift film 30 to 18 GPa or more and 23 GPa or less, when wet etching is performed using a wet etching liquid, the wet etching liquid easily penetrates in the film thickness direction of the phase shift film 30, thereby increasing the wet etching speed and shortening the wet etching time. Moreover, it not only has better characteristics as a phase shift film 30, but also can form a phase shift film pattern 30a with a good cross-sectional shape, and can suppress the surface roughness of the transparent substrate 20, and can improve the washing resistance of the phase shift film 30. The atomic ratio of transition metal and silicon contained in the phase shift film 30 is preferably transition metal: silicon = 1:3 or more and 1:15 or less. If it is within this range, the effect of suppressing the decrease in wet etching rate when forming the pattern of the phase shift film 30 by using the columnar structure can be increased. In addition, the washing resistance of the phase shift film 30 can be improved, and the transmittance can also be easily improved. Furthermore, if it is within this range, the effect of suppressing the decrease in wet etching rate during pattern formation of the phase shift film 30 can be increased by setting the indentation hardness to 18 GPa or more and 23 GPa or less. From the perspective of improving the washability of the phase shift film 30, the atomic ratio of transition metal and silicon contained in the phase shift film 30 is preferably transition metal: silicon = 1:4 or more and 1:15 or less, and more preferably transition metal: silicon = 1:5 or more and 1:15 or less.

The transmittance of the phase shift film 30 to the exposure light satisfies the value required as the phase shift film 30. The transmittance of the phase shift film 30 to the light of a specific wavelength contained in the exposure light (hereinafter referred to as the representative wavelength) is preferably 1% to 80%, more preferably 15% to 65%, and further preferably 20% to 60%. That is, when the exposure light is a composite light containing light in a wavelength range of 313 nm to 436 nm, the phase shift film 30 has the above transmittance to the light of the representative wavelength contained in the wavelength range. For example, when the exposure light is a composite light containing i-line, h-line and g-line, the phase shift film 30 has the above transmittance to any one of the i-line, h-line and g-line. The transmittance can be measured using a phase shift measurement device, etc.

The phase difference of the phase shift film 30 with respect to the exposure light satisfies the value required as the phase shift film 30. The phase difference of the phase shift film 30 with respect to the light of the representative wavelength included in the exposure light is preferably 160° to 200°, and more preferably 170° to 190°. According to this property, the phase of the light of the representative wavelength included in the exposure light can be changed to 160° to 200°. Therefore, a phase difference of 160° to 200° is generated between the light of the representative wavelength that passes through the phase shift film 30 and the light of the representative wavelength that passes only through the transparent substrate 20. That is, when the exposure light is a composite light including light in the wavelength range of 313 nm to 436 nm, the phase shift film 30 has the above-mentioned phase difference with respect to the light of the representative wavelength included in the wavelength range. For example, when the exposure light is a composite light including i-line, h-line and g-line, the phase shift film 30 has the above-mentioned phase difference for any one of the i-line, h-line and g-line. The phase difference can be measured using a phase shift amount measuring device, etc.

The back reflectivity of the phase shift film 30 is 15% or less in the wavelength range of 365 nm to 436 nm, preferably 10% or less. In addition, when the exposure light includes j-line, the back reflectivity of the phase shift film 30 is preferably 20% or less, and more preferably 17% or less for light in the wavelength range of 313 nm to 436 nm. More preferably, it is 15% or less. In addition, the back reflectivity of the phase shift film 30 is 0.2% or more in the wavelength range of 365 nm to 436 nm, and preferably 0.2% or more for light in the wavelength range of 313 nm to 436 nm. The back reflectivity can be measured using a spectrophotometer or the like.

The phase shift film 30 may be composed of a plurality of layers or a single layer. A phase shift film 30 composed of a single layer is preferred in that it is difficult to form an interface in the phase shift film 30 and the cross-sectional shape is easily controlled. On the other hand, a phase shift film 30 composed of a plurality of layers is preferred in terms of ease of film formation.

The etching mask film 40 is disposed on the upper side of the phase shift film 30 and is composed of a material having an etching resistance to an etching solution for etching the phase shift film 30 (having an etching selectivity different from that of the phase shift film 30). In addition, the etching mask film 40 may also have a function of shielding exposure light from passing through, and further, may also have a function of reducing the film surface reflectance of the phase shift film 30 in a manner such that the film surface reflectance of the light incident from the side of the phase shift film 30 becomes 15% or less in a wavelength region of 350 nm to 436 nm. The etching mask film 40 includes a chromium-based material containing chromium (Cr). More specifically, as the chromium-based material, chromium (Cr) or a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C) may be cited. Alternatively, materials including chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C) and further including fluorine (F) can be listed. For example, as materials constituting the etching mask film 40, Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF can be listed. The etching mask film 40 can be formed by sputtering.

When the etching mask film 40 has the function of shielding the exposure light from passing through, the optical density of the exposure light in the portion where the phase shift film 30 and the etching mask film 40 are laminated is preferably 3 or more, more preferably 3.5 or more, and further preferably 4 or more. The optical density can be measured using a spectrophotometer or an OD (Optical Density) meter.

The etching mask film 40 may include a single film having a uniform composition, a plurality of films having different compositions, or a single film having a composition that continuously changes in the thickness direction, depending on its function.

Furthermore, the phase shift mask substrate 10 shown in FIG. 1 has an etching mask film 40 on the phase shift film 30 , but a phase shift mask substrate having an etching mask film 40 on the phase shift film 30 and a photoresist film on the etching mask film 40 can also be applied to the present invention.

Next, the manufacturing method of the phase shift mask substrate 10 of the embodiments 1 and 2 is described. The phase shift mask substrate 10 shown in FIG1 is manufactured by performing the following phase shift film forming step and etching mask film forming step. The phase shift mask substrate 10 shown in FIG2 is manufactured by the phase shift film forming step. Below, each step is described in detail.

1. Phase shift film formation step First, prepare a transparent substrate 20. The transparent substrate 20 may be made of any glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, sodium calcium glass, low thermal expansion glass ( _SiO2 - _TiO2 glass, etc.) if it is transparent to exposure light.

Next, a phase shift film 30 is formed on the transparent substrate 20 by sputtering. The film formation of the phase shift film 30 is performed by using a transition metal silicide target containing transition metal and silicon as the main components of the material constituting the phase shift film 30, or a transition metal silicide target containing transition metal, silicon, oxygen and/or nitrogen as a sputtering target, in a sputtering atmosphere, such as a gas containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon, or a mixed gas containing the above inert gas and an active gas selected from the group consisting of oxygen, nitrogen, carbon dioxide, nitric oxide and nitrogen dioxide and containing at least oxygen and nitrogen. Furthermore, the phase shift film 30 is formed when the gas pressure in the film forming chamber during sputtering is 0.7 Pa or more and 3.0 Pa or less. Preferably, the phase shift film 30 is formed when the gas pressure in the film forming chamber during sputtering is 0.8 Pa or more and 3.0 Pa or less. By setting the gas pressure range in this way, a columnar structure can be formed in the phase shift film 30. By using this columnar structure, side etching can be suppressed when the pattern is formed as described below, and a high etching rate can be achieved. Here, the columnar structure has a greater effect in suppressing the decrease in wet etching speed, and can improve the washing resistance of the phase shift film 30, and it is also easy to improve the transmittance and other aspects. It is better that the atomic ratio of transition metal and silicon in the transition metal silicide target is transition metal: silicon = 1:3 or more and 1:15 or less.

The composition and thickness of the phase shift film 30 are adjusted in such a way that the phase shift film 30 has the above-mentioned phase difference and transmittance. The composition of the phase shift film 30 can be controlled by the content ratio of the elements constituting the sputtering target (for example, the ratio of the content ratio of the transition metal to the content ratio of silicon), the composition and flow rate of the sputtering gas, etc. The thickness of the phase shift film 30 can be controlled by the sputtering power, the sputtering time, etc. In addition, the phase shift 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 phase shift film 30 can also be controlled by the transport speed of the substrate. In this way, the content ratio of the light element components including oxygen and nitrogen in the phase shift film 30 is controlled to be greater than 40 atomic % and less than 70 atomic %.

When the phase shift film 30 includes a single film, the composition and flow rate of the sputtering gas are appropriately adjusted, and the above film forming process is performed once. When the phase shift film 30 includes a plurality of films having different compositions, the composition and flow rate of the sputtering gas are appropriately adjusted, and the above film forming process is performed multiple times. The phase shift film 30 may also be formed using targets having different content ratios of elements constituting the sputtering target. When the film forming process is performed multiple times, the sputtering power applied to the sputtering target may be changed in each film forming process.

2. Surface treatment step When the phase shift film 30 includes an oxygen-containing transition metal silicide material such as a transition metal silicide oxide containing transition metal, silicon and oxygen or a transition metal silicide nitride oxide containing transition metal, silicon, oxygen and nitrogen, a surface treatment step for adjusting the surface oxidation state of the phase shift film 30 can be performed on the surface of the phase shift film 30 to suppress the penetration of the etching solution caused by the presence of the transition metal oxide. Furthermore, when the phase shift film 30 includes a transition metal silicide nitride containing transition metal, silicon and nitrogen, the content of the transition metal oxide is less than that of the above-mentioned oxygen-containing transition metal silicide material. Therefore, when the material of the phase shift film 30 is transition metal silicide nitride, the above-mentioned surface treatment step may be performed or not performed. As a surface treatment step for adjusting the surface oxidation state of the phase shift film 30, a method of surface treatment using an acidic aqueous solution, a method of surface treatment using an alkaline aqueous solution, a method of surface treatment by dry treatment such as ashing, etc. can be listed. In this way, the phase shift mask substrate 10 of the implementation form 2 is obtained. In the manufacture of the phase shift mask substrate 10 of the implementation form 1, the following etching mask film formation step is further performed.

3. Etching mask film formation step After the phase shift film formation step, surface treatment is performed to adjust the surface oxidation state of the phase shift film 30 as needed, and then an etching mask film 40 is formed on the phase shift film 30 by sputtering. The etching mask film 40 is preferably formed using an inline sputtering device. When the sputtering device is an inline sputtering device, the thickness of the etching mask film 40 can also be controlled by using the transport speed of the transparent substrate 20. The formation of the etching mask film 40 is carried out using a sputtering target containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxycarbide, etc.) in a sputtering atmosphere, wherein the sputtering atmosphere is, for example, a gas containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon, or a mixed gas containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon and at least one active gas selected from the group consisting of oxygen, nitrogen, nitric oxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon gas and fluorine gas. Examples of hydrocarbon gases include methane gas, butane gas, propane gas, and styrene gas. Furthermore, by adjusting the gas pressure in the film forming chamber during sputtering, the etching mask film 40 can be formed into a columnar structure similar to the phase shift film 30. This can suppress side etching during pattern formation described below, and can achieve a high etching rate.

When the etching mask film 40 contains a single film with uniform composition, the above film forming process is performed once without changing the composition and flow rate of the sputtering gas. When the etching mask film 40 contains multiple films with different compositions, the composition and flow rate of the sputtering gas are changed in each film forming process, and the above film forming process is performed multiple times. When the etching mask film 40 contains a single film with a composition that continuously changes in the thickness direction, the above film forming process is performed once while changing the composition and flow rate of the sputtering gas together with the elapsed time of the film forming process. In this way, the phase shift mask substrate 10 of the implementation form 1 is obtained.

Furthermore, the phase shift mask substrate 10 shown in FIG1 has an etching mask film 40 on the phase shift film 30, and therefore, when manufacturing the phase shift mask substrate 10, an etching mask film forming step is performed. Also, when manufacturing a phase shift mask substrate having an etching mask film 40 on the phase shift film 30 and a photoresist film on the etching mask film 40, after the etching mask film forming step, a photoresist film is formed on the etching mask film 40. Moreover, in the phase shift mask substrate 10 shown in FIG2, when manufacturing a phase shift mask substrate having a photoresist film on the phase shift film 30, a photoresist film is formed after the phase shift film forming step.

The phase shift mask substrate 10 of the first embodiment has an etching mask film 40 formed on the phase shift film 30, and at least the phase shift film 30 has a columnar structure. In addition, the phase shift mask substrate 10 of the second embodiment has a phase shift film 30 formed thereon, and the phase shift film 30 has a columnar structure.

The phase shift mask substrate 10 of the embodiments 1 and 2 promotes etching in the film thickness direction and suppresses side etching when the phase shift film 30 is patterned by wet etching, so that a phase shift film pattern with a good cross-sectional shape and a desired transmittance (for example, a higher transmittance) can be formed in a shorter etching time. Therefore, a phase shift mask substrate capable of manufacturing the following phase shift mask can be obtained, which does not cause the transmittance of the transparent substrate to decrease due to damage to the substrate by the wet etching liquid, and can transfer a high-precision phase shift film pattern with good accuracy. In addition, when the phase shift film 30 is formed on the transparent substrate 20, it can also be formed when the gas pressure in the film forming chamber during sputtering is 0.7 Pa or more and 2.4 Pa or less. By setting the range of gas pressure in this way, the phase shift film 30 having an indentation hardness of 18 GPa or more and 23 GPa or less by the nano-indentation method can be formed. By setting the indentation hardness of the phase shift film 30 to 18 GPa or more and 23 GPa or less, side etching during pattern formation described below can be suppressed, a high etching rate can be achieved, and surface roughness of the transparent substrate 20 can be suppressed. Here, the effect of suppressing the decrease of wet etching rate by setting the indentation hardness to 18 GPa or more and 23 GPa or less is greater, which can improve the washing resistance of the phase shift film 30 and easily improve the transmittance and other aspects. It is preferable that the atomic ratio of transition metal and silicon in the transition metal silicide target is transition metal: silicon = 1:3 or more and 1:15 or less as described above.

Implementation form 3.4. In implementation forms 3 and 4, a method for manufacturing a phase shift mask is described.

FIG3 is a schematic diagram showing a method for manufacturing a phase shift mask of embodiment 3. FIG4 is a schematic diagram showing a method for manufacturing a phase shift mask of embodiment 4. The method for manufacturing a phase shift mask shown in FIG3 is a method for manufacturing a phase shift mask using the phase shift mask substrate 10 shown in FIG1, and includes: forming a photoresist film on an etching mask film 40 of the following phase shift mask substrate 10; forming a photoresist film pattern 50 by drawing/developing a desired pattern on the photoresist film (first photoresist film pattern forming step); forming a photoresist film pattern 50 by drawing/developing a desired pattern on the photoresist film; ... 0 as a mask, wet-etching the etching mask film 40 to form an etching mask film pattern 40a on the phase shift film 30 (the first etching mask film pattern forming step); and using the etching mask film pattern 40a as a mask, wet-etching the phase shift film 30 to form a phase shift film pattern 30a on the transparent substrate 20 (the phase shift film pattern forming step). Moreover, it further includes a second photoresist film pattern forming step and a second etching mask film pattern forming step.

The manufacturing method of the phase shift mask shown in FIG4 is a method of manufacturing the phase shift mask using the phase shift mask substrate 10 shown in FIG2, and includes: a step of forming a photoresist film on the phase shift mask substrate 10 below; forming a photoresist film pattern 50 by drawing/developing a desired pattern on the photoresist film (a first photoresist film pattern forming step); and a step of wet-etching the phase shift film 30 using the photoresist film pattern 50 as a mask to form a phase shift film pattern 30a on the transparent substrate 20 (a phase shift film pattern forming step). Below, each step of the manufacturing step of the phase shift mask of implementation forms 3 and 4 is described in detail.

Manufacturing steps of the phase shift mask of embodiment 3 1. First photoresist film pattern forming step In the first photoresist film pattern forming step, first, a photoresist film is formed on the etching mask film 40 of the phase shift mask substrate 10 of embodiment 1. There is no particular limitation on the photoresist film material used. For example, it can be a photoresist film that is sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm described below. In addition, the photoresist film can be either positive or negative. Thereafter, a desired pattern is drawn on the photoresist film using laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm. The pattern drawn on the photoresist film is a pattern formed on the phase shift film 30. As the pattern drawn on the photoresist film, a line gap pattern or a hole pattern can be listed. Afterwards, the photoresist film is developed using a specific developer, and as shown in FIG3(a), a first photoresist film pattern 50 is formed on the etching mask film 40.

2. First etching mask film pattern forming step In the first etching mask film pattern forming step, first, the etching mask film 40 is etched using the first photoresist film pattern 50 as a mask to form the first etching mask film pattern 40a. The etching mask film 40 is formed of a chromium-based material including chromium (Cr). When the etching mask film 40 has a columnar structure, it is better in terms of faster etching speed and ability to suppress side etching. The etching liquid 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 ammonium nitrate and perchloric acid can be cited. Thereafter, the first photoresist film pattern 50 is peeled off using a photoresist stripping solution or by ashing as shown in FIG. 3(b). Depending on the situation, the subsequent phase shift film pattern formation step can be performed without peeling off the first photoresist film pattern 50.

3. Phase shift film pattern forming step In the first phase shift film pattern forming step, the phase shift film 30 is wet-etched using the first etching mask film pattern 40a as a mask, as shown in FIG. 3(c), to form a phase shift film pattern 30a. As the phase shift film pattern 30a, a line gap pattern or a hole pattern can be listed. The etching liquid for etching the phase shift film 30 is not particularly limited as long as it can selectively etch the phase shift film 30. For example, an etching liquid containing ammonium fluoride, phosphoric acid and hydrogen peroxide, and an etching liquid containing ammonium hydrogen fluoride and hydrogen peroxide can be listed. Preferably, wet etching is performed for a longer time (over-etching time) than the time (reasonable etching time) until the transparent substrate 20 is exposed in the phase shift film pattern 30a in order to make the cross-sectional shape of the phase shift film pattern 30a good. As the over-etching time, if the influence on the transparent substrate 20 is considered, it is preferably set to a time obtained by adding 20% of the reasonable etching time to the reasonable etching time, and more preferably set to a time obtained by adding 10% of the reasonable etching time.

4. Second photoresist film pattern forming step In the second photoresist film pattern forming step, first, a photoresist film covering the first etching mask film pattern 40a is formed. There is no particular limitation on the photoresist film material used. For example, it can be sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm described below. In addition, the photoresist film can be either positive or negative. Thereafter, a laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm is used to draw the desired pattern on the photoresist film. The pattern drawn on the photoresist film is a shading band pattern that shields the peripheral area of the area where the pattern is formed on the phase shift film 30, or a shading band pattern that shields the central part of the phase shift film pattern, etc. Furthermore, the pattern drawn on the photoresist film may not have a light-shielding band pattern that shields the central portion of the phase-shift film pattern 30a due to the transmittance of the phase-shift film 30 to the exposure light. Afterwards, the photoresist film is developed using a specific developer, and as shown in FIG. 3(d), a second photoresist film pattern 60 is formed on the first etching mask film pattern 40a.

5. Second etching mask film pattern forming step In the second etching mask film pattern forming step, the first etching mask film pattern 40a is etched using the second photoresist film pattern 60 as a mask, as shown in FIG. 3(e), to form the second etching mask film pattern 40b. The first etching mask film pattern 40a is formed of a chromium-based material containing chromium (Cr). The etching solution 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 nitrate and perchloric acid can be cited. Thereafter, the second photoresist film pattern 60 is peeled off using a photoresist stripping liquid or by ashing. In this way, the phase shift mask 100 is obtained. Furthermore, in the above description, the case where the etching mask film 40 has the function of shielding the transmission of the exposure light is described, but in the case where the etching mask film 40 only has the function of a hard mask when etching the phase shift film 30, in the above description, the second photoresist film pattern forming step and the second etching mask film pattern forming step are not performed, and after the phase shift film pattern forming step, the first etching mask film pattern is peeled off to produce the phase shift mask 100.

According to the manufacturing method of the phase shift mask of the third embodiment, since the phase shift mask substrate of the first embodiment is used, the etching time can be shortened, and a phase shift film pattern with a good cross-sectional shape can be formed. Therefore, a phase shift mask capable of transferring a high-precision phase shift film pattern with good accuracy can be manufactured. The phase shift mask manufactured in this way can cope with the miniaturization of line gap patterns or contact holes.

Manufacturing steps of the phase shift mask of embodiment 4 1. Photoresist film pattern forming step In the photoresist film pattern forming step, first, a photoresist film is formed on the phase shift film 30 of the phase shift mask substrate 10 of embodiment 2. The photoresist film material used is the same as that described in embodiment 3. Furthermore, the phase shift film 30 may be subjected to surface modification treatment as needed before forming the photoresist film to achieve good adhesion with the phase shift film 30. Similarly to the above, after forming the photoresist film, a laser light having any wavelength selected from the wavelength region of 350 nm to 436 nm is used to draw the desired pattern on the photoresist film. Thereafter, the photoresist film is developed using a specific developer, and as shown in FIG. 4(a), a photoresist film pattern 50 is formed on the phase shift film 30. 2. Phase shift film pattern forming step In the phase shift film pattern forming step, the phase shift film 30 is etched using the photoresist film pattern as a mask, as shown in FIG4(b), to form a phase shift film pattern 30a. The phase shift film pattern 30a or the etching liquid or over-etching time for etching the phase shift film 30 is the same as that described in Implementation Form 3. Thereafter, the photoresist film pattern 50 is stripped using a photoresist stripping liquid or by ashing (FIG4(c)). In this way, a phase shift mask 100 is obtained. According to the manufacturing method of the phase shift mask of the fourth embodiment, since the phase shift mask base of the second embodiment is used, the transmittance of the transparent substrate is not reduced due to the damage of the wet etching solution to the substrate, the etching time can be shortened, and a phase shift film pattern with a good cross-sectional shape can be formed. Therefore, a phase shift mask that can transfer a high-precision phase shift film pattern with good accuracy can be manufactured. The phase shift mask manufactured in this way can cope with the miniaturization of line gap patterns or contact holes. Furthermore, when a phase shift mask substrate having a phase shift film 30 having an indentation hardness of 18 GPa or more and 23 GPa or less derived by nanoindentation is used to manufacture a phase shift mask, in addition to the above-mentioned effects, the surface roughness of the transparent substrate 20 can be suppressed and the washability of the phase shift film 30 can be improved.

Implementation form 5. In implementation form 5, a method for manufacturing a display device is described. The display device is manufactured by performing a step (mask loading step) of using a phase shift mask 100 manufactured using the above-mentioned phase shift mask substrate 10 or a phase shift mask 100 manufactured by the above-mentioned method for manufacturing the phase shift mask 100 and a step (exposure step) of exposing a transfer pattern to a photoresist film on the display device. Below, each step is described in detail.

1. Loading step In the loading step, the phase shift mask manufactured in Implementation 3 is loaded on the mask stage of the exposure device. Here, the phase shift mask is arranged in a manner opposite to the photoresist film formed on the display device substrate via the projection optical system of the exposure device.

2. Pattern transfer step In the pattern transfer step, the phase shift mask 100 is irradiated with exposure light to transfer the phase shift film pattern to the photoresist film formed on the display device substrate. The exposure light includes a composite light of multiple wavelengths selected from the wavelength range of 365 nm to 436 nm or a monochromatic light in which a certain wavelength range is cut off from the wavelength range of 365 nm to 436 nm using a filter or the like. For example, the exposure light includes a composite light of i-line, h-line and g-line or a monochromatic light of i-line. If the composite light is used as the exposure light, the exposure light intensity can be increased, thereby increasing the output, and thus reducing the manufacturing cost of the display device.

According to the manufacturing method of the display device of the embodiment 3, a high-resolution, high-precision display device with a fine line gap pattern or a contact hole can be manufactured. Furthermore, in the above embodiments, the use of a phase-shift mask base with a phase-shift mask film or a phase-shift mask with a phase-shift mask film pattern as a mask base with a pattern-forming film or a mask with a transfer pattern is described, but it is not limited to the above. For example, the present invention can also be applied to a binary mask base with a light-shielding film as a pattern-forming film or a binary mask with a light-shielding film pattern. [Example]

Example 1. A. Phase-shift mask substrate and manufacturing method thereof To manufacture the phase-shift mask substrate of Example 1, first, prepare a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) as the transparent substrate 20.

Then, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward and carried into the chamber of the inline sputtering apparatus. In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, an inert gas including argon (Ar) gas, nitrogen (N ₂ ) gas and helium (He) gas (Ar: 18 sccm, N ₂ : 13 sccm, He: 50 sccm) is introduced into the first chamber while the sputtering gas pressure is set to 1.6 Pa. Then, a sputtering power of 7.6 kW is applied to the first sputtering target containing molybdenum and silicon (molybdenum:silicon=1:9), and a nitride of molybdenum silicide containing molybdenum, silicon and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering. Then, a phase shift film 30 with a film thickness of 150 nm is formed.

Next, the transparent substrate 20 with the phase shift film 30 is moved into the second chamber, and a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) gas (Ar: 65 sccm, N ₂ : 15 sccm) is introduced into the second chamber. Then, a sputtering power of 1.5 kW is applied to the second sputtering target containing chromium, and chromium nitride (CrN) containing chromium and nitrogen (film thickness 15 nm) is formed on the phase shift film 30 by reactive sputtering. Next, a mixed gas (30 sccm) of argon (Ar) and methane (CH ₄ :4.9%) was introduced into the third chamber under a specific vacuum degree, and a sputtering power of 8.5 kW was applied to the third sputtering target containing chromium to form chromium carbide (CrC) containing chromium and carbon on CrN by reactive sputtering (film thickness 60 nm). Finally, in a state where the fourth chamber is brought to a certain vacuum, a mixed gas of argon (Ar) gas and methane (CH ₄ : 5.5%) gas and a mixed gas of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas (Ar+CH ₄ : 30 sccm, N ₂ : 8 sccm, O ₂ : 3 sccm) are introduced, and a sputtering power of 2.0 kW is applied to the fourth sputtering target containing chromium, and chromium carbonitride oxide (CrCON) containing chromium, carbon, oxygen and nitrogen is formed on CrC by reactive sputtering (film thickness 30 nm). As described above, an etching mask film 40 having a laminated structure of a CrN layer, a CrC layer and a CrCON layer is formed on the phase shift film 30. In this way, a phase shift mask substrate 10 having a phase shift film 30 and an etching mask film 40 formed on a transparent substrate 20 is obtained.

The transmittance and phase difference of the phase shift film 30 (the surface of the phase shift film 30) of the obtained phase shift mask substrate 10 were measured using MPM-100 manufactured by Lasertec. The transmittance and phase difference of the phase shift film 30 were measured using a substrate with a phase shift film (virtual substrate) on the main surface of a synthetic quartz glass substrate produced on the same tray. The transmittance and phase difference of the phase shift film 30 were measured by taking the substrate with a phase shift film (virtual substrate) out of the chamber before forming the etching mask film 40. As a result, the transmittance was 27% (wavelength: 405 nm) and the phase difference was 178° (wavelength: 405 nm).

In addition, the obtained phase shift mask substrate 10 was subjected to composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). In the composition analysis results in the depth direction of the phase shift mask substrate 10 obtained by XPS, the content of each constituent element of the phase shift film 30 is approximately constant in the depth direction, and Mo is 8 atomic%, Si is 40 atomic%, N is 48 atomic%, and O is 4 atomic%. In addition, the atomic ratio of molybdenum to silicon is 1:5, which is within the range of 1:3 to 1:15. In addition, the total content of oxygen and nitrogen as light elements is 52 atomic%, which is within the range of 50 atomic% to 65 atomic%. Furthermore, the presence of oxygen in the phase shift film 30 can be considered that the sputtering gas pressure is as high as 0.8 Pa or more, and there is a trace amount of oxygen in the chamber during film formation. In addition, after measuring the indentation hardness of the obtained phase shift film 30 (the measurement method is described below), the indentation hardness satisfies 18 GPa or more and 23 GPa or less.

Next, a cross-sectional SEM (scanning electron microscope) observation was performed at a magnification of 80,000 times at the center of the transfer pattern formation area of the obtained phase shift mask substrate 10, and it was confirmed that the phase shift film 30 had a columnar structure. That is, it was confirmed that the particles of the molybdenum silicide compound constituting the phase shift film 30 had a columnar particle structure extending in the film thickness direction of the phase shift film 30. Moreover, it was confirmed that the columnar particle structure of the phase shift film 30 was a state in which columnar particles in the film thickness direction were irregularly formed, and the length of the columnar particles in the film thickness direction was also inconsistent. In addition, it was also confirmed that the sparse portion of the phase shift film 30 was continuously formed in the film thickness direction. Furthermore, for the image obtained by the cross-sectional SEM observation, the region including the center portion in the thickness direction of the phase shift film 30 was captured with image data of 64 pixels in length and 256 pixels in width (Fig. 5(a)). Furthermore, the image data shown in Fig. 5 was Fourier transformed (Fig. 5(b)). In the spatial frequency spectrum distribution obtained by Fourier transform, it was confirmed that the signal intensity (maximum signal intensity) at the origin of the spatial frequency was 3136000, and that, different from the above maximum signal intensity, there was a spatial frequency spectrum with a signal intensity of 66150. The maximum signal intensity of the spatial frequency spectrum corresponding to the origin of the spatial frequency is 66150/3136000=0.021 (ie, 2.1%), and the phase shift film 30 is a columnar structure having a signal intensity of more than 1.0%.

In addition, the phase shift film 30 has the following columnar structure, which is that for the Fourier transformed image of FIG. 5(b), the origin of the spatial frequency, i.e., the center of the image of FIG. 5(b), is taken as the origin (0), and the maximum spatial frequency corresponding to both ends of the horizontal axis 256 pixels is set to 1 (100%), and the signal with a signal intensity of 2.1% relative to the maximum signal intensity corresponding to the origin of the spatial frequency has a signal at a position 0.055, i.e., 5.5% away from the origin. Furthermore, the same is true for the Fourier transformed images of the following embodiments and comparative examples. In addition, a plate-shaped sample of 100 nm in the perpendicular direction to the film thickness direction (in-plane direction of the substrate) was collected near the center of the film thickness of the phase shift film 30, and dark field plan STEM observation was performed. The dark field plan STEM (scanning transmission electron microscope) observation results are shown in FIG6. As shown in FIG6, gray-white and gray-black spot patterns were observed in the particle part (gray-white part) regarded as a columnar shape and between particles (gray-black part). For the gray-white and gray-black parts, quantitative analysis of the elements (Mo, Si, N, O) constituting the phase shift film 30 was performed by EDX analysis (energy-dispersive X-ray analysis) (not shown). As a result, it was confirmed that the detected amount (count value) of Si in the gray-black portion and the gray-white portion was higher than that of Mo, and the detected amount (count value) of the constituent elements of the phase shift film 30 in the gray-black portion was lower than that in the gray-white portion. In particular, the detected amount (count value) of Si in the gray-black portion was 600 (Counts), and the detected amount (count value) of Si in the gray-white portion was 400 (Counts), and the difference in the detected amount (count value) was larger than that of other elements. Based on this result, it was confirmed that the phase shift film 30 was formed with a relatively high-density particle portion (gray-white portion) and a relatively low-density sparse portion (gray-black portion). The particle portion corresponds to the columnar particles shown in FIG. 5 or FIG. 7. Furthermore, the overall film density of the phase shift film 30 is lower than the film density of the previous phase shift film.

B. Phase-shift mask and its manufacturing method In order to manufacture the phase-shift mask 100 using the phase-shift mask substrate 10 manufactured in the above manner, first, a photoresist film is coated on the etching mask film 40 of the phase-shift mask substrate 10 using a photoresist coating device. Thereafter, a photoresist film with a film thickness of 520 nm is formed through heating and cooling steps. Thereafter, a laser drawing device is used to draw the photoresist film, and through development and rinsing steps, a photoresist film pattern with a hole pattern of 1.5 μm in diameter is formed on the etching mask film.

Thereafter, the etching mask film is wet-etched using a chromium etching solution containing ammonium nitrate and perchloric acid, using the photoresist film pattern as a mask, to form a first etching mask film pattern 40a.

Then, the first etching mask film pattern 40a is used as a mask, and the phase shift film 30 is wet-etched using a molybdenum silicide etching solution obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water to form a phase shift film pattern 30a. The wet etching is performed with an over-etching time of 110% to verticalize the cross-sectional shape and form the required fine pattern. The appropriate etching time in Example 1 is 0.15 times the appropriate etching time in the following comparative example, thereby significantly shortening the etching time. Then, the photoresist film pattern is peeled off.

Then, a photoresist coating device is used to coat the photoresist film in a manner covering the first etching mask film pattern 40a. Then, a photoresist film having a film thickness of 520 nm is formed through heating and cooling steps. Then, a laser drawing device is used to draw the photoresist film, and through development and rinsing steps, a second photoresist film pattern 60 for forming a light shielding band is formed on the first etching mask film pattern 40a.

Then, the first etching mask film pattern 40a formed in the transfer pattern forming area is wet-etched using the second photoresist film pattern 60 as a mask and a chromium etching solution containing ammonium nitrate and perchloric acid. Then, the second photoresist film pattern 60 is peeled off.

In this way, a phase shift mask 100 is obtained. The phase shift mask 100 has a phase shift film pattern 30a with an aperture of 1.5 μm in the transfer pattern forming area and a light shielding belt having a laminated structure of the phase shift film pattern 30a and the etching mask film pattern 40b formed on the transparent substrate 20.

The cross section of the phase shift mask observed using a scanning electron microscope. The cross section of the phase shift film pattern includes the upper surface, lower surface and side of the phase shift film pattern. The angle of the cross section of the phase shift film pattern refers to the angle formed by the portion where the upper surface and the side of the phase shift film pattern meet (upper side) and the portion where the side and the lower surface meet (lower side). The cross section angle of the phase shift film pattern 30a of the obtained phase shift mask is 74°, and has a cross section shape that is close to vertical. The phase shift film pattern 30a formed on the phase shift mask of Example 1 has a cross section shape that can fully exert the phase shift effect. It can be considered that the phase shift film pattern 30a has a good cross section shape by setting the phase shift film 30 to a columnar structure due to the following mechanism. According to the observation results of the cross-sectional SEM photograph of FIG7, the phase shift film 30 has a columnar particle structure (columnar structure), and columnar particles extending in the film thickness direction are irregularly formed. In addition, according to the observation results of the dark field plan STEM photograph of FIG6 and the observation results of the cross-sectional SEM photograph of FIG7, the phase shift film 30 is formed of columnar particle parts with relatively high density and sparse parts with relatively low density. According to these facts, when the phase shift film 30 is patterned by wet etching, the etching liquid penetrates into the sparse parts in the phase shift film 30, thereby making etching easy in the film thickness direction. On the other hand, columnar particles are irregularly formed in the direction perpendicular to the film thickness direction (the direction in the substrate plane), and the sparse parts in this direction are formed intermittently, so that etching in this direction is difficult to proceed, and side etching is suppressed, so that the phase shift film pattern 30a obtains a good cross-sectional shape close to perpendicular. In addition, in the phase shift film pattern, no penetration is observed at either the interface with the etching mask film pattern or the interface with the substrate. Therefore, in the exposure light including the light with a wavelength range of 300 nm to 500 nm, more specifically, in the exposure light including the composite light of i-line, h-line and g-line, a phase shift mask with excellent phase shift effect is obtained. Therefore, it can be said that when the phase shift mask of Example 1 is placed on the mask stage of the exposure device and then exposed and transferred to the photoresist film on the display device, a fine pattern less than 2.0 μm can be transferred with high precision.

Furthermore, the cross-sectional SEM photograph of FIG. 7 is a cross-sectional SEM photograph of the phase shift mask manufacturing step of Example 1, in which the first etching mask film pattern 40a is used as a mask, the phase shift film 30 is wet-etched (110% overetching) using a molybdenum silicide etchant to form the phase shift film pattern 30a, and the photoresist film pattern is peeled off. As shown in FIG. 7, the phase shift film pattern 30a maintains the columnar structure of the phase shift film 30, and the surface of the transparent substrate 20 exposed after the phase shift film 30 is removed is smooth, and the state of the decrease in transmittance caused by the rough surface of the transparent substrate 20 can be ignored.

Example 2. A. Phase shift mask substrate and manufacturing method thereof To manufacture the phase shift mask substrate of Example 2, a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) was prepared as a transparent substrate in the same manner as in Example 1. The synthetic quartz glass substrate was moved into the chamber of an inline sputtering device by the same method as in Example 1. The same sputtering target materials as in Example 1 were used as the first sputtering target, the second sputtering target, the third sputtering target, and the fourth sputtering target. Furthermore, a mixed gas of an inert gas including argon (Ar) gas, helium (He) gas and nitrogen (N ₂ ) gas and a nitrogen oxide gas (NO) as a reactive gas (Ar: 18 sccm, N ₂ : 15 sccm, He: 50 sccm, NO: 4 sccm) is introduced into the first chamber while the sputtering gas pressure is set to 1.6 Pa. Then, a sputtering power of 7.6 kW is applied to the first sputtering target including molybdenum and silicon (molybdenum: silicon = 1:9), and a nitride oxide of molybdenum silicide containing molybdenum, silicon, oxygen and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering. Then, a phase shift film 30 with a film thickness of 140 nm is formed. Next, after the phase shift film is formed on the transparent substrate, it is taken out of the chamber and the surface of the phase shift film is cleaned with pure water. The pure water cleaning conditions are set to a temperature of 30 degrees and a cleaning time of 60 seconds. Thereafter, an etching mask film 40 is formed by the same method as in Example 1. In this way, a phase shift mask base 10 having a phase shift film 30 and an etching mask film 40 formed on a transparent substrate 20 is obtained.

The transmittance and phase difference of the phase shift film of the obtained phase shift mask substrate 10 (the phase shift film after the surface of the phase shift film was washed with pure water) were measured using MPM-100 manufactured by Lasertec. In the measurement of the transmittance and phase difference of the phase shift film, a substrate with a phase shift film (dummy substrate) having a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate placed on the same tray was used. The transmittance and phase difference of the phase shift film 30 were measured by taking the substrate with a phase shift film (dummy substrate) out of the chamber before forming the etching mask film. As a result, the transmittance was 33% (wavelength: 365 nm) and the phase difference was 169 degrees (wavelength: 365 nm).

In addition, the obtained phase shift mask substrate was subjected to composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). As a result, similar to Example 1, except for the composition gradient region at the interface between the transparent substrate 20 and the phase shift film 30, and the composition gradient region at the interface between the phase shift film 30 and the etching mask film 40, the content of each constituent element in the phase shift film 30 is roughly constant in the depth direction, with Mo being 7 atomic%, Si being 38 atomic%, N being 45 atomic%, and O being 10 atomic%. In addition, the atomic ratio of molybdenum to silicon is 1:5.4, which is within the range of 1:3 or more and 1:15 or less. In addition, the total content of oxygen, nitrogen, and carbon as light elements is 55 atomic%, which is within the range of 50 atomic% or more and 65 atomic% or less. Next, a cross-sectional SEM observation was performed at a magnification of 80,000 times at the center of the transfer pattern formation area of the obtained phase shift mask substrate 10, and it was confirmed that the phase shift film 30 had a columnar structure. That is, it was confirmed that the particles of the molybdenum silicide compound constituting the phase shift film 30 had a columnar particle structure extending in the film thickness direction of the phase shift film 30. Moreover, it was confirmed that the columnar particle structure of the phase shift film 30 was a state in which the columnar particles in the film thickness direction were irregularly formed, and the length of the columnar particles in the film thickness direction was also inconsistent. In addition, it was also confirmed that the sparse portion of the phase shift film 30 was continuously formed in the film thickness direction. Furthermore, for the image obtained by the cross-sectional SEM observation, the region including the center portion in the thickness direction of the phase shift film 30 was captured with image data of 64 pixels in length and 256 pixels in width (Fig. 8(a)). Furthermore, the image data shown in Fig. 8(a) was Fourier transformed (Fig. 8(b)). In the spatial frequency spectrum distribution obtained by Fourier transform, it was confirmed that the signal intensity (maximum signal intensity) at the origin of the spatial frequency was 2406000, and that, different from the above maximum signal intensity, there was a spatial frequency spectrum with a signal intensity of 39240. The maximum signal intensity of the spatial frequency spectrum relative to the origin of the spatial frequency becomes 39240/2406000=0.016 (i.e. 1.6%), and the phase shift film 30 is a columnar structure with a signal intensity of more than 1.0%.

In addition, the phase shift film 30 has a fine columnar structure, which is a signal having a signal intensity of 1.6% relative to the maximum signal intensity corresponding to the origin of the spatial frequency when the origin (0) of the Fourier transformed image of FIG. 8(b) is set as the center of the image of FIG. 8(b) and both ends of the horizontal axis 256 pixels are set as 1 (100%). In addition, as in Example 1, a dark field plan STEM observation was performed near the film thickness center of the phase shift film 30. As a result, as in Example 1, it was confirmed that each columnar particle part and sparse part were formed in the phase shift film 30.

B. Phase shift mask and its manufacturing method Using the phase shift mask substrate manufactured in the above manner, a phase shift mask having a phase shift film pattern with an aperture of 1.5 μm is manufactured by the same method as in Example 1. The wet etching of the phase shift film 30 is performed with an overetching time of 110% to verticalize the cross-sectional shape and form the required fine pattern. The reasonable etching time in Example 2 is 0.07 times the reasonable etching time in the comparative example below, thereby being able to significantly shorten the etching time.

The cross section of the obtained phase shift mask was observed using a scanning electron microscope. The cross section angle of the phase shift film pattern 30a of the phase shift mask was 74°, and had a cross section shape close to vertical. In addition, in the phase shift film pattern, no penetration was found at either the interface with the etching mask film pattern or the interface with the substrate. Therefore, in the exposure light including the light with a wavelength range of 300 nm to 500 nm, more specifically, the exposure light including the composite light of i-line, h-line and g-line, a phase shift mask with excellent phase shift effect was obtained. Therefore, it can be said that when the phase shift mask of Example 2 is placed on the mask stage of the exposure device and then exposed and transferred to the photoresist film on the display device, a fine pattern less than 2.0 μm can be transferred with high precision.

Furthermore, the cross-sectional SEM photograph of FIG9 is a cross-sectional SEM photograph of the phase shift mask manufacturing step of Example 2, in which the first etching mask film pattern 40a is used as a mask, the phase shift film 30 is wet-etched (110% overetching) using a molybdenum silicide etchant to form the phase shift film pattern 30a, and the photoresist film pattern is peeled off. As shown in FIG9, the phase shift film pattern 30a maintains the columnar structure of the phase shift film 30, and the surface of the transparent substrate 20 exposed after the phase shift film 30 is removed is smooth, and the state of the decrease in transmittance caused by the rough surface of the transparent substrate 20 can be ignored.

Example 3. A. Phase-shift mask substrate and manufacturing method thereof The phase-shift mask substrate of Example 3 is a phase-shift mask substrate that does not have the etching mask film of the phase-shift mask substrate of Example 1. To manufacture the phase-shift mask substrate of Example 3, a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) is prepared as a transparent substrate 20 as in Example 1. To form a phase-shift film 30 on the main surface of the transparent substrate 20 using the same film forming method as in Example 1, first, an inert gas including argon (Ar) gas, nitrogen (N ₂ ) gas, and helium (He) gas (Ar: 18 sccm, N ₂ : 13.5 sccm, He: 50 sccm) is introduced while the sputtering gas pressure in the first chamber is set to 1.4 Pa. Under the film forming conditions, a phase shift film 30 (film thickness: 150 nm) including oxynitride of molybdenum silicide is formed on the transparent substrate 20. In this way, the phase shift mask base 10 having the phase shift film 30 formed on the transparent substrate 20 is obtained.

The transmittance and phase difference of the phase shift film of the obtained phase shift mask substrate 10 were measured using MPM-100 manufactured by Lasertec. In the measurement of the transmittance and phase difference of the phase shift film, a substrate with a phase shift film (dummy substrate) having a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate produced on the same tray was used. As a result, the transmittance was 24% (wavelength: 405 nm) and the phase difference was 183 degrees (wavelength: 405 nm).

The phase shift film 30 of the obtained phase shift mask substrate 10 was analyzed in the depth direction by X-ray photoelectron spectroscopy (XPS). The results showed that, similar to Example 1, the content of each constituent element of the phase shift film 30 was substantially constant in the depth direction. In addition, the atomic ratio of molybdenum to silicon was 1:5, which was within the range of 1:3 to 1:15. In addition, the total content of oxygen, nitrogen, and carbon as light elements was 52 atomic %, which was within the range of 50 atomic % to 65 atomic %. In addition, the content of oxygen was 0.3 atomic %, which was within the range of more than 0 atomic % and less than 40 atomic %.

Next, a cross-sectional SEM observation was performed at a magnification of 80,000 times at the center of the transfer pattern formation area of the obtained phase shift mask substrate 10, and it was confirmed that the phase shift film 30 had a columnar structure. That is, it was confirmed that the particles of the molybdenum silicide compound constituting the phase shift film 30 had a columnar particle structure extending in the film thickness direction of the phase shift film 30. Moreover, it was confirmed that the columnar particle structure of the phase shift film 30 was a state in which the columnar particles in the film thickness direction were irregularly formed, and the length of the columnar particles in the film thickness direction was also inconsistent. In addition, it was also confirmed that the sparse portion of the phase shift film 30 was continuously formed in the film thickness direction. Furthermore, for the image obtained by the cross-sectional SEM observation, the region including the center portion in the thickness direction of the phase shift film 30 was captured with image data of 64 pixels in length and 256 pixels in width (Fig. 10(a)). Furthermore, the image data shown in Fig. 10(a) was Fourier transformed (Fig. 10(b)). In the spatial frequency spectrum distribution obtained by Fourier transform, it was confirmed that the signal intensity (maximum signal intensity) at the origin of the spatial frequency was 31590000, and that, different from the above maximum signal intensity, there was a spatial frequency spectrum with a signal intensity of 47230. The maximum signal intensity of the spatial frequency spectrum relative to the origin of the spatial frequency is 47230/3159000=0.015 (ie, 1.5%), and the phase shift film 30 is a columnar structure having a signal intensity of more than 1.0%.

In addition, the phase shift film 30 has a fine columnar structure with a relatively large spatial frequency. The columnar structure is a signal having a signal intensity of 1.5% relative to the maximum signal intensity corresponding to the origin of the spatial frequency when the origin (0) of the Fourier transformed image of FIG. 10 (b) is set to 1 (100%) at both ends of the horizontal axis 256 pixels. In addition, as in Example 1, a dark field plan STEM observation was performed near the film thickness center of the phase shift film 30. As a result, as in Example 1, it was confirmed that columnar particles and sparse portions were formed in the phase shift film 30.

B. Phase shift mask and its manufacturing method Using the phase shift mask substrate 10 manufactured in the above manner, a phase shift mask having a phase shift film pattern with an aperture of 1.5 μm is manufactured by the same method as in Example 1. The wet etching of the phase shift film 30 is performed with an overetching time of 110% to verticalize the cross-sectional shape and form the required fine pattern. The reasonable etching time in Example 3 is 0.20 times the reasonable etching time in the following comparative example, thereby being able to significantly shorten the etching time.

The cross section of the obtained phase shift mask was observed using a scanning electron microscope. The cross section angle of the phase shift film pattern 30a of the phase shift mask was 80°, and had a cross section shape close to vertical. In addition, in the phase shift film pattern, no penetration was found at either the interface with the etching mask film pattern or the interface with the substrate. Therefore, in the exposure light including the light with a wavelength range of 300 nm to 500 nm, more specifically, the exposure light including the composite light of i-line, h-line and g-line, a phase shift mask with excellent phase shift effect was obtained. Therefore, it can be said that when the phase shift mask of Example 3 is placed on the mask stage of the exposure device and then exposed and transferred to the photoresist film on the display device, a fine pattern less than 2.0 μm can be transferred with high precision.

Furthermore, the cross-sectional SEM photograph of FIG. 11 is a cross-sectional SEM photograph of the phase shift mask manufacturing step of Example 3, in which the first etching mask film pattern 40a is used as a mask, the phase shift film 30 is wet-etched (110% overetching) using a molybdenum silicide etching solution to form the phase shift film pattern 30a, and the photoresist film pattern is peeled off. As shown in FIG. 11, the phase shift film pattern 30a maintains the columnar structure of the phase shift film 30, and the surface of the transparent substrate 20 exposed after the phase shift film 30 is removed is smooth, and the transmittance caused by the surface roughness of the transparent substrate 20 can be ignored. The line edge roughness is better than that of Example 1.

Furthermore, in the above-mentioned embodiment, the case of using molybdenum as a transition metal is described, but the case of other transition metals can also obtain the same effect as the above. In addition, in the above-mentioned embodiment, the example of a phase shift mask substrate or a phase shift mask for display device manufacturing is described, but it is not limited to this. The phase shift mask substrate or phase shift mask of the present invention can also be used for semiconductor device manufacturing purposes, MEMS (microelectromechanical system) manufacturing purposes, printed circuit board purposes, etc. In addition, the present invention can also be applied to a binary mask substrate having a light-shielding film as a thin film for pattern formation or a binary mask having a light-shielding film pattern. Furthermore, in the above-mentioned embodiment, an example of a transparent substrate with a size of 1214 (1220 mm×1400 mm×13 mm) is described, but it is not limited to this. In the case of a phase shift mask substrate for display device manufacturing, a large (Large Size) transparent substrate is used, and the size of the transparent substrate is a length of 300 mm or more on one side. The size of the transparent substrate used in the phase shift mask substrate for display device manufacturing is, for example, 330 mm×450 mm or more and 2280 mm×3130 mm or less. In addition, in the case of a phase shift mask substrate for semiconductor device manufacturing, MEMS manufacturing, and printed circuit board manufacturing, a small (Small Size) transparent substrate is used, and the size of the transparent substrate is a length of 9 inches or less on one side. The size of the transparent substrate used in the phase shift mask substrate for the above purposes is, for example, 63.1 mm × 63.1 mm or more and 228.6 mm × 228.6 mm or less. Generally, the 6025 size (152 mm × 152 mm) or 5009 size (126.6 mm × 126.6 mm) is used for semiconductor manufacturing and MEMS manufacturing, and the 7012 size (177.4 mm × 177.4 mm) or 9012 size (228.6 mm × 228.6 mm) is used for printed circuit board applications.

Comparative Example 1. A. Phase-shifted mask substrate and its manufacturing method To manufacture the phase-shifted mask substrate of Comparative Example 1, a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) was prepared as a transparent substrate in the same manner as in Example 1. The synthetic quartz glass substrate was moved into the chamber of the inline sputtering device by the same method as in Example 1. Then, a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) gas (Ar: 30 sccm, N ₂ : 30 sccm) was introduced while the sputtering gas pressure in the first chamber was set to 0.5 Pa. Next, a sputtering power of 7.6 kW is applied to the first sputtering target containing molybdenum and silicon (molybdenum:silicon=1:9), and a nitride of molybdenum silicide containing molybdenum, silicon and nitrogen is deposited on the main surface of the transparent substrate by reactive sputtering. In this way, a phase shift film with a film thickness of 144 nm is formed. The indentation hardness of the phase shift film in Example 1 does not meet 18 GPa or more and 23 GPa or less. Thereafter, an etching mask film is formed by the same method as in Example 1. In this way, a phase shift mask substrate having a phase shift film and an etching mask film formed on a transparent substrate is obtained.

The transmittance and phase difference of the phase shift film of the phase shift mask substrate were measured using MPM-100 manufactured by Lasertec. The transmittance and phase difference of the phase shift film were measured using a substrate (dummy substrate) with a phase shift film formed on the main surface of a synthetic quartz glass substrate placed on the same tray. The transmittance and phase difference of the phase shift film were measured by taking the substrate (dummy substrate) with the phase shift film out of the chamber before forming the etching mask film. The results showed that the transmittance was 30% (wavelength: 405 nm) and the phase difference was 177 degrees (wavelength: 405 nm).

Furthermore, the obtained phase shift mask substrate was subjected to composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). As a result, the content of each constituent element of the phase shift film 30 is approximately constant in the depth direction, with Mo being 8 atomic %, Si being 39 atomic %, N being 52 atomic %, and O being 1 atomic %, except for the composition gradient region of the interface between the transparent substrate 20 and the phase shift film 30 and the composition gradient region of the interface between the phase shift film 30 and the etching mask film 40. Furthermore, the atomic ratio of molybdenum to silicon is 1:4.9, which is within the range of 1:3 or more and 1:15 or less. Furthermore, the total content of oxygen, nitrogen, and carbon as light elements is 53 atomic %, which is within the range of 50 atomic % or more and 65 atomic % or less.

Next, a cross-sectional SEM observation was performed at a magnification of 80,000 times at the center of the transfer pattern formation area of the obtained phase shift mask substrate 10. As a result, no columnar structure could be confirmed in the phase shift film, but an ultrafine crystalline structure or amorphous structure could be confirmed. For the image obtained by the cross-sectional SEM observation, the image data of 64 pixels in length and 256 pixels in width in the thickness direction of the phase shift film 30 including the center part was captured (Figure 12 (a)). Furthermore, the image data shown in Figure 12 (a) was Fourier transformed (Figure 12 (b)). In the spatial frequency spectrum distribution obtained by Fourier transform, the signal intensity (maximum signal intensity) at the origin of the spatial frequency is 2073000, and no stronger signal different from the maximum intensity signal is confirmed, and there is only a spatial frequency spectrum with a signal intensity of 12600. The spatial frequency spectrum is 12600/2073000=0.006 (i.e., 0.6%) relative to the maximum signal intensity corresponding to the origin of the spatial frequency, and the phase shift film 30 does not have an ultrafine crystalline structure or an amorphous structure with a signal intensity of more than 1.0%.

B. Phase-shift mask and its manufacturing method Using the phase-shift mask substrate manufactured in the above manner, a phase-shift mask is manufactured by the same method as in Example 1. The wet etching of the phase-shift film is performed with an overetching time of 110% to verticalize the cross-sectional shape and form the required fine pattern. The reasonable etching time in Example 1 is 142 minutes, which is a longer time. In addition, the cross-sectional SEM photograph of FIG13 is a cross-sectional SEM photograph of the phase shift mask manufacturing step of the comparative example, in which the first etching mask film pattern 40a is used as a mask, and the phase shift film 30 is wet-etched (110% overetching) using a molybdenum silicide etching solution to form the phase shift film pattern 30a, and before the photoresist film pattern is peeled off. As shown in FIG13, the surface of the transparent substrate 20 exposed after the phase shift film 30 is removed is rough, and it is also cloudy to my eyes. Therefore, the decrease in transmittance caused by the surface roughness of the transparent substrate 20 is significant. Therefore, it is predicted that when the phase-shift mask of Comparative Example 1 is placed on the mask stage of the exposure device and then exposed and transferred to the photoresist film on the display device, fine patterns less than 2.0 μm cannot be transferred.

Hereinafter, other embodiments 1 to 4 and other comparative examples 1 and 2 (hereinafter, also referred to as each example) are described to more specifically illustrate the implementation form of the present invention. A. Phase shift mask substrate and manufacturing method thereof For each of other embodiments 1 to 4 and other comparative examples 1 and 2, in order to manufacture the phase shift mask substrate, first, a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) is prepared as a transparent substrate 20.

Thereafter, in each case, the synthetic quartz glass substrate was placed on a tray (not shown) with the main surface facing downward, and was carried into the chamber of the inline sputtering device. In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, a mixed gas including argon (Ar) gas, helium (He) gas, and nitrogen (N ₂ ) gas was introduced into the first chamber. The sputtering gas pressure during the introduction was set to different values in each case by adjusting the flow rates of argon (Ar) gas, helium (He) gas, and nitrogen (N ₂ ) gas within the range where the phase shift film satisfies a specific transmittance and phase difference (see Table 1 below). As shown in Table 1, the sputtering gas pressure in each of the other Examples 1 to 4 satisfies the range of 0.7 Pa to 2.4 Pa, and the sputtering gas pressure in the other Comparative Examples 1 and 2 does not satisfy the range of 0.7 Pa to 2.4 Pa. In addition, in each example, a sputtering power of 7.6 kW is applied to the first sputtering target containing molybdenum and silicon (molybdenum: silicon = 1:9), and a nitride of molybdenum silicide containing molybdenum, silicon and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering to form a phase shift film 30. In each example, the film thickness of the phase shift film 30 is 144 nm to 170 nm.

Then, in each case, the transparent substrate 20 with the phase shift film 30 was moved into the second chamber, and a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced into the second chamber. Then, a sputtering power of 1.5 kW was applied to the second sputtering target containing chromium, and chromium nitride (CrN) containing chromium and nitrogen (film thickness 15 nm) was formed on the phase shift film 30 by reactive sputtering. Next, a mixed gas of argon (Ar) and methane (CH ₄ : 4.9%) was introduced into the third chamber under a state of a specific vacuum degree, and a sputtering power of 8.5 kW was applied to the third sputtering target containing chromium, thereby forming chromium carbide (CrC) containing chromium and carbon on CrN by reactive sputtering (film thickness 60 nm). Finally, in a state where the fourth chamber is brought into a specific vacuum, a mixed gas of argon (Ar) gas and methane (CH ₄ : 5.5%) gas and a mixed gas of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas are introduced, and a sputtering power of 2.0 kW is applied to the fourth sputtering target containing chromium, so that chromium oxycarbonitride (CrCON) (film thickness 30 nm) containing chromium, carbon, oxygen and nitrogen is formed on CrC by reactive sputtering. As described above, in each case, an etching mask film 40 having a laminated structure of a CrN layer, a CrC layer and a CrCON layer is formed on the phase shift film 30. In this way, in each case, a phase shift mask substrate 10 having a phase shift film 30 and an etching mask film 40 formed on a transparent substrate 20 is obtained.

In each example, the transmittance and phase difference of the phase shift film 30 (the surface of the phase shift film 30) of the obtained phase shift mask substrate 10 were measured using MPM-100 manufactured by Lasertec. The transmittance and phase difference of the phase shift film 30 were measured using a substrate with a phase shift film (dummy substrate) in which the phase shift film 30 was formed on the main surface of a synthetic quartz glass substrate and placed on the same tray. In each example, the transmittance and phase difference of the phase shift film 30 were measured by taking the substrate with the phase shift film (dummy substrate) out of the chamber before forming the etching mask film 40. As a result, in each example, the transmittance and phase difference satisfied the required range (transmittance: 10-50% at a wavelength of 405 nm, phase difference: 160° or more and 200° or less at a wavelength of 405 nm).

In each example, the obtained phase shift mask substrate 10 was subjected to composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). In each example, in the composition analysis results in the depth direction obtained by XPS analysis of the phase shift mask substrate 10, the content of each constituent element of the phase shift film 30 was approximately constant in the depth direction except for the composition gradient region of the interface between the transparent substrate 20 and the phase shift film 30 and the composition gradient region of the interface between the phase shift film 30 and the etching mask film 40. In addition, in each example, the atomic ratio of molybdenum to silicon was within the range of 1:3 or more and 1:15 or less.

Furthermore, in each example, the indentation hardness of the obtained phase shift film 30 was measured. Specifically, in the phase shift film 30 in each example, 6×6 matrix positions (36 locations) with a measurement position interval of 50 μm were set, and a special probe with a diamond indenter was pressed at a maximum of 0.5 mN at each position to measure the change in load. From the measured values obtained at each position, the abnormal values and the maximum and minimum values were removed, and the indentation hardness in each example was calculated (see Table 1). Furthermore, by removing the abnormal values and the maximum and minimum values, it was confirmed that the standard deviation relative to the measured value became 7% or less of the measured value.

As shown in Table 1, the indentation hardness of other Examples 1 to 4 satisfies 18 GPa or more and 23 GPa or less, and the indentation hardness of other Comparative Examples 1 and 2 does not satisfy 18 GPa or more and 23 GPa or less.

B. Phase-shift mask and its manufacturing method In order to manufacture the phase-shift mask 100 using the phase-shift mask substrate 10 manufactured in the above manner, first, in each case, a photoresist film is coated on the etching mask film 40 of the phase-shift mask substrate 10 using a photoresist coating device. Thereafter, a photoresist film with a film thickness of 520 nm is formed through heating and cooling steps. Thereafter, a laser drawing device is used to draw the photoresist film, and through development and rinsing steps, a photoresist film pattern with a hole pattern of 1.5 μm in diameter is formed on the etching mask film.

Thereafter, in each case, the photoresist film pattern is used as a mask, and a chromium etching solution containing ammonium nitrate and perchloric acid is used to wet-etch the etching mask film to form a first etching mask film pattern 40a.

Thereafter, in each example, the first etching mask film pattern 40a is used as a mask, and the phase shift film 30 is wet-etched using a molybdenum silicide etching solution obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water to form a phase shift film pattern 30a. The wet etching is performed at an overetching time of 110% in each example to verticalize the cross-sectional shape and form the required fine pattern. The etching rate of the phase shift film 30 in each example is shown in Table 1. As shown in Table 1, the etching rate in other comparative example 1 is the smallest 1.0 nm/minute, and the etching rate in other comparative example 2 is the largest 12.0 nm/minute. Thereafter, the photoresist film pattern is peeled off.

Then, in each case, a photoresist coating device is used to coat the photoresist film in a manner covering the first etching mask film pattern 40a. Then, a photoresist film having a film thickness of 520 nm is formed through heating and cooling steps. Then, a laser drawing device is used to draw the photoresist film, and through development and rinsing steps, a second photoresist film pattern 60 for forming a light shielding band is formed on the first etching mask film pattern 40a.

Then, the first etching mask film pattern 40a formed in the transfer pattern formation area is wet-etched using a chromium etching solution containing ammonium nitrate and perchloric acid, using the second photoresist film pattern 60 as a mask. Then, the second photoresist film pattern 60 is peeled off. In each example, a cleaning treatment using a chemical solution (sulfuric acid hydrogen peroxide mixture (SPM), ammonia hydrogen peroxide mixture (SC1), ozone water) is appropriately performed.

In this way, a phase shift mask 100 is obtained in each example. The phase shift mask 100 is formed on the transparent substrate 20, and includes a phase shift film pattern 30a with an aperture of 1.5 μm in the transfer pattern forming area, and a light shielding belt having a laminated structure of the phase shift film pattern 30a and the etching mask film pattern 40b.

[Table 1] Other Embodiments 1 Other Embodiments 2 Other Embodiments 3 Other Embodiments 4 Other Comparison Example 1 Other Comparison Example 2 Pressure [Pa] 1.6 1.9 1.1 0.7 0.5 2.5 Etching rate [nm/min] 7.4 8.6 5.8 3.3 1.0 12.0 Indentation hardness[GPa] 19.3 18.3 21.3 23.0 26.2 17.5 Rough substrate surface OK OK OK OK NG OK Washability OK OK OK OK OK NG

Table 1 shows the sputtering gas pressure (Pa) during the formation of the phase shift film 30 in other embodiments 1 to 4 and other comparative examples 1 and 2, the etching rate (nm/min) of the phase shift film 30, the indentation hardness (GPa) of the phase shift film 30, the presence or absence of surface roughness of the transparent substrate 20 caused by wet etching, and the cleaning resistance of the phase shift film 30.

14 is a graph showing the relationship between the etching rate, the sputtering gas pressure, and the indentation hardness in the phase shift film 30 of the phase shift mask 100 of other embodiments 1 to 4 and other comparative examples 1 and 2. In FIG14 , from the left side to the right side (in order of etching rate from small to large), the indentation hardness and the sputtering gas pressure in other comparative example 1, other embodiment 4, other embodiment 3, other embodiment 2, other embodiment 1, and other comparative example 2 are shown. As shown in FIG14 , it can be seen that there is a correlation between the etching rate in the phase shift film 30 and the indentation hardness or the sputtering gas pressure.

The cross section of the obtained phase shift mask is observed using a scanning electron microscope. The cross section of the phase shift film pattern includes the upper surface, lower surface and side surface of the phase shift film pattern. The angle of the cross section of the phase shift film pattern refers to the angle formed by the portion where the upper surface and the side surface of the phase shift film pattern are connected (upper side) and the portion where the side surface and the lower surface are connected (lower side). As a result, the cross-sectional shape of the phase shift film pattern 30a of the phase shift mask of other embodiments 1 to 4 and other comparison example 2 is in the range of 65° to 75°, and all have a cross-sectional shape that can fully exert the phase shift effect. The surface of the exposed transparent substrate 20 of the phase shift mask 100 in other embodiments 1 to 4 is smooth, and the state of reduced transmittance caused by the rough surface of the transparent substrate 20 can be ignored. Therefore, in the exposure light including the light in the wavelength range of 300 nm to 500 nm, more specifically, in the exposure light including the composite light of i-line, h-line and g-line, a phase shift mask with excellent phase shift effect is obtained. Therefore, when the phase shift mask of other embodiments 1 to 4 is placed on the mask stage of the exposure device and then exposed and transferred to the photoresist film on the display device, it can be transferred with high precision to a fine pattern less than 2.0 μm. Furthermore, in the phase shift film pattern 30a of the phase shift mask 100 in other embodiments 1 to 4, a columnar structure is found.

In contrast, the surface of the exposed transparent substrate 20 of the phase shift mask 100 in other comparative example 1 is rough and also appears cloudy. Therefore, the transmittance decreases significantly due to the rough surface of the transparent substrate 20. Therefore, it is predicted that when the phase shift mask 100 in other comparative example 1 is placed on the mask stage of the exposure device and then exposed to the photoresist film on the display device, fine patterns less than 2.0 μm cannot be transferred.

In addition, the surface of the exposed transparent substrate 20 of the phase shift mask 100 in other comparative example 2 is smooth, and the state of reduced transmittance caused by the rough surface of the transparent substrate 20 can be ignored. However, the transmittance variation and phase difference variation caused by the chemical solution (sulfuric acid hydrogen peroxide mixture (SPM), ammonia hydrogen peroxide mixture (SC1), ozone water) used in the cleaning of the phase shift mask 100 are large, and the transmittance or phase difference required for the phase shift mask 100 is not satisfied. Therefore, it is predicted that when the phase shift mask of other comparative example 2 is placed on the mask stage of the exposure device and then exposed and transferred to the photoresist film on the display device, fine patterns less than 2.0 μm cannot be transferred. Furthermore, no columnar structure is found in the phase shift film pattern 30a of the phase shift mask 100 in other comparative example 1. The same is true in the phase shift film pattern 30a of the phase shift mask 100 in other comparative example 2.

10: Phase shift mask substrate 20: Transparent substrate 30: Phase shift film 30a: Phase shift film pattern 40: Etching mask film 40a: 1st etching mask film pattern 40b: 2nd etching mask film pattern 50: 1st photoresist film pattern 60: 2nd photoresist film pattern 100: Phase shift mask

FIG1 is a schematic diagram showing the film structure of the phase shift mask substrate of embodiment 1. FIG2 is a schematic diagram showing the film structure of the phase shift mask substrate of embodiment 2. FIG3(a) to (e) are schematic diagrams showing the manufacturing steps of the phase shift mask of embodiment 3. FIG4(a) to (c) are schematic diagrams showing the manufacturing steps of the phase shift mask of embodiment 4. FIG5(a) is an enlarged photograph (image data) of the center part of the thickness direction of the phase shift film in the cross-sectional SEM (scanning electron microscope) image of the phase shift mask substrate of embodiment 1. (b) is the result of Fourier transforming the enlarged photograph (image data) of (a). FIG6 is a dark field plane STEM (scanning transmission electron microscopy) photograph of the phase shift film in the phase shift mask substrate of Example 1. FIG7 is a cross-sectional photograph of the phase shift mask of Example 1. FIG8(a) is an enlarged photograph (image data) of the center of the thickness direction of the phase shift film in the cross-sectional SEM image of the phase shift mask substrate of Example 2. FIG8(b) is the result obtained by Fourier transforming the enlarged photograph (image data) of FIG8(a). FIG9 is a cross-sectional photograph of the phase shift mask of Example 2. FIG10(a) is an enlarged photograph (image data) of the center of the thickness direction of the phase shift film in the cross-sectional SEM image of the phase shift mask substrate of Example 3. FIG10(b) is the result obtained by Fourier transforming the enlarged photograph (image data) of FIG10(a). FIG11 is a cross-sectional photograph of the phase shift mask of Example 3. FIG12(a) is an enlarged photograph (image data) of the center portion of the thickness direction of the phase shift film in the cross-sectional SEM image of the phase shift mask base of Comparative Example 1. FIG12(b) is the result of Fourier transforming the enlarged photograph (image data) of FIG12(a). FIG13 is a cross-sectional photograph of the phase shift mask of Comparative Example 1. FIG14 is a graph showing the relationship between the etching rate, sputtering gas pressure, and indentation hardness in the phase shift film of the phase shift mask of other Examples 1 to 4 and other Comparative Examples 1 and 2.

Claims (11)

A photomask base, characterized in that: it has a pattern-forming thin film on a transparent substrate, the pattern-forming thin film contains transition metal, silicon and nitrogen, the pattern-forming thin film has a columnar structure, and the indentation hardness of the pattern-forming thin film derived by nano-indentation method is 18 GPa or more and 23 GPa or less. A mask base as claimed in claim 1, wherein the pattern-forming thin film has a columnar particle structure extending in the film thickness direction. A mask substrate as claimed in claim 1 or 2, wherein the pattern forming thin film comprises any one of a nitride of a transition metal silicide, an oxide of a transition metal silicide, an oxynitride of a transition metal silicide, and a nitride-oxycarbide of a transition metal silicide. A mask substrate as claimed in claim 1 or 2, wherein the transition metal is molybdenum. A mask substrate as claimed in claim 1 or 2, wherein the nitrogen content is greater than 35 atomic % and less than 60 atomic %. A mask substrate as claimed in claim 1 or 2, wherein the pattern-forming film is a phase shift film having optical properties such that the transmittance of the representative wavelength of the exposure light is greater than 1% and less than 80% and the phase difference is greater than 160° and less than 200°. A mask base as claimed in claim 1 or 2, wherein an etching mask film having an etching selectivity different from that of the pattern forming film is provided on the above-mentioned pattern forming film. A mask substrate as claimed in claim 7, wherein the etching mask film contains chromium. A method for manufacturing a photomask, characterized by comprising the following steps: Preparing a photomask base as in any one of claims 1 to 6; and Forming a photoresist film on the above-mentioned pattern-forming film, using the photoresist film pattern formed by the above-mentioned photoresist film as a mask, wet-etching the above-mentioned pattern-forming film to form a transfer pattern on the above-mentioned transparent substrate. A method for manufacturing a photomask, characterized by comprising the following steps: Preparing a photomask substrate as claimed in claim 7 or 8; Forming a photoresist film on the etching mask film, using the photoresist film pattern formed by the photoresist film as a mask, wet etching the etching mask film to form an etching mask film pattern on the pattern forming film; and Using the etching mask film pattern as a mask, wet etching the pattern forming film to form a transfer pattern on the transparent substrate. A method for manufacturing a display device is characterized by having an exposure step, wherein a mask obtained by the method for manufacturing a mask as in claim 9 or 10 is placed on a mask stage of an exposure device, and the transfer pattern formed on the mask is exposed and transferred to a photoresist formed on a substrate of the display device.