TWI782237B - 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, method of manufacturing photomask, and method of manufacturing display device

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

In recent years, in display devices such as FPD (Flat Panel Display) represented by LCD (Liquid Crystal Display, liquid crystal display device), high-definition and high-speed display have been achieved along with larger screen size and wider viewing angle. Rapid development. One of the elements required for this high-definition and high-speed display is the production of electronic circuit patterns such as components and wiring with fine and high dimensional accuracy. Photolithography is often used in the patterning of electronic circuits for display devices. Therefore, there is a need for a photomask such as a phase shift mask or a binary mask for display device manufacture in which fine and high-precision patterns are formed.

For example, Patent Document 1 discloses a phase inversion mask base having a phase inversion film on a transparent substrate. In the mask substrate, the phase inversion film has a reflectance of less than 35% and a reflectance of 1% to 40% for exposure light of composite wavelengths including i-line (365nm), h-line (405nm), and g-line (436nm). % transmittance, and it includes two or more layers of multilayer films in such a way that the gradient of the pattern section is formed rapidly when forming the pattern, and the above multilayer film contains at least one of oxygen (O), nitrogen (N), and carbon (C) The metal silicide compound of the light element substance, the metal silicide compound is formed by injecting the reactive gas and the inert gas containing the above light element substance at a ratio of 0.5:9.5~4:6.

Also, in Patent Document 2, a phase shift mask substrate is disclosed. The phase shift mask substrate has: a transparent substrate; series material; and etching mask film, which contains chromium series material. In the phase shift mask substrate, a composition gradient area 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 rate of the light semitransmissive film increases toward the depth direction. Furthermore, the content of oxygen in the composition gradient region is 10 atomic % or less.

[Prior Art Literature] [Patent Document]

[Patent Document 1] Korean Registered Patent No. 1801101

[Patent Document 2] Japanese Patent No. 6101646

As a phase shift mask used in the production of high-definition (above 1000ppi) panels in recent years, In order to realize high-resolution pattern transfer, a phase shift mask having a fine phase shift film pattern with an aperture of 6 μm or less and a line width of 4 μm or less is required as a phase shift mask. Specifically, a phase shift mask in which a fine phase shift film pattern with an aperture diameter of 1.5 μm is formed is required.

In addition, in order to achieve pattern transfer with higher resolution, it is required to have a phase shift mask substrate with a phase shift film whose transmittance to exposed light is 15% or more, and a substrate formed with a transmittance to exposed light. Phase shift mask for more than 15% phase shift film pattern. Furthermore, in the cleaning resistance (chemical characteristics) of the phase shift mask base or the phase shift mask, it is required to form a film having a phase shift film or a phase shift film pattern to reduce or the composition change of the surface causes A phase shift mask substrate of a wash-resistant phase shift film in which changes in optical characteristics are suppressed, and a phase shift mask formed with a wash-resistant phase shift film pattern.

In order to meet the requirements for the transmittance of exposed light and the requirements for cleaning resistance, the ratio of silicon in the atomic ratio of metal and silicon in the metal silicide compound (metal silicide-based material) constituting the phase shift film is increased. It is more effective, but there are the following problems: the wet etching speed is greatly slowed down (the wet etching time becomes longer), and the substrate is damaged by the wet etching solution, and the transmittance of the transparent substrate is reduced.

Moreover, in the case of a binary mask substrate having a light-shielding film containing a transition metal and silicon, when a light-shielding pattern is formed on the light-shielding film by wet etching, there is a requirement for cleaning resistance, so there is a difference from the above. same problem.

Therefore, the present invention is completed to solve the above problems. The purpose of the present invention is to provide a photomask substrate, a method for manufacturing a photomask substrate, a method for manufacturing a photomask, and a method for manufacturing a display device. Wet etching can shorten the wet etching time when forming a transfer pattern on a thin film for pattern formation such as a phase shift film or a light-shielding film containing transition metals and silicon, Thus, a transfer pattern having a good cross-sectional shape can be formed.

The inventors of the present invention have earnestly studied measures to solve these problems. First, the atomic ratio of the transition metal and silicon in the pattern forming film is set to be a transition metal:silicon ratio of 1:3 or more, and in order to shorten the wet etching time of the wet etching solution in the pattern forming film, And the oxygen gas contained in the sputtering gas introduced into the film-forming chamber is adjusted so that the thin film for pattern formation contains a large amount of oxygen (O), and the thin film for pattern formation is formed. As a result, although the wet etching speed for forming the transfer pattern becomes faster, the refractive index of the phase shift film in the phase shift mask substrate with respect to the exposed light is lowered, thus resulting in obtaining the desired phase difference (for example, 180°) the required film thickness becomes thicker. Also, the extinction coefficient of the light-shielding film in the binary mask substrate with respect to the exposed light decreases, thus resulting in a change in the film thickness required to obtain the desired light-shielding performance (for example, an optical density (OD) of 3 or more). thick. The increase in film thickness of the thin film for pattern formation is disadvantageous in pattern formation by wet etching, and there is a limit to the shortening effect of wet etching time due to increase in film thickness. On the other hand, if the atomic ratio of the above-mentioned transition metal to silicon is set (transition metal:silicon = 1:3 or more), there are advantages such as improving the cleaning resistance of the thin film for pattern formation. Therefore, in this point , It is not good to deviate from the above-mentioned composition ratio of transition metals and silicon.

Therefore, the inventors of the present invention changed the concept and studied to adjust the pressure of the sputtering gas in the film forming chamber to change the film structure. When forming a thin film for pattern formation on a substrate, the sputtering gas pressure in the film forming chamber is usually set at 0.1-0.5Pa. However, the present inventors ventured to make the sputtering gas pressure higher than 0.5 Pa to form a thin film for pattern formation. Moreover, it was found that when the sputtering pressure is not less than 0.7Pa and not more than 3.0Pa, preferably the sputtering gas pressure is not less than 0.8Pa and not more than 3.0Pa. After using a thin film, it not only has better characteristics as a thin film, but also can greatly shorten the etching time when forming a transfer pattern on a pattern forming thin film by wet etching, and can form a transfer pattern with a good cross-sectional shape. Furthermore, the thin film for pattern formation formed in this way has a columnar structure which is not seen in the usual thin film for pattern formation. The present invention has been accomplished as a result of intensive studies as described above, and has the following constitutions.

(Constitution 1) A photomask base having a thin film for pattern formation on a transparent substrate, and the photomask base is used to form the thin film for pattern formation on the transparent substrate by wet etching An original plate of a photomask with a transfer pattern, wherein the pattern-forming thin film contains transition metal and silicon, and the pattern-forming thin film has a columnar structure.

(Structure 2) The photomask substrate as described in Composition 1, wherein the above-mentioned thin film for pattern formation is obtained by observing the cross-section of the above-mentioned photomask substrate with a scanning electron microscope at a magnification of 80,000 times. The area in the thickness direction including the central part is captured with image data of 64 pixels in length and 256 pixels in width. In the spatial frequency spectrum distribution obtained by Fourier transforming the above image data, there is a relative to the origin of the spatial frequency The corresponding maximum signal strength has a spatial frequency spectrum with a signal strength above 1.0%.

(Structure 3) The photomask substrate as described in the composition 2, wherein the above-mentioned thin film for pattern formation is at a distance of 2.0 from the origin of the spatial frequency when the maximum spatial frequency is set to 100% for the signal having a signal strength of 1.0% or more. % above the spatial frequency.

(Structure 4) The photomask substrate described in any one of the constitutions 1 to 3, wherein the atomic ratio of the transition metal contained in the pattern forming film to the silicon is transition metal:silicon=1:3 to 1: 15 or less.

(Structure 5) The photomask base according to any one of the structures 1 to 4, wherein the pattern forming thin film contains at least nitrogen or oxygen.

(Structure 6) The photomask substrate as described in Structure 5, wherein the pattern forming thin film contains nitrogen, and the atomic ratio of the transition metal contained in the pattern forming film to the silicon is such that transition metal:silicon = 1:3 or more 1:15 or less, and the indentation hardness of the film for pattern formation derived by nano-indentation method is not less than 18 GPa and not more than 23 GPa.

(Structure 7) The photomask base as described in the structure 6 whose content rate of the said nitrogen is 35 atomic % or more and 60 atomic % or less.

(Structure 8) The photomask base described in any one of the structures 1 to 7, wherein the transition metal is molybdenum.

(Structure 9) The photomask base described in any one of the structures 1 to 8, wherein the above-mentioned pattern-forming film has a typical wavelength transmittance of 1% to 80% for the exposed light and a phase difference of 160° Phase shift film with optical characteristics above 200°.

(Structure 10) The photomask substrate according to any one of the structures 1 to 9, wherein an etching mask film having an etching selectivity different from that of the pattern forming thin film is provided on the pattern forming thin film.

(Structure 11) The photomask substrate according to the composition 10, wherein the etching mask film contains chromium And substantially no silicon material.

(Structure 12) A method of manufacturing a photomask substrate, characterized in that: it forms a thin film for pattern formation containing transition metal and silicon on a transparent substrate by sputtering, and the thin film for pattern formation is used for film formation. A transition metal silicide target containing transition metal and silicon is used in the chamber, and the sputtering gas pressure in the film forming chamber supplied with sputtering gas is 0.7Pa to 3.0Pa.

(Structure 13) The method for manufacturing a photomask substrate according to the composition 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.

(Structure 14) The method of manufacturing a photomask substrate as described in Configuration 12 or 13, wherein an etching mask is formed on the above-mentioned thin film for pattern formation using a sputtering target containing a material having an etching selectivity different from that of the thin film for pattern formation. Membrane.

(Structure 15) The method of manufacturing a photomask substrate as described in Structure 14, wherein the pattern forming thin film and the etching mask film are formed using an in-line sputtering apparatus.

(Structure 16) A method for manufacturing a photomask, which is characterized in that it includes the following steps: preparing a photomask substrate as described in any one of Constitutions 1 to 9, or by preparing a photomask substrate as described in Constitution 12 or 13 The photomask substrate manufactured by the manufacturing method; 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, performing wet etching on the above-mentioned pattern-forming film, and on transparent substrate A pattern for transfer is formed.

(Structure 17) A method for manufacturing a photomask, which is characterized in that it includes the following steps: preparing a photomask substrate as described in composition 10 or 11, or manufacturing a photomask substrate as described in composition 14 or 15. Photomask base; forming a photoresist film on the above-mentioned etching mask film, using the photoresist film pattern formed by the above-mentioned photoresist film as a mask, performing wet etching on the above-mentioned etching mask film, on the above-mentioned pattern forming film Forming an etching mask pattern; and using the etching mask pattern as a mask, performing wet etching on the pattern forming thin film to form a transfer pattern on the transparent substrate.

(Structure 18) A method of manufacturing a display device, characterized by including an exposure step of placing a photomask obtained by the method of manufacturing a photomask described in Configuration 16 or 17 on a mask of an exposure device and a stage for exposing and transferring the transfer pattern formed on the photomask to the photoresist formed on the display device substrate.

Furthermore, the present inventors studied the film structure by adjusting the pressure of the sputtering gas in the film forming chamber, and found the following other configurations. As described above, the present inventors ventured to make the sputtering gas pressure more than 0.5 Pa to form a thin film for pattern formation. Moreover, it was found that when a pattern-forming thin film is formed at a sputtering gas pressure of 0.7 Pa or more, the etching time can be greatly shortened, a transfer pattern with a good cross-sectional shape can be formed, and surface roughness of the transparent substrate can be suppressed. On the other hand, it turns out that when the sputtering gas pressure at the time of film formation is excessively increased, sufficient cleaning resistance cannot be obtained in the thin film for pattern formation. The inventors of the present invention have conducted earnest research, and found that by forming a thin film for pattern formation at a sputtering gas pressure of 0.7Pa to 2.4Pa, not only the thin film for pattern formation can be used. The better characteristics of the film, and can form a transfer pattern with a good cross-sectional shape, and can suppress the surface roughness of the transparent substrate, and can improve the cleaning resistance of the film for pattern formation.

Furthermore, the present inventors further searched for physical indicators of a thin film for pattern formation having such excellent characteristics. As a result, it was found that there is a relationship between the indentation hardness of the thin film for pattern formation and the wet etching rate. As a result of further intensive research on this point, it was found that if the indentation hardness derived by the nano-indentation method is 18GPa to 23GPa, it not only has better characteristics as a thin film for pattern formation, but also can be used for wet etching. When the transfer pattern is formed on the pattern-forming film, a transfer pattern with a good cross-sectional shape can be formed, the surface roughness of the transparent substrate can be suppressed, and the cleaning resistance of the pattern-forming film can be improved.

(Other configuration 1) A photomask base having a thin film for pattern formation on a transparent substrate, wherein the photomask base is used to form the thin film for pattern formation on the transparent substrate by wet etching The original plate of a photomask with a transfer pattern, the above-mentioned thin film for pattern formation contains transition metal, silicon and nitrogen, and the atomic ratio of the above-mentioned transition metal contained in the above-mentioned thin film for pattern formation to the above-mentioned silicon is transition metal:silicon = 1:3 or more 1:15 or less, the above film for pattern formation has an indentation hardness of 18 GPa to 23 GPa derived by nano-indentation method.

(Other configuration 2) The photomask substrate as described in the other configuration 1, wherein the transition metal is molybdenum.

(Other configuration 3) The photomask substrate according to the other configuration 1 or 2, wherein the nitrogen content is 35 atomic % or more and 60 atomic % or less.

(Other configuration 4) The photomask base described in any one of other configurations 1 to 3, wherein the above-mentioned pattern-forming film has a typical wavelength transmittance of 1% to 80% for the exposed light and a phase difference of Phase shift film with optical characteristics of 160° to 200°.

(Other configuration 5) The photomask substrate according to any one of other configurations 1 to 4, wherein an etching mask film having an etching selectivity different from that of the pattern forming thin film is provided on the pattern forming thin film.

(Other configuration 6) The photomask substrate according to the other configuration 5, wherein the etching mask film is made of a material containing chromium and substantially not containing silicon.

(Other configuration 7) A method of manufacturing a photomask, characterized by comprising the steps of: preparing a photomask substrate 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 photoresist film as a mask, the above film for pattern formation is wet-etched to form a transfer pattern on the above transparent substrate.

(Other configuration 8) A method of manufacturing a photomask, which is characterized in that it includes the following steps: preparing a photomask substrate as described in other configuration 5 or 6; forming a photoresist film on the above-mentioned etching mask film, so that the above-mentioned photoresist The photoresist film pattern formed by the film is used as a mask, and the above-mentioned etching mask film is wet-etched to form an etching mask film pattern on the above-mentioned pattern forming thin film; and the above-mentioned etching mask film pattern is used as a mask, and the above-mentioned Wet etching of thin films for patterning Engraving, forming a transfer pattern on the above-mentioned transparent substrate.

(Other configuration 9) A method of manufacturing a display device, characterized by including an exposure step of placing a photomask obtained by the method of manufacturing a photomask described in other configuration 7 or 8 on an exposure device The mask stage is used to expose and transfer the above-mentioned transfer pattern formed on the above-mentioned photomask to the photoresist formed on the display device substrate.

According to the photomask substrate or the manufacturing method of the photomask substrate of the present invention, the following photomask substrate can be obtained, and the photomask substrate is formed on the film for transfer pattern by wet etching to form the required fine transfer pattern Even when the thin film for pattern formation is made of a silicon-rich metal silicide compound from the viewpoint of cleaning resistance, etc., the transmittance of the transparent substrate does not decrease due to damage to the substrate by the wet etching solution, and can be used in A transfer pattern with a good cross-sectional shape is formed within a short etching time. In addition, according to the photomask base of other configurations of the present invention, it is possible to obtain a photomask base capable of forming a desired fine transfer pattern on a transfer pattern film by wet etching. A transfer pattern with a good cross-sectional shape can be formed, the surface roughness of the transparent substrate can be suppressed, and the cleaning resistance of the film for transferring the pattern can be improved.

Moreover, according to the manufacturing method of the photomask of this invention, a photomask is manufactured using the said photomask base. Therefore, even when the thin film for pattern formation is made of a silicon-rich metal silicide compound from the viewpoint of cleaning resistance, etc., the transmittance of the transparent substrate does not decrease due to damage to the substrate by the wet etching solution. It is possible to manufacture a photomask having a transferred pattern with good transfer accuracy. The photomask can cope with miniaturization of line gap pattern or contact hole. Moreover, according to the manufacturing method of the photomask of the other structure of this invention, the transfer pattern which can form the good cross-sectional shape can be manufactured, and can suppress transparent The surface of the substrate is rough, and the mask can improve the cleaning resistance of the film for transfer pattern.

Also, according to the method for manufacturing a display device of the present invention, a display device is manufactured using a photomask manufactured using the above-mentioned photomask substrate or a photomask obtained by the above-mentioned method for manufacturing a photomask. Therefore, a display device having fine line gap patterns or contact holes can be manufactured.

10: Phase offset mask base

20: Transparent substrate

30:Phase shift film

30a: phase shift film pattern

40: Etching mask film

40a: the first etching mask film pattern

40b: The second etching mask film pattern

50: The first photoresist film pattern

60: The second photoresist film pattern

100: phase offset mask

Fig. 1 is a schematic diagram showing the film constitution of a phase shift mask base in Embodiment 1.

Fig. 2 is a schematic diagram showing the film constitution of the phase shift mask base of the second embodiment.

3(a)-(e) are schematic diagrams showing the manufacturing steps of the phase shift mask of the third embodiment.

4(a)-(c) are schematic diagrams showing the manufacturing steps of the phase shift mask of the fourth embodiment.

Fig. 5(a) is a magnified photo (image data) of the central part of the phase shift film in the thickness direction of the cross-sectional SEM (scanning electron microscope, scanning electron microscope) image of the phase shift mask substrate of Example 1 .

(b) is the result of Fourier transform of the enlarged photo (image data) in (a).

FIG. 6 is a dark field planar STEM (scanning transmission electron microscopy, scanning transmission electron microscope) photograph of the phase shift film in the phase shift mask substrate of Example 1. FIG.

7 is a cross-sectional photo of the phase shift mask of Embodiment 1.

Fig. 8(a) is an enlarged photo (image data) of the central part of the phase shift film in the thickness direction of the cross-sectional SEM image of the phase shift mask substrate of Example 2. Figure 8(b) is the result of Fourier transform of the enlarged photo (image data) in Figure 8(a).

9 is a cross-sectional photo of the phase shift mask of Embodiment 2.

Fig. 10(a) is an enlarged photo (image data) of the central part of the phase shift film in the thickness direction in the cross-sectional SEM image of the phase shift mask substrate of Example 3. Figure 10(b) is the result of Fourier transform of the enlarged photo (image data) in Figure 10(a).

Fig. 11 is a cross-sectional photo of the phase shift mask of Embodiment 3.

Fig. 12(a) is an enlarged photograph (image data) of the central part in the thickness direction of the phase shift film in the cross-sectional SEM image of the phase shift mask substrate of Comparative Example 1. Fig. 12(b) is the result of Fourier transform of the enlarged photo (image data) in Fig. 12(a).

FIG. 13 is a cross-sectional photo of the phase shift mask of Comparative Example 1. FIG.

14 is a graph showing the relationship between the etching rate, the sputtering gas pressure, and the 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.

Implementation form 1.2.

In Embodiments 1 and 2, a phase shift mask base will be described. The phase shift mask base of Embodiment 1 is used to use the etching mask film pattern with the desired pattern formed on the etching mask film as a mask, and the phase shift film is formed on the transparent substrate by wet etching Master plate of phase shift mask with phase shift film pattern. In addition, the phase shift mask base of Embodiment 2 is used to use the photoresist film pattern formed with the desired pattern on the photoresist film as a mask, and the phase shift film is formed on the transparent substrate by wet etching. An original plate of a phase shift film with a phase shift film pattern.

FIG. 1 is a schematic diagram showing the film configuration of a phase shift mask substrate 10 according to the first embodiment.

The phase shift mask base 10 shown in FIG. 1 includes 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 configuration of the phase shift mask substrate 10 according to the second embodiment.

The phase shift mask base 10 shown in FIG. 2 includes a transparent substrate 20 and a phase shift film 30 formed on the transparent substrate 20 .

Hereinafter, the transparent substrate 20, the phase shift film 30, and the etching mask film 40 constituting the phase shift mask base 10 of Embodiment 1 and Embodiment 2 will be described.

The transparent substrate 20 is transparent to the exposure light. The transparent substrate 20 has a transmittance of more than 85%, preferably more than 90%, for the exposed light when it is assumed that there is no surface reflection loss. The transparent substrate 20 includes materials containing silicon and oxygen, and may include glass materials such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.). In the case where the transparent substrate 20 includes low thermal expansion glass, it is possible to suppress the position change of the phase shift film pattern due to thermal deformation of the transparent substrate 20 . In addition, the transparent substrate 20 used for the display device is usually a rectangular substrate whose short side length is 300 mm or more. The present invention is a phase shift mask substrate, which can provide a large size even if the length of the short side of the transparent substrate is 300 mm or more, and can stably transfer the material formed on the transparent substrate, for example, less than 2.0 μm The phase shift mask of the fine phase shift film pattern.

The phase shift film 30 includes a transition metal silicide-based material containing transition metal and silicon. As the transition metal, molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr) and the like are preferable, and molybdenum (Mo) is particularly preferable.

In addition, the phase shift film 30 preferably contains at least nitrogen or oxygen. In the above-mentioned transition metal silicide-based materials, oxygen, which is a light element component, has lower The effect of low extinction coefficient, therefore, can reduce the content of other light element components (nitrogen, etc.) to obtain the desired transmittance, and can also effectively reduce the reflectance of the front and back of the phase shift film 30 . In addition, in the above-mentioned transition metal silicide-based material, nitrogen, which is a light element component, has an effect of not lowering the refractive index compared with oxygen, which is also a light element component. The film thickness is thin. In addition, the total content of light element components including oxygen and nitrogen included in the phase shift film 30 is preferably 40 atomic % or more. More preferably, it is 40 atomic % or more and 70 atomic % or less, More preferably, it is 50 atomic % or more and 65 atomic % or less. Moreover, when oxygen is contained in the phase shift film 30, it is preferable that the content rate of oxygen exceeds 0 atomic % and is 40 atomic % or less in terms of defect quality and chemical resistance.

Examples of transition metal silicide-based materials include transition metal silicide nitride, transition metal silicide oxide, transition metal silicide oxynitride, and transition metal silicide oxycarbide. Also, if the transition metal silicide-based material is a molybdenum silicide-based material (MoSi-based material), a zirconium silicide-based material (ZrSi-based material), or a molybdenum-zirconium silicide-based material (MoZrSi-based material), it is easy to use wet Etching is preferable to obtain an excellent pattern cross-sectional shape, and molybdenum silicide-based materials (MoSi-based materials) are especially preferable.

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

The phase shift film 30 has the function of adjusting the reflectance of light incident from the transparent substrate 20 side (hereinafter, sometimes referred to as the back reflectance) and the function of adjusting the transmittance and phase difference of exposed 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 used in phase shift film 30 was confirmed by cross-sectional SEM observation. That is, the columnar structure in the present invention means that the particles of the transition metal silicide compound containing transition metal and silicon constituting the phase shift film 30 extend toward the film thickness direction of the phase shift film 30 (the direction in which the above-mentioned particles are deposited) The state of the columnar particle structure. Furthermore, in this case, those whose length in the film thickness direction is longer than the length in the vertical direction are defined as columnar particles. That is, the phase shift film 30 is formed with columnar particles extending in the film thickness direction all over the surface of the transparent substrate 20 . In addition, the phase shift film 30 is also formed with sparse portions (hereinafter, sometimes simply referred to as “sparse portions”) whose density is relatively lower than that of columnar particles by adjusting the film forming conditions (sputtering pressure, etc.). Furthermore, in order to effectively suppress the undercut during wet etching and improve the cross-sectional shape of the pattern, the columnar structure of the phase shift film 30 is a preferred form, preferably extending in the film thickness direction. Columnar particles are irregularly formed in the film thickness direction. Furthermore, it is preferable that the columnar particles of the phase shift film 30 have different lengths in the film thickness direction. Furthermore, the sparse portions of the phase shift film 30 are preferably formed continuously in the film thickness direction. Also, it is preferable that the sparse portions of the phase shift film 30 are intermittently formed in a direction perpendicular to the film thickness direction. As a preferable 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, and it can be expressed as follows. That is, the columnar structure of the phase shift film 30 is preferably in a state where the phase shift film The area in the thickness direction of 30 including the central part is captured with image data of 64 pixels in length and 256 pixels in width, and the spatial frequency spectrum obtained by Fourier transforming the image data is at the origin relative to the spatial frequency The corresponding maximum signal strength has a signal strength above 1.0%. By making the phase shift film 30 into the above-described columnar structure, the wet etchant easily permeates the phase shift film 30 in the film thickness direction during wet etching using a wet etchant. The wet etching speed becomes faster, so that the wet etching time can be greatly shortened. Therefore, even if the phase shift film 30 is silicon-rich metal silicide compound, and the transmittance of the transparent substrate will not decrease due to the damage of the wet etching solution to the substrate. In addition, since the phase shift film 30 has a columnar structure extending in the film thickness direction, side etching during wet etching is suppressed, and thus the cross-sectional shape of the pattern becomes favorable.

In addition, the phase shift film 30 is preferably such that the signal having an intensity signal of 1.0% or more relative to the maximum signal intensity of the spatial frequency spectral distribution obtained by Fourier transform is at the spatial frequency when the maximum spatial frequency is set to 100%. Spatial frequencies whose origins are more than 2.0% apart. A signal having an intensity signal of 1.0% or more relative to the maximum signal intensity is separated by 2.0% or more, indicating that a spatial frequency component higher than a certain level is included. That is, it means that the phase shift film 30 is in the state of a fine columnar structure, and the farther the spatial frequency is from the origin, the phase shift film pattern 30a obtained by wet etching is formed on the phase shift film 30 The smaller the roughness of the line edge, the better.

The indentation hardness of the phase shift film 30 is preferably not less than 18 GPa and not more than 23 GPa. The indentation hardness is the hardness measured using the principle of the nano-indentation method stipulated in ISO14577.

By setting the indentation hardness of the phase shift film 30 to 18 GPa or more and 23 GPa or less, the wet etchant easily permeates in the film thickness direction of the phase shift film 30 during wet etching using a wet etchant, Therefore, the wet etching rate becomes faster, and the wet etching time can be shortened. Moreover, it not only has better characteristics as the 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 resistance of the phase shift film 30. Detergency.

The atomic ratio of the 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, it is possible to increase the phase suppression by using the columnar structure The effect of reducing the wet etching rate during patterning of the offset film 30 . In addition, the washing resistance of the phase shift film 30 can be improved, and the transmittance can be easily improved. Moreover, if it is this range, the effect of suppressing the fall of the wet etching rate at the time of pattern formation of the phase shift film 30 by making indentation hardness into 18 GPa or more and 23 GPa or less can be enlarged. From the viewpoint of improving the cleaning resistance of the phase shift film 30, the atomic ratio of the 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 It is a transition metal: silicon = 1:5 or more and 1:15 or less.

The transmittance of the phase shift film 30 to the exposed light satisfies the value required as the phase shift film 30 . The transmittance of the phase shift film 30 is preferably not less than 1% and not more than 80%, more preferably not less than 15% and not more than 65%, with respect to light of a specific wavelength (hereinafter referred to as a representative wavelength) included in the exposed light, and further preferably Preferably it is more than 20% and less than 60%. That is, when the light to be exposed is composite light including light in a wavelength range of 313 nm to 436 nm, the phase shift film 30 has the above-mentioned transmittance for light of a representative wavelength included in the wavelength range. For example, when the light to be exposed is composite light including i-line, h-line, and g-line, the phase shift film 30 has the above-mentioned transmittance for any one of i-line, h-line, and g-line.

The transmittance can be measured using a phase shift measurement device or the like.

The phase difference of the phase shift film 30 with respect to the exposed light satisfies the value required as the phase shift film 30 . The phase difference of the phase shift film 30 is preferably not less than 160° and not more than 200°, more preferably not less than 170° and not more than 190°, with respect to light of a representative wavelength included in the exposed light. According to this property, the phase of the light of the representative wavelength included in the exposure light can be changed to 160° or more and 200° or less. Therefore, the difference between the light of the representative wavelength transmitted through the phase shift film 30 and the light of the representative wavelength transmitted only through the transparent substrate 20 Between them, a phase difference of 160° to 200° is generated. That is, when the light to be exposed is composite light including light in a wavelength range of 313 nm to 436 nm, the phase shift film 30 has the above-mentioned phase difference for light of a representative wavelength included in the wavelength range. For example, when the light to be exposed is 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 i-line, h-line, and g-line.

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

The back surface reflectance of the phase shift film 30 is 15% or less, preferably 10% or less in the wavelength region of 365 nm to 436 nm. In addition, the back reflectance of the phase shift film 30 is preferably 20% or less, more preferably 17% or less, for light in the wavelength region of 313nm to 436nm when the j-line is included in the exposed light. More preferably, it is more preferably 15% or less. In addition, the back reflectance of the phase shift film 30 is 0.2% or more in the wavelength region of 365nm to 436nm, preferably 0.2% or more for light in the wavelength region of 313nm to 436nm.

The back reflectance can be measured using a spectrophotometer or the like.

The phase shift film 30 may be composed of a plurality of layers, or may be composed of a single layer. The phase shift film 30 composed of a single layer is preferable in that it is difficult to form an interface in the phase shift film 30 and it is easy to control the cross-sectional shape. On the other hand, the phase shift film 30 composed of plural layers is preferable in terms of easiness of film formation and the like.

The etching mask film 40 is arranged on the upper side of the phase shift film 30 , and is made of a material having etching resistance (different etching selectivity from the phase shift film 30 ) to the etchant for etching the phase shift film 30 . Moreover, the etching mask film 40 may also have the function of shielding the light from being exposed to pass through, and furthermore, it may also be It has the function of reducing the film surface reflectance of the phase shift film 30 so that the film surface reflectance of the light incident from the phase shift film 30 side becomes 15% or less in the wavelength region of 350 nm to 436 nm. The etching mask film 40 contains a chromium-based material containing chromium (Cr). More specifically, the chromium-based material includes chromium (Cr), or a material containing chromium (Cr) and at least any one of oxygen (O), nitrogen (N), and carbon (C). Alternatively, a material containing chromium (Cr) and at least any one of oxygen (O), nitrogen (N), and carbon (C) and further containing fluorine (F) may be used. For example, as a material constituting the etching mask film 40, Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF are exemplified.

The etching mask film 40 can be formed by sputtering.

In the case where the etching mask film 40 has the function of shielding the transmission of exposed light, the optical density of the exposed light at the layered portion of the phase shift film 30 and the etching mask film 40 is preferably 3 or more, more preferably 3.5 or more, and more preferably 4 or more.

Optical density can be measured using a spectrophotometer, an OD (Optical Density, optical density) meter, etc.

Depending on the function, the etching mask film 40 may include a single film with a uniform composition, a plurality of films with different compositions, or a single film with a composition continuously changing in the thickness direction.

Furthermore, the phase shift mask substrate 10 shown in FIG. A phase shift mask substrate with a photoresist film thereon is also applicable to the present invention.

Next, the manufacturing method of the phase shift mask substrate 10 of the first and second embodiments will be described. The phase shift mask substrate 10 shown in FIG. 1 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 FIG. 2 is manufactured through a phase shift film forming step.

Hereinafter, each step will be described in detail.

1. Phase shift film formation steps

First, a transparent substrate 20 is prepared. The transparent substrate 20 may be made of any glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.) if it is transparent to the exposed light.

Next, the phase shift film 30 is formed on the transparent substrate 20 by sputtering.

The phase shift film 30 is formed 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 containing transition metal, silicon, oxygen, and/or nitrogen. The silicide target is used as a sputtering target, and it is carried out under the following sputtering atmosphere. Gas, or a mixed gas containing the above-mentioned inert gas and an active gas selected from the group consisting of oxygen, nitrogen, carbon dioxide gas, nitrogen monoxide gas, and nitrogen dioxide gas and containing at least oxygen and nitrogen. In addition, the phase shift film 30 is formed when the gas pressure in the film-forming chamber is 0.7 Pa or more and 3.0 Pa or less when sputtering is performed. Preferably, the phase shift film 30 is formed when the gas pressure in the film-forming chamber during sputtering is 0.8 Pa to 3.0 Pa. By setting the gas pressure range in this way, a columnar structure can be formed on the phase shift film 30 . Using this columnar structure, Undercutting at the time of pattern formation described later can be suppressed, and a high etching rate can be achieved. Here, transition metal silicide is preferable in terms of suppressing the decrease in wet etching rate by using the columnar structure, and improving the cleaning resistance of the phase shift film 30, and easily improving the transmittance. The atomic ratio of transition metal and silicon in the 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 so that the phase shift film 30 has the aforementioned retardation 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 transition metal content to the silicon content), the composition and flow rate of the sputtering gas, and the like. The thickness of the phase shift film 30 can be controlled by sputtering power, sputtering time, and the like. 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 using the transport speed of the substrate. In this way, the content of the light element components including oxygen and nitrogen in the phase shift film 30 is controlled so as to be 40 atomic % or more and 70 atomic % or less.

When the phase shift film 30 consists of a single film, the composition and flow rate of the sputtering gas are appropriately adjusted, and the above-mentioned film formation process is performed once. When the phase shift film 30 includes a plurality of films with different compositions, the composition and flow rate of the sputtering gas are appropriately adjusted, and the above-mentioned film formation process is performed a plurality of times. The phase shift film 30 can also be formed into a film using the target which differs in the content ratio of the element which comprises a sputtering target. When performing a plurality of film forming processes, the sputtering power applied to the sputtering target can also be changed in each film forming process.

2. Surface treatment steps

The phase shift film 30 includes transition metal silicide oxide containing transition metal, silicon and oxygen In the case of an oxygen-containing transition metal silicide material such as a transition metal, silicon, oxygen, and nitrogen transition metal silicide oxynitride, the surface of the phase shift film 30 can also be adjusted. The surface treatment step of the oxidized state of the surface to inhibit the penetration of the etching solution caused by the existence of transition metal oxides. Furthermore, when the phase shift film 30 includes a transition metal silicide-nitride containing transition metal, silicon, and nitrogen, the oxide content of the transition metal is smaller than that of the oxygen-containing transition metal silicide material. Therefore, in the case where the material of the phase shift film 30 is a transition metal silicide nitride, the above surface treatment step may or may not be performed.

As the surface treatment step for adjusting the surface oxidation state of the phase shift film 30, a method of surface treatment with an acidic aqueous solution, a method of surface treatment with an alkaline aqueous solution, and a method of surface treatment with dry treatment such as ashing Wait.

In this way, the phase shift mask substrate 10 of the second embodiment is obtained. In the manufacture of the phase shift mask substrate 10 of Embodiment 1, the following etching mask film forming steps are further performed.

3. Etching mask film formation step

After the phase shift film forming step, if necessary, perform surface treatment to adjust the surface oxidation state of the surface of the phase shift film 30, and then form an etching mask on the phase shift film 30 by sputtering. Cover film 40 . The etching mask film 40 is preferably formed using an in-line sputtering device. When the sputtering device is an in-line sputtering device, the transport speed of the transparent substrate 20 can also be used to control the thickness of the etching mask film 40 .

The etching mask film 40 is formed using a sputtering target containing chromium or chromium compounds (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxycarbide, etc.), under the following sputtering atmosphere, the The sputtering atmosphere system contains, for example, a gas selected from the group consisting of helium, neon, argon, krypton and xenon. At least one inert gas in the group, or containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon together with oxygen, nitrogen, nitric oxide Gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon gas, and fluorine gas are at least one active gas mixture. As hydrocarbon-based gas, methane gas, butane gas, propane gas, styrene gas, etc. are mentioned, for example. Furthermore, the etching mask film 40 can be made into a columnar structure similarly to the phase shift film 30 by adjusting the gas pressure in the film-forming chamber at the time of sputtering. Thereby, side etching at the time of pattern formation mentioned later can be suppressed, and a high etching rate can be achieved.

When the etching mask film 40 includes a single film with a uniform composition, the above-mentioned film formation process is performed once without changing the composition and flow rate of the sputtering gas. When the etching mask film 40 includes a plurality of films with different compositions, the composition and flow rate of the sputtering gas are changed for each film forming process, and the above film forming process is performed a plurality of times. When the etching mask film 40 consists of a single film whose composition continuously changes in the thickness direction, the above-mentioned film-forming process is performed once while changing the composition and flow rate of the sputtering gas along with the elapsed time of the film-forming process.

In this way, the phase shift mask substrate 10 of Embodiment 1 was obtained.

Furthermore, the phase shift mask substrate 10 shown in FIG. 1 has an etching mask film 40 on the phase shift film 30 , 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, the etching mask A photoresist film is formed on the cover film 40 . Also, in the phase shift mask substrate 10 shown in FIG. After the step, a photoresist film is formed.

In the phase shift mask substrate 10 of the first embodiment, an etching mask film 40 is formed on the phase shift film 30, and at least the phase shift film 30 has a columnar structure. In addition, the phase shift film 30 is formed on the phase shift mask base 10 of Embodiment 2, and the phase shift film 30 has a columnar structure.

The phase shift mask substrate 10 of the first and second embodiments facilitates the etching in the film thickness direction and suppresses the side etching when the phase shift film 30 is patterned by wet etching. A phase shift film pattern with good cross-sectional shape and desired transmittance (for example, high transmittance) is formed within a short etching time. Therefore, it is possible to obtain a phase shift mask substrate capable of manufacturing a phase shift mask whose transmittance of the transparent substrate does not decrease due to damage to the substrate by the wet etching solution, and which can be fabricated with high precision. Transfer high-definition phase shift film pattern.

In addition, when forming the phase shift film 30 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 the gas pressure in this way, the phase shift film 30 can be formed in which the indentation hardness derived by the nanoindentation method is 18 GPa or more and 23 GPa or less. By setting the indentation hardness of the phase shift film 30 to 18 GPa or more and 23 GPa or less, side etching at the time of pattern formation described below can be suppressed, and a high etching rate can be achieved, and surface roughness of the transparent substrate 20 can be suppressed. Here, by setting the indentation hardness to 18 GPa to 23 GPa, the effect of suppressing the decrease of the wet etching rate is large, the cleaning resistance of the phase shift film 30 can be improved, and the transmittance can be easily improved. Preferably, the atomic ratio of the 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 Embodiments 3 and 4, a method of manufacturing a phase shift mask will be described.

Fig. 3 is a schematic diagram showing a method of manufacturing a phase shift mask according to Embodiment 3. Fig. 4 is a schematic diagram showing a method of manufacturing a phase shift mask according to Embodiment 4.

The manufacturing method of the phase shift mask shown in FIG. 3 is a method of manufacturing a phase shift mask using the phase shift mask substrate 10 shown in FIG. 1 , and includes: on the following phase shift mask substrate 10 The step of forming a photoresist film on the etching mask film 40; forming a photoresist film pattern 50 (the first photoresist film pattern forming step) by drawing/developing the desired pattern on the photoresist film; taking the photoresist film pattern 50 as Mask, wet etching the etching mask film 40, forming the step of etching mask film pattern 40a on the phase shift film 30 (the first etching mask film pattern forming step); and using the above etching mask film pattern 40a is a mask, the step of wet etching the phase shift film 30 to form the phase shift film pattern 30a on the transparent substrate 20 (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 FIG. 4 is a method of manufacturing a phase shift mask using the phase shift mask substrate 10 shown in FIG. 2 , and includes: on the following phase shift mask substrate 10 A step of forming a photoresist film on the photoresist film; forming a photoresist film pattern 50 by drawing/developing a desired pattern on the photoresist film (the first photoresist film pattern forming step); and using the photoresist film pattern 50 as a mask, the The step of wet etching the phase shift film 30 to form the phase shift film pattern 30 a on the transparent substrate 20 (phase shift film pattern forming step).

In the following, each step of the manufacturing steps of the phase shift mask of Embodiment 3 and 4 will be described in detail. Be explained.

Manufacturing Steps of Phase Shift Mask of Embodiment 3 1. The 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 the first embodiment. The photoresist material used is not particularly limited. For example, those sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm described below may be sufficient. In addition, the photoresist film may be either positive type or negative type.

Thereafter, a desired pattern is drawn on the photoresist film using laser light having any wavelength selected from the wavelength range of 350nm to 436nm. The pattern drawn on the photoresist film is the pattern formed on the phase shift film 30 . Examples of the pattern drawn on the photoresist film include a line-space pattern and a hole pattern.

Thereafter, the photoresist film is developed using a specific developer, and as shown in FIG. 3( a ), a first photoresist film pattern 50 is formed on the etching mask film 40 .

2. The first etching mask film pattern forming step

In the step of forming the first etching mask pattern, first, the etching mask film 40 is etched using the first photoresist film pattern 50 as a mask to form the first etching mask 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 preferable in that the etching rate is fast and side etching can be suppressed. The etchant for etching the etching mask film 40 is not particularly limited as long as it can selectively etch the etching mask film 40 . Specifically, an etching solution containing ceric ammonium nitrate and perchloric acid is mentioned.

Thereafter, as shown in FIG. 3( b ), the first photoresist film pattern 50 is peeled off using a photoresist stripping solution or by ashing. It may also be possible to carry out the second phase without peeling off the first photoresist film pattern 50. Offset film patterning step.

3. Phase shift film pattern formation step

In the step of forming the first phase shift film pattern, the phase shift film 30 is wet-etched using the first etching mask film pattern 40a as a mask, and as shown in FIG. 3( c), a phase shift film is formed. Pattern 30a. As the phase shift film pattern 30a, a line gap pattern or a hole pattern can be mentioned. The etchant 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 solution containing ammonium fluoride, phosphoric acid, and hydrogen peroxide, and an etching solution containing ammonium hydrogen fluoride and hydrogen peroxide are mentioned.

Preferably, the wet etching is performed longer (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 considering the impact on the transparent substrate 20, etc., it is preferably set to the time obtained by adding 20% of the reasonable etching time to the reasonable etching time, and it is more preferably set to plus a reasonable etching time. The time obtained by 10% of the time.

4. The second photoresist film pattern forming step

In the second photoresist pattern forming step, first, a photoresist covering the first etching mask pattern 40a is formed. The photoresist material used is not particularly limited. For example, those sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm described below may be sufficient. In addition, the photoresist film may be either positive type or negative type.

Thereafter, a desired pattern is drawn on the photoresist film using laser light having any wavelength selected from the wavelength range of 350nm to 436nm. The pattern drawn on the photoresist film is a light-shielding belt pattern that will shield the peripheral area of the region where the phase shift film 30 is formed with a pattern, or a pattern of the phase shift film pattern. The pattern of the shading belt for shading the central part, etc. Furthermore, depending on the transmittance of the phase shift film 30 to the exposed light, the pattern drawn on the photoresist film may not have a pattern of a light-shielding band pattern that shields the central portion of the phase shift film pattern 30 a from light.

Thereafter, the photoresist film is developed with 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 40 a.

5. The second etching mask film pattern forming step

In the second etching mask pattern forming step, the first etching mask pattern 40a is etched with the second photoresist pattern 60 as a mask, as shown in FIG. 3( e), forming a second etching mask. Mask pattern 40b. The first etching mask pattern 40a is formed of a chromium-based material containing chromium (Cr). The etchant for etching the first etching mask pattern 40a is not particularly limited as long as it can selectively etch the first etching mask pattern 40a. For example, an etchant containing ammonium cerium nitrate and perchloric acid is mentioned.

Thereafter, the second photoresist film pattern 60 is peeled off using a photoresist stripping solution or by ashing.

In this way, a 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 exposed light has been described, but in the case where the etching mask film 40 only has a hard mask when etching the phase shift film 30 In the case of the function, in the above description, the second photoresist film pattern forming step and the second etching mask film pattern forming step are not performed, but after the phase shift film pattern forming step, the first etching mask film pattern The phase shift mask 100 is produced by peeling off.

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 with a good cross-sectional shape can be formed. Bit-shifted film pattern. Therefore, it is possible to manufacture a phase shift mask capable of accurately transferring a high-definition phase shift film pattern. The phase shift mask manufactured in this way can cope with the miniaturization of line gap pattern or contact hole.

Manufacturing Steps of Phase Shift Mask of Embodiment 4 1. Photoresist film pattern formation steps

In the step of patterning the photoresist film, first, a photoresist film is formed on the phase shift film 30 of the phase shift mask substrate 10 of the second embodiment. The photoresist material used is the same as that described in the third embodiment. Furthermore, before forming the photoresist film, the phase shift film 30 may be subjected to surface modification treatment as needed, so as to make good adhesion with the phase shift film 30 . In the same manner as above, after the photoresist film is formed, a desired pattern is drawn on the photoresist film using laser light having any wavelength selected from the wavelength region of 350nm to 436nm. Thereafter, the photoresist film is developed with a specific developer, as shown in FIG. 4( a ), and a photoresist film pattern 50 is formed on the phase shift film 30 .

2. Phase shift film pattern formation step

In the step of forming the phase shift film pattern, the phase shift film 30 is etched using the photoresist film pattern as a mask, as shown in FIG. 4( b ), to form a phase shift film pattern 30 a. The phase shift film pattern 30a, the etchant for etching the phase shift film 30, and the overetching time are the same as those described in the third embodiment.

Thereafter, the photoresist film pattern 50 is stripped using a photoresist stripping liquid or by ashing ( FIG. 4( 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 substrate of the second embodiment is used, the transmittance of the transparent substrate does not decrease due to the damage of the wet etching solution to the substrate, and the shortening can be shortened. Etching time, and can form a phase shift film with a good cross-sectional shape case. Therefore, it is possible to manufacture a phase shift mask capable of accurately transferring a high-definition phase shift film pattern. The phase shift mask manufactured in this way can cope with the miniaturization of line gap pattern or contact hole. In addition, when a phase shift mask is manufactured using 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 the nanoindentation method, in addition to the above effects, The surface roughness of the transparent substrate 20 can also be suppressed, and the cleaning resistance of the phase shift film 30 can be improved.

Implementation form 5.

In Embodiment 5, a method of manufacturing a display device will be described. The display device is obtained by performing the step of using the phase shift mask 100 manufactured using the phase shift mask substrate 10 described above or the phase shift mask 100 manufactured by the method for manufacturing the phase shift mask 100 described above (mask Mounting step) and the step of exposing the transfer pattern to the photoresist film on the display device (exposure step).

Hereinafter, each step will be described in detail.

1. Loading steps

In the mounting step, the phase shift mask manufactured in Embodiment 3 is mounted on the mask stage of the exposure device. Here, the phase shift mask is disposed so as to face 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. Exposure light system contains selected from 365 Composite light of multiple wavelengths in the wavelength region of nm~436nm or monochromatic light selected by using a filter to cut off a certain wavelength region in the wavelength region of 365nm~436nm. For example, the exposure light is composite light including i-line, h-line and g-line or monochromatic light of i-line. If the composite light is used as the exposure light, the intensity of the exposure light can be increased, thereby increasing the throughput, and thus the manufacturing cost of the display device can be reduced.

According to the method of manufacturing a display device according to the third embodiment, it is possible to manufacture a high-resolution, high-definition display device having fine line gap patterns or contact holes.

Furthermore, in the above embodiments, the use of the phase shift mask substrate with the phase shift mask film or the phase shift mask with the phase shift mask film pattern as the photomask with the pattern forming film The case of a substrate or a photomask having a pattern for transfer has been described, but is not limited thereto. For example, the present invention can also be applied to a binary mask base having a light-shielding film as a thin film for pattern formation or a binary mask having a light-shielding film pattern.

[Example] Example 1. A. Phase-Shifting Mask Substrates and Methods of Making the Same

To manufacture the phase shift mask substrate of Example 1, first, a synthetic quartz glass substrate with a size of 1214 (1220 mm×1400 mm) was prepared as the transparent substrate 20 .

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

In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, in the state where the sputtering gas pressure in the first chamber is set to 1.6 Pa, a gas containing argon (Ar) and nitrogen (N ₂ ) is introduced. Helium (He) gas and inert gas (Ar: 18 sccm, N ₂ : 13 sccm, He: 50 sccm). Then, a sputtering power of 7.6 kW was applied to the first sputtering target (molybdenum:silicon=1:9) containing molybdenum and silicon, and by reactive sputtering, deposits containing molybdenum and silicon were deposited on the main surface of the transparent substrate 20. And nitrogen molybdenum silicide nitride. Next, a phase shift film 30 having a film thickness of 150 nm was formed.

Then, move the transparent substrate 20 with the phase shift film 30 into the second chamber, and introduce a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) gas (Ar: 65 sccm, N ₂ : 15 sccm) 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 was formed on the phase shift film 30 by reactive sputtering (thickness: 15 nm). . Then, in the state of making the third chamber a certain degree of vacuum, introduce a mixed gas (30 sccm) of argon (Ar) gas and methane (CH ₄ : 4.9%) gas, and apply 8.5 to the third sputtering target containing chromium. With a sputtering power of kW, chromium carbide (CrC) containing chromium and carbon (film thickness 60nm) is formed on CrN by reactive sputtering. Finally, in the state where the fourth chamber has a certain degree of vacuum, a mixed gas of argon (Ar) gas and methane (CH ₄ : 5.5%) gas and a mixture of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas are introduced. Mixed gas (Ar+CH ₄ : 30sccm, N ₂ : 8sccm, O ₂ : 3sccm), apply 2.0kW sputtering power to the 4th sputtering target containing chromium, form chromium-containing sputtering target on CrC by reactive sputtering , carbon, oxygen and nitrogen chromium carbide nitride oxide (CrCON) (film thickness 30nm). As described above, on the phase shift film 30, the etching mask film 40 of the laminated structure of the CrN layer, the CrC layer, and the CrCON layer is formed.

In this way, the phase shift mask base 10 in which the phase shift film 30 and the etching mask film 40 are formed on the transparent substrate 20 is obtained.

For the phase shift film 30 (the surface of the phase shift film 30) of the obtained phase shift mask substrate 10, utilize MPM-100 manufactured by Lasertec to measure transmittance and phase difference. The transmittance and phase difference of the phase shift film 30 The measurement of the difference is to use a substrate with a phase shift film (dummy substrate) with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate produced on the same tray. The transmittance of the phase shift film 30, The phase difference was measured by taking out the substrate (dummy substrate) with the phase shift film from the chamber before forming the etching mask film 40. As a result, the transmittance was 27% (wavelength: 405nm) and the phase difference was 178°( Wavelength: 405nm).

In addition, for the obtained phase shift mask substrate 10, the composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS).

In the composition analysis results of the phase shift mask substrate 10 obtained by XPS in the depth direction, the phase shift film 30 except the composition gradient region of the interface between the transparent substrate 20 and the phase shift film 30, and the phase shift film Except for the composition gradient region of the interface between 30 and the etching mask film 40, the content of each constituent element is substantially constant toward the depth direction, and Mo is 8 atomic %, Si is 40 atomic %, N is 48 atomic %, and O is 4 atomic %. %. Moreover, the atomic ratio of molybdenum and silicon is 1:5, and exists in the range of 1:3 or more and 1:15 or less. Moreover, the total content rate of oxygen and nitrogen which are light elements is 52 atomic %, and it exists in the range of 50 atomic % or more and 65 atomic % or less. Furthermore, the presence of oxygen in the phase shift film 30 can be considered as the sputtering gas pressure is as high as 0.8 Pa or more, and a small amount of oxygen exists in the chamber during film formation.

In addition, when the indentation hardness of the obtained phase shift film 30 is measured (the measurement method will be described later), the indentation hardness satisfies not less than 18 GPa and not more than 23 GPa.

Then, in the center of the transfer pattern forming area of the obtained phase shift mask substrate 10 As a result of cross-sectional SEM (scanning electron microscope) observation at a magnification of 80,000 times, it was confirmed that the phase shift film 30 has 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 . Furthermore, it was confirmed that the columnar particle structure of the phase shift film 30 is irregularly formed with columnar particles in the film thickness direction, and the lengths of the columnar particles in the film thickness direction are not uniform. Also, it was confirmed that the sparse portions of the phase shift film 30 were continuously formed in the film thickness direction. Furthermore, for the image obtained by the cross-sectional SEM observation, the region including the central part in the thickness direction of the phase shift film 30 was captured as an image data of 64 pixels in length and 256 pixels in width (FIG. 5(a)) . Furthermore, Fourier transform is performed on the image data shown in FIG. 5 (FIG. 5(b)). In the spatial frequency spectral distribution obtained by Fourier transform, it was confirmed that the signal strength (maximum signal strength) at the origin of the spatial frequency was 3,136,000, and different from the above maximum signal strength, there was a spatial frequency spectrum with a signal strength of 66,150 . The maximum signal intensity corresponding to the origin of the spatial frequency in this spatial frequency spectrum is 66150/3136000=0.021 (ie 2.1%), and the phase shift film 30 has a columnar structure having a signal intensity of 1.0% or more.

Also, the phase shift film 30 has a columnar structure that is based on the origin of the spatial frequency, that is, the position of the image in FIG. The center is the origin (0), and when the maximum spatial frequency corresponding to the two ends of the 256 pixels on the horizontal axis is set to 1 (100%), the signal corresponding to the maximum signal strength corresponding to the origin of the above spatial frequency is 2.1% The intensity of the signal has a signal at a position 0.055 away from the above origin, that is, 5.5%. It should be noted that the same applies to the Fourier-transformed images of the following Examples and Comparative Examples.

In addition, near the film thickness center of the phase shift film 30, a plate-shaped sample of 100 nm (in-plane direction of the substrate) relative to the film thickness direction was collected for dark-field planar STEM observation. inspect. The results of dark-field planar STEM (scanning transmission electron microscope) observation are shown in FIG. 6 . As shown in FIG. 6 , off-white and off-white speckle patterns were observed between the particle portion (gray-white portion) and between the particles (gray-black portion) considered to be columnar. For the off-white and off-white parts, the elements (Mo, Si, N, O) constituting the phase shift film 30 were quantified by EDX analysis (energy-dispersive X-ray analysis, energy-dispersive X-ray analysis). analysis (not shown). As a result, it was confirmed that the detection amount (count value) of Si was higher than that of Mo in the gray-black part and the gray-white part, and the detected amount (count value) of the constituent elements of the phase shift film 30 in the gray-black part was lower than the gray-white part. The detection amount (count value) of the constituent elements of a part of the phase shift film 30. In particular, the detection amount (count value) of Si in the gray-black part is 600 (Counts), and the detection amount (count value) of Si in the gray-white part is 400 (Counts). Compared with other elements, the detection amount ( Count value) has a large difference. From this result, it was confirmed that the phase shift film 30 has a relatively high-density particle portion (off-white portion) and a relatively low-density sparse portion (gray-black portion). The particle part corresponds to the columnar particle shown in FIG. 5 or FIG. 7 . Furthermore, the film density of the entire phase shift film 30 is lower than that of the conventional phase shift film.

B. Phase Shift Masks and Methods of Making the Same

In order to manufacture the phase shift mask 100 using the phase shift mask substrate 10 manufactured in the above manner, first, on the etching mask film 40 of the phase shift mask substrate 10, a photoresist coating device is used to coat a photoresist. barrier film.

Thereafter, a photoresist film with a film thickness of 520 nm was formed through heating and cooling steps.

Thereafter, the photoresist film was drawn using a laser drawing device, and a photoresist film pattern with a hole diameter of 1.5 μm was formed on the etching mask film through the steps of developing and rinsing.

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

Thereafter, using the first etching mask film pattern 40a as a mask, the phase shift film 30 is wet-etched using the molybdenum silicide etching solution obtained by diluting the mixed solution of ammonium bifluoride and hydrogen peroxide with pure water, A phase shift film pattern 30a is formed. The wet etching is carried out with an overetching time of 110%, so that the cross-sectional shape is verticalized and the required fine pattern is formed. The appropriate etching time in Example 1 is 0.15 times the appropriate etching time in the following comparative example, and the etching time can be significantly shortened.

Thereafter, the photoresist film pattern is peeled off.

Thereafter, a photoresist film is applied so as to cover the first etching mask film pattern 40a using a photoresist coating device.

Thereafter, a photoresist film with a film thickness of 520 nm was formed through heating and cooling steps.

Thereafter, the photoresist film is drawn using a laser drawing device, and the second photoresist film pattern 60 for forming a light-shielding band is formed on the first etching mask film pattern 40a through developing and rinsing steps.

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

Thereafter, the second photoresist film pattern 60 is peeled off.

In this way, the phase shift mask 100 is obtained, and the phase shift mask 100 is placed on the transparent substrate 20 A light-shielding zone including a phase shift film pattern 30a with a hole diameter of 1.5 μm in the transfer pattern formation area, and a laminated structure of the phase shift film pattern 30a and the etching mask film pattern 40b is formed on it.

The cross section of the obtained phase shift mask was observed with a scanning electron microscope. The section of the phase shift film pattern includes the upper surface, the lower surface and the 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 part where the upper surface of the phase shift film pattern meets the side (upper side) and the part where the side side meets the lower surface (lower side). The phase shift film pattern 30a of the obtained phase shift mask had a cross-sectional angle of 74° and a nearly vertical cross-sectional shape. The phase shift film pattern 30a formed on the phase shift mask of the first embodiment has a cross-sectional shape capable of fully exerting the phase shift effect. It is considered that the good cross-sectional shape of the phase shift film pattern 30 a by making the phase shift film 30 a columnar structure depends on the following mechanism. According to the observation result of the cross-sectional SEM photograph of FIG. 7 , the phase shift film 30 has a columnar particle structure (columnar structure), and columnar particles extending in the film thickness direction are irregularly formed. Also, according to the observation results of the dark field planar STEM photo of FIG. 6 and the observation results of the cross-sectional SEM photo of FIG. form. According to these facts, when the phase shift film 30 is patterned by wet etching, the etchant penetrates into the sparse portion in the phase shift film 30, whereby etching is easily performed in the film thickness direction. On the other hand, In the direction perpendicular to the film thickness direction (the direction in the substrate surface), columnar particles are irregularly formed, and the sparse parts in this direction are intermittently formed. Therefore, etching in this direction is difficult, and side etching is suppressed, it is considered that the phase shift film pattern 30a obtains a good cross-sectional shape close to vertical. Also, in the phase shift film pattern, no permeation was observed at any of the interface with the etching mask film pattern and the interface with the substrate. Therefore, the exposure light including light in the wavelength range of 300nm to 500nm, more specifically composite light including i-line, h-line and g-line In the exposed light, 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 to the photoresist film transferred on the display device, it can be transferred with high precision. pattern.

Moreover, the cross-sectional SEM photo of FIG. 7 is in the manufacturing step of the phase shift mask in Embodiment 1, using the first etching mask film pattern 40a as a mask, and using molybdenum silicide etching solution to coat the phase shift film 30. Wet etching (110% overetching) is performed to form a phase shift film pattern 30a, and a cross-sectional SEM photo of the photoresist film pattern is stripped. 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 transparent substrate 20 can be ignored. The state in which the transmittance decreases due to rough surface.

Example 2. A. Phase-Shifting Mask Substrates and Methods of Making the Same

In order to manufacture the phase shift mask base of Example 2, in the same manner as in Example 1, a synthetic quartz glass substrate with a size of 1214 (1220 mm×1400 mm) was prepared as a transparent substrate.

By the same method as in Example 1, the synthetic quartz glass substrate was carried into the chamber of an in-line sputtering device. The sputtering target material similar to Example 1 was used as a 1st sputtering target, a 2nd sputtering target, a 3rd sputtering target, and a 4th sputtering target. Then, in the state where the sputtering gas pressure in the first chamber is set to 1.6 Pa, an inert gas including argon (Ar) gas, helium (He) gas, and nitrogen (N ₂ ) gas and a reactive gas as reactive gas are introduced. Nitric oxide gas (NO) mixed gas (Ar: 18 sccm, N ₂ : 15 sccm, He: 50 sccm, NO: 4 sccm). Then, a sputtering power of 7.6 kW was applied to the first sputtering target (molybdenum:silicon=1:9) containing molybdenum and silicon, and by reactive sputtering, on the main surface of the transparent substrate 20, deposits containing molybdenum, Nitride of molybdenum silicides of silicon, oxygen and nitrogen. Next, a phase shift film 30 having a film thickness of 140 nm was formed.

Then, after the phase shift film is formed on the transparent substrate, it is taken out from the chamber, and the surface of the phase shift film is cleaned with pure water. The pure water washing conditions were set at a temperature of 30°C and a washing time of 60 seconds.

Thereafter, by the same method as in Example 1, the etching mask film 40 is formed into a film.

In this way, the phase shift mask base 10 in which the phase shift film 30 and the etching mask film 40 are formed on the transparent substrate 20 is obtained.

The transmittance and phase difference of the obtained phase shift film of the phase shift mask substrate 10 (the phase shift film obtained by washing the surface of the phase shift film with pure water) were measured using MPM-100 manufactured by Lasertec Corporation. In the measurement of the transmittance and phase difference of the phase shift film, a substrate with a phase shift film (dummy substrate) with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate fabricated on the same tray was used. ). The transmittance and phase difference of the phase shift film 30 were measured by taking out the substrate with the phase shift film (dummy substrate) from 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).

Also, for the obtained phase shift mask substrate, the composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS).

As a result, the same as in Example 1, the phase shift film 30 except 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, the content of each constituent element is substantially constant toward the depth direction, Mo Si is 7 atomic %, Si is 38 atomic %, N is 45 atomic %, and O is 10 atomic %. Moreover, the atomic ratio of molybdenum and silicon is 1:5.4, and it exists in the range of 1:3 or more and 1:15 or less. In addition, the total content rate of oxygen, nitrogen, and carbon as light elements is 55 atomic %, and 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 central position of the transfer pattern forming region of the obtained phase shift mask substrate 10 , and it was confirmed that the phase shift film 30 has 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 . Furthermore, it was confirmed that the columnar particle structure of the phase shift film 30 is irregularly formed in the film thickness direction, and the lengths of the columnar particles in the film thickness direction are not uniform. Also, it was confirmed that the sparse portions of the phase shift film 30 were continuously formed in the film thickness direction. Furthermore, for the image obtained by the cross-sectional SEM observation, the region including the central part in the thickness direction of the phase shift film 30 was captured as an image data of 64 pixels in length and 256 pixels in width ( FIG. 8( a )) . Furthermore, Fourier transform is performed on the image data shown in FIG. 8( a ) ( FIG. 8( b )). In the spatial frequency spectrum distribution obtained by Fourier transform, it was confirmed that the signal strength (maximum signal strength) at the origin of the spatial frequency was 2,406,000, and different from the above maximum signal strength, there was a spatial frequency spectrum with a signal strength of 39,240 . This spatial frequency spectrum is 39240/2406000=0.016 (ie 1.6%) relative to the maximum signal strength corresponding to the origin of the spatial frequency, and the phase shift film 30 has a columnar structure with a signal strength of 1.0% or more.

In addition, the phase shift film 30 has a fine columnar structure as follows, and the columnar structure is based on the origin of the spatial frequency, that is, the graph of FIG. The center of the image is the origin (0), and when the two ends of the horizontal axis of 256 pixels are set to 1 (100%), relative to the above space The origin of the frequency corresponds to a signal with a maximum signal strength of 1.6% at a position 0.023, ie, 2.3%, away from the above-mentioned origin.

Also, in the same manner as in Example 1, dark-field planar STEM observation was performed in the vicinity of the film thickness center of the phase shift film 30 . As a result, similarly to Example 1, it was confirmed that columnar particle portions and sparse portions were formed in the phase shift film 30 .

B. Phase Shift Masks and Methods of Making the Same

Using the phase shift mask substrate manufactured in the above manner, by the same method as in Example 1, a phase shift mask having a phase shift film pattern with an aperture of 1.5 μm was manufactured. The wet etching of the phase shift film 30 is performed with an overetching time of 110%, so that the cross-sectional shape is verticalized and a required fine pattern is formed. The reasonable etching time in Example 2 was 0.07 times the reasonable etching time in the following comparative example, and it was possible to significantly shorten the etching time.

The cross section of the obtained phase shift mask was observed with a scanning electron microscope. The angle of the cross section of the phase shift film pattern 30a of the phase shift mask is 74°, and has a cross-sectional shape close to vertical. Also, in the phase shift film pattern, no permeation was observed at any of the interface with the etching mask film pattern and the interface with the substrate. Therefore, in the exposure light including light in the wavelength range of 300nm to 500nm, more specifically, the composite light including i-line, h-line, and g-line, a phase having an excellent phase shift effect is obtained. Offset mask.

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 to the photoresist film transferred on the display device, it can be transferred with high precision. pattern.

Moreover, the cross-sectional SEM photo of FIG. 9 is in the manufacturing step of the phase shift mask in Example 2, using the first etching mask film pattern 40a as a mask, and using molybdenum silicide etching solution to coat the phase shift film 30. Wet etching (110% overetching) is performed to form a phase shift film pattern 30a, and a cross-sectional SEM photo of the photoresist film pattern is stripped. As shown in FIG. 9, 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 transparent substrate 20 can be ignored. The state in which the transmittance decreases due to rough surface.

Example 3. A. Phase-Shifting Mask Substrates and Methods of Making the Same

The phase shift mask substrate of Embodiment 3 is a phase shift mask substrate without the etching mask film in the phase shift mask substrate of Embodiment 1.

In order to manufacture the phase shift mask base of Example 3, in the same manner as in Example 1, a synthetic quartz glass substrate with a size of 1214 (1220 mm×1400 mm) was prepared as the transparent substrate 20 .

In order to form the phase shift film 30 on the main surface of the transparent substrate 20 using the same film-forming method as in Example 1, first, in the state where the sputtering gas pressure in the first chamber is set to 1.4Pa, introduce Argon (Ar) gas, nitrogen (N ₂ ) gas and helium (He) gas inert gas (Ar: 18 sccm, N ₂ : 13.5 sccm, He: 50 sccm). Using these film-forming conditions, a phase shift film 30 (thickness: 150 nm) made of molybdenum silicide-oxynitride was formed on the transparent substrate 20 .

In this way, the phase shift mask base 10 in which the phase shift film 30 is formed on the transparent substrate 20 is obtained.

For the phase shift film of the obtained phase shift mask substrate 10, Lasertec Co., Ltd. Made MPM-100 to measure transmittance and phase difference. In the measurement of the transmittance and phase difference of the phase shift film, a substrate with a phase shift film (dummy) with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate is used which is placed on the same tray and manufactured. substrate). As a result, the transmittance was 24% (wavelength: 405 nm) and the phase difference was 183 degrees (wavelength: 405 nm).

For the phase shift film 30 of the obtained phase shift mask substrate 10, X-ray photoelectron spectroscopy (XPS) was used to analyze the composition of the depth direction. As a result, the phase shift film 30 was the same as in Example 1. The content of the constituent elements is substantially constant toward the depth direction. Moreover, the atomic ratio of molybdenum and silicon is 1:5, and exists in the range of 1:3 or more and 1:15 or less. Moreover, the total content rate of oxygen, nitrogen, and carbon which are light elements is 52 atomic %, and it exists in the range of 50 atomic % or more and 65 atomic % or less. Moreover, the content rate of oxygen is 0.3 atomic %, and it exists in the range which exceeds 0 atomic % and is 40 atomic % or less.

Then, a cross-sectional SEM observation was performed at a magnification of 80,000 times at the central position of the transfer pattern forming region 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 . Furthermore, it was confirmed that the columnar particle structure of the phase shift film 30 is irregularly formed in the film thickness direction, and the lengths of the columnar particles in the film thickness direction are not uniform. Also, it was confirmed that the sparse portions of the phase shift film 30 were continuously formed in the film thickness direction. Furthermore, for the image obtained by the cross-sectional SEM observation, the region including the central part in the thickness direction of the phase shift film 30 was captured as an image data of 64 pixels in length and 256 pixels in width ( FIG. 10( a )) . Furthermore, Fourier transform is performed on the image data shown in Fig. 10(a) (Fig. 10(b)). In the spatial frequency spectral distribution obtained by Fourier transform, it is confirmed that The signal strength (maximum signal strength) to the origin of the spatial frequency is 31590000, and unlike the above-mentioned maximum signal strength, there is a spatial frequency spectrum with a signal strength of 47230. This spatial frequency spectrum is 47230/3159000=0.015 (that is, 1.5%) relative to the maximum signal strength corresponding to the origin of the spatial frequency, and the phase shift film 30 has a columnar structure having a signal strength of 1.0% or more.

In addition, the phase shift film 30 has a fine columnar structure with a large spatial frequency as follows. The columnar structure is based on the origin of the spatial frequency, that is, the origin of the spatial frequency in FIG. The center of the image in (b) is the origin (0), and when the two ends of the 256 pixels on the horizontal axis are set to 1 (100%), the maximum signal strength corresponding to the origin of the above spatial frequency is 1.5%. The signal of signal strength has a signal at a position 0.078 away from the above origin, that is, 7.8%.

Also, in the same manner as in Example 1, dark-field planar STEM observation was performed in the vicinity of the film thickness center of the phase shift film 30 . As a result, similarly to Example 1, it was confirmed that columnar particles and sparse portions were formed in the phase shift film 30 .

B. Phase Shift Masks and Methods of Making the Same

Using the phase shift mask substrate 10 manufactured in the above manner, by the same method as in Example 1, a phase shift mask having a phase shift film pattern with an aperture of 1.5 μm was manufactured. The wet etching of the phase shift film 30 is performed with an overetching time of 110%, so that the cross-sectional shape is verticalized and a required fine pattern is formed. The reasonable etching time in Example 3 was 0.20 times the reasonable etching time in the following comparative example, and it was possible to significantly shorten the etching time.

The cross section of the obtained phase shift mask was observed using a scanning electron microscope. Phase deviation The cross-sectional angle of the phase shift film pattern 30a of the shift mask is 80°, and has a nearly vertical cross-sectional shape. Also, in the phase shift film pattern, no permeation was observed at any of the interface with the etching mask film pattern and the interface with the substrate. Therefore, in the exposure light including light in the wavelength range of 300nm to 500nm, more specifically, the composite light including i-line, h-line, and g-line, a phase having an excellent phase shift effect is obtained. Offset mask.

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 to the photoresist film transferred on the display device, it can be transferred with high precision. pattern.

Moreover, the cross-sectional SEM photo of FIG. 11 is in the manufacturing step of the phase shift mask in Example 3, using the first etching mask film pattern 40a as a mask, and using a molybdenum silicide etching solution to coat the phase shift film 30. Wet etching (110% overetching) is performed to form a phase shift film pattern 30a, and a cross-sectional SEM photo of the photoresist film pattern is stripped. 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 transparent substrate 20 can be ignored. The state of the transmittance caused by the surface roughness. The line edge roughness was better than Example 1.

Furthermore, in the above-mentioned embodiments, the case of using molybdenum as the transition metal has been described, but the same effect as above can be obtained in the case of other transition metals.

In addition, in the above-mentioned embodiments, an example of a phase shift mask substrate for display device manufacture or a phase shift mask for display device manufacture was described, but it is not limited thereto. The phase shift mask substrate or phase shift mask of the present invention can also be applied to semiconductor device manufacturing applications, MEMS (microelectromechanical system, microelectromechanical system) manufacturing applications, printing substrates, etc. Board use, etc. In addition, the present invention can also be applied to a binary mask base having a light-shielding film as a thin film for pattern formation or a binary mask having a light-shielding film pattern.

In addition, in the above-mentioned embodiments, an example in which the size of the transparent substrate is 1214 size (1220 mm×1400 mm×13 mm) has been described, but it is not limited thereto. In the case of a phase shift mask substrate for display device manufacturing, a large size transparent substrate is used, and the size of the transparent substrate is 300mm or more in length on one side. The size of the transparent substrate used in the phase shift mask base for display device manufacturing is, for example, 330mm×450mm or more and 2280mm×3130mm or less.

In addition, in the case of phase shift mask substrates for semiconductor device manufacturing, MEMS manufacturing, and printed substrates, a small-sized (Small Size) transparent substrate is used, and the size of the transparent substrate is that the length of one side is 9 inches or less . The size of the transparent substrate used in the phase shift mask base for the above-mentioned application is, for example, 63.1mm×63.1mm or more and 228.6mm×228.6mm or less. Generally, semiconductor manufacturing applications and MEMS manufacturing applications use 6025 size (152mm×152mm) or 5009 size (126.6mm×126.6mm), and printed substrate applications use 7012 size (177.4mm×177.4mm) or 9012 size (228.6mm×126mm) 228.6mm).

Comparative example 1. A. Phase-Shifting Mask Substrates and Methods of Making the Same

In order to manufacture the phase shift mask substrate of Comparative Example 1, a synthetic quartz glass substrate having a size of 1214 (1220 mm×1400 mm) was prepared as a transparent substrate in the same manner as in Example 1.

By the same method as in Example 1, the synthetic quartz glass substrate was carried into the chamber of an in-line sputtering device. Next, a mixed gas (Ar: 30 sccm, N ₂ : 30 sccm) of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced with the sputtering gas pressure in the first chamber at 0.5 Pa. Then, a sputtering power of 7.6kW was applied to the first sputtering target (molybdenum:silicon=1:9) containing molybdenum and silicon, and by reactive sputtering, a layer containing molybdenum, silicon and silicon was deposited on the main surface of the transparent substrate. Nitride of nitrogen molybdenum silicide. In this manner, a phase shift film having a film thickness of 144 nm was formed.

The indentation hardness of the phase shift film in Comparative Example 1 did not satisfy 18 GPa or more and 23 GPa or less.

Thereafter, by the same method as in Example 1, an etching mask film was formed.

In this way, a phase shift mask base in which a phase shift film and an etching mask film are formed on a transparent substrate is obtained.

The transmittance and phase difference of the phase shift film obtained as a base of the phase shift mask were measured using MPM-100 manufactured by Lasertec Corporation. In the measurement of the transmittance and phase difference of the phase shift film, a substrate with a phase shift film (dummy substrate) with a phase shift film formed on the main surface of a synthetic quartz glass substrate manufactured on the same tray is used. ). The transmittance and phase difference of the phase shift film were measured by taking out the substrate with the phase shift film (dummy substrate) from the chamber before forming the etching mask film. As a result, the transmittance was 30% (wavelength: 405 nm) and the phase difference was 177 degrees (wavelength: 405 nm).

Also, for the obtained phase shift mask substrate, the composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS). As a result, the phase shift film 30, except 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, the content of each constituent element The ratio is substantially constant toward the depth direction, and Mo is 8 atomic %, Si is 39 atomic %, N is 52 atomic %, and O is 1 atomic %. Moreover, the atomic ratio of molybdenum and silicon is 1:4.9, and it exists in the range of 1:3 or more and 1:15 or less. Also, as a light element The total content of oxygen, nitrogen, and carbon in element is 53 atomic %, which is within the range of 50 atomic % to 65 atomic %.

Next, at the central position of the transfer pattern formation area of the obtained phase shift mask substrate 10, a cross-sectional SEM observation was carried out at a magnification of 80,000 times. As a result, the columnar structure could not be confirmed in the phase shift film, but it could be confirmed that To ultra-fine crystal structure or amorphous structure. For the image obtained by the cross-sectional SEM observation, the region including the central portion in the thickness direction of the phase shift film 30 was captured as image data of 64 pixels in length and 256 pixels in width ( FIG. 12( a )). Furthermore, Fourier transform is performed on the image data shown in Fig. 12(a) (Fig. 12(b)). In the spatial frequency spectral distribution obtained by Fourier transform, the signal strength (maximum signal strength) at the origin of the spatial frequency is 2,073,000, and no strong signal different from the above-mentioned maximum strength signal can be confirmed, and only one with 12600 exists. Spatial frequency spectrum of signal strength. This spatial frequency spectrum is 12600/2073000=0.006 (ie 0.6%) relative to the maximum signal strength corresponding to the origin of the spatial frequency, and the phase shift film 30 is an ultra-fine crystal structure that does not have a signal strength above 1.0%. or amorphous structure.

B. Phase Shift Masks and Methods of Making the Same

Using the phase shift mask substrate manufactured in the above manner, a phase shift mask was manufactured by the same method as in Example 1. The wet etching of the phase shift film is carried out with an overetching time of 110%, so that the cross-sectional shape is verticalized and the required fine pattern is formed. The reasonable etching time in Comparative Example 1 is 142 minutes, which is a relatively long time.

In addition, the cross-sectional SEM photo of FIG. 13 is in the manufacturing step of the phase shift mask of the comparative example, using the first etching mask film pattern 40a as a mask, using molybdenum silicide etching solution to shift the phase The film 30 is subjected to wet etching (110% overetching) to form a phase shift film pattern 30a, and a cross-sectional SEM photo of the photoresist film pattern before peeling off. As shown in FIG. 13 , the surface of the transparent substrate 20 exposed after removing the phase shift film 30 is rough and cloudy even when viewed visually. Therefore, the decrease in transmittance due to the rough surface 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 to the photoresist film transferred on the display device, a fine pattern of less than 2.0 μm cannot be transferred.

Hereinafter, other Examples 1 to 4 and other Comparative Examples 1 and 2 (hereinafter, may be simply referred to as each example) for more concretely describing the embodiment of the present invention will be described.

A. Phase-Shifting Mask Substrates and Methods of Making the Same

For each of other Examples 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 with a size of 1214 (1220 mm×1400 mm) was prepared as the transparent substrate 20 .

Thereafter, in each example, the synthetic quartz glass substrate was mounted on a tray (not shown) with the main surface facing downward, and carried into the chamber of the in-line sputtering apparatus.

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 is introduced into the first chamber. The sputtering gas pressure at the time of introduction is by adjusting the flow rate of argon (Ar) gas, helium (He) gas and nitrogen (N ₂ ) gas in the range where the phase shift film satisfies a specific transmittance and phase difference, and in Different values were used in each example (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 0.7Pa to 2.4Pa, and the sputtering gas pressure in other comparative examples 1 and 2 does not meet the range of 0.7Pa to 2.4Pa. scope. Furthermore, in each example, a sputtering power of 7.6 kW was applied to the first sputtering target (molybdenum:silicon=1:9) containing molybdenum and silicon, and the main surface of the transparent substrate 20 was deposited on the main surface of the transparent substrate 20 by reactive sputtering. The nitride of molybdenum silicide containing molybdenum, silicon and nitrogen is deposited to form the phase shift film 30 . In each example, the film thickness of the phase shift film 30 is 144 nm to 170 nm.

Next, in each example, the transparent substrate 20 with the phase shift film 30 was carried 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 was formed on the phase shift film 30 by reactive sputtering (thickness: 15 nm). . Then, in the state where the third chamber is made into a certain vacuum degree, a mixed gas of argon (Ar) gas and methane (CH ₄ : 4.9%) gas is introduced, and 8.5kW sputtering is applied to the third sputtering target containing chromium. Plating power, chromium carbide (CrC) containing chromium and carbon (film thickness 60nm) is formed on CrN by reactive sputtering. Finally, in the state of making the fourth chamber a certain degree of vacuum, a mixed gas of argon (Ar) gas and methane (CH ₄ : 5.5%) gas and a mixture of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas are introduced. Mixed gas, apply 2.0kW sputtering power to the 4th sputtering target containing chromium, and form chromium carbide nitride oxide (CrCON) (film) containing chromium, carbon, oxygen and nitrogen on CrC by reactive sputtering 30nm thick). As described above, in each example, the etching mask film 40 of the laminated structure of the CrN layer, the CrC layer, and the CrCON layer was formed on the phase shift film 30 .

In each example, the phase shift mask base 10 in which the phase shift film 30 and the etching mask film 40 were formed on the transparent substrate 20 was obtained.

In each example, the transmittance and phase difference of the phase shift film 30 (surface of the phase shift film 30 ) of the obtained phase shift mask substrate 10 were measured using MPM-100 manufactured by Lasertec Corporation. In the measurement of the transmittance and phase difference of the phase shift film 30, a substrate with a phase shift film 30 formed on the main surface of a synthetic quartz glass substrate (dummy substrate). In each example, the transmittance and retardation of the phase shift film 30 were measured by taking out the substrate with the phase shift film (dummy substrate) from the chamber before forming the etching mask film 40 . As a result, in each example, the transmittance and retardation both satisfies the required range (transmittance: 10-50% at wavelength 405nm, retardation: 160° to 200° at wavelength 405nm).

In addition, in each example, the composition analysis in the depth direction was performed on the obtained phase shift mask substrate 10 by X-ray photoelectron spectroscopy (XPS).

In each example, in the composition analysis results in the depth direction of the phase shift mask substrate 10 obtained by XPS analysis, the phase shift film 30 except the composition gradient region of the interface between the transparent substrate 20 and the phase shift film 30, and Except for 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 is substantially constant toward the depth direction. In addition, in each example, the atomic ratio of molybdenum and silicon is in the range of not less than 1:3 and not more than 1:15.

And, 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, a 6×6 matrix position (36 positions) with a pitch of 50 μm was set at the measurement position, and a diamond indenter equipped with a diamond indenter was pressed into each position with a maximum of 0.5 mN. Special probes to measure changes in load. From the measured values obtained at each position, remove abnormal values, maximum values, and minimum values, and calculate the indentation hardness in each case (refer to Table 1). Furthermore, it was confirmed that the standard deviation was 7% or less of the measured value with respect to the measured value by removing the abnormal value and the maximum value and the minimum value.

As shown in Table 1, the indentation hardness in other Examples 1 to 4 satisfies 18 GPa to 23 GPa, and the indentation hardness in other Comparative Examples 1 and 2 does not meet 18 GPa to 23 GPa.

B. Phase Shift Masks and Methods of Making the Same

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, on the etching mask film 40 of the phase shift mask substrate 10, a photoresist coating The device coats the photoresist film.

Thereafter, a photoresist film with a film thickness of 520 nm was formed through heating and cooling steps.

Thereafter, the photoresist film was drawn using a laser drawing device, and a photoresist film pattern with a hole diameter of 1.5 μm was formed on the etching mask film through the steps of developing and rinsing.

Thereafter, in each example, the photoresist film pattern was used as a mask, and the etching mask film was wet-etched using a chromium etching solution containing ammonium cerium nitrate and perchloric acid to form a first etching mask film pattern 40a .

Thereafter, in each example, using the first etching mask film pattern 40a as a mask, the phase shift film 30 was formed by diluting the mixed solution of ammonium bifluoride and hydrogen peroxide with pure water to obtain a molybdenum silicide etchant. Wet etching is performed to form the phase shift film pattern 30a.

The wet etching was carried out with an overetching time of 110% in each case, so that the cross-sectional shape was verticalized and a required fine pattern was formed.

Table 1 shows the etching rate of the phase shift film 30 in each example. As shown in Table 1, the etching rate in other comparative example 1 is the minimum 1.0nm/min, and the etching rate in other comparative example 2 is Maximum 12.0nm/min.

Thereafter, the photoresist film pattern is peeled off.

Thereafter, in each example, a photoresist film was applied so as to cover the first etching mask film pattern 40 a using a photoresist coating device.

Thereafter, a photoresist film with a film thickness of 520 nm was formed through heating and cooling steps.

Thereafter, the photoresist film is drawn using a laser drawing device, and the second photoresist film pattern 60 for forming a light-shielding band is formed on the first etching mask film pattern 40a through developing and rinsing steps.

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

Thereafter, the second photoresist film pattern 60 is peeled off.

In addition, in each example, cleaning treatment using a chemical solution (sulfuric acid hydrogen peroxide mixture (SPM), ammonia water hydrogen peroxide mixture (SC1), ozone water) was appropriately performed.

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

Table 1 shows the sputtering gas pressure (Pa) and the etching rate (nm/min) of the phase shift film 30 during the film formation of the phase shift film 30 in other examples 1 to 4 and other comparative examples 1 and 2 respectively. . 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 result of the cleaning resistance of the phase shift film 30 .

14 is a graph showing the relationship between the etching rate, sputtering gas pressure, and indentation hardness in the phase shift film 30 of the phase shift mask 100 of other Examples 1 to 4, and other Comparative Examples 1 and 2. In FIG. 14 , from left to right (according to the order of etching rate from small to large), other comparative example 1, other example 4, other example 3, other example 2, other example 1, and other comparative examples are shown. 2 indentation hardness, sputtering gas pressure. As shown in FIG. 14 , 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 was observed using a scanning electron microscope. The section of the phase shift film pattern includes the upper surface, the lower surface and the 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 part where the upper surface of the phase shift film pattern meets the side (upper side) and the part where the side side meets the lower surface (lower side). As a result, the cross-section of the phase shift film pattern 30a of the phase shift mask of other examples 1 to 4 and other comparative example 2 The surface shape ranges from 65° to 75°, and all have cross-sectional shapes that can fully exert the effect of phase shifting. 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 decrease in transmittance caused by the rough surface of the transparent substrate 20 can be ignored. Therefore, in the exposure light including light in the wavelength range of 300nm to 500nm, more specifically, the composite light including i-line, h-line, and g-line, a phase having an excellent phase shift effect is obtained. Offset mask.

Therefore, it can be said that when the phase shift masks of other embodiments 1 to 4 are placed on the mask stage of the exposure device and then exposed to the photoresist film transferred on the display device, it can be transferred with high precision of less than 2.0 micron pattern.

Moreover, the columnar structure is found in the phase shift film pattern 30a of the phase shift mask 100 in other embodiments 1-4.

On the other hand, the exposed surface of the transparent substrate 20 of the phase shift mask 100 in the other comparative example 1 is rough, and it is also in a cloudy state visually. Therefore, the decrease in transmittance due to the rough surface of the transparent substrate 20 is significant.

Therefore, it is predicted that when the phase shift mask 100 of other comparative example 1 is placed on the mask stage of the exposure device and then exposed to the photoresist film transferred on the display device, it is not possible to transfer a fine pattern less than 2.0 μm .

In addition, the exposed surface of the transparent substrate 20 of the phase shift mask 100 in Comparative Example 2 is smooth, and the decrease in transmittance due to the rough surface of the transparent substrate 20 can be ignored. However, the amount of change in transmittance, phase The amount of change in the difference is large, which does not satisfy the transmittance or phase difference required for the phase shift mask 100 .

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 to the photoresist film transferred on the display device, it is predicted that a fine pattern less than 2.0 μm cannot be transferred.

Furthermore, in the phase shift film pattern 30a of the phase shift mask 100 in other comparative example 1, no columnar structure was found. The same is true for the phase shift film pattern 30 a of the phase shift mask 100 in other comparative example 2.

Claims (16)

A photomask base, characterized in that: it has a thin film for pattern formation on a transparent substrate, and the photomask base is formed on the transparent substrate by wet etching the thin film for pattern formation. The original plate of the photomask of the pattern, the above-mentioned thin film for pattern formation contains transition metal and silicon, the above-mentioned thin film for pattern formation has a columnar structure formed by columnar particles extending in the film thickness direction throughout the surface of the above-mentioned transparent substrate, the above-mentioned pattern formation In the thin film, there are the above-mentioned columnar particle parts with relatively high density and sparse parts with relatively low density. A photomask base, characterized in that: it has a thin film for pattern formation on a transparent substrate, and the photomask base is formed on the transparent substrate by wet etching the thin film for pattern formation. The original plate of the photomask of the pattern, the above-mentioned thin film for pattern formation contains transition metal and silicon, the above-mentioned thin film for pattern formation has a columnar structure formed by columnar particles extending in the film thickness direction throughout the surface of the above-mentioned transparent substrate, the above-mentioned pattern formation In the thin film for pattern formation, there are columnar particle portions in which the detection number of the constituent elements of the pattern formation thin film is relatively high by energy dispersive X-ray analysis of the pattern formation thin film, and the detection number of the above constituent elements is relatively low The sparse part. The photomask substrate according to claim 1 or 2, wherein the atomic ratio of the transition metal contained in the pattern forming thin film to the silicon is transition metal:silicon = 1:3 to 1:15. A photomask base, characterized in that: it has a thin film for pattern formation on a transparent substrate, and the photomask base is formed on the transparent substrate by wet etching the thin film for pattern formation. The original plate of the photomask of the pattern, the above-mentioned pattern-forming film contains transition metal and silicon, the atomic ratio of the above-mentioned transition metal to the above-mentioned silicon is transition metal:silicon = 1:3 to 1:15, and the above-mentioned pattern-forming film has an orientation film A columnar structure formed by columnar particles extending in the thickness direction throughout the surface of the above-mentioned transparent substrate. In the above-mentioned thin film for pattern formation, the detection number of silicon detected by energy-dispersive X-ray analysis of the thin film for pattern formation is relatively large. Particles with higher columnar shape and sparse parts with relatively low detection number of silicon. The photomask substrate according to any one of claims 1, 2, and 4, wherein the columnar particles are irregularly formed in a direction perpendicular to the film thickness direction of the pattern-forming thin film. The photomask substrate according to any one of claims 1, 2, and 4, wherein the columnar structure of the above-mentioned pattern-forming thin film is an image obtained by observing the cross-section of the above-mentioned photomask substrate with a scanning electron microscope at a magnification of 80,000 times , the region including the central part in the thickness direction of the above-mentioned pattern-forming film is captured with image data of 64 pixels in length and 256 pixels in width, and is obtained by Fourier transforming the above-mentioned image data. In the image of the obtained spatial frequency spectral distribution, the center of the image of the above spatial frequency spectral distribution is set as the origin of the spatial frequency, and the maximum signal intensity in the image of the above spatial frequency spectral distribution is located at the origin of the above spatial frequency , and there is a state in which the spatial frequency spectrum has a signal strength of 1.0% or more relative to the signal strength corresponding to the origin of the above-mentioned spatial frequency. Such as the photomask substrate of claim 6, wherein the columnar structure of the above-mentioned pattern-forming film is on the above-mentioned image data, and the above-mentioned origin is set to 0%, corresponding to the two ends of the direction of the horizontal 256 pixels of the above-mentioned image data When the maximum spatial frequency is set to 100%, the above-mentioned signal having a signal strength of 1.0% or more exists at a position on the horizontal axis that is 2.0% or more away from the origin of the above-mentioned spatial frequency. The photomask substrate according to any one of claims 1, 2, and 4, wherein the pattern-forming thin film contains at least nitrogen or oxygen. The photomask substrate according to any one of claims 1, 2, and 4, wherein the transition metal is molybdenum. The photomask substrate according to any one of claims 1, 2, and 4, wherein the film for pattern formation has a transmittance of 1% to 80% for the representative wavelength of the exposed light and a phase difference of 160° to 200° Phase shift film with optical properties below °. The photomask substrate according to claim 10, wherein the phase shift film contains at least nitrogen or oxygen, and the total content of light element components including oxygen and nitrogen contained in the phase shift film is not less than 40 atomic % and not more than 70 atomic % . The photomask substrate according to any one of claims 1, 2, and 4, wherein an etching mask film having an etching selectivity different from that of the pattern forming film is provided on the pattern forming film. The photomask substrate according to claim 12, wherein the above-mentioned etching mask film comprises a material containing chromium and substantially not containing silicon. A method for manufacturing a photomask, characterized in that it includes the following steps: preparing a photomask substrate according to any one of Claims 1 to 11; and forming a photoresist film on the above-mentioned film for pattern formation, so as to form The pattern of the photoresist film is used as a mask, and the above-mentioned thin film for pattern formation is wet-etched to form a transfer pattern on the above-mentioned transparent substrate. A method for manufacturing a photomask, characterized in that it includes the following steps: preparing a photomask substrate as claimed in claim 12 or 13; forming a photoresist film on the above-mentioned etching mask film, and using the photoresist film pattern formed by the above-mentioned photoresist film For masking, the above-mentioned etching mask film is wet-etched, and an etching mask film pattern is formed on the above-mentioned pattern-forming thin film; and the above-mentioned etching mask film pattern is used as a mask, and the above-mentioned pattern-forming film is wet Etching to form a transfer pattern on the transparent substrate. A method of manufacturing a display device, characterized in that it has an exposure step of placing the photomask obtained by the method of manufacturing a photomask according to claim 14 or 15 on an exposure device A mask stage for exposing and transferring the above-mentioned transfer pattern formed on the above-mentioned photomask to the photoresist formed on the display device substrate.

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