JP7130577B2 - Photomask blank, method for manufacturing photomask blank, method for manufacturing photomask, and method for manufacturing display device - Google Patents

Description

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

2. Description of the Related Art In recent years, display devices such as FPDs (Flat Panel Displays) typified by LCDs (Liquid Crystal Displays) are rapidly increasing in screen size and viewing angle, as well as high definition and high speed display. One of the factors required for achieving high-definition and high-speed display is the fabrication of electronic circuit patterns such as fine elements and wiring with high dimensional accuracy. Photolithography is often used for patterning electronic circuits for display devices. Therefore, there is a need for photomasks such as phase shift masks and binary masks for manufacturing display devices on which fine and highly accurate patterns are formed.

Materials made of Cr-based materials are generally used as light-shielding films for photomask blanks for FPDs. Patent Document 1 discloses a light-shielding film using materials made of MoSi-based materials in addition to Cr-based materials. A photomask blank has been proposed that suggests
Further, in Patent Document 2, as a photomask substrate for preventing electrostatic breakdown, a photomask in which a light shielding film pattern made of a Cr-based material is formed on a photomask substrate on which a transparent conductive film is formed. is proposed.

Korea Registered Patent No. 147163 Patent No. 6111672

Photomasks used in recent years to manufacture high-definition (1000 ppi or more) panels require fine patterns with a hole diameter of 6 µm or less and a line width of 4 µm or less, in order to enable high-resolution pattern transfer. Formed photomasks are required. Specifically, there is a demand for a photomask on which a fine pattern with a hole diameter of 1.5 μm is formed.
Along with such miniaturization of patterns, the spacing between patterns is also becoming narrower. Destruction is more likely to occur.
In order to prevent electrostatic damage, a photomask substrate and a photomask have been proposed in Patent Document 3. However, when forming a transparent conductive film on a substrate, a film formation process unrelated to pattern formation is required. In addition, there are problems such as defects tending to occur along with this, which is not preferable.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a light shielding film pattern having a favorable cross-sectional shape when forming a light shielding film pattern on a light shielding film by wet etching. It is an object of the present invention to provide a photomask blank, a method for manufacturing a photomask blank, a method for manufacturing a photomask, and a method for manufacturing a display device, capable of suppressing electrostatic breakdown of a light shielding film pattern.

The inventor of the present invention has earnestly studied measures for solving these problems. First, in order to suppress the occurrence of electrostatic breakdown, the light-shielding film is formed of a metal silicide-based material containing a transition metal and silicon instead of a Cr-based material. Specifically, the light-shielding film has a laminated structure of a light-shielding layer and a surface antireflection layer, and in the case of a Cr-based material, a (CrN/CrC) light-shielding layer/CrON surface antireflection layer, and a metal silicide-based material (MoSi-based material In the case of ), photomasks with a light shielding film pattern space of 2 μm were prepared as the MoSi light shielding layer/MoSiON surface antireflection layer. (The Cr-based material is a Cr target and the gas pressure is 0.5 Pa when the film is formed. The MoSi-based material is a MoSi target of Mo:Si=1:4 and the gas pressure is 0.5 Pa when the film is formed. The optical density of each light-shielding film was 5.0, and the reflectance characteristics of the front antireflection layer were 10% or less at h-line (wavelength 405 nm) and 10% or less at drawing wavelength 413 nm. The film thicknesses and composition ratios of the light-shielding layer and the front-surface antireflection layer were adjusted as appropriate. Then, by changing the voltage applied between the light-shielding film patterns of the photomask, the effect of suppressing electrostatic breakdown was confirmed with the voltage at which the pattern disappeared due to electrostatic breakdown. As a result, in the case of the Cr-based material, the light-shielding film pattern disappeared at 0.5 kV, whereas in the case of the metal silicide-based material, the light-shielding film pattern disappeared at 1.6 kV. The effect of suppressing electrostatic breakdown was confirmed by changing the composition ratio of the Cr-based material and the MoSi-based material, and the effect of suppressing electrostatic breakdown was greater for the MoSi-based material than for the Cr-based material. Also, even when the metal silicide-based materials were changed to TaSi-based materials and ZrSi-based materials, the TaSi-based materials and ZrSi-based materials were more effective in suppressing electrostatic breakdown than the Cr-based materials.
Next, the cross-sectional shapes of the light-shielding film patterns of the Cr-based material and the MoSi-based material were confirmed by cross-sectional SEM observation. As a result, although the cross-sectional shape of the light-shielding film pattern made of Cr-based material is nearly vertical, the cross-sectional shape of the light-shielding film pattern made of MoSi-based material is such that the etching rate of the front antireflection layer is higher than the etching rate of the light-shielding layer. Since it is quite slow, the light-shielding film pattern has an eaves shape (overhang shape). The cross-sectional shape of the light-shielding film pattern was evaluated by changing the composition of the MoSi-based material within a range that does not deviate from the above optical properties, but the eaves shape (overhang shape) was not improved.
Next, in order to improve the cross-sectional shape of the light-shielding film pattern made of MoSi-based material, the gas pressure during the formation of the front-surface antireflection layer was changed to 1.5 Pa, and the cross-sectional shape of the light-shielding film pattern was observed by cross-sectional SEM observation. confirmed. As a result, the eaves shape (overhang shape) of the light shielding film pattern was improved. In order to ascertain the cause of the improvement in the cross-sectional shape of the light-shielding film pattern, a sample obtained by forming a single-layer MoSi light-shielding layer on a substrate under a film-forming condition of 0.5 Pa and a MoSi light-shielding layer under a film-forming condition of 1.6 Pa were prepared. When the film-formed samples were prepared and the cross sections of the MoSi light-shielding layers were observed with a scanning electron microscope (SEM), it was found that the average grain size of the crystal grains constituting the former MoSi light-shielding layer was larger than that of the latter MoSi light-shielding layer. It was confirmed that the average grain size of the crystal grains constituting the From these results, the present inventors found that by controlling the average grain size of the crystal grains in each layer constituting the light shielding film, it is possible to form a light shielding film pattern having a better cross-sectional shape, which is similar to MoSi-based materials. It was found that the electrostatic breakdown of the light-shielding film pattern can be suppressed by applying a metal silicide-based material.
The present invention was made as a result of the above earnest studies, and has the following configurations.

(Configuration 1) A photomask blank having a light shielding film on a transparent substrate,
The photomask blank is an original plate for forming a photomask having a light shielding film pattern on the transparent substrate by wet etching the light shielding film,
The light shielding film is made of a transition metal silicide material containing a transition metal and silicon,
The light shielding film has a structure in which a light shielding layer and a surface antireflection layer are laminated from the transparent substrate side,
The front antireflection layer further contains nitrogen or oxygen,
A photomask blank, wherein an average grain size of crystal grains forming the front-surface antireflection layer is larger than an average grain size of crystal grains forming the light-shielding layer.

(Configuration 2) A photomask blank having a light shielding film on a transparent substrate,
The photomask blank is an original plate for forming a photomask having a light shielding film pattern on the transparent substrate by wet etching the light shielding film,
The light shielding film is made of a transition metal silicide material containing a transition metal and silicon,
The light-shielding film has a structure in which a back-surface antireflection layer, a light-shielding layer, and a front-surface antireflection layer are laminated from the transparent substrate side,
The back antireflection layer and the front antireflection layer further contain nitrogen or oxygen,
A photomask blank, wherein an average grain size of crystal grains forming the front antireflection layer and the back antireflection layer is larger than an average grain size of crystal grains forming the light shielding layer.

(Structure 3) The photomask blank according to structure 1 or 2, wherein the light shielding layer contains at least nitrogen or oxygen.
(Structure 4) The photomask blank according to any one of Structures 1 to 3, wherein the transition metal is molybdenum.

(Structure 5) The photomask blank according to any one of Structures 1 to 4, further comprising an etching mask film having an etching selectivity different from that of the light shielding film on the light shielding film.

(Structure 6) A step of preparing the photomask blank according to any one of Structures 1 to 4;
forming a resist film on the light-shielding film, and wet-etching the light-shielding film using a resist film pattern formed from the resist film as a mask to form a light-shielding film pattern on the transparent substrate. A method of manufacturing a photomask, characterized by:

(Configuration 7) A step of preparing the photomask blank according to Configuration 5;
forming a resist film on the etching mask film, wet-etching the etching mask film using a resist film pattern formed from the resist film as a mask, and forming an etching mask film pattern on the light shielding film;
and wet-etching the light-shielding film using the etching mask film pattern as a mask to form a light-shielding film pattern on the transparent substrate.

(Structure 8) A display device comprising an exposure step of exposing and transferring a resist film formed on a display device substrate using a photomask obtained by the method of manufacturing a photomask according to structure 6 or 7. manufacturing method.

According to the photomask blank according to the present invention, a light-shielding film pattern having a favorable cross-sectional shape can be formed when forming a required fine transfer pattern by wet etching, and electrostatic breakdown of the light-shielding film pattern can be suppressed. A photomask blank can be obtained from which a photomask can be manufactured.

Further, according to the photomask manufacturing method of the present invention, a photomask is manufactured using the photomask blank described above. Therefore, a light-shielding film pattern having a favorable cross-sectional shape can be formed, and a photomask capable of suppressing electrostatic breakdown of the light-shielding film pattern can be manufactured. This photomask can be applied to miniaturization of line-and-space patterns and contact holes.

Further, according to the display device manufacturing method of the present invention, the display device is manufactured using the photomask obtained by the above-described photomask manufacturing method. Therefore, a display device having fine line-and-space patterns and contact holes can be manufactured.

2 is a schematic diagram showing the film configuration of the binary mask blank according to the first embodiment; FIG. FIG. 10 is a schematic diagram showing a film configuration of a binary mask blank according to a second embodiment; FIG. 11 is a schematic diagram showing a manufacturing process of a binary mask according to a third embodiment; FIG. 14 is a schematic diagram showing a manufacturing process of a binary mask according to a fourth embodiment;

Embodiment 1.2.
In Embodiments 1 and 2, binary mask blanks will be described. The binary mask blank of the first embodiment is formed by wet-etching the light-shielding film using an etching mask film pattern in which a desired pattern is formed on the etching mask film as a mask to form a binary mask having the light-shielding film pattern on the transparent substrate. It is the original version for In the binary mask blank of the second embodiment, a resist film pattern in which a desired pattern is formed on a resist film is used as a mask to wet-etch the light-shielding film to form a light-shielding film having a light-shielding film pattern on a transparent substrate. It is the original version for

FIG. 1 is a schematic diagram showing the film configuration of a binary mask blank 10 according to the first embodiment.
A binary mask blank 10 shown in FIG. 1 includes a transparent substrate 20 , a light shielding film 30 formed on the transparent substrate 20 , and an etching mask film 40 formed on the light shielding film 30 .
FIG. 2 is a schematic diagram showing the film configuration of the binary mask blank 10 according to the second embodiment.
A binary mask blank 10 shown in FIG. 2 includes a transparent substrate 20 and a light shielding film 30 formed on the transparent substrate 20 .
The transparent substrate 20, the light shielding film 30, and the etching mask film 40 that constitute the binary mask blank 10 of the first and second embodiments will be described below.

The transparent substrate 20 is transparent to exposure light. The transparent substrate 20 has a transmittance of 85% or more, preferably 90% or more, with respect to exposure light, assuming that there is no surface reflection loss. The transparent substrate 20 is made of a material containing silicon and oxygen, and may be made of a glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ —TiO ₂ glass, etc.). can be done. When the transparent substrate 20 is made of low thermal expansion glass, it is possible to suppress the positional change of the light shielding film pattern due to the thermal deformation of the transparent substrate 20 . The binary mask blank transparent substrate 20 used for the display device is generally a rectangular substrate having a short side length of 300 mm or more. INDUSTRIAL APPLICABILITY According to the present invention, a fine light-shielding film pattern of, for example, less than 2.0 μm formed on a transparent substrate can be stably transferred even if the short side of the transparent substrate has a large size of 300 mm or more. A binary mask blank that can provide a binary mask.

The light shielding film 30 is composed of a transition metal silicide material containing a transition metal and silicon. Molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr), and the like are suitable as transition metals, and molybdenum (Mo) is particularly preferred.
The light shielding film 30 has a structure in which a light shielding layer 31 and a front antireflection layer 32 are laminated from the transparent substrate 20 side, or a back antireflection layer 33, a light shielding layer 31 and a surface antireflection layer 33 are laminated from the transparent substrate 20 side. It has a structure in which an antireflection layer 32 is laminated. When the light-shielding film 30 has a structure in which the light-shielding layer 31 and the front-surface antireflection layer 32 are laminated, the average grain size of the crystal grains forming the front-surface anti-reflection layer 32 is the average grain size of the crystal grains forming the light-shielding layer 31. larger than the particle size. When the light shielding film 30 has a structure in which the back antireflection layer 33, the light shielding layer 31, and the front antireflection layer 32 are laminated, the average grain size of the crystal grains constituting the front antireflection layer 32 and the back antireflection layer 33 is is larger than the average grain size of the crystal grains forming the light shielding layer 31 .
When the light shielding film 30 has a structure in which the light shielding layer 31 and the front antireflection layer 32 are laminated from the transparent substrate side, the average grain size of the crystal grains of the front antireflection layer 32 is the average grain size of the crystal grains of the light shielding layer 31. By making the diameter larger than the diameter, wet etching progresses by making it easier for the wet etchant to permeate between the crystal grains. Therefore, the overhang shape of the light shielding film pattern caused by the wet etching rate of the front antireflection layer 32 being lower than that of the light shielding layer 31 can be improved.
Further, when the light shielding film 30 has a structure in which the back antireflection layer 33, the light shielding layer 31, and the front antireflection layer 32 are laminated from the transparent substrate side, the average grain size of the crystal grains of the front antireflection layer 32 is By making the grain size larger than the average grain size of the crystal grains of the layer 31, the overhang shape of the light shielding film pattern can be improved in the same manner as described above. Furthermore, by making the average grain size of the crystal grains of the back antireflection layer 33 larger than the average grain size of the crystal grains of the light shielding layer 31, the tapered shape on the transparent substrate side caused by the slow wet etching rate is improved. be able to.
The average grain size of the crystal grains in each layer can be calculated from the size of each crystal grain observed by cross-sectional SEM.
In addition, the average grain size (average size) of the crystal grains forming the front antireflection layer 32 and the back antireflection layer 33 is 3 to 15 nm, and the average grain size (average size) of the crystal grains forming the light shielding layer 31. is preferably 1 to 8 nm.
In the light shielding film 30, the front antireflection layer 32 and the back antireflection layer 33 preferably contain at least nitrogen or oxygen. In the transition metal silicide-based material, nitrogen or oxygen, which is a light element component, can effectively reduce the reflectance of the front and back surfaces of the light shielding film 30 . From the viewpoint of transfer accuracy during pattern transfer using a photomask, the reflectance of the surface of the light shielding film 30 on the front antireflection layer 32 side and the back surface of the light shielding film 30 on the back antireflection layer 33 side at the exposure wavelength should be 15% or less. Therefore, the total content of light element components including oxygen and nitrogen contained in the front antireflection layer 32 and the back antireflection layer 33 is preferably 35 atomic % or more. More preferably, it is 40 atomic % or more and 70 atomic % or less, and 45 atomic % or more and 65 atomic % or less. Also, the oxygen content is preferably more than 0 atomic % and 40 atomic % or less in terms of defect quality and chemical resistance. Also, the light shielding layer 31 can contain at least nitrogen or oxygen. The total content of light element components including oxygen and nitrogen contained in the light shielding layer 31 is preferably 20 atomic % or less. If it exceeds 20 atomic %, the light shielding performance of the light shielding layer 31 is lowered, and the film thickness for obtaining the optical density necessary for the light shielding film 30 is increased, which is not preferable. More preferably, it is 15 atomic % or less and 10 atomic % or less.
Examples of transition metal silicide-based materials include transition metal silicides, nitrides of transition metal silicides, oxides of transition metal silicides, oxynitrides of transition metal silicides, oxycarbides of transition metal silicides, and oxynitride carbides of transition metal silicides. is mentioned. In addition, when 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), an excellent pattern cross section can be obtained by wet etching. A molybdenum silicide-based material (MoSi-based material) is particularly preferable because it is easy to obtain a shape.
In addition to oxygen and nitrogen described above, the light shielding film 30 may contain other light element components such as carbon and helium for the purpose of reducing film stress and controlling the wet etching rate.
The light shielding film 30 can be formed by a sputtering method.

The surface reflectance of the light shielding film 30 (the surface reflectance on the side where the surface antireflection layer 32 is formed) is 15% or less, preferably 10% or less, in the wavelength range of 365 nm to 436 nm. In addition, the surface reflectance of the light shielding film 30 is preferably 20% or less, more preferably 17% or less, with respect to light in the wavelength range from 313 nm to 436 nm when the j-line is included in the exposure light. More preferably, it should be 15% or less. In particular, in the case of the mask blank 10 without the etching mask film 40, the surface reflectance of the light shielding film 30 is preferably 10% or less with respect to light with a wavelength of 413 nm, which is the laser drawing wavelength. Further, the surface reflectance of the light shielding film 30 is preferably 0.2% or more in the wavelength range of 365 nm to 436 nm, and preferably 0.2% or more for light in the wavelength range of 313 nm to 436 nm.
Surface reflectance can be measured using a spectrophotometer or the like.

In the case where the light shielding film 30 has a structure in which the back antireflection layer 33, the light shielding layer 31, and the front antireflection layer 32 are laminated from the transparent substrate 20 side, the back antireflection layer 33 is formed. The back surface reflectance on the side with the substrate is 15% or less, preferably 10% or less, in the wavelength range of 365 nm to 436 nm. Further, when the j-line is included in the exposure light, the back surface reflectance of the light shielding film 30 is preferably 20% or less, more preferably 17% or less, for light in the wavelength range from 313 nm to 436 nm. More preferably, it should be 15% or less. Further, the back surface reflectance of the light shielding film 30 is preferably 0.2% or more in the wavelength range of 365 nm to 436 nm, and preferably 0.2% or more for light in the wavelength range of 313 nm to 436 nm.
The back surface reflectance can be measured using a spectrophotometer or the like.
The light shielding film 30 preferably has an optical density of 3 or more, more preferably 3.5 or more, and still more preferably 4 or more with respect to the exposure light. The optical density can be measured using a spectrophotometer, an OD meter, or the like.

The etching mask film 40 is disposed above the light shielding film 30, that is, on the surface antireflection layer 32, and is made of a material that has etching resistance to an etchant that etches the light shielding film 30 (etching selectivity is different from that of the light shielding film 30). consists of The etching mask film 40 may have a function of blocking transmission of the exposure light, and furthermore, the surface reflectance of the light shielding film 30 with respect to the light incident from the light shielding film 30 side, that is, from the surface antireflection layer 32 side. of 15% or less in the wavelength range of 350 nm to 436 nm. In particular, the surface reflectance of the etching mask film 40 is preferably 10% or less with respect to light with a wavelength of 413 nm, which is the laser drawing wavelength. The etching mask film 40 is composed of a material containing chromium (Cr) and substantially free of silicon. More specifically, the chromium-containing material contains chromium (Cr) or at least one of chromium (Cr) and oxygen (O), nitrogen (N), and carbon (C). materials to be used. Alternatively, a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C), and further containing fluorine (F) can be used. For example, materials forming the etching mask film 40 include Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF.
The etching mask film 40 can be formed by a sputtering method.

The etching mask film 40 may be composed of a single film having a uniform composition according to its function, may be composed of a plurality of films having different compositions, or may be composed of different compositions in the thickness direction. It may be composed of a single continuously changing film.

Note that the binary mask blank 10 shown in FIG. The present invention can also be applied to mask blanks.

Next, a method for manufacturing the binary mask blank 10 of the first and second embodiments will be described. The binary mask blank 10 shown in FIG. 1 is manufactured by performing the following light shielding film forming process and etching mask film forming process. The binary mask blank 10 shown in FIG. 2 is manufactured by a light shielding film forming process.
Each step will be described in detail below.

1. Light-Shielding Film Forming Step First, the transparent substrate 20 is prepared. The transparent substrate 20 is 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.), as long as it is transparent to exposure light. It may be

Next, a light-shielding film 30 having a light-shielding layer 31 and a front-surface antireflection layer 32, or a back-surface anti-reflection layer 33, a light-shielding layer 31, and a front-surface antireflection layer 32 are formed on the transparent substrate 20 by a sputtering method. and a light shielding film 30 is formed.
The light shielding layer 31, the front antireflection layer 32, and the back antireflection layer 33 of the layers constituting the light shielding film 30 are formed by using a transition metal silicide target containing transition metal and silicon, which are the main components of the materials constituting these layers, Alternatively, a transition metal silicide target containing a transition metal, silicon, oxygen and/or nitrogen is used as a sputtering target, for example, containing at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas and xenon gas A sputtering gas atmosphere composed of an inert gas, or an active gas containing at least oxygen and nitrogen selected from the group consisting of the above inert gas and oxygen gas, nitrogen gas, carbon dioxide gas, nitrogen monoxide gas, and nitrogen dioxide gas is performed in a sputtering gas atmosphere consisting of a mixed gas with

The composition and thickness of the light shielding layer 31, the front antireflection layer 32, and the back antireflection layer 33 of each layer constituting the light shielding film 30 are determined so that the light shielding film 30 has the above optical properties (optical density, surface reflectance, back reflectance). is adjusted to have The composition of the light shielding layer 31, the front antireflection layer 32, and the back antireflection layer 33 of each layer constituting the light shielding film 30 depends on the content ratio of the elements constituting the sputtering target (for example, the transition metal content and the silicon content). ratio), the composition and flow rate of the sputtering gas, and the like. The thicknesses of the light shielding layer 31, the front antireflection layer 32, and the back antireflection layer 33 of each layer constituting the light shielding film 30 can be controlled by sputtering power, sputtering time, and the like. Moreover, the light shielding layer 31, the front antireflection layer 32, and the back antireflection layer 33 of each layer constituting the light shielding film 30 are preferably formed using an in-line sputtering apparatus. When the sputtering apparatus is an in-line sputtering apparatus, the thickness of the light shielding film 30 can be controlled also by the transport speed of the transparent substrate 20 . In the light shielding film 30, the front antireflection layer 32 and the back antireflection layer 33 preferably contain at least nitrogen or oxygen. From the viewpoint of transfer accuracy during pattern transfer using a photomask, the reflectance of the front surface of the light shielding film 30 on the front antireflection layer 32 side and the back surface of the light shielding film 30 on the back antireflection layer side at the exposure wavelength should be 15% or less. For this purpose, the total content of light element components including oxygen and nitrogen contained in the front antireflection layer 32 and the back antireflection layer 33 is controlled to 35 atomic % or more. Preferably, the total content of light element components including oxygen and nitrogen contained in the antireflection layer 32 and the back antireflection layer 3 is controlled to be 40 atomic % or more and 70 atomic % or less.

When the light-shielding film 30 has a two-layer structure of the light-shielding layer 31 and the front-surface antireflection layer 32, the above-described film formation process is performed so that the average grain size of the crystal grains constituting the front-surface anti-reflection layer 32 constitutes the light-shielding layer 31. The gas pressure, composition and flow rate of the sputtering gas are appropriately adjusted for each film formation process so that the average grain size is larger than the average grain size of the crystal grains, and the sputtering is performed twice. Further, when the light-shielding film 30 has a three-layer structure of the back antireflection layer 33, the light shielding layer 31, and the front antireflection layer 32, the above-described film forming process is applied to form the front antireflection layer 32 and the back antireflection layer 33. The gas pressure, composition, and flow rate of the sputtering gas are appropriately adjusted for each film formation process, and the sputtering is performed three times so that the average grain size of the crystal grains formed is larger than the average grain size of the crystal grains forming the light shielding layer 31 . The light shielding layer 31, the front antireflection layer 32, and the back antireflection layer 33 of each layer constituting the light shielding film 30 may be formed using targets having different content ratios of the elements constituting the sputtering target.

2. Surface treatment process Oxygen-containing transition metal silicides such as transition metal, silicon and oxygen containing transition metal silicide oxides or transition metal, silicon, oxygen and nitrogen containing transition metal silicide oxynitrides The light shielding film 30 (surface antireflection layer 32) after forming the light shielding film 30 made of a material is treated with the light shielding film 30 (surface antireflection layer 32) in order to suppress penetration of the etchant due to the presence of oxides of transition metals. A surface treatment step of 32) for adjusting the state of surface oxidation may be performed.
As the surface treatment process for adjusting the state of surface oxidation of the light shielding film 30 (surface antireflection layer 32), there are a method of surface treatment with an acidic aqueous solution, a method of surface treatment with an alkaline aqueous solution, and a dry treatment such as ashing. and methods to do so.
Thus, the binary mask blank 10 of Embodiment 2 is obtained. To manufacture the binary mask blank 10 of the first embodiment, the following etching mask film formation step is further performed.

3. Etching Mask Film Forming Step After surface treatment for adjusting the state of surface oxidation of the surface of the light shielding film 30 (surface antireflection layer 32) is performed as necessary, an etching mask film 40 is formed on the light shielding film 30 by a sputtering method. Form. The etching mask film 40 is preferably formed using an in-line sputtering apparatus. When the sputtering apparatus is an in-line sputtering apparatus, the thickness of the etching mask film 40 can also be controlled by the transport speed of the transparent substrate 20 .
The etching mask film 40 is formed using a sputtering target containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium carbide oxynitride, etc.), for example, helium gas, neon gas, argon. A sputtering gas atmosphere consisting of an inert gas containing at least one selected from the group consisting of gas, krypton gas and xenon gas, or at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas and xenon gas. and an active gas containing at least one selected from the group consisting of oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon-based gas, and fluorine-based gas It is carried out in a sputter gas atmosphere of Hydrocarbon gases include, for example, methane gas, butane gas, propane gas, and styrene gas.

When the etching mask film 40 is composed of a single film with a uniform composition, the above-described film formation process is performed only once without changing the composition and flow rate of the sputtering gas. When the etching mask film 40 is composed of a plurality of films with different compositions, the film formation process described above is performed a plurality of times while changing the composition and flow rate of the sputtering gas for each film formation process. When the etching mask film 40 is composed of a single film whose composition changes continuously in the thickness direction, the film formation process described above is repeated while changing the composition and flow rate of the sputtering gas with the elapsed time of the film formation process. do it only once.
Thus, the binary mask blank 10 of Embodiment 1 is obtained.

Since the binary mask blank 10 shown in FIG. 1 has the etching mask film 40 on the light shielding film 30, an etching mask film forming process is performed when manufacturing the binary mask blank 10. FIG. When manufacturing a binary mask blank having the etching mask film 40 on the light shielding film 30 and the resist film on the etching mask film 40, the resist film is formed on the etching mask film 40 after the etching mask film forming step. do. When manufacturing a binary mask blank having a resist film on the light shielding film 30 in the binary mask blank 10 shown in FIG. 2, the resist film is formed after the light shielding film forming step.

The binary mask blanks 10 of the first and second embodiments have a good cross-sectional shape, and a light-shielding film pattern capable of suppressing electrostatic breakdown can be formed by wet etching. Therefore, it is possible to obtain a binary mask blank capable of manufacturing a binary mask capable of accurately transferring a high-definition light-shielding film pattern.

Embodiment 3.4.
In Embodiments 3 and 4, a method for manufacturing a binary mask will be described.

FIG. 3 is a schematic diagram showing a method of manufacturing a binary mask according to the third embodiment. FIG. 4 is a schematic diagram showing a method of manufacturing a binary mask according to the fourth embodiment.
The binary mask manufacturing method shown in FIG. 3 is a method of manufacturing the binary mask 100 using the binary mask blank 10 shown in FIG. A resist film pattern 50 is formed by drawing and developing a desired pattern on the resist film (resist film pattern forming step), and the etching mask film 40 is wet-etched using the resist film pattern 50 as a mask. a step of forming an etching mask film pattern 40a on the light shielding film 30 (etching mask film pattern forming step); and a step of forming the light shielding film pattern 30a (light shielding film pattern forming step).

The binary mask manufacturing method shown in FIG. 4 is a method of manufacturing the binary mask 100 using the binary mask blank 10 shown in FIG. By drawing and developing a desired pattern on the film, a resist film pattern 50 is formed (resist film pattern forming step), and the light shielding film 30 is wet-etched using the resist film pattern 50 as a mask to form the transparent substrate 20. and a step of forming a light shielding film pattern 30a thereon (light shielding film pattern forming step).
Each step of the binary mask manufacturing process according to the third and fourth embodiments will be described in detail below.

Binary mask manufacturing process according to the third embodiment 1. Resist Film Pattern Forming Step In the resist film pattern forming step, first, a resist film is formed on the etching mask film 40 of the binary mask blank 10 of the first embodiment. The resist film material to be used is not particularly limited. For example, any material may be used as long as it is sensitive to laser light having a wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Moreover, the resist film may be either positive type or negative type.
After that, a desired pattern is drawn on the resist film using a laser beam having a wavelength selected from a wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film is the pattern formed on the light shielding film 30 . Patterns drawn on the resist film include line-and-space patterns and hole patterns.
Thereafter, the resist film is developed with a predetermined developer to form a resist film pattern 50 on the etching mask film 40 as shown in FIG. 3(a).

2. Etching Mask Film Pattern Forming Step In the etching mask film pattern forming step, first, the etching mask film 40 is etched using the resist film pattern 50 as a mask to form an etching mask film pattern 40a. The etching mask film 40 is made of a chromium-based material containing chromium (Cr) and substantially free of silicon. 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 etchant containing ceric ammonium nitrate and perchloric acid is mentioned.
Thereafter, the resist film pattern 50 is removed using a resist remover or by ashing, as shown in FIG. 3(b). In some cases, the next light-shielding film pattern forming step may be performed without removing the resist film pattern 50 .

3. Light-Shielding Film Pattern Forming Step In the light-shielding film pattern forming step, the light-shielding film 30 is wet-etched using the etching mask film pattern 40a as a mask to form a light-shielding film pattern 30a as shown in FIG. 3(c). As the light shielding film pattern 30a, a line-and-space pattern and a hole pattern can be used. The etchant for etching the light shielding film 30 is not particularly limited as long as it can selectively etch the light shielding film 30 . For example, an etchant containing ammonium fluoride, phosphoric acid and hydrogen peroxide, and an etchant containing ammonium hydrogen fluoride and hydrogen peroxide can be used.
In order to improve the cross-sectional shape of the light shielding film pattern 30a, the wet etching can be performed for a time (overetching time) longer than the time required for the transparent substrate 20 to be exposed in the light shielding film pattern 30a (just etching time). preferable. Considering the influence on the transparent substrate 20, etc., it is preferable that the over-etching time be within the time obtained by adding 10% of the just-etching time to the just-etching time.

After the light-shielding film pattern forming step, the etching mask film pattern 40a is peeled off, and the binary mask 100 is obtained.

According to the binary mask manufacturing method of the third embodiment, since the binary mask blank 10 of the first embodiment is used, it is possible to form the light shielding film pattern 30a which has a good cross-sectional shape and can suppress electrostatic breakdown. can. Therefore, it is possible to manufacture a binary mask having a high-definition light-shielding film pattern 30a. A binary mask manufactured in this way can correspond to miniaturization of line-and-space patterns and contact holes.

Binary mask manufacturing process according to the fourth embodiment 1. Resist Film Pattern Forming Step In the resist film pattern forming step, first, a resist film is formed on the light shielding film 30 of the binary mask blank 10 of the second embodiment. The resist film material used is the same as that described in the third embodiment. In addition, before forming the resist film, the light shielding film 30 may be subjected to a surface modification treatment in order to improve the adhesion to the light shielding film 30 as necessary. After forming a resist film in the same manner as described above, a desired pattern is drawn on the resist film using a laser beam having a wavelength selected from the wavelength range of 350 nm to 436 nm. Thereafter, the resist film is developed with a predetermined developer to form a resist film pattern 50 on the light shielding film 30 as shown in FIG. 4(a).
2. Light-Shielding Film Pattern Forming Step In the light-shielding film pattern forming step, the light-shielding film 30 is etched using the resist film pattern 50 as a mask to form a light-shielding film pattern 30a as shown in FIG. 4B. The etchant for etching the light shielding film pattern 30a and the light shielding film 30 is the same as that described in the third embodiment.
Thereafter, the resist film pattern 50 is removed using a resist remover or by ashing (FIG. 4(c)).
A binary mask 100 is thus obtained.
According to the binary mask manufacturing method of the fourth embodiment, since the binary mask blank 10 of the second embodiment is used, it is possible to form a light-shielding film pattern that has a good cross-sectional shape and can suppress electrostatic breakdown. . Therefore, it is possible to manufacture a binary mask having a high-definition light-shielding film pattern. A binary mask manufactured in this way can correspond to miniaturization of line-and-space patterns and contact holes.

Embodiment 5.
In Embodiment 5, a method for manufacturing a display device will be described. The display device uses the binary mask 100 manufactured using the binary mask blank 10 described above, or uses the binary mask 100 manufactured by the binary mask manufacturing method described above (mask placing step); A process (exposure process) of exposing and transferring a light shielding film pattern onto the upper resist film is performed.
Each step will be described in detail below.

1. Mounting Step In the mounting step, the binary mask 100 manufactured in Embodiment 3 is mounted on the mask stage of the exposure apparatus. Here, the binary mask 100 is arranged so as to face the resist film formed on the display device substrate via the projection optical system of the exposure device.

2. Pattern Transfer Process In the pattern transfer process, the binary mask 100 is irradiated with exposure light to transfer the pattern to the resist film formed on the display device substrate. The exposure light is compound light containing light of a plurality of wavelengths selected from a wavelength range of 365 nm to 436 nm, or monochromatic light selected by cutting a certain wavelength range from the wavelength range of 365 nm to 436 nm with a filter or the like. For example, the exposure light is compound light including i-line, h-line and g-line, or i-line monochromatic light. When compound light is used as the exposure light, the intensity of the exposure light can be increased and the throughput can be increased, so that the manufacturing cost of the display device can be reduced.

According to the manufacturing method of the display device of the third embodiment, it is possible to manufacture a high-definition display device having high resolution and fine line-and-space patterns and contact holes.
In the above embodiments, the case of using a binary mask blank having a light shielding film or a binary mask having a light shielding film pattern as a photomask blank or photomask has been described, but the present invention is not limited to these. For example, the present invention can be applied to photomask blanks for recessed Levenson, mask blanks for CPL masks, and the like. Alternatively, a phase shift film may be formed on a transparent substrate, and the light shielding film described in the embodiment may be formed thereon.

Example 1.
A. Binary Mask Blank and Manufacturing Method Thereof To manufacture the binary mask blank of Example 1, first, a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) was prepared as the transparent substrate 20 .

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

In order to form the first layer of the light shielding film 30 on the main surface of the transparent substrate 20, first, argon (Ar) gas and helium (He) gas are supplied so that the sputtering gas pressure in the first chamber is 0.5 Pa. A mixed gas consisting of Then, by applying a predetermined sputtering power to a first sputtering target (molybdenum:silicon=1:4) containing molybdenum and silicon and sputtering, molybdenum silicide containing molybdenum and silicon is formed on the main surface of transparent substrate 20. A light shielding layer 31 having a thickness of 88 nm was formed.

Next, the transparent substrate 20 on which the light shielding layer 31 is formed is carried into the second chamber, and argon (Ar) gas and nitrogen monoxide are added so that the sputtering gas pressure in the second chamber is 1.7 Pa. A mixed gas composed of (NO) gas and helium (He) gas was introduced. Then, a predetermined sputtering power is applied to a second sputtering target (molybdenum:silicon=1:4) containing molybdenum and silicon, and reactive sputtering is performed to deposit molybdenum, silicon, oxygen, and nitrogen on the light shielding layer 31. A surface antireflection layer 32 of molybdenum silicide oxynitride was formed to a thickness of 45 nm.

Then, the transparent substrate 20 on which the light shielding layer 31 and the front antireflection layer 32 are formed is carried into the third chamber, and argon (Ar) gas is supplied so that the sputtering gas pressure in the third chamber becomes 0.3 Pa. and nitrogen (N ₂ ) gas was introduced. Then, a predetermined sputtering power is applied to a third sputtering target made of chromium, and reactive sputtering is performed to form an etching mask film 40 of chromium nitride containing chromium and nitrogen on the surface antireflection layer 32 . A film having a thickness of 30 nm was formed.

In this manner, a binary mask blank 10 was obtained in which a light shielding film 30 having a laminate structure of a light shielding layer 31 and a front antireflection layer 32 and an etching mask film 40 were formed on a transparent substrate 20 .

Various characteristics of the light-shielding film 30 having a laminated structure of the light-shielding layer 31 and the front antireflection layer 32 and the etching mask film 40 in the obtained binary mask blank 10 were measured as follows.
[Optical Density (OD)]
The optical density (OD) of the light-shielding film 30 composed of the laminated structure of the light-shielding layer 31 and the front antireflection layer 32 was measured with a spectrophotometer and found to be 3.6 (wavelength: 405 nm). The optical density of the light-shielding film 30 was measured by setting the light-shielding film 30 on the main surface of the synthetic quartz glass substrate which was set on the same tray. A substrate (dummy substrate) with a light shielding film was used. The optical density (OD) of the light shielding film 30 was measured by taking out the substrate with the light shielding film (dummy substrate) from the chamber before forming the etching mask film 40 .
[Surface reflectance]
The surface reflectance of the light shielding film 30 composed of the laminated structure of the light shielding layer 31 and the surface antireflection layer 32 and the reflectance of the etching mask film 40 were measured with a spectrophotometer. As a result, the surface reflectance of the light shielding film 30 was 8.3. % (wavelength 405 nm), and the surface reflectance of the etching mask film 40 was 7.7% (wavelength 413 nm (corresponding to laser drawing wavelength)). From the above results, it can be said that the surface antireflection layer 32 of the light shielding film 30 mainly has the surface antireflection function. The surface reflectance of the light-shielding film 30 is measured by taking out the substrate with the light-shielding film from the chamber before forming the etching mask film 40 and measuring the surface reflectance of the etching mask film 40 in the same manner as described above. A dummy substrate having a light shielding film 30 and an etching mask film 40 formed on a synthetic quartz glass substrate was taken out from the chamber and measured.

[refractive index (n), extinction coefficient (k)]
As a result of measuring the refractive index (n) and the extinction coefficient (k) of the light shielding layer 31 and the front antireflection layer 32 with an n & k analyzer, the refractive index (wavelength 405 nm) of the light shielding layer 31 is 4.52, the extinction coefficient (wavelength 405 nm) was 2.68, the refractive index (wavelength 405 nm) of the front antireflection layer 32 was 2.56, and the extinction coefficient (wavelength 405 nm) was 0.37. The refractive indices and extinction coefficients of the light shielding layer 31 and the front antireflection layer 32 were measured using a substrate with the light shielding layer 31 formed on a synthetic quartz glass substrate under the same film formation conditions as in Example 1, A substrate with a front-surface antireflection layer 32 was prepared.
[Crystal grain size, average grain size]
As a result of observing and measuring the size of the crystal grains of the light shielding layer 31 and the front antireflection layer 32 with a cross-sectional SEM, the size of the crystal grains of the light shielding layer 31 is 3 to 5 nm, and the average size of the crystal grains (average grain size, hereinafter ) was 4 nm. The grain size of the surface antireflection layer 32 was 6 to 10 nm, and the average grain size was 8 nm.
That is, the average grain size of the crystal grains of the front antireflection layer 32 constituting the light shielding film 30 in the binary mask blank 10 of Example 1 was larger than the average grain size of the crystal grains of the light shielding layer 31 .

B. Binary Mask and Its Manufacturing Method In order to manufacture the binary mask 100 using the binary mask blank 10 manufactured as described above, first, a photoresist is applied onto the etching mask film 40 of the binary mask blank 10 using a resist coater. A resist film was applied.
After that, a photoresist film was formed through heating and cooling processes.
After that, the photoresist film was drawn using a laser lithography device, and through developing and rinsing processes, a resist film pattern 50 having a hole pattern with a hole diameter of 1.5 μm was formed on the etching mask film.

Thereafter, using the resist film pattern 50 as a mask, the etching mask film 40 was wet-etched with a Cr etchant containing ceric ammonium nitrate and perchloric acid to form an etching mask film pattern 40a. Next, using the etching mask film pattern 40a as a mask, the light shielding film 30 is wet-etched with a molybdenum silicide etchant obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water to remove the light shielding film pattern 30a. formed. This wet etching was performed with an over-etching time of 110% in order to make the cross-sectional shape vertical and to form a required fine pattern.
Thereafter, after removing the etching mask film 40 with the Cr etchant, the resist film pattern 50 was removed.

A cross section of the obtained binary mask 100 was observed with a scanning electron microscope. The cross-sectional shape of the light-shielding film pattern 30a formed on the binary mask of Example 1 had an improved canopy shape (overhang shape), and had a favorable cross-sectional shape that was substantially vertical at 75°. The angle of the cross-sectional shape of the light shielding film pattern 30a was evaluated by the angle formed by the portion (upper side) where the upper surface and the side surface are in contact with each other and the portion (lower side) where the side surface and the lower surface are in contact in the cross section of the light shielding film pattern. (The same applies to Example 2 and Comparative Examples 1 and 2 below). In addition, no seepage was observed at the interface with the transparent substrate 20 in the light shielding film pattern 30a. Therefore, a binary mask having excellent transfer performance can be obtained in exposure light including light in the wavelength range of 300 nm or more and 500 nm or less, more specifically exposure light of compound light including i-line, h-line and g-line. rice field.

Also, the obtained binary mask was subjected to an electrostatic breakdown test. First, a binary mask was prepared by forming a light shielding film pattern at a predetermined interval (1.5 μm) on the light shielding film. Then, the voltage applied to the binary mask was increased at regular intervals (every 0.1 kV), and it was observed whether or not the pattern was destroyed for each applied voltage. As a result, pattern destruction did not occur up to an applied voltage of 1.6 kV. Therefore, it can be said that the light-shielding film pattern of the binary mask of Example 1 can suppress electrostatic breakdown.

Therefore, when the binary mask of Example 1 is set on the mask stage of the exposure apparatus and is exposed and transferred to the resist film on the display device, it can be said that a fine pattern of less than 2.0 μm can be transferred with high accuracy.

Example 2.
A. Binary Mask Blank and Manufacturing Method Thereof To manufacture the binary mask blank of Example 2, as in Example 1, a synthetic quartz glass substrate of 1214 size (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 the in-line type sputtering apparatus. Then, a mixed gas composed of argon (Ar) gas, nitric oxide (NO) gas, and helium (He) gas was introduced so that the sputtering gas pressure in the first chamber was 1.7 Pa. Then, a predetermined sputtering power is applied to a first sputtering target (molybdenum:silicon=1:4) containing molybdenum and silicon, and reactive sputtering is performed to deposit molybdenum, silicon, and oxygen on the main surface of transparent substrate 20. and nitrogen-containing molybdenum silicide oxynitride rear antireflection layer 33 having a thickness of 34 nm.

Next, the transparent substrate 20 with the back antireflection layer 33 formed thereon was carried into the second chamber. A mixed gas composed of argon (Ar) gas and helium (He) gas was introduced so that the sputtering gas pressure in the second chamber was 0.5 Pa. Then, a predetermined sputtering power is applied to a second sputtering target (molybdenum:silicon=1:4) containing molybdenum and silicon, and sputtering is performed to form molybdenum silicide containing molybdenum and silicon on the back surface antireflection film 33 . A light shielding layer 31 was formed to a film thickness of 128 nm.

Then, the transparent substrate 20 on which the back antireflection layer 33 and the light shielding layer 31 were formed was carried into the third chamber. Argon (Ar) gas and a mixed gas composed of nitrogen monoxide (NO) gas and helium (He) were introduced so that the sputtering gas pressure in the third chamber was 1.7 Pa. Then, a predetermined sputtering power is applied to a third sputtering target (molybdenum:silicon=1:4) containing molybdenum and silicon, and molybdenum containing molybdenum, silicon, oxygen, and nitrogen is formed on the light shielding layer 31 by reactive sputtering. A surface antireflection layer 32 of silicide oxynitride was formed to a thickness of 34 nm.

In this manner, a binary mask blank 10 was obtained in which the light shielding film 30 having a laminated structure of the back antireflection layer 33 , the light shielding layer 31 and the front antireflection layer 32 was formed on the transparent substrate 20 .

Various characteristics of the light-shielding film having a laminated structure of the rear anti-reflection layer 33, the light-shielding layer 31, and the front anti-reflection layer 32 in the obtained binary mask blank 10 were measured.
[Optical Density (OD)]
The optical density (OD) of the light shielding film 30 composed of the laminated structure of the back antireflection layer 33, the light shielding layer 31 and the front antireflection layer 32 was measured with a spectrophotometer and found to be 4.9 (wavelength 405 nm).
[Front Reflectance/Back Reflectance]
The surface reflectance of the light-shielding film 30 having a laminated structure of the back-surface antireflection layer 33, the light-shielding layer 31, and the front-surface antireflection layer 32 was 3.3% (wavelength: 405 nm). The back surface reflectance of the light shielding film 30 (reflectance on the back surface antireflection layer 33 side) was 2.6% (wavelength: 405 nm). From these results, it can be said that the back surface antireflection layer of the light shielding film 30 mainly has the back surface antireflection function, and the antireflection layer 32 of the light shielding film 30 mainly has the front surface antireflection function.
[refractive index (n), extinction coefficient (k)]
The refractive index (n) and extinction coefficient (k) of the back antireflection layer 33, the light shielding layer 31, and the front antireflection layer 32 were measured with an n&k analyzer. .35, the extinction coefficient (wavelength 405 nm) is 0.30, the refractive index of the light shielding layer 31 (wavelength 405 nm) is 4.45, the extinction coefficient (wavelength 405 nm) is 2.75, the refractive index of the antireflection layer 32 ( (wavelength 405 nm) was 2.35, and the extinction coefficient (wavelength 405 nm) was 0.30. The refractive index and extinction coefficient of the back antireflection layer 33 were measured by preparing a substrate with the back antireflection layer 33 formed on a synthetic quartz glass substrate under the same film formation conditions as in Example 2 above. I did it.

[Crystal grain size, average grain size]
As a result of observing and measuring the size of each crystal grain of the back antireflection layer 33, the light shielding layer 31, and the front antireflection layer 32 with a cross-sectional SEM, the size of the crystal grain of the back antireflection layer 33 is 6 to 10 nm. The average size was 8 nm. The crystal grain size of the light shielding layer 31 was 3 to 5 nm, and the average crystal grain size was 4 nm. The grain size of the surface antireflection layer 32 was 6 to 10 nm, and the average grain size was 8 nm.
That is, the average grain size of the crystal grains of the front antireflection layer 32 and the back antireflection layer 33 that constitute the light shielding film 30 in the binary mask blank 10 of Example 2 is larger than the average grain size of the crystal grains of the light shielding layer 31. It was big.

B. Binary Mask and Its Manufacturing Method In order to manufacture the binary mask 100 using the binary mask blank 10 manufactured as described above, first, the surface of the light shielding film 30 (the surface of the front antireflection layer 32) is coated with HMDS (hexamethyl hexamethyl methacrylate). After the disilazane) treatment, a photoresist film was applied using a resist coating apparatus. After that, a photoresist film was formed through heating and cooling processes.
After that, the photoresist film was drawn using a laser lithography device, and through developing and rinsing processes, a resist film pattern 50 having a hole pattern with a hole diameter of 1.5 μm was formed on the etching mask film.
Then, using the resist film pattern 50 as a mask, the light shielding film 30 was wet-etched with a molybdenum silicide etchant obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water to form a light shielding film pattern 30a. . This wet etching was performed with an over-etching time of 110% in order to make the cross-sectional shape vertical and to form a required fine pattern.
After that, the resist film pattern 50 was removed.

A cross section of the obtained binary mask 100 was observed with a scanning electron microscope. The cross-sectional shape of the light-shielding film pattern 30a formed in the binary mask of Example 2 is improved in the shape of an eaves (overhang shape) on the surface of the light-shielding film pattern, and the tapered shape of the light-shielding film pattern on the transparent substrate side is also improved. , and had a good cross-sectional shape that was almost vertical at 72°. In addition, no seepage was observed at the interface with the transparent substrate 20 in the light shielding film pattern 30a. Therefore, a binary mask having excellent transfer performance can be obtained in exposure light including light in the wavelength range of 300 nm or more and 500 nm or less, more specifically exposure light of compound light including i-line, h-line and g-line. rice field.

Also, the obtained binary mask was subjected to an electrostatic breakdown test in the same manner as in Example 1. As a result, pattern destruction did not occur up to an applied voltage of 1.7 kV. Therefore, it can be said that the light-shielding film pattern of the binary mask of Example 2 can suppress electrostatic breakdown.

Therefore, when the binary mask of Example 2 is set on the mask stage of the exposure apparatus and is exposed and transferred to the resist film on the display device, it can be said that a fine pattern of less than 2.0 μm can be transferred with high accuracy.

Although molybdenum is used as the transition metal in the above-described embodiments, the same effects as those described above can be obtained with other transition metals.
Further, in the above-described embodiments, examples of binary mask blanks for manufacturing display devices and binary masks for manufacturing display devices have been described, but the present invention is not limited to these. The binary mask blank and binary mask of the present invention can also be applied to semiconductor device manufacturing, MEMS manufacturing, printed circuit boards, and the like.
Also, in the above embodiment, the size of the transparent substrate is 1214 size (1220 mm×1400 mm×13 mm), but it is not limited to this. In the case of binary mask blanks for manufacturing display devices, a large size transparent substrate is used, and the size of the transparent substrate has a side length of 300 mm or more. The size of the transparent substrate used for binary mask blanks for manufacturing display devices is, for example, 330 mm×450 mm or more and 2280 mm×3130 mm or less.
In the case of binary mask blanks for semiconductor device manufacturing, MEMS manufacturing, and printed circuit board, a small size transparent substrate is used, and the size of the transparent substrate is 9 inches or less on one side. . The size of the transparent substrate used for the binary mask blank for the above application is, for example, 63.1 mm×63.1 mm or more and 228.6 mm×228.6 mm or less. Normally, 6025 size (152 mm x 152 mm) and 5009 size (126.6 mm x 126.6 mm) are used for semiconductor manufacturing and MEMS manufacturing, and 7012 size (177.4 mm x 177.4 mm) is used for printed circuit boards. Alternatively, the 9012 size (228.6 mm×228.6 mm) is used.

Comparative example 1.
A. Binary Mask Blank and Manufacturing Method Thereof To manufacture the binary mask blank of Comparative Example 1, a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) was prepared as a transparent substrate in the same manner as in Example 1.
By the same method as in Example 1, the synthetic quartz glass substrate was carried into the chamber of the in-line type sputtering apparatus. Then, a mixed gas composed of argon (Ar) gas and helium (He) gas was introduced so that the sputtering gas pressure in the first chamber was 0.5 Pa. Then, by applying a predetermined sputtering power to a first sputtering target (molybdenum:silicon=1:4) containing molybdenum and silicon and sputtering, molybdenum silicide containing molybdenum and silicon is formed on the main surface of transparent substrate 20. A light shielding layer 31 having a thickness of 88 nm was formed.
Next, the transparent substrate 20 on which the light shielding layer 31 is formed is carried into the second chamber, and argon (Ar) gas and nitrogen monoxide are added so that the sputtering gas pressure in the second chamber is 0.5 Pa. A mixed gas composed of (NO) gas and helium (He) gas was introduced. Then, a predetermined sputtering power is applied to a second sputtering target (molybdenum:silicon=1:4) containing molybdenum and silicon, and reactive sputtering is performed to deposit molybdenum, silicon, oxygen, and nitrogen on the light shielding layer 31. A surface antireflection layer 32 of molybdenum silicide oxynitride was formed to a thickness of 45 nm.
Then, the transparent substrate 20 on which the light shielding layer 31 and the front antireflection layer 32 are formed is carried into the third chamber, and argon (Ar) gas is supplied so that the sputtering gas pressure in the third chamber becomes 0.3 Pa. and nitrogen (N ₂ ) gas was introduced. Then, a predetermined sputtering power is applied to a third sputtering target made of chromium, and reactive sputtering is performed to form an etching mask film 40 of chromium nitride containing chromium and nitrogen on the surface antireflection layer 32 . A film having a thickness of 30 nm was formed.
In this manner, a binary mask blank 10 was obtained in which a light shielding film 30 having a laminate structure of a light shielding layer 31 and a front antireflection layer 32 and an etching mask film 40 were formed on a transparent substrate 20 .
Various characteristics of the light-shielding film having a laminated structure of the rear anti-reflection layer 33, the light-shielding layer 31, and the front anti-reflection layer 32 in the obtained binary mask blank 10 were measured.
Various characteristics of the light shielding film 30 having a laminated structure of the light shielding layer 31 and the front antireflection layer 32 and the etching mask film 40 in the obtained binary mask blank 10 were measured.
As a result, optical density (OD), surface reflectance, refractive index (n), and extinction coefficient (k) were equivalent to those of Example 1.
[Crystal grain size, average grain size]
The crystal grain sizes of the light shielding layer 31 and the front antireflection layer 32 were observed and measured by a cross-sectional SEM. . The grain size of the surface antireflection layer 32 was 1 to 3 nm, and the average grain size was 2 nm.
That is, the average grain size of the crystal grains of the front antireflection layer forming the light shielding film in the binary mask blank of Comparative Example 1 was smaller than the average grain size of the crystal grains of the light shielding layer.
B. Binary Mask and its Manufacturing Method A binary mask was manufactured in the same manner as in Example 1 using the binary mask blank manufactured as described above.
The obtained binary mask was subjected to an electrostatic breakdown test. First, a binary mask was prepared by forming a light shielding film pattern at a predetermined interval (1.5 μm) on the light shielding film. Then, the voltage applied to the binary mask was increased at regular intervals (every 0.1 kV), and it was observed whether or not the pattern was destroyed for each applied voltage. As a result, pattern destruction did not occur up to an applied voltage of 1.6 kV. Therefore, it can be said that the light-shielding film pattern of the binary mask of Comparative Example 1 can suppress electrostatic breakdown.
Moreover, the cross section of the obtained binary mask was observed with a scanning electron microscope. The cross-sectional shape of the light-shielding film pattern formed on the binary mask of Comparative Example 1 had an eaves shape (overhang shape) in which the front-surface antireflection layer protruded. Therefore, the obtained binary mask has sufficient transfer performance in exposure light including light in the wavelength range of 300 nm or more and 500 nm or less, more specifically exposure light of compound light including i-line, h-line and g-line. is not obtained.
For this reason, when the binary mask of Comparative Example 1 is set on the mask stage of the exposure apparatus and is exposed and transferred to the resist film on the display device, it is expected that a fine pattern of less than 2.0 μm cannot be transferred with high accuracy. be done.
Comparative example 2.
A. Binary Mask Blank and Manufacturing Method Thereof In order to manufacture the binary mask blank of Comparative Example 2, as in Example 1, a 1214 size (1220 mm×1400 mm) synthetic quartz glass substrate 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 the in-line type sputtering apparatus. Then, a mixed gas composed of argon (Ar) gas and carbon dioxide (CO ₂ ) gas was introduced so that the sputtering gas pressure in the first chamber was 0.3 Pa. Then, by applying a predetermined sputtering power to the first sputtering target containing chromium and performing reactive sputtering, a back antireflection layer of chromium oxide containing chromium and oxygen is formed on the main surface of the transparent substrate. A film having a thickness of 30 nm was formed.

Next, the transparent substrate on which the back antireflection layer was formed was carried into the second chamber, and an argon (Ar) mixed gas was introduced so that the sputtering gas pressure in the second chamber was 0.3 Pa. . Then, a predetermined sputtering power was applied to a second sputtering target containing chromium, and sputtering was performed to form a light-shielding layer 31 made of chromium with a thickness of 95 nm on the back-surface antireflection layer.

Then, the transparent substrate on which the back antireflection layer and the light shielding layer are formed is carried into the third chamber, and argon (Ar) gas and carbon dioxide are added so that the sputtering gas pressure in the third chamber becomes 0.3 Pa. A mixed gas consisting of (CO ₂ ) gas was introduced. Then, a predetermined sputtering power is applied to a third sputtering target containing chromium, and reactive sputtering is performed to form a surface antireflection layer of chromium oxide containing chromium and oxygen on the light shielding layer with a thickness of 30 nm. A film was formed.

Thus, a binary mask blank having a light shielding film formed on a transparent substrate was obtained.

Various properties of the light-shielding film having a laminate structure of the rear antireflection layer, the light-shielding layer, and the front antireflection layer in the obtained binary mask blank were measured.
[Optical Density (OD)]
The optical density (OD) of the light-shielding film composed of a laminated structure of a back antireflection layer, a light-shielding layer and a front antireflection layer was measured with a spectrophotometer and found to be 4.0 (wavelength: 405 nm).
[Front Reflectance/Back Reflectance]
The surface reflectance of the light-shielding film composed of the laminated structure of the back-surface antireflection layer, the light-shielding layer, and the front-surface antireflection layer was 11.8% (wavelength: 405 nm) and 11.5% (wavelength: 413 nm (corresponding to laser drawing wavelength)). rice field. The back surface reflectance of the light shielding film (reflectance on the back surface antireflection layer side) was 10.3% (wavelength: 405 nm). From these results, it can be said that the back antireflection layer of the light shielding film 30 mainly has the back antireflection function, and the front antireflection layer 32 of the light shielding film 30 mainly has the front antireflection function.

B. Binary Mask and its Manufacturing Method In order to manufacture a binary mask using the binary mask blank manufactured as described above, first, the surface of the light shielding film (the surface of the front antireflection layer) is coated with a resist coater. A photoresist film was applied. After that, a photoresist film was formed through heating and cooling processes.
After that, a photoresist film was drawn using a laser drawing device, and a resist film pattern of a hole pattern with a hole diameter of 1.5 μm was formed on the light-shielding film through development and rinsing steps.
Thereafter, using the resist film pattern as a mask, the light shielding film was wet-etched with a Cr etchant containing ceric ammonium nitrate and perchloric acid to form a light shielding film pattern. After that, the resist film pattern was peeled off.
A cross section of the obtained binary mask was observed with a scanning electron microscope. As a result, the cross-sectional shape of the light shielding film pattern formed on the binary mask had a favorable cross-sectional shape that was substantially vertical at 79°.
Next, the obtained binary mask was subjected to an electrostatic breakdown test. First, a binary mask was prepared by forming a light shielding film pattern at a predetermined interval (1.5 μm) on the light shielding film. Then, the voltage applied to the binary mask was increased at regular intervals (every 0.1 kV), and it was observed whether or not the pattern was destroyed for each applied voltage. As a result, the pattern was not destroyed up to an applied voltage of 0.4 kV, but the pattern was destroyed at an applied voltage of 0.5 kV. Therefore, the light-shielding film pattern of the binary mask of Comparative Example 2 could not suppress the electrostatic breakdown.
For this reason, when the binary mask of Comparative Example 2 is set on the mask stage of an exposure apparatus and is exposed and transferred to a resist film on a display device, electrostatic breakdown occurs in the mask pattern due to electrification or the like, resulting in a fine pattern of less than 2.0 μm. cannot be transcribed.

DESCRIPTION OF SYMBOLS 10... Binary mask blank, 20... Transparent substrate, 30... Light shielding film,
30a... Light shielding film pattern, 40... Etching mask film,
40a... Etching mask film pattern, 50... Resist film pattern,
100 Binary mask

Claims (8)

A photomask blank having a light shielding film on a transparent substrate,
The photomask blank is an original plate for forming a photomask having a light shielding film pattern on the transparent substrate by wet etching the light shielding film,
The light shielding film is made of a transition metal silicide material containing a transition metal and silicon,
The light shielding film has a structure in which a light shielding layer and a surface antireflection layer are laminated from the transparent substrate side,
The front antireflection layer further contains nitrogen or oxygen,
A photomask blank, wherein an average grain size of crystal grains forming the front-surface antireflection layer is larger than an average grain size of crystal grains forming the light-shielding layer. A photomask blank having a light shielding film on a transparent substrate,
The photomask blank is an original plate for forming a photomask having a light shielding film pattern on the transparent substrate by wet etching the light shielding film,
The light shielding film is made of a transition metal silicide material containing a transition metal and silicon,
The light-shielding film has a structure in which a back-surface antireflection layer, a light-shielding layer, and a front-surface antireflection layer are laminated from the transparent substrate side,
The back antireflection layer and the front antireflection layer further contain nitrogen or oxygen,
A photomask blank, wherein an average grain size of crystal grains forming the front antireflection layer and the back antireflection layer is larger than an average grain size of crystal grains forming the light shielding layer. 3. A photomask blank according to claim 1, wherein said light shielding layer contains at least nitrogen or oxygen. 4. The photomask blank according to claim 1, wherein said transition metal is molybdenum. 5. The photomask blank according to any one of claims 1 to 4, further comprising an etching mask film having an etching selectivity different from that of the light shielding film on the light shielding film. A step of preparing a photomask blank according to any one of claims 1 to 4;
forming a resist film on the light-shielding film, and wet-etching the light-shielding film using a resist film pattern formed from the resist film as a mask to form a light-shielding film pattern on the transparent substrate. A method of manufacturing a photomask, characterized by: preparing a photomask blank according to claim 5;
forming a resist film on the etching mask film, wet-etching the etching mask film using a resist film pattern formed from the resist film as a mask, and forming an etching mask film pattern on the light shielding film;
and wet-etching the light-shielding film using the etching mask film pattern as a mask to form a light-shielding film pattern on the transparent substrate. 8. A method of manufacturing a display device, comprising: using a photomask obtained by the method of manufacturing a photomask according to claim 6 or 7, an exposure step of exposing and transferring a resist film formed on a substrate of a display device. .

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