Mask blank, transfer mask, and method for manufacturing display device

Abstract

The invention relates to a mask blank, a transfer mask, and a method for manufacturing a display device. [Problem] The present invention addresses the problem of providing a mask blank that can sufficiently ensure adhesion between a semi-transparent film and a resist film when patterning the semi-transparent film by wet etching, and that can improve the in-plane CD of a semi-transparent pattern after patterning the semi-transparent film by wet etching. [Solution] A mask blank provided with a thin film for forming a transfer pattern on a translucent substrate, the mask blank being characterized in that the thin film contains chromium, silicon and nitrogen, the most element contained in the thin film is chromium, the silicon content of the thin film is 2.8 at% or less, and the thin film has a columnar structure.

Description

Technical Field

[0001] The present invention relates to a mask blank, a transfer mask, and a method for manufacturing a display device. Background Art

[0002] In recent years, in display devices such as FPD (Flat Panel Display) represented by LCD (Liquid Crystal Display), as the screen size and viewing angle become larger, high-definition and high-speed display are rapidly advancing. One of the elements required for this high-definition and high-speed display is the production of electronic circuit patterns such as components or wiring with fine and high dimensional accuracy. Photolithography is often used in the patterning of electronic circuits for such display devices. Therefore, a transfer mask for display device manufacturing with a fine and high-precision pattern is required.

[0003] For example, Patent Document 1 discloses a gray-tone mask having a pattern consisting of light-shielding portions, light-transmitting portions, and semi-transmitting portions, and a gray-tone mask blank used for manufacturing the same. The mask blank comprises a light-shielding film pattern on a transparent substrate and a semi-transmitting film formed on the light-shielding film pattern. The light-shielding film is composed of a material containing chromium (Cr) as a main component, and the semi-transmitting film is composed of a material containing chromium (Cr) and nitrogen (N).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-268035 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Chromium-based materials are widely used as materials for forming semi-transparent films used in semi-transparent patterns in transfer masks such as multi-tone masks. Typically, wet etching is used in the etching process for forming patterns on thin films on translucent substrates during the manufacture of transfer masks used in FPD manufacturing.

[0009] Generally speaking, the semi-transparent pattern of a multi-tone mask is required to transmit exposure light at a predetermined transmittance. Methods for achieving high transmittance in a semi-transparent pattern include reducing the thickness of the semi-transparent film or using a material with lower light-shielding properties (a lower extinction coefficient k for exposure light) for the semi-transparent film.

[0010] Chromium metal films have a high shielding property against exposure light, making them unsuitable for semi-transparent films that require exposure light to pass through at a predetermined transmittance. Consequently, materials containing nitrogen in chromium (chromium nitride-based materials) are often used for semi-transparent films. However, thin films made of chromium nitride-based materials present the following challenges, depending on the required optical properties, such as transmittance. As described below, when wet etching these films to form a thin film pattern, it is difficult to control (improve) the in-plane CD.

[0011] The semi-transparent pattern in a multi-tone mask has a relatively large variation in density within the surface. When the thickness of a semi-transparent film made of a chromium nitride material is reduced to achieve higher transmittance, the CD is significantly reduced in areas with a sparse pattern during wet etching. This is because significantly reducing the thickness of the semi-transparent film significantly shortens the wet etching time, tightening the etching control.

[0012] On the other hand, in order to achieve higher transmittance for a semi-transparent film made of a chromium nitride-based material, even when a chromium nitride-based material with a high nitrogen content is used for the semi-transparent film, when the semi-transparent film is patterned by wet etching, the CD will be significantly reduced in areas with a sparse pattern. This is because the wet etching rate becomes too fast due to the formation of a semi-transparent film made of a highly nitrided chromium nitride-based material, and etching control becomes stricter.

[0013] Furthermore, in order to form a transfer pattern having a good cross-sectional shape in a transfer mask, it is also required to ensure sufficient adhesion between the semi-transparent film and the resist film.

[0014] Therefore, the present invention is completed to solve the above-mentioned problems, and the purpose of the present invention is to provide a mask blank, a transfer mask and a manufacturing method of a display device, wherein the mask blank can fully ensure the close adhesion between the semi-transparent film and the anti-etching film when the semi-transparent film is patterned by wet etching, and can improve the in-plane CD of the semi-transparent pattern after the semi-transparent film is patterned by wet etching.

[0015] Means for solving problems

[0016] The present inventors have conducted intensive studies on solutions to these problems.

[0017] As mentioned above, it is difficult to increase the in-plane CD of the semi-transparent pattern in the existing method of increasing the transmittance of the semi-transparent film. After in-depth research, the inventors have studied the method of reducing the etching rate of wet etching by including a small amount of silicon in the semi-transparent film of the chromium nitride-based material. However, although the etching rate can be reduced, the following problem has been newly discovered: the semi-transparent film of the chromium nitride-based material containing silicon has lower adhesion to the resist film than the semi-transparent film of the chromium nitride material not containing silicon. Specifically, when wet etching is performed using the resist pattern as an etching mask, the etching liquid invades the interface between the resist pattern and the semi-transparent film, and the semi-transparent film in the portion covered by the resist pattern is also etched from its surface (i.e., the interface direction between the resist pattern and the semi-transparent film), resulting in the phenomenon that the pattern cannot be formed normally on the semi-transparent film. Depending on the adhesion between the semi-transparent film and the resist film, the resist pattern also detaches from the semi-transparent film during wet etching.

[0018] In order to improve the adhesion between the semi-transparent film of the chromium nitride-based material containing silicon and the resist film, the inventors conducted further research. The results showed that by making the internal structure of the semi-transparent film a columnar structure, the reduction in adhesion between the semi-transparent film and the resist film can be suppressed. However, it was also found that if the silicon content of the semi-transparent film exceeds 2.8 atomic%, sufficient adhesion cannot be achieved between the semi-transparent film and the resist film. It was also found that by both making the internal structure of the semi-transparent film a columnar structure and making the silicon content of the semi-transparent film less than 2.8 atomic%, sufficient adhesion can be ensured between the semi-transparent film and the resist film, and the in-plane CD of the semi-transparent pattern after patterning the semi-transparent film by wet etching can be improved.

[0019] The present invention has been extensively studied as described above, and has the following configuration as a result.

[0020] (Configuration 1) A mask blank comprising a thin film for transfer pattern formation on a light-transmitting substrate, characterized in that:

[0021] The above film contains chromium, silicon and nitrogen,

[0022] The most abundant element in the above film is chromium.

[0023] The silicon content of the thin film is 2.8 atomic % or less.

[0024] The thin film has a columnar structure.

[0025] (Configuration 2) The mask blank according to Configuration 1, wherein a ratio of a silicon content to a chromium content in the thin film is 0.035 or less.

[0026] (Configuration 3) The mask blank according to Configuration 1, wherein the chromium content in the thin film is 50 atomic % or more.

[0027] (Configuration 4) The mask blank according to Configuration 1, wherein the nitrogen content in the thin film is 25 atomic % or more.

[0028] (Configuration 5) The mask blank according to Configuration 1, wherein the total content of chromium, silicon, and nitrogen in the thin film is 90 atomic % or more.

[0029] (Configuration 6) The mask blank according to Configuration 1 is characterized in that the columnar structure of the thin film is a structure in which columnar particles extending in the film thickness direction are formed within the plane of the light-transmitting substrate.

[0030] (Configuration 7) The mask blank according to Configuration 6 is characterized in that the thin film includes a portion where the columnar particles have a relatively high density and a sparse portion where the density is relatively low.

[0031] (Configuration 8) The mask blank according to Configuration 1, wherein the thin film has a transmittance of 3% or more with respect to light having a wavelength of 365 nm.

[0032] (Configuration 9) A transfer mask comprising a thin film having a transfer pattern formed thereon on a light-transmitting substrate, wherein:

[0033] The above film contains chromium, silicon and nitrogen,

[0034] The most abundant element in the above film is chromium.

[0035] The silicon content of the thin film is 2.8 atomic % or less.

[0036] The thin film has a columnar structure.

[0037] (Configuration 10) The transfer mask according to Configuration 9, wherein a ratio of a silicon content to a chromium content in the thin film is 0.035 or less.

[0038] (Configuration 11) The transfer mask according to Configuration 9, wherein the chromium content in the thin film is 50 atomic % or more.

[0039] (Configuration 12) The transfer mask according to Configuration 9, wherein the nitrogen content in the thin film is 25 atomic % or more.

[0040] (Configuration 13) The transfer mask according to Configuration 9, wherein the total content of chromium, silicon, and nitrogen in the thin film is 90 atomic % or more.

[0041] (Configuration 14) The transfer mask according to Configuration 9 is characterized in that the columnar structure of the thin film is a structure in which columnar particles extending in the film thickness direction are formed within the surface of the light-transmitting substrate.

[0042] (Configuration 15) The transfer mask according to Configuration 14 is characterized in that the thin film includes a portion where the columnar particles have a relatively high density and a sparse portion where the density is relatively low.

[0043] (Configuration 16) The transfer mask according to Configuration 9 is characterized in that the transmittance of the thin film to light with a wavelength of 365 nm is 3% or more.

[0044] (Composition 17) A method for manufacturing a display device, characterized in that it has an exposure step: placing the transfer mask described in any one of Compositions 9 to 16 on a mask stage of an exposure device, and exposing the transfer pattern formed on the transfer mask to the resist formed on the display device substrate.

[0045] Effects of the Invention

[0046] According to the mask blank of the present invention, a mask blank can be obtained that can sufficiently ensure the adhesion between the semi-transparent film and the resist film when patterning the semi-transparent film by wet etching, and can improve the in-plane CD of the semi-transparent pattern after patterning the semi-transparent film by wet etching.

[0047] Furthermore, according to the transfer mask of the present invention, it is possible to produce a transfer mask having a transfer pattern with good transfer accuracy.

[0048] Furthermore, according to the method for manufacturing a display device of the present invention, the display device is manufactured using the transfer mask described above, so that the display device can be manufactured with a high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a schematic diagram showing the film structure of the mask blank according to the first embodiment.

[0050] Figure 2 This is a schematic diagram showing the film structure of the mask blank according to the second embodiment.

[0051] Figure 3 This is a schematic diagram showing a transfer mask according to the third embodiment.

[0052] Figure 4 This is a schematic diagram showing a transfer mask according to a fourth embodiment.

[0053] Figure 5 This is a cross-sectional photograph of the transfer mask of Example 1.

[0054] Figure 6This is a cross-sectional photograph of the transfer mask of Example 2.

[0055] Figure 7 This is a cross-sectional photograph of the transfer mask of Example 3.

[0056] Figure 8 This is a cross-sectional photograph of the transfer mask of Example 4.

[0057] Figure 9 This is a cross-sectional photograph of the transfer mask of Comparative Example 1.

[0058] Figure 10 This is a cross-sectional photograph of the transfer mask of Comparative Example 2.

[0059] Figure 11 It is a graph showing the relationship between the nitrogen content and the etching rate in Examples 1 to 3 and Comparative Example 3. DETAILED DESCRIPTION

[0060] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments are merely one way of embodying the present invention and do not limit the scope of the present invention. It should be noted that in the drawings, identical or equivalent parts may be denoted by the same reference numerals to simplify or omit their description.

[0061] Implementation method 1.2.

[0062] In the first and second embodiments, the mask blank is described.

[0063] Figure 1 、 Figure 2 The following is a schematic diagram showing the film structure of multi-tone mask blanks 10A and 10B (hereinafter sometimes referred to as "mask blanks 10") according to the first and second embodiments. These multi-tone mask blanks 10A and 10B are used to manufacture Figure 3 、 Figure 4 The multi-tone masks 100A and 100B (hereinafter sometimes simply referred to as “transfer masks 100 ”) shown include a light-transmitting portion 11 , a semi-light-transmitting portion 12 , and a light-blocking portion 13 .

[0064] Figure 1 The mask blank 10A shown includes a light-transmitting substrate 1 , a semi-transmitting film 2 formed on the light-transmitting substrate 1 , and a light-shielding film 3 formed on the semi-transmitting film 2 .

[0065] The light-transmitting substrate 1 is transparent to the exposure light. When there is no surface reflection loss, the light-transmitting substrate 1 has a transmittance of 85% or more, preferably a transmittance of 90% or more, for the exposure light. The light-transmitting substrate 1 is made of a material containing silicon and oxygen, and can be made of a glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda-lime glass, or low thermal expansion glass (SiO2-TiO2 glass, etc.). When the light-transmitting substrate 1 is made of low thermal expansion glass, the position change of the semi-transparent pattern caused by the thermal deformation of the light-transmitting substrate 1 can be suppressed. In addition, the light-transmitting substrate 1 used in display devices is usually a rectangular substrate, and the length of the short side of the light-transmitting substrate is 300 mm or more. The present invention is to provide a multi-grayscale mask blank for a transfer mask that can stably transfer a fine semi-transparent pattern formed on a light-transmitting substrate even if the short side of the light-transmitting substrate is large in size and is 300 mm or more.

[0066] The semi-transparent film 2 is a thin film used to form the transfer pattern. It contains chromium, silicon, and nitrogen. Chromium is the most abundant element in the semi-transparent film 2. Furthermore, the silicon content of the semi-transparent film 2 is less than 2.8 atomic percent, and the semi-transparent film 2 has a columnar structure.

[0067] The chromium content in the semi-transparent film 2 is preferably 50 atomic % or more. The chromium content in the semi-transparent film 2 is preferably 90 atomic % or less.

[0068] The ratio of the silicon content to the chromium content in the semi-transparent film 2 is preferably 0.035 or less. The ratio of the silicon content to the chromium content in the semi-transparent film 2 is preferably 0.005 or more, more preferably 0.01 or more.

[0069] Furthermore, the content of silicon in the semi-transparent film 2 is greater than 0 atomic %, more preferably 1 atomic % or more, and further preferably 1.5 atomic %.

[0070] The nitrogen content in the semi-transparent film 2 is preferably 25 atomic % or more, more preferably 30 atomic % or more. The nitrogen content in the semi-transparent film 2 is preferably less than 50 atomic %, more preferably 45 atomic % or less.

[0071] The total content of chromium, silicon, and nitrogen in the semi-transparent film 2 is preferably 90 atomic % or more, more preferably 95 atomic % or more, and preferably 100 atomic % or less.

[0072] In addition to the aforementioned nitrogen, the semi-transparent film 2 may also contain other light elements such as oxygen, carbon, and helium to reduce film stress and control the wet etching rate. In particular, oxygen, as a light element, has the effect of lowering the extinction coefficient compared to nitrogen, also a light element. Therefore, it is preferred to reduce the content of other light elements (such as nitrogen) required to achieve the desired transmittance while also effectively reducing the reflectivity of the surface and back surfaces of the semi-transparent film 2. The oxygen content in the semi-transparent film 2 is preferably 1 atomic % or greater. Furthermore, the oxygen content in the semi-transparent film 2 is preferably 10 atomic % or less.

[0073] The semi-transparent film 2 has at least a function of adjusting the transmittance of exposure light.

[0074] The semi-transparent film 2 can be formed by sputtering.

[0075] The semi-transparent film 2 has a columnar structure. The columnar structure can be confirmed by cross-sectional SEM (Scanning Electron Microscope) observation of the semi-transparent film 2. That is, the columnar structure in the present invention refers to the state in which the particles of the chromium-based silicide compound containing chromium, silicon and nitrogen that constitute the semi-transparent film 2 have a columnar particle structure extending in the film thickness direction of the semi-transparent film 2 (the direction of the above-mentioned particle accumulation). It should be noted that, in this application, particles whose length in the film thickness direction is longer than their length in the perpendicular direction are referred to as columnar particles. That is, the semi-transparent film 2 is formed with columnar particles extending in the film thickness direction within the surface of the translucent substrate 1. In addition, the semi-transparent film 2 is formed into a portion with a relatively high density of columnar particles and a sparse portion with a relatively low density compared to the columnar particles (hereinafter sometimes referred to as a "sparse portion"). It should be noted that, in order to effectively suppress side etching during wet etching and further improve the cross-sectional shape of the pattern, the semi-transparent film 2 preferably has a columnar structure in which columnar particles extending along the film thickness direction are irregularly formed in the film thickness direction. It is further preferred that the columnar particles of the semi-transparent film 2 have a state in which the lengths in the film thickness direction are inconsistent. Furthermore, it is preferred that the sparse portion of the semi-transparent film 2 is formed continuously in the film thickness direction. Furthermore, it is preferred that the sparse portion of the semi-transparent film 2 is formed intermittently in a direction perpendicular to the film thickness direction.

[0076] The transmittance of the semi-transparent film 2 to the exposure light satisfies the value required as the semi-transparent film 2. For light of a specified wavelength contained in the exposure light (for example, light with a wavelength of 365 nm, hereinafter referred to as the representative wavelength), the transmittance of the semi-transparent film 2 is preferably 3% or more, more preferably 4% or more, and further preferably 5% or more. In addition, for the representative wavelength, the transmittance of the semi-transparent film 2 is more preferably 70% or less, and further preferably 50% or less. In the case where the exposure light is a composite light containing light in a wavelength range of 313 nm to 436 nm, the semi-transparent film 2 has the above-mentioned transmittance for light of the representative wavelength contained in the wavelength range. For example, in the case where the exposure light is a composite light containing i-rays, h-rays, and g-rays, the semi-transparent film 2 has the above-mentioned transmittance for any one of the i-rays, h-rays, and g-rays.

[0077] The transmittance can be measured using a phase shift measurement device or the like.

[0078] The semi-transparent film 2 may be composed of multiple layers or a single layer. A single-layer semi-transparent film 2 is preferred because it is difficult to form an interface within the semi-transparent film 2, making it easier to control the cross-sectional shape. On the other hand, a multi-layer semi-transparent film 2 is preferred for ease of film formation. Furthermore, the semi-transparent film 2 may be a composition gradient film in which the silicon content decreases with increasing thickness.

[0079] The light-shielding film 3 is arranged on the upper side of the semi-transparent film 2 and has the function of blocking the transmission of exposure light. The light-shielding film 3 is preferably made of a chromium-based material containing chromium (Cr). However, in this case, it is necessary to provide an etching stopper film 4 made of a material with different etching selectivity between the semi-transparent film 2 and the light-shielding film 3. The etching stopper film 4 is preferably made of a transition metal silicide-based material with silicon as the main component, for example. The light-shielding film 3 is more preferably made of a material containing chromium and substantially free of silicon. Substantially free of silicon means that the silicon content is less than 1 atomic %. As chromium-based materials, more specifically, materials composed of a single substance of chromium (Cr), or materials containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C) can be cited. On the other hand, the semi-transparent film 2 can also be made of a material with different etching selectivity (for example, a transition metal silicide-based material with silicon as the main component). In this case, there is no need to provide an etching stopper film 4.

[0080] The optical density of the portion where the semi-transparent film 2 , the etching stopper film 4 , and the light-shielding film 3 are stacked (light-shielding portion 13 ) to the exposure light is preferably 3 or higher, more preferably 3.5 or higher, and even more preferably 4 or higher.

[0081] Optical density can be measured using a spectrophotometer, an OD meter, or the like.

[0082] The light-shielding film 3 may be composed of a single film having a uniform composition, a plurality of films having different compositions, or a single film having a composition that continuously changes in the thickness direction, depending on its function.

[0083] It should be noted that Figure 1 The mask blank 10 shown in the figure has an etching stopper film 4 and a light shielding film 3 on a semi-transparent film 2. However, the present invention can also be applied to a multi-tone mask blank having an etching stopper film 4 and a light shielding film 3 on a semi-transparent film 2 and an etching resist film on the light shielding film 3. In addition, the mask blank of the present invention is not limited to a multi-tone mask blank, and may also be a mask blank having a semi-transparent film 2 on a light-transparent substrate 1 (for Figure 2 The same is true for the mask blank shown).

[0084] Next, use Figure 2 A multi-tone mask blank 10B according to the second embodiment will be described.

[0085] Figure 2 The mask blank 10B shown includes a transparent substrate 1 and a semi-transparent film 2 formed on the transparent substrate 1. A light-shielding pattern 3B is provided between the transparent substrate 1 and the semi-transparent film 2. The structures of the transparent substrate 1 and the semi-transparent film 2 are the same as those in the first embodiment, and therefore their description will be omitted as appropriate. The light-shielding pattern 3B is disposed on the main surface of the transparent substrate 1. The light-shielding pattern 3B functions to block the transmission of exposure light.

[0086] The material forming the light-shielding pattern 3B is not particularly limited as long as it has the function of blocking the transmission of exposure light. For example, chromium-based materials can be mentioned. Examples of chromium-based materials include chromium (Cr), or chromium-based materials containing chromium (Cr), and at least one of carbon (C) and nitrogen (N). In addition, examples include: chromium-based materials containing chromium (Cr), and at least one of oxygen (O) and fluorine (F); or chromium-based materials containing chromium (Cr), and at least one of carbon (C) and nitrogen (N), and further containing at least one of oxygen (O) and fluorine (F). For example, as materials forming the light-shielding pattern 3B, examples include Cr, CrC, CrN, and CrCN.

[0087] The light-shielding pattern 3B can be formed by patterning a light-shielding film formed by sputtering by etching.

[0088] The optical density of the portion where the semi-transparent film 2 and the light-shielding pattern 3B are stacked with respect to the exposure light is preferably 3 or more, more preferably 3.5 or more.

[0089] Optical density can be measured using a spectrophotometer, an OD meter, or the like.

[0090] The light-shielding pattern 3B may be composed of a single film having a uniform composition, may be composed of a plurality of films having different compositions, or may be composed of a single film having a composition that continuously changes in the thickness direction.

[0091] Note that a resist film may be provided on the semi-transparent film 2 .

[0092] Next, a method for manufacturing the mask blank 10 according to the first and second embodiments will be described.

[0093] 1. Preparation process

[0094] In the preparation process, in the manufacturing Figure 1 In the case of the mask blank 10A shown, first, the light-transmitting substrate 1 is prepared.

[0095] In manufacturing Figure 2 In the case of the mask blank 10B shown, a light-shielding film made of, for example, a chromium-based material is formed on a light-transmitting substrate 1 by sputtering. A resist pattern is then formed on the light-shielding film, and the light-shielding film is etched using the resist pattern as a mask to form a light-shielding pattern 3B. The resist pattern is then removed.

[0096] 2. Semi-transparent film formation process

[0097] In the semi-transparent film forming process, Figure 1 In the case of the mask blank 10A shown, the semi-transparent film 2 containing chromium, silicon, and nitrogen is formed on the translucent substrate 1 by sputtering.

[0098] In manufacturing Figure 2 In the case of the mask blank 10B shown, a semi-transparent film 2 containing chromium, silicon, and nitrogen is formed on a light-transmitting substrate 1 having a light-shielding pattern 3B formed thereon, covering the light-shielding pattern 3B and the exposed surface of the light-transmitting substrate 1 .

[0099] In the formation of the semi-transparent film 2, a sputtering target material is used, which is a mixed sintered target material containing chromium and silicon as the main components of the material constituting the semi-transparent film 2. For example, the sputtering is carried out in a sputtering gas atmosphere consisting of a mixed gas containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon, and an active gas selected from the group consisting of oxygen, nitrogen, carbon dioxide, nitric oxide and nitrogen dioxide and containing at least nitrogen. In addition, for the semi-transparent film 2, by making the sputtering power (voltage) in the film forming chamber during sputtering lower than when forming a semi-transparent film 2 having an ultra-fine crystalline structure or an amorphous structure under the same sputtering gas atmosphere, a columnar structure can be formed on the semi-transparent film 2 (the specific sputtering power varies depending on the film forming device). Through this columnar structure, the adhesion between the semi-transparent film and the resist film during pattern formation described later can be fully ensured.

[0100] The composition and thickness of the semi-transparent film 2 are adjusted so that the semi-transparent film 2 becomes the above-mentioned transmittance (when the semi-transparent film 2 is a phase shift film, it is adjusted to become the above-mentioned transmittance and the desired phase difference (for example, a phase difference in the range of 150 degrees to 210 degrees)). The composition of the semi-transparent film 2 can be controlled by the content ratio of the elements constituting the sputtering target (for example, the ratio of the chromium content to the silicon content), the composition and flow rate of the sputtering gas, the gas pressure in the film forming chamber, etc. The thickness of the semi-transparent film 2 can be controlled by the sputtering power, the sputtering time, etc. In addition, the semi-transparent film 2 is preferably formed using an in-line sputtering device. When the sputtering device is an in-line sputtering device, the thickness of the semi-transparent film 2 can also be controlled by the conveying speed of the substrate. In this way, the composition and thickness of the semi-transparent film 2 are controlled.

[0101] When the semi-transparent film 2 is composed of a single film, the composition and flow rate of the sputtering gas are appropriately adjusted, and the above-mentioned film forming process is performed only once. When the semi-transparent film 2 is composed of multiple films with different compositions, the composition and flow rate of the sputtering gas are appropriately adjusted, and the above-mentioned film forming process is performed multiple times. The semi-transparent film 2 can also be formed using targets having different content ratios of elements constituting the sputtering target. When performing multiple film forming processes, the sputtering power applied to the sputtering target can also be changed for each film forming process.

[0102] In this manner, the mask blank 10B of Embodiment 2 is obtained. In the production of the mask blank 10A of Embodiment 1, the following etching stopper film forming step and light shielding film forming step are further performed.

[0103] 3. Etching stop film formation process

[0104] After the semi-transparent film forming step, an etching stopper film 4 is formed by sputtering on the semi-transparent film 2. The etching stopper film 4 is preferably formed using an in-line sputtering device.

[0105] The etching stop film 4 is formed using a sputtering target containing a transition metal and silicon, for example, in a sputtering gas atmosphere consisting of an inert gas containing at least one selected from the group consisting of helium, neon, argon, krypton and xenon; or a sputtering gas atmosphere consisting of a mixed gas containing at least one inert gas selected from the group consisting of helium, neon, argon, krypton and xenon, and at least one active gas selected from the group consisting of oxygen, nitrogen, nitric oxide gas, nitrogen dioxide gas, carbon dioxide gas and fluorine-based gases.

[0106] 4. Light-shielding film formation process

[0107] After the etching stopper film formation step, the light shielding film 3 is formed on the etching stopper film 4 by sputtering. The light shielding film 3 is preferably formed using an inline sputtering device. In the case of an inline sputtering device, the thickness of the light shielding film 3 can also be controlled by the conveying speed of the transparent substrate 1.

[0108] The light-shielding film 3 is formed using a sputtering target containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxynitride carbide, etc.) in a sputtering gas atmosphere comprising, for example, at least one inert gas selected from the group consisting of helium, neon, argon, krypton, and xenon; or a sputtering gas atmosphere comprising a mixture of at least one inert gas selected from the group consisting of helium, neon, argon, krypton, and xenon, and at least one active gas selected from the group consisting of oxygen, nitrogen, nitric oxide, nitrogen dioxide, carbon dioxide, hydrocarbon-based gases, and fluorine-based gases. Examples of hydrocarbon-based gases include methane, butane, propane, and styrene. Furthermore, by adjusting the sputtering voltage within the film-forming chamber during sputtering, the light-shielding film 3 can be formed into a columnar structure, similar to the semi-transparent film 2.

[0109] When the light-shielding film 3 is composed of a single film with a uniform composition, the above film-forming process is performed only once without changing the composition and flow rate of the sputtering gas. When the light-shielding film 3 is composed of multiple 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 multiple times. When the light-shielding film 3 is composed of a single film with a composition that continuously changes in the thickness direction, the composition and flow rate of the sputtering gas are changed as the film-forming process elapses, and the above film-forming process is performed only once.

[0110] In this manner, the mask blank 10A of the first embodiment is obtained.

[0111] Note that, when manufacturing a multi-tone mask blank including the light-shielding film 3 on the semi-transparent film 2 and a resist film on the light-shielding film 3 , the resist film is formed on the light-shielding film 3 after the light-shielding film forming step.

[0112] The mask blanks 10 of the first and second embodiments comprise a semi-transparent film 2 for forming a transfer pattern on a translucent substrate 1. The semi-transparent film 2 contains chromium, silicon, and nitrogen, with chromium being the most abundant element in the semi-transparent film 2. The silicon content of the semi-transparent film 2 is 2.8 atomic percent or less, and the semi-transparent film 2 has a columnar structure. Consequently, a multi-tone mask blank is obtained that can ensure sufficient adhesion between the semi-transparent film and the resist film when patterning the semi-transparent film by wet etching, and can also improve the in-plane CD of the semi-transparent pattern formed by wet etching.

[0113] Implementation method 3.4.

[0114] Transfer masks 100A and 100B and a method for manufacturing the same in Embodiments 3 and 4 (hereinafter, sometimes simply referred to as “transfer masks 100 ”) will be described.

[0115] Figure 3 This is a schematic diagram showing a transfer mask 100A according to the third embodiment. Figure 4 This is a schematic diagram showing a transfer mask 100B according to the fourth embodiment.

[0116] The transfer mask 100A of embodiment 3 has a semi-transparent pattern 2A in which a transfer pattern is formed on the semi-transparent film 2, and has an etching stop pattern 4A and a light-shielding pattern 3A corresponding to the light-shielding portion 13 on the etching stop film 4 and the light-shielding film 3. Other than this, it has the same structure as the mask blank 10A of embodiment 1.

[0117] In manufacturing Figure 3 In the case of the transfer mask 100A shown in FIG. Figure 1 The mask blank 10A shown includes a light-transmitting substrate 1 on which a semi-transparent film 2 , an etching stopper film 4 , and a light-shielding film 3 are formed.

[0118] Next, the process of forming a light-shielding portion 13 having a predetermined pattern on the etching stopper film 4 and the light-shielding film 3 will be described. First, a first resist film is formed on the light-shielding film 3. The resist material used is not particularly limited. For example, it can be exposed to a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. The first resist film can be either positive or negative.

[0119] Then, a laser having an arbitrary wavelength selected from the wavelength range of 350 nm to 436 nm is used to draw a desired pattern corresponding to the light-shielding portion 13 on the first resist film. Thereafter, the first resist film is developed using a predetermined developer to form a first resist pattern corresponding to the light-shielding portion 13 on the light-shielding film 3.

[0120] First, using the first resist pattern as a mask, the light-shielding film 3 is etched to form a light-shielding pattern 3A. A columnar structure of the light-shielding film 3 is preferred because it increases the etching speed and suppresses side etching. The etchant used to etch the light-shielding film 3 is not particularly limited, as long as it selectively etches the light-shielding film 3. Next, using the first resist pattern and the light-shielding pattern 3A as masks, the etching stopper film 4 is etched to form an etching stopper pattern 4A.

[0121] Thereafter, the first resist pattern is removed using a resist stripping solution or by ashing.

[0122] In the second resist pattern forming step, a second resist film is first formed to cover the semi-transparent film 2 and the light-shielding pattern 3A. Then, the laser beam is used to create a desired pattern corresponding to the light-transmitting portions 11 on the second resist film. The second resist film is then developed using a predetermined developer, forming a second resist pattern having the pattern of the light-transmitting portions 11 on the semi-transparent film 2 and the light-shielding pattern 3A.

[0123] Then, the semi-transparent film 2 is wet-etched using the second resist pattern as a mask. Figure 3 As shown, a semi-transparent pattern 2A is formed. The etching liquid for etching the semi-transparent film 2 is not particularly limited as long as it can selectively etch the semi-transparent film 2 .

[0124] As described above, the semi-transparent film 2 contains chromium, silicon, and nitrogen, with chromium being the most abundant element. The silicon content of the semi-transparent film 2 is 2.8 atomic percent or less, and the semi-transparent film 2 has a columnar structure. This ensures sufficient adhesion between the semi-transparent film 2 and the resist film (second resist pattern) during wet etching, and improves the in-plane CD of the semi-transparent pattern 2A formed by wet etching of the semi-transparent film 2.

[0125] Thereafter, the second resist pattern is removed using a resist stripping solution or by ashing.

[0126] In this way, it is possible to produce Figure 3 The transfer mask 100A is shown.

[0127] The transfer mask 100B of the fourth embodiment has the same structure as the mask blank 10B of the second embodiment, except that it includes a semi-transparent pattern 2B in which a transfer pattern is formed on the semi-transparent film 2 .

[0128] In manufacturing Figure 4 In the case of the transfer mask 100B shown, prepare Figure 2 The mask blank 10B shown in FIG. 1 includes a light-transmitting substrate 1 and a semi-transparent film 2 formed on the light-transmitting substrate 1 , and includes a light-shielding pattern 3B between the light-transmitting substrate 1 and the semi-transparent film 2 .

[0129] Next, a resist film is formed on the semi-transparent film 2. Thereafter, a desired pattern corresponding to the light-transmitting portion 11 is drawn on the resist film using the aforementioned laser.

[0130] Thereafter, the resist film is developed using a predetermined developer to form a resist pattern having a pattern of the light-transmitting portion 11 on the semi-transmitting film 2 .

[0131] Then, using the resist pattern as a mask, the semi-transparent film 2 is wet-etched to form the semi-transparent pattern 2B so as to expose the translucent substrate 1 in the translucent portion 11. Thus, the translucent substrate 1 is exposed in the translucent portion 11, only the semi-translucent pattern 2B is formed on the translucent substrate 1 in the semi-translucent portion 12, and the light-shielding pattern 3B and the semi-translucent pattern 2B are stacked on the translucent substrate 1 in the light-shielding portion 13.

[0132] As described above, the semi-transparent film 2 contains chromium, silicon, and nitrogen, with chromium being the most abundant element. The silicon content of the semi-transparent film 2 is 2.8 atomic percent or less, and the semi-transparent film 2 has a columnar structure. This ensures sufficient adhesion between the semi-transparent film 2 and the resist film (resist pattern) during wet etching, and improves the in-plane CD of the semi-transparent pattern formed by wet etching.

[0133] In this way, you can create Figure 4 The transfer mask 100B is shown.

[0134] According to the transfer masks 100A and 100B of these embodiments 3 and 4, a transfer mask can be made, which can fully ensure the close adhesion between the semi-transparent film and the anti-etching film when the semi-transparent film is patterned by wet etching, and can improve the in-plane CD of the semi-transparent pattern after the semi-transparent film is patterned by wet etching.

[0135] Implementation method 5.

[0136] In Embodiment 5, a method for manufacturing a display device will be described. The display device is manufactured by performing a step of using the transfer mask 100 (mask placement step) and a step of transferring the transfer pattern to a resist film on the display device by exposure (exposure step).

[0137] Hereinafter, each step will be described in detail.

[0138] 1. Loading process

[0139] In the placement step, the transfer mask 100 in Embodiments 3 and 4 is placed on a mask stage of an exposure apparatus. Here, the transfer mask 100 is arranged to face the resist film formed on the display device substrate via the projection optical system of the exposure apparatus.

[0140] 2. Pattern transfer process

[0141] In the pattern transfer process, the transfer mask 100 is irradiated with exposure light, transferring the semi-transparent pattern to the resist film formed on the display device substrate. The exposure light is a composite light comprising multiple wavelengths selected from the wavelength range of 365nm to 436nm, or a monochromatic light selected by cutting off a wavelength range from the wavelength range of 365nm to 436nm using a filter or the like. For example, the exposure light can be a composite light comprising i-rays, h-rays, and g-rays, or a monochromatic light consisting of i-rays. Using composite light as the exposure light can increase the exposure light intensity, improve production capacity, and thus reduce the manufacturing cost of the display device.

[0142] According to the method for manufacturing a display device of this fifth embodiment, a display device can be manufactured with a high yield.

[0143] Example

[0144] Example 1.

[0145] To produce the mask blank of Example 1, first, a 1214-size (1220 mm×1400 mm) synthetic quartz glass substrate was prepared as the light-transmitting substrate 1 .

[0146] Thereafter, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is carried into a chamber of an in-line sputtering apparatus.

[0147] To form the semi-transparent film 2 on the main surface of the translucent substrate 1, an inert gas composed of argon (Ar) and nitrogen (N2) was introduced into the chamber. The film-forming gas flow ratio (N2 / Ar) was 0.20. A sputtering voltage of 500 V was then applied to a sputtering target containing chromium and silicon (chromium:silicon = 96:4). Through reactive sputtering, a chromium silicide nitride containing chromium, silicon, and nitrogen was deposited on the main surface of the translucent substrate 1. This formed a semi-translucent film 2 with a thickness of 85 nm.

[0148] After the semi-transparent film 2 is formed on the translucent substrate 1 , the substrate 1 is taken out of the chamber and the surface of the semi-transparent film 2 is cleaned with pure water.

[0149] In this manner, the mask blank 10 of Example 1 was produced.

[0150] Furthermore, the semi-transparent film 2 of the mask blank 10 obtained under the film forming conditions of Example 1 was subjected to a depth-wise composition analysis using X-ray photoelectron spectroscopy (XPS). Within the semi-transparent film 2, the contents of the constituent elements were approximately constant along the depth direction, excluding the composition gradient region at the interface between the transparent substrate 1 and the semi-transparent film 2 and the surface region of the semi-transparent film 2: carbon (C) at 1.3 atomic %, nitrogen (N) at 29.5 atomic %, oxygen (O) at 4.0 atomic %, silicon (Si) at 2.2 atomic %, and chromium (Cr) at 63.0 atomic %. Thus, Cr was the most abundant element, with Si at less than 2.8 atomic %. Furthermore, the ratio of silicon content to chromium content (Si / Cr) was 0.0349, which was less than 0.035.

[0151] Next, a cross-sectional SEM observation was performed at a magnification of 80,000x at the center of the transfer pattern formation region of the resulting mask blank 10. The results confirmed that the semi-transparent film 2 had a columnar structure. Specifically, it was confirmed that the particles containing chromium, silicon, and nitrogen that constituted the semi-transparent film 2 had a columnar particle structure extending in the thickness direction of the semi-transparent film 2. Furthermore, it was confirmed that the columnar particle structure of the semi-transparent film 2 was such that the columnar particles were irregularly formed in the film thickness direction, and the lengths of the columnar particles in the film thickness direction were also inconsistent. Furthermore, it was confirmed that the sparse portions of the semi-transparent film 2 were formed continuously in the film thickness direction.

[0152] Furthermore, dark field planar STEM (Scanning Transmission Electron Microscope) observation was performed near the film thickness center of the semi-transparent film 2. As a result, it was confirmed that columnar grain portions and sparse portions were formed in the semi-transparent film 2.

[0153] Next, a photoresist film is applied using a resist coating apparatus so as to cover the semi-transparent film 2 .

[0154] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0155] Then, using the resist pattern as a mask, the semi-transparent film 2 was wet-etched with a chromium etching solution containing ammonium cerium nitrate and perchloric acid to form a semi-transparent pattern 2A, thereby manufacturing the transfer mask 100 of Example 1.

[0156] While the resist pattern remained, the cross section of the transfer mask was observed using a scanning electron microscope. Figure 5This is a cross-sectional photograph of the transfer mask of Example 1. As shown in this figure, the semi-transparent pattern of the transfer mask has a good cross-sectional shape that is nearly vertical. Furthermore, no penetration of the semi-transparent pattern was observed at the interface with the resist pattern or the interface with the substrate, confirming good adhesion to the resist film. Furthermore, the etching rate of the transfer mask of Example 1 was measured and found to be 2.57 nm / s, which is within the range capable of good CD control.

[0157] Furthermore, under the film forming conditions of Example 1, a semi-transparent film 2 having a thickness of 23 nm was formed on a light-transmitting substrate 1 having a light-shielding pattern 3B having a thickness of 110 nm formed thereon and made of chromium metal.

[0158] The transmittance of the semi-transparent film of the resulting mask blank 10 was measured using an MPM-100 manufactured by Lasertec. The transmittance of the semi-transparent film was measured using a substrate (dummy substrate) with a semi-transparent film formed on the main surface of a synthetic quartz glass substrate, prepared on the same tray. The transmittance was 9.9% (wavelength: 365 nm), which was 3% or higher.

[0159] Then, a photoresist film is applied by a resist coating apparatus so as to cover the semi-transparent film 2 .

[0160] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0161] Thereafter, the semi-transparent film 2 was wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid using the resist pattern as a mask to form a semi-transparent pattern 2B, thereby manufacturing the transfer mask 100B of Example 1.

[0162] The cross section of the obtained transfer mask was observed by a scanning electron microscope. The semi-transparent pattern 2B of the obtained transfer mask had a cross-sectional shape that was close to vertical. The semi-transparent pattern 2B formed on the transfer mask of Example 1 had a cross-sectional shape that could fully exert the function of a multi-grayscale mask. In addition, in the semi-transparent pattern 2B, no infiltration was found at the interface with the resist pattern and the interface with the substrate, confirming good adhesion to the resist film. In addition, the CD of each pattern within the surface of the transfer mask was measured, and the results confirmed that the uniformity of the CD of the pattern within the surface was high. Based on the above results, it can be said that a transfer mask with excellent transfer performance was obtained.

[0163] In addition, based on these results, it can be said that when a mask blank having an etching stop film 4 and a light-shielding film 3 stacked thereon is used in the mask blank 10 of Example 1, and a transfer mask 100 having an etching stop pattern 4A and a light-shielding pattern 3A on a semi-transparent pattern 2A is manufactured, a transfer mask having a transfer pattern with good transfer accuracy can also be manufactured.

[0164] Therefore, when the transfer mask of Example 1 is set on the mask stage of an exposure device and the resist film on the display device is exposed and transferred, it can be said that the pattern can be transferred with high precision, and the display device can be manufactured with high yield.

[0165] Example 2.

[0166] To produce the mask blank of Example 2, similarly to Example 1, a 1214-size (1220 mm×1400 mm) synthetic quartz glass substrate was prepared as a light-transmitting substrate.

[0167] Thereafter, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is carried into a chamber of an in-line sputtering apparatus.

[0168] To form the semi-transparent film 2 on the main surface of the translucent substrate 1, an inert gas composed of argon (Ar) and nitrogen (N2) was introduced into the chamber. The film-forming gas flow ratio (N2 / Ar) was 0.30. A sputtering voltage of 500 V was then applied to a sputtering target containing chromium and silicon (chromium:silicon = 96:4). Through reactive sputtering, a chromium silicide nitride containing chromium, silicon, and nitrogen was deposited on the main surface of the translucent substrate 1. This formed a 99 nm thick semi-translucent film 2.

[0169] After the semi-transparent film 2 is formed on the translucent substrate 1 , the substrate 1 is taken out of the chamber and the surface of the semi-transparent film 2 is cleaned with pure water.

[0170] In this way, the mask blank 10 of Example 2 is manufactured.

[0171] Furthermore, the semi-transparent film 2 of the mask blank 10 obtained under the same film forming conditions as in Example 2 was subjected to a composition analysis in the depth direction using X-ray photoelectron spectroscopy (XPS). In the semi-transparent film 2, except for the composition gradient region at the interface between the transparent substrate 1 and the semi-transparent film 2 and the surface region of the semi-transparent film 2, the content of each constituent element was approximately constant in the depth direction: C was 0.6 atomic %, N was 35.9 atomic %, O was 3.3 atomic %, Si was 1.8 atomic %, and Cr was 58.4 atomic %. Thus, Cr was the most abundant element, and Si was less than 2.8 atomic %. Furthermore, the ratio of silicon content to chromium content (Si / Cr) was 0.031, which was less than 0.035.

[0172] Next, a cross-sectional SEM observation was performed at a magnification of 80,000x at the center of the transfer pattern formation region of the resulting mask blank 10. The results confirmed that the semi-transparent film 2 had a columnar structure. Specifically, it was confirmed that the particles containing chromium, silicon, and nitrogen that constituted the semi-transparent film 2 had a columnar particle structure extending in the thickness direction of the semi-transparent film 2. Furthermore, it was confirmed that the columnar particle structure of the semi-transparent film 2 was such that the columnar particles were irregularly formed in the film thickness direction, and the lengths of the columnar particles in the film thickness direction were also inconsistent. Furthermore, it was confirmed that the sparse portions of the semi-transparent film 2 were formed continuously in the film thickness direction.

[0173] Furthermore, dark field plan STEM observation was performed near the film thickness center of the semi-transparent film 2. As a result, it was confirmed that columnar grain portions and sparse portions were formed in the semi-transparent film 2.

[0174] Next, a photoresist film is applied using a resist coating apparatus so as to cover the semi-transparent film 2 .

[0175] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0176] Then, using the resist pattern as a mask, the semi-transparent film 2 was wet-etched with a chromium etching solution containing ammonium cerium nitrate and perchloric acid to form a semi-transparent pattern 2A, thereby manufacturing the transfer mask 100 of Example 2.

[0177] The cross section of the obtained transfer mask was observed with a scanning electron microscope. Figure 6 This is a cross-sectional photograph of the transfer mask of Example 2. As shown in this figure, the semi-transparent pattern of the transfer mask has a good cross-sectional shape that is nearly vertical. Furthermore, no penetration of the semi-transparent pattern was observed at the interface with the resist pattern or the interface with the substrate, confirming good adhesion to the resist film. Furthermore, the etching rate of the transfer mask of Example 2 was measured and found to be 4.94 nm / s, which is within the range capable of good CD control.

[0178] Furthermore, under the same film forming conditions as in Example 2, a 16 nm thick semi-transparent film 2 was formed on the translucent substrate 1 on which a 110 nm thick light-shielding pattern 3B made of chromium metal was formed.

[0179] The transmittance of the semi-transparent film of the resulting mask blank 10 was measured using an MPM-100 manufactured by Lasertec. The transmittance of the semi-transparent film was measured using a substrate (dummy substrate) with a semi-transparent film formed on the main surface of a synthetic quartz glass substrate, prepared on the same tray. The transmittance was 20.3% (wavelength: 365 nm), which was 3% or higher.

[0180] Then, a photoresist film is applied by a resist coating apparatus so as to cover the semi-transparent film 2 .

[0181] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0182] Thereafter, the semi-transparent film 2 was wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid using the resist pattern as a mask to form a semi-transparent pattern 2B, thereby manufacturing a transfer mask 100B of Example 2.

[0183] The cross section of the obtained transfer mask was observed by a scanning electron microscope. The semi-transparent pattern 2B of the obtained transfer mask has a cross-sectional shape that is close to vertical. The semi-transparent pattern 2B formed on the transfer mask of Example 2 has a cross-sectional shape that can fully exert the function of being a multi-grayscale mask. In addition, in the semi-transparent pattern 2B, no infiltration was found in the interface with the resist pattern and the interface with the substrate, confirming good adhesion with the resist film. In addition, the CD of each pattern in the surface of the transfer mask was measured, and the results confirmed that the uniformity of the CD of the pattern in the surface was high. Based on the above results, it can be said that a transfer mask with excellent transfer performance was obtained.

[0184] In addition, based on these results, it can be said that when a mask blank having an etching stop film 4 and a light-shielding film 3 stacked thereon is used in the mask blank 10 of Example 2, and a transfer mask 100 having an etching stop pattern 4A and a light-shielding pattern 3A on a semi-transparent pattern 2A is manufactured, a transfer mask having a transfer pattern with good transfer accuracy can also be manufactured.

[0185] Therefore, when the transfer mask of Example 2 is set on the mask stage of the exposure device and the resist film on the display device is exposed and transferred, it can be said that the pattern can be transferred with high precision, and the display device can be manufactured with high yield.

[0186] Example 3.

[0187] In order to produce the mask blank of Example 3, similarly to Example 1, a synthetic quartz glass substrate of 1214 size (1220 mm×1400 mm) was prepared as a light-transmitting substrate.

[0188] Thereafter, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is carried into a chamber of an in-line sputtering apparatus.

[0189] To form the semi-transparent film 2 on the main surface of the translucent substrate 1, an inert gas composed of argon (Ar) and nitrogen (N2) was introduced into the chamber. The film-forming gas flow ratio (N2 / Ar) was 0.66. A sputtering voltage of 500 V was then applied to a sputtering target containing chromium and silicon (chromium:silicon = 96:4). Through reactive sputtering, a chromium silicide nitride containing chromium, silicon, and nitrogen was deposited on the main surface of the translucent substrate 1. This formed a semi-translucent film 2 with a thickness of 57 nm.

[0190] After the semi-transparent film 2 is formed on the translucent substrate 1 , the substrate 1 is taken out of the chamber and the surface of the semi-transparent film 2 is cleaned with pure water.

[0191] In this manner, the mask blank 10 of Example 3 was produced.

[0192] Furthermore, the semi-transparent film 2 of the mask blank 10 obtained under the same film forming conditions as in Example 3 was subjected to a composition analysis in the depth direction using X-ray photoelectron spectroscopy (XPS). In the semi-transparent film 2, excluding the composition gradient region at the interface between the transparent substrate 1 and the semi-transparent film 2 and the surface region of the semi-transparent film 2, the content of each constituent element was approximately constant in the depth direction: C was 0.8 atomic %, N was 43.2 atomic %, O was 4.2 atomic %, Si was 1.5 atomic %, and Cr was 50.3 atomic %. Thus, Cr was the most abundant element, and Si was less than 2.8 atomic %. Furthermore, the ratio of silicon content to chromium content (Si / Cr) was 0.030, which was less than 0.035.

[0193] Next, a cross-sectional SEM observation was performed at a magnification of 80,000x at the center of the transfer pattern formation region of the resulting mask blank 10. The results confirmed that the semi-transparent film 2 had a columnar structure. Specifically, it was confirmed that the particles containing chromium, silicon, and nitrogen that constituted the semi-transparent film 2 had a columnar particle structure extending in the thickness direction of the semi-transparent film 2. Furthermore, it was confirmed that the columnar particle structure of the semi-transparent film 2 was such that the columnar particles were irregularly formed in the film thickness direction, and the lengths of the columnar particles in the film thickness direction were also inconsistent. Furthermore, it was confirmed that the sparse portions of the semi-transparent film 2 were formed continuously in the film thickness direction.

[0194] Furthermore, dark field plan STEM observation was performed near the film thickness center of the semi-transparent film 2. As a result, it was confirmed that columnar grain portions and sparse portions were formed in the semi-transparent film 2.

[0195] Next, a photoresist film is applied using a resist coating apparatus so as to cover the semi-transparent film 2 .

[0196] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0197] Then, using the resist pattern as a mask, the semi-transparent film 2 was wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid to form a semi-transparent pattern 2A, thereby manufacturing the transfer mask 100 of Example 3.

[0198] The cross section of the obtained transfer mask was observed with a scanning electron microscope. Figure 7 This is a cross-sectional photograph of the transfer mask of Example 3. As shown in the figure, the semi-transparent pattern of the transfer mask has a good cross-sectional shape that is close to vertical. In addition, in the semi-transparent pattern, no infiltration was found at the interface with the resist pattern and the interface with the substrate, confirming that the resist film has good adhesion. In addition, the etching rate of the transfer mask of Example 3 was measured, and the result was 5.65nm / second, which is within the range that can perform good CD control. In addition, under the same film forming conditions as in Example 3, a semi-transparent film 2 was formed on a translucent substrate 1 on which a light-shielding pattern 3B was formed, and the semi-transparent film 2 was wet-etched in the same manner as described in Examples 1 and 2 to form a semi-transparent pattern 2B, thereby producing the transfer mask 100B of Example 3. The CD of each pattern within the surface of the transfer mask was measured, and the results confirmed that the CD uniformity of the pattern within the surface was high. Based on the above results, it can be said that a transfer mask with excellent transfer performance was obtained.

[0199] In addition, based on these results, it can be said that when a mask blank having an etching stop film 4 and a light-shielding film 3 stacked thereon is used in the mask blank 10 of Example 3, and a transfer mask 100 having an etching stop pattern 4A and a light-shielding pattern 3A on a semi-transparent pattern 2A is manufactured, a transfer mask having a transfer pattern with good transfer accuracy can also be manufactured.

[0200] Therefore, when the transfer mask of Example 3 is set on the mask stage of the exposure device and the resist film on the display device is exposed and transferred, it can be said that the pattern can be transferred with high precision, and the display device can be manufactured with high yield.

[0201] Example 4.

[0202] In order to produce the mask blank of Example 4, similarly to Example 1, a 1214-size (1220 mm×1400 mm) synthetic quartz glass substrate was prepared as a light-transmitting substrate.

[0203] Thereafter, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is carried into a chamber of an in-line sputtering apparatus.

[0204] To form the semi-transparent film 2 on the main surface of the transparent substrate 1, an inert gas composed of argon (Ar) was introduced into the chamber. The film-forming gas flow ratio (N2 / Ar) was 0.01. A sputtering voltage of 485 V was then applied to a sputtering target composed of chromium and silicon (chromium:silicon = 96:4). Through reactive sputtering, a chromium silicide nitride containing chromium, silicon, and nitrogen was deposited on the main surface of the transparent substrate 1. This formed a semi-transparent film 2 with a thickness of 79 nm.

[0205] After the semi-transparent film 2 is formed on the translucent substrate 1 , the substrate 1 is taken out of the chamber and the surface of the semi-transparent film 2 is cleaned with pure water.

[0206] In this manner, the mask blank 10 of Example 4 was produced.

[0207] Furthermore, the semi-transparent film 2 of the mask blank 10 obtained under the same film forming conditions as in Example 4 was subjected to a composition analysis in the depth direction using X-ray photoelectron spectroscopy (XPS). In the semi-transparent film 2, excluding the composition gradient region at the interface between the transparent substrate 1 and the semi-transparent film 2 and the surface region of the semi-transparent film 2, the content of each constituent element was approximately constant in the depth direction: C was 0.8 atomic %, N was 0.7 atomic %, O was 8.9 atomic %, Si was 2.6 atomic %, and Cr was 87.0 atomic %. Thus, Cr was the most abundant element, and Si was less than 2.8 atomic %. Furthermore, the ratio of the silicon content to the chromium content (Si / Cr) was 0.030, which was less than 0.035.

[0208] Next, a cross-sectional SEM observation was performed at a magnification of 80,000x at the center of the transfer pattern formation region of the resulting mask blank 10. The results confirmed that the semi-transparent film 2 had a columnar structure. Specifically, it was confirmed that the particles containing chromium, silicon, and nitrogen that constituted the semi-transparent film 2 had a columnar particle structure extending in the thickness direction of the semi-transparent film 2. Furthermore, it was confirmed that the columnar particle structure of the semi-transparent film 2 was such that the columnar particles were irregularly formed in the film thickness direction, and the lengths of the columnar particles in the film thickness direction were also inconsistent. Furthermore, it was confirmed that the sparse portions of the semi-transparent film 2 were formed continuously in the film thickness direction.

[0209] Furthermore, dark field plan STEM observation was performed near the film thickness center of the semi-transparent film 2. As a result, it was confirmed that columnar grain portions and sparse portions were formed in the semi-transparent film 2.

[0210] Next, a photoresist film is applied using a resist coating apparatus so as to cover the semi-transparent film 2 .

[0211] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0212] Then, using the resist pattern as a mask, the semi-transparent film 2 was wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid to form a semi-transparent pattern 2A, thereby manufacturing the transfer mask 100 of Example 4.

[0213] The cross section of the obtained transfer mask was observed with a scanning electron microscope. Figure 8 This is a cross-sectional photograph of the transfer mask of Example 4. As shown in the figure, the semi-transparent pattern of the transfer mask has a good cross-sectional shape that is close to vertical. In addition, in the semi-transparent pattern, no infiltration was found at the interface with the resist pattern and the interface with the substrate, confirming that the resist film has good adhesion. In addition, the etching rate of the transfer mask of Example 4 was measured, and the result was 1.71nm / second, which is within the range that can perform good CD control. In addition, under the same film forming conditions as in Example 4, a semi-transparent film 2 was formed on a translucent substrate 1 on which a light-shielding pattern 3B was formed, and the semi-transparent film 2 was wet-etched in the same manner as described in Examples 1 and 2 to form a semi-transparent pattern 2B, thereby producing the transfer mask 100B of Example 4. The CD of each pattern within the surface of the transfer mask was measured, and the results confirmed that the CD uniformity of the pattern within the surface was high. Based on the above results, it can be said that a transfer mask with excellent transfer performance was obtained.

[0214] In addition, based on these results, it can be said that when a mask blank having an etching stop film 4 and a light-shielding film 3 stacked thereon is used in the mask blank 10 of Example 4, and a transfer mask 100 having an etching stop pattern 4A and a light-shielding pattern 3A on a semi-transparent pattern 2A is manufactured, a transfer mask having a transfer pattern with good transfer accuracy can also be manufactured.

[0215] Therefore, when the transfer mask of Example 4 is set on the mask stage of the exposure device and the resist film on the display device is exposed and transferred, it can be said that the pattern can be transferred with high precision, and the display device can be manufactured with high yield.

[0216] It should be noted that while the above embodiments illustrate examples of multi-tone mask blanks and transfer masks for display device manufacturing, the present invention is not limited thereto. The mask blanks and transfer masks of the present invention can also be used for semiconductor device manufacturing, MEMS manufacturing, printed circuit boards, and the like. Furthermore, the present invention can also be applied to binary mask blanks having a light-shielding film as a pattern-forming thin film, or binary masks having a light-shielding pattern.

[0217] In the above embodiment, the transparent substrate is described as having a size of 1214 mm (1220 mm × 1400 mm × 13 mm), but the present invention is not limited to this. In the case of multi-tone mask blanks for display device manufacturing, a large-sized transparent substrate is used, with a side length of 300 mm or greater. The size of the transparent substrate used in multi-tone mask blanks for display device manufacturing is, for example, 330 mm × 450 mm or greater and 2280 mm × 3130 mm or less.

[0218] In addition, in the case of multi-grayscale mask blanks for semiconductor device manufacturing, MEMS manufacturing, and printed circuit boards, a small-sized translucent substrate is used, the size of which is 9 inches or less on one side. The size of the translucent substrate used in the multi-grayscale mask blanks for the above-mentioned purposes is, for example, 63.1 mm × 63.1 mm or more and 228.6 mm × 228.6 mm or less. Generally, translucent substrates used in semiconductor manufacturing and MEMS manufacturing use 6025 size (152 mm × 152 mm) and 5009 size (126.6 mm × 126.6 mm), and translucent substrates used in printed circuit boards use 7012 size (177.4 mm × 177.4 mm) and 9012 size (228.6 mm × 228.6 mm).

[0219] Comparative Example 1.

[0220] In order to produce the mask blank of Comparative Example 1, a 1214-size (1220 mm×1400 mm) synthetic quartz glass substrate was prepared as a light-transmitting substrate in the same manner as in Example 1.

[0221] Thereafter, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is carried into a chamber of an in-line sputtering apparatus.

[0222] To form the semi-transparent film 2 on the main surface of the translucent substrate 1, an inert gas composed of argon (Ar) and nitrogen (N2) was introduced into the chamber. The film-forming gas flow ratio (N2 / Ar) was 0.54. A sputtering voltage of 550 V was then applied to a sputtering target containing chromium and silicon (chromium:silicon = 96:4). Through reactive sputtering, a chromium silicide nitride containing chromium, silicon, and nitrogen was deposited on the main surface of the translucent substrate 1. This formed a semi-translucent film 2 with a thickness of 81 nm.

[0223] After the semi-transparent film 2 is formed on the translucent substrate 1 , the substrate 1 is taken out of the chamber and the surface of the semi-transparent film 2 is cleaned with pure water.

[0224] In this manner, the mask blank 10 of Comparative Example 1 was produced.

[0225] Furthermore, the semi-transparent film 2 of the mask blank 10 obtained under the same film forming conditions as in Comparative Example 1 was subjected to a composition analysis in the depth direction using X-ray photoelectron spectroscopy (XPS). In the semi-transparent film 2, except for the composition gradient region at the interface between the transparent substrate 1 and the semi-transparent film 2 and the surface region of the semi-transparent film 2, the content of each constituent element is approximately constant in the depth direction: C is 0.6 atomic %, N is 31.5 atomic %, O is 0.6 atomic %, Si is 2.6 atomic %, and Cr is 64.7 atomic %. Thus, Cr is the most abundant element, and Si is less than 2.8 atomic %. On the other hand, the ratio of the silicon content to the chromium content (Si / Cr) is 0.040, which is not less than 0.035.

[0226] Next, a cross-sectional SEM observation was performed at a magnification of 80,000 times at the center of the transferred pattern formation region of the obtained mask blank 10. No columnar structure was confirmed in the semi-transparent film, and an ultrafine crystal structure or an amorphous structure was confirmed.

[0227] Next, a photoresist film is applied using a resist coating apparatus so as to cover the semi-transparent film 2 .

[0228] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0229] Then, using the resist pattern as a mask, the semi-transparent film 2 was wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid to form a semi-transparent pattern 2A, thereby manufacturing a transfer mask 100 of Comparative Example 1.

[0230] The cross section of the obtained transfer mask was observed with a scanning electron microscope. Figure 9 This is a cross-sectional photograph of the transfer mask of Comparative Example 1. As shown, the semi-transparent pattern of the transfer mask is observed to be intruding into the interface with the resist pattern, significantly deteriorating the cross-sectional shape. The etching rate of the transfer mask of Comparative Example 1 was measured and found to be 5.41 nm / sec.

[0231] Therefore, when the transfer mask of Comparative Example 1 is set on a mask stage of an exposure device and the resist film on the display device is exposed and transferred, it is expected that the pattern cannot be transferred.

[0232] Comparative Example 2.

[0233] In order to produce the mask blank of Comparative Example 2, similarly to Example 1, a 1214-size (1220 mm×1400 mm) synthetic quartz glass substrate was prepared as a light-transmitting substrate.

[0234] Thereafter, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is carried into a chamber of an in-line sputtering apparatus.

[0235] To form the semi-transparent film 2 on the main surface of the translucent substrate 1, an inert gas composed of argon (Ar) and nitrogen (N2) was introduced into the chamber. The film-forming gas flow ratio (N2 / Ar) was 0.66. A sputtering voltage of 550 V was then applied to a sputtering target containing chromium and silicon (chromium:silicon = 96:4). Through reactive sputtering, a chromium silicide nitride containing chromium, silicon, and nitrogen was deposited on the main surface of the translucent substrate 1. This formed a semi-translucent film 2 with a thickness of 80 nm.

[0236] After the semi-transparent film 2 is formed on the translucent substrate 1 , the substrate 1 is taken out of the chamber and the surface of the semi-transparent film 2 is cleaned with pure water.

[0237] In this manner, the mask blank 10 of Comparative Example 2 was produced.

[0238] Furthermore, the semi-transparent film 2 of the mask blank 10 obtained under the same film forming conditions as in Comparative Example 2 was subjected to a composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). In the semi-transparent film 2, except for the composition gradient region at the interface between the transparent substrate 1 and the semi-transparent film 2 and the surface region of the semi-transparent film 2, the content of each constituent element was approximately constant in the depth direction: C was 0.1 atomic %, N was 34.2 atomic %, O was 0.3 atomic %, Si was 2.4 atomic %, and Cr was 63.0 atomic %. Thus, Cr was the most abundant element, and Si was less than 2.8 atomic %. On the other hand, the ratio of the silicon content to the chromium content (Si / Cr) was 0.038, which was not less than 0.035.

[0239] Next, a cross-sectional SEM observation was performed at a magnification of 80,000 times at the center of the transferred pattern formation region of the obtained mask blank 10. No columnar structure was confirmed in the semi-transparent film, and an ultrafine crystal structure or an amorphous structure was confirmed.

[0240] Next, a photoresist film is applied using a resist coating apparatus so as to cover the semi-transparent film 2 .

[0241] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0242] Then, using the resist pattern as a mask, the semi-transparent film 2 was wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid to form a semi-transparent pattern 2A, thereby manufacturing a transfer mask 100 of Comparative Example 2.

[0243] The cross section of the obtained transfer mask was observed with a scanning electron microscope. Figure 10 This is a cross-sectional photograph of the transfer mask of Comparative Example 2. As shown, the semi-transparent pattern of the transfer mask is observed to be intruding into the interface with the resist pattern, significantly deteriorating the cross-sectional shape. The etching rate of the transfer mask of Comparative Example 2 was measured and found to be 6.15 nm / sec.

[0244] Therefore, when the transfer mask of Comparative Example 2 is set on the mask stage of an exposure device and the resist film on the display device is exposed and transferred, it is expected that the pattern cannot be transferred.

[0245] Comparative Example 3.

[0246] In order to produce the mask blank of Comparative Example 3, similarly to Example 1, a 1214-size (1220 mm×1400 mm) synthetic quartz glass substrate was prepared as a light-transmitting substrate.

[0247] Thereafter, the synthetic quartz glass substrate is placed on a tray (not shown) with its main surface facing downward, and is carried into a chamber of an in-line sputtering apparatus.

[0248] To form the semi-transparent film 2 on the main surface of the translucent substrate 1, an inert gas composed of argon (Ar) and nitrogen (N2) was introduced into the chamber. The film-forming gas flow ratio (N2 / Ar) was 0.60. A sputtering voltage of 485 V was then applied to a sputtering target composed of chromium. Chromium nitride containing chromium and nitrogen was deposited on the main surface of the translucent substrate 1 through reactive sputtering. This resulted in a 23 nm thick semi-transparent film 2.

[0249] After the semi-transparent film 2 is formed on the translucent substrate 1 , the substrate 1 is taken out of the chamber and the surface of the semi-transparent film 2 is cleaned with pure water.

[0250] In this manner, the mask blank 10 of Comparative Example 3 was produced.

[0251] Furthermore, the semi-transparent film 2 of the mask blank 10 obtained under the same film-forming conditions as in Comparative Example 3 was subjected to a composition analysis in the depth direction using X-ray photoelectron spectroscopy (XPS). In the semi-transparent film 2, except for the composition gradient region at the interface between the transparent substrate 1 and the semi-transparent film 2 and the surface region of the semi-transparent film 2, the contents of the constituent elements were substantially constant in the depth direction: C was 0.7 atomic %, N was 45.8 atomic %, O was 0.8 atomic %, Si was 0.0 atomic %, and Cr was 52.7 atomic %. Thus, Cr was the most abundant element, and Si was absent.

[0252] Next, a cross-sectional SEM observation was performed at a magnification of 80,000 times at the center of the transfer pattern formation region of the obtained mask blank 10. As a result, it was confirmed that the semi-transparent film 2 had a columnar structure.

[0253] The transmittance of the semi-transparent film of the resulting mask blank 10 was measured using an MPM-100 manufactured by Lasertec. The transmittance of the semi-transparent film was measured using a substrate with a semi-transparent film (dummy substrate) prepared on the same tray and having the semi-transparent film 2 formed on the main surface of a synthetic quartz glass substrate. The transmittance was 14.1% (wavelength: 365 nm).

[0254] Next, a photoresist film is applied using a resist coating apparatus so as to cover the semi-transparent film 2 .

[0255] Thereafter, the photoresist film is drawn using a laser drawing device, and a resist pattern is formed on the semi-transparent film 2 through a development / rinsing process.

[0256] Then, using the resist pattern as a mask, the semi-transparent film 2 was wet-etched with a chromium etchant containing ammonium cerium nitrate and perchloric acid to form a semi-transparent pattern 2A. Thus, a transfer mask 100 of Comparative Example 3 was manufactured.

[0257] Figure 11 This is a graph showing the relationship between nitrogen content and etching rate for Examples 1 to 3 and Comparative Example 3. As shown in the graph, the etching rate of the transfer mask of Comparative Example 3 was measured to be 7.48 nm / sec, which is significantly higher than the etching rates in Examples 1 to 3 and outside the range for good CD control.

[0258] The transfer mask of Comparative Example 3 was observed with a scanning electron microscope. As a result, it was confirmed that the CD was significantly reduced in the region where the pattern was relatively sparse.

[0259] Therefore, when the transfer mask of Comparative Example 3 is set on a mask stage of an exposure device and the resist film on the display device is exposed and transferred, it is expected that the pattern cannot be transferred with good accuracy.

[0260] Description of Reference Numerals

[0261] 1Transparent substrate

[0262] 2 semi-transparent film

[0263] 3 shading film

[0264] 2A, 2B semi-transparent pattern (semi-transparent film with transferred pattern)

[0265] 3A, 3B shading patterns

[0266] 10 (10A, 10B) mask blank

[0267] 11 light-transmitting part

[0268] 12 semi-transparent part

[0269] 13 shading part

[0270] 100 (100A, 100B) transfer mask.

Claims

1. A mask blank comprising a thin film for transfer pattern formation on a light-transmitting substrate, characterized in that: The film contains chromium, silicon and nitrogen, The most abundant element in the film is chromium. The silicon content of the thin film is 2.8 atomic % or less, The film has a columnar structure.

2. The mask blank according to claim 1, wherein The ratio of the silicon content to the chromium content in the thin film is 0.035 or less.

3. The mask blank according to claim 1, wherein The chromium content in the thin film is 50 atomic % or more.

4. The mask blank according to claim 1, wherein The nitrogen content in the thin film is 25 atomic % or more.

5. The mask blank according to claim 1, wherein The total content of chromium, silicon and nitrogen in the thin film is greater than 90 atomic %.

6. The mask blank according to claim 1, wherein The columnar structure of the thin film is a structure in which columnar particles extending in the film thickness direction are formed within the surface of the light-transmitting substrate.

7. The mask blank according to claim 6, wherein The thin film includes a portion where the density of the columnar particles is relatively high and a sparse portion where the density is relatively low.

8. The mask blank according to claim 1, wherein The transmittance of the film to light with a wavelength of 365 nm is greater than 3%.

9. A transfer mask comprising a thin film having a transfer pattern formed thereon on a light-transmitting substrate, wherein: The film contains chromium, silicon and nitrogen, The most abundant element in the film is chromium. The silicon content of the thin film is 2.8 atomic % or less, The film has a columnar structure.

10. The transfer mask according to claim 9, wherein The ratio of the silicon content to the chromium content in the thin film is 0.035 or less.

11. The transfer mask according to claim 9, wherein The chromium content in the thin film is 50 atomic % or more.

12. The transfer mask according to claim 9, wherein The nitrogen content in the thin film is 25 atomic % or more.

13. The transfer mask according to claim 9, wherein The total content of chromium, silicon and nitrogen in the thin film is greater than 90 atomic %.

14. The transfer mask according to claim 9, wherein The columnar structure of the thin film is a structure in which columnar particles extending in the film thickness direction are formed within the surface of the light-transmitting substrate.

15. The transfer mask according to claim 14, wherein The thin film includes a portion where the density of the columnar particles is relatively high and a sparse portion where the density is relatively low.

16. The transfer mask according to claim 9, wherein The transmittance of the film to light with a wavelength of 365 nm is greater than 3%.

17. A method for manufacturing a display device, characterized in that: The invention comprises an exposure step of placing the transfer mask according to any one of claims 9 to 16 on a mask stage of an exposure device, and transferring the transfer pattern formed on the transfer mask to a resist formed on a display device substrate by exposure.

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