Mask substrate, transfer mask, method for manufacturing the same, and method for manufacturing semiconductor device

Abstract

A mask substrate is provided that is capable of forming a pattern on a photoresist film having a line width smaller than the wavelength of a laser beam from a laser drawing device. The mask substrate includes a light-shielding film on a substrate. The light-shielding film is composed of a material containing a metal element. The light-shielding film is a composition-inclined film in which the content of the metal element varies in the thickness direction. When the light-shielding film is divided into a light-shielding portion and an anti-reflection portion in sequence from the side closest to the substrate, the refractive index n of the anti-reflection portion with respect to light in the wavelength range of 350 nm to 520 nm is A The phase difference caused by light in the wavelength range when light in the wavelength range passes through the antireflection portion is 28 degrees or more.

Description

Technical Field

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

[0002] Generally speaking, photolithography is used to form fine patterns in the manufacturing process of semiconductor devices. Furthermore, multiple transfer masks are typically used to form these fine patterns. These transfer masks are typically used to form light-shielding fine patterns made of, for example, metal thin films on translucent glass substrates, and photolithography is also used in their manufacture.

[0003] In the manufacture of a transfer mask using photolithography, a mask substrate having a light-shielding film on a translucent substrate such as a glass substrate is used. In the manufacture of a transfer mask using this mask substrate, an exposure step is performed to expose the photoresist film formed on the mask substrate in a desired pattern; a development step is performed to develop the photoresist film according to the desired pattern exposure to form a photoresist pattern; an etching step is performed to etch the light-shielding film along the photoresist pattern; and a step is performed to peel off and remove the remaining photoresist pattern. In the development step, after the photoresist film formed on the mask substrate has been exposed in the desired pattern, a developer is supplied to dissolve the soluble portions of the photoresist film in the developer, thereby forming a photoresist pattern. Furthermore, in the etching step, dry etching is performed using the photoresist pattern as a mask to dissolve the exposed portions of the light-shielding film where the photoresist pattern is not formed, thereby forming the desired mask pattern on the translucent substrate. In this manner, the transfer mask is completed.

[0004] For example, Patent Document 1 discloses a mask substrate having a light-shielding film made of a chromium-based material. Furthermore, Patent Document 2 discloses a process of forming an i-line photoresist film on the light-shielding film made of a chromium-based material, exposing a pattern using a laser exposure device, performing a development process to form a photoresist pattern, and finally performing etching using the photoresist pattern as a mask to form a pattern on the light-shielding film.

[0005] Patent Document 1: Japanese Patent No. 3276954

[0006] Patent Document 2: Japanese Patent Application Laid-Open No. 2004-077800 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] Electron beam exposure is used to expose (expose) fine patterns on photoresist films. However, existing electron beam drawing systems have the problem of requiring a significant amount of time to expose and draw patterns on photoresist films. This is primarily due to the electron beam irradiator (electron gun) exposing and drawing patterns in a single pass, and typical electron beam drawing systems are equipped with only one electron beam irradiator.

[0009] On the other hand, the laser drawing device has a mechanism that can irradiate multiple laser beams from a single laser light source onto the photoresist film. Therefore, compared to exposure drawing by electron beam, exposure drawing by laser has the advantage of being significantly faster. In addition, compared to the line width of laser, the line width of exposure drawing by electron beam is significantly reduced. However, since it is not always necessary to generate the transfer pattern with the line width of the electron beam, there are cases where it is not necessary to use electron beam for exposure drawing. If the number of cases where the electron beam exposure drawing device can be omitted in the exposure drawing of the photoresist film by the mask substrate increases, efficient use of resources can be achieved. In addition, the processing capacity of the mask substrate for exposure drawing of the pattern of the photoresist film is also greatly improved.

[0010] However, the wavelength of the laser used in laser drawing systems is, at the very least, around 350nm. Meanwhile, the line width of the transferred pattern may sometimes be even smaller, around 300nm. Conventionally, even when a pattern with a line width smaller than the wavelength of the laser light is exposed and drawn on a photoresist film on a mask substrate using a laser drawing system, it is difficult to form the exposed pattern on the photoresist film during the development process after exposure and drawing.

[0011] The present invention is made to solve the above-mentioned existing technical problems, and its purpose is to provide a mask substrate, a transfer mask, a method for manufacturing a transfer mask, and a method for manufacturing a semiconductor device that can form a pattern imaging with a line width smaller than the wavelength of the laser of the laser drawing device on a photoresist film.

[0012] Technical solutions to technical problems

[0013] In order to solve the above-mentioned technical problems, the present invention has the following configurations.

[0014] (Composition 1)

[0015] A mask substrate is provided with a light-shielding film on a substrate, characterized in that:

[0016] The light-shielding film is made of a material containing a metal element.

[0017] The light shielding film is a composition gradient film in which the content of the metal element varies in the thickness direction.

[0018] When the light-shielding film is divided into the light-shielding portion and the anti-reflection portion in order from the side close to the substrate,

[0019] The refractive index n of the antireflection portion with respect to light in the wavelength range of 350 nm to 520 nm is A is below 2.1,

[0020] When light in the wavelength range passes through the antireflection portion, a phase difference generated by light in the wavelength range is 28 degrees or more.

[0021] (Composition 2)

[0022] The mask substrate according to Configuration 1 is characterized in that:

[0023] The phase difference is less than 42 degrees.

[0024] (Composition 3)

[0025] The mask substrate according to configuration 1 or 2 is characterized in that:

[0026] The refractive index n of the anti-reflection portion A It is above 1.9.

[0027] (Composition 4)

[0028] The mask substrate according to any one of Configurations 1 to 3 is characterized in that:

[0029] The refractive index n of the light shielding portion S It is above 1.9.

[0030] (Composition 5)

[0031] The mask substrate according to any one of Configurations 1 to 4 is characterized in that:

[0032] The refractive index n of the light shielding portion S Below 2.8.

[0033] (Composition 6)

[0034] The mask substrate according to any one of Configurations 1 to 5 is characterized in that:

[0035] The attenuation coefficient k of the light shielding portion for light in the wavelength range S It is above 2.8.

[0036] (Composition 7)

[0037] The mask substrate according to any one of Configurations 1 to 6 is characterized in that:

[0038] The attenuation coefficient k of the anti-reflection portion for light in the wavelength rangeA Below 1.0.

[0039] (Composition 8)

[0040] The mask substrate according to any one of Configurations 1 to 7 is characterized in that:

[0041] The light-shielding film is formed of a material containing chromium.

[0042] (Composition 9)

[0043] The mask substrate according to any one of Configurations 1 to 8 is characterized in that:

[0044] The light-shielding film has an optical density of 3 or more with respect to exposure light.

[0045] (Composition 10)

[0046] The mask substrate according to any one of Configurations 1 to 9 is characterized in that:

[0047] A photoresist film is formed in contact with a surface of the light-shielding film.

[0048] (Composition 11)

[0049] The mask substrate according to Configuration 10 is characterized in that:

[0050] The refractive index n of the photoresist film with respect to light in the wavelength range R Above 1.50.

[0051] (Composition 12)

[0052] The mask substrate according to configuration 10 or 11 is characterized in that:

[0053] The photoresist film is formed of a material that is photosensitized by exposure light in a wavelength range of 350 nm to 520 nm.

[0054] (Composition 13)

[0055] A transfer mask comprises a light-shielding film having a transfer pattern on a substrate, characterized in that:

[0056] The light-shielding film is made of a material containing a metal element.

[0057] The light shielding film is a composition gradient film in which the content of the metal element varies in the thickness direction.

[0058] When the light-shielding film is divided into the light-shielding portion and the anti-reflection portion in order from the side close to the substrate,

[0059] The refractive index n of the antireflection portion with respect to light in the wavelength range of 350 nm to 520 nm is A is below 2.1,

[0060] When light in the wavelength range passes through the antireflection portion, a phase difference generated by light in the wavelength range is 28 degrees or more.

[0061] (Composition 14)

[0062] The transfer mask according to Configuration 13 is characterized in that:

[0063] The phase difference is less than 42 degrees.

[0064] (Composition 15)

[0065] The transfer mask according to configuration 13 or 14 is characterized in that:

[0066] The refractive index n of the anti-reflection portion A It is above 1.9.

[0067] (Composition 16)

[0068] The transfer mask according to any one of Configurations 13 to 15 is characterized in that:

[0069] The refractive index n of the light shielding portion S It is above 1.9.

[0070] (Composition 17)

[0071] The transfer mask according to any one of Configurations 13 to 16 is characterized in that:

[0072] The refractive index n of the light shielding portion S Below 2.8.

[0073] (Composition 18)

[0074] The transfer mask according to any one of Configurations 13 to 17 is characterized in that:

[0075] The attenuation coefficient k of the light shielding portion for light in the wavelength range S It is above 2.8.

[0076] (Composition 19)

[0077] The transfer mask according to any one of Configurations 13 to 18 is characterized in that:

[0078] The attenuation coefficient k of the anti-reflection portion for light in the wavelength range A Below 1.0.

[0079] (Composition 20)

[0080] The transfer mask according to any one of Configurations 13 to 19 is characterized in that:

[0081] The light-shielding film is formed of a material containing chromium.

[0082] (Composition 21)

[0083] The transfer mask according to any one of Configurations 13 to 20 is characterized in that:

[0084] The light-shielding film has an optical density of 3 or more with respect to exposure light.

[0085] (Composition 22)

[0086] A method for manufacturing a transfer mask, using the mask substrate according to any one of configurations 10 to 12, characterized by comprising:

[0087] After exposing the photoresist film to a transfer pattern by exposure light having a wavelength of 350 nm to 520 nm, the photoresist film is developed to form a photoresist film having the transfer pattern;

[0088] A step of forming a transfer pattern on the light shielding film by etching using a photoresist film having the transfer pattern as a mask.

[0089] (Composition 23)

[0090] The method for manufacturing a transfer mask according to Configuration 22 is characterized in that:

[0091] In the step of forming the transfer pattern on the light-shielding film, the transfer pattern is formed on the light-shielding film by dry etching using a chlorine-containing gas.

[0092] (Composition 24)

[0093] A method for manufacturing a semiconductor device, comprising the step of exposing and transferring a transfer pattern onto a photoresist film on a semiconductor substrate using the transfer mask according to any one of configurations 13 to 21.

[0094] (Composition 25)

[0095] A method for manufacturing a semiconductor device, characterized by comprising a step of exposing and transferring a transfer pattern onto a photoresist film on a semiconductor substrate using a transfer mask manufactured by the method for manufacturing a transfer mask according to configuration 22 or 23.

[0096] Effects of the Invention

[0097] The mask substrate of the present invention can form a pattern on a photoresist film with a line width smaller than the wavelength of the laser light from the laser drawing device. This can increase the number of cases where the mask substrate can be used to draw patterns on the photoresist film without using an electron beam exposure drawing device, thereby achieving efficient resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1 It is a schematic diagram showing the structure of a mask blank in an embodiment of the present invention.

[0099] Figure 2 (a) to (e) are schematic diagrams showing the steps of manufacturing a transfer mask in an embodiment of the present invention.

[0100] Figure 3 This is a graph showing the relationship between the phase difference and the surface reflectance in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention, and a curve calculated based on the relationship.

[0101] Description of Reference Numerals

[0102] 1: Light-transmitting substrate, 2: Light-shielding film, 2a: Light-shielding pattern (transfer pattern), 3: Photoresist film, 3a: Photoresist pattern, 10: Mask substrate, 20: Transfer mask. DETAILED DESCRIPTION

[0103] First, the process of arriving at the present invention will be described.

[0104] The inventors of the present invention have conducted in-depth research on the composition of a mask substrate for forming a pattern on a photoresist film with a line width smaller than the wavelength of the laser of a laser drawing device. The mask substrate for manufacturing a transfer mask has a light-shielding film on the substrate, and a photoresist film is formed on the light-shielding film. In addition, as the exposure wavelength of the laser (i.e., exposure light) used in the laser drawing device, light in a wavelength range of 350 nm or more and 520 nm or less is generally used. The inventors of the present invention did not change the film-forming conditions of the photoresist film but changed the film-forming conditions of the light-shielding film to manufacture a plurality of mask substrates. As the exposure light used in laser drawing, a plurality of lasers with different wavelengths are selected from the range of the above-mentioned wavelength range. Then, laser drawing is performed on the photoresist film of each mask substrate using the above-mentioned selected lasers. In addition, the photoresist film of each mask substrate after drawing is developed, and the formation accuracy of the pattern (photoresist pattern) formed on the photoresist film of each mask substrate is compared. As a result, it was found that even for photoresist films of the same material and thickness, the formation accuracy of the photoresist pattern would vary greatly depending on the characteristics of the light-shielding film.

[0105] The inventors of the present invention have further investigated the main factors that affect the accuracy of photoresist pattern formation. In order to improve the photosensitivity of the photoresist to a certain level within the wavelength range of 350 nm to 520 nm, the reflectivity of the light-shielding film must be below a certain level. However, when the light-shielding film is constructed as a single or multi-layer stack with a uniform composition in the thickness direction, while the reflectivity at specific wavelengths can be suppressed, it is difficult to maintain the reflectivity below a certain level across the wider wavelength range of 350 nm to 520 nm.

[0106] Therefore, the inventors of the present invention have studied making the light-shielding film a component tilted film in which the content of the metal element varies in the thickness direction. By becoming a component tilted film, the reflectivity can be suppressed in a wide range of wavelength regions. Among them, in the case of a component tilted film, it is advantageous to suppress the fluctuation amplitude of the reflectivity relative to the wavelength region, but it is extremely difficult to directly calculate the optical properties that should be satisfied. In order to solve this problem, the inventors of the present invention have studied making the component tilted film, i.e., the light-shielding film, simulated as a virtual double-layer structure. Specifically, for the light-shielding film on the substrate, the transmittance, surface reflectivity, and back reflectivity were measured respectively for the above-mentioned wavelength region by a spectroscopic ellipsometer. Then, a plurality of (at least two or more, more preferably three or more) wavelengths are selected from the range of the above-mentioned wavelength region, and the film thickness, refractive index, and attenuation coefficient of the upper and lower parts of the refractive index and attenuation coefficient that are consistent with the measured values ​​at each wavelength are obtained by simulation. It should be noted that the lower part obtained by the simulation mainly acts as a light-shielding portion, and the upper part mainly acts as an anti-reflection portion.

[0107] Therefore, the inventors of the present invention studied the optical properties that should be satisfied when a composition gradient film, i.e., a light shielding film, is divided into a light shielding portion and an anti-reflection portion. As a result, it was found that if the refractive index n of the anti-reflection portion with respect to light in the wavelength range of 350 nm to 520 nm is A is less than 2.1, and the phase difference generated by the light in the wavelength region when the light in the wavelength region passes through the anti-reflection part is greater than 28 degrees, then the reflectivity of the light-shielding film in the above-mentioned wavelength region can be suppressed to less than 15%, which can improve the formation accuracy of the photoresist pattern.

[0108] That is, the mask blank of the present invention is characterized in that a light-shielding film is provided on a substrate, the light-shielding film is composed of a material containing a metal element, the light-shielding film is a composition gradient film in which the content of the metal element varies in the thickness direction, and when the light-shielding film is divided into a light-shielding portion and an anti-reflection portion in sequence from the side closest to the substrate, the refractive index n of the anti-reflection portion with respect to light in a wavelength range of 350 nm to 520 nm is Ais 2.1 or less, and the phase difference produced by light in the wavelength range when light in the wavelength range passes through the anti-reflection portion is 28 degrees or more. It should be noted that, unless otherwise specified, the optical properties (reflectivity, refractive index, attenuation coefficient, phase difference, etc.) mentioned below are optical properties relative to light in the wavelength range of 350 nm to 520 nm.

[0109] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0110] Figure 1 It is a schematic diagram showing the structure of a mask blank in an embodiment of the present invention. Figure 1 The mask substrate 10 has a structure in which a light-shielding film 2 is sequentially laminated on a light-transmitting substrate 1. Here, the light-transmitting substrate 1 is generally a glass substrate. Glass substrates have excellent flatness and smoothness. When transferring a pattern onto a semiconductor substrate using a transfer mask, this allows for highly accurate pattern transfer without causing distortion of the transferred pattern.

[0111] The mask substrate 10 in this embodiment includes a light-shielding film 2. The light-shielding film 2 is made of a material containing a metal element. As the metal element, it is preferably formed by a material containing chromium. The material containing chromium may be a single substance of chromium, or it may contain chromium and an additive element. As such additive elements, oxygen and / or nitrogen are preferably used from the viewpoint of accelerating the dry etching speed. It should be noted that the light-shielding film 2 may also contain elements such as carbon, hydrogen, boron, indium, tin, and molybdenum. In addition, as long as the optical properties described in this specification are met, the light-shielding film 2 may also use materials other than chromium-based materials. For example, the material forming the light-shielding film 2 within the range that meets the required optical properties may use silicon-based materials, transition metal silicide-based materials, tantalum-based materials, etc.

[0112] The light-shielding film 2 preferably has a surface reflectivity of 15% or less, and further preferably 13% or less, with respect to light of the laser drawing wavelength (laser light of a wavelength within the aforementioned wavelength range) when the photoresist film is not laminated (i.e., when the upper surface of the light-shielding film 2 is exposed). Furthermore, the light-shielding film 2 preferably has a transmittance of 0.1% or less, and further preferably 0.05% or less, with respect to light of the laser drawing wavelength (laser light of a wavelength within the aforementioned wavelength range).

[0113] The method for forming the light shielding film 2 is not particularly limited, but is preferably formed using a continuous sputtering device, for example. Continuous sputtering makes it easy to produce a composition gradient film with strictly controlled optical properties (reflectivity, etc.).

[0114] The thickness of the above-mentioned light-shielding film 2 is preferably less than 150nm, more preferably less than 120nm. By making the film thickness thinner to some extent, the aspect ratio of the pattern (the ratio of pattern depth to pattern width) can be reduced, and the line width error caused by the macro loading effect and the micro loading effect can be reduced. Relative to the exposure light of more than 350nm and less than 520nm. The light-shielding film 2 in the present invention can also obtain the desired optical density (usually more than 3.0) when the film thickness is made into a thin film of less than 150nm. As for the lower limit of the film thickness of the light-shielding film 2, it can be thinned as long as the desired optical density can be obtained.

[0115] Furthermore, when the light-shielding film 2 is divided into a light-shielding portion and an anti-reflection portion as described above, while meeting the aforementioned thickness requirements, the thickness of the anti-reflection portion is preferably greater than 20 nm, more preferably at least 30 nm. By increasing the thickness of the anti-reflection portion to a certain extent, the fluctuation amplitude of the light-shielding film's surface reflectivity relative to light in the wavelength band of the laser drawing wavelength can be reduced. Furthermore, the thickness of the anti-reflection portion is preferably 60 nm or less, more preferably 50 nm or less. If the anti-reflection portion is thicker, the overall thickness of the light-shielding film 2 becomes significantly thicker. On the other hand, if the overall thickness of the light-shielding film 2 is not desired, the thickness of the light-shielding portion must be significantly thinner. In this case, there is the problem of insufficient optical density relative to the exposure light of the light-shielding film 2. Based on the above descriptions of the thickness of the light-shielding film 2 and the thickness of the anti-reflection portion, the thickness of the light-shielding portion is preferably at least 30 nm, more preferably at least 40 nm. Furthermore, the thickness of the light-shielding portion is preferably at most 90 nm, more preferably at most 80 nm.

[0116] Furthermore, when the light-shielding film 2 is divided into the light-shielding portion and the anti-reflection portion as described above, the phase difference φ between the light of the laser drawing wavelength generated by the light in the wavelength region and the light transmitted through the air at a distance equal to the thickness of the anti-reflection portion is 28 degrees or more. On the other hand, the phase difference of the anti-reflection portion is preferably 42 degrees or less, and more preferably 40 degrees or less. It should be noted that the phase difference φ [degrees] is calculated when the refractive index of the anti-reflection portion is n A The thickness of the anti-reflection part is d A [nm], when the wavelength of light is λ [nm], it can pass through φ = 360 × d A ×(n A -1) / λ. As shown in the above formula, in order to increase the phase difference φ of the anti-reflection part, it is necessary to increase the film thickness d A or refractive index n A However, in general, the refractive index n A Materials with large refractive index n A The tendency of the change range to be large with respect to the change of the wavelength of light is not preferable. Also, as mentioned above, it is not desirable to make the film thickness dA Thicken.

[0117] From the viewpoint of increasing the phase difference φ with a thinner film thickness of the anti-reflection portion, the refractive index n of the anti-reflection portion is A It is preferably 1.9 or more, more preferably 1.92 or more. A From the perspective of the change range with respect to the change in the wavelength of light, the refractive index n of the antireflection portion is A It is preferably 2.1 or less.

[0118] From the viewpoint of thinning the light-shielding film 2, the attenuation coefficient k of the anti-reflection portion is A It is preferably 0.7 or more, and more preferably 0.8 or more. In addition, from the viewpoint of reducing the surface reflectivity of the light-shielding film 2, the attenuation coefficient k of the anti-reflection portion is A It is preferably 1.0 or less.

[0119] Refractive index n of the light-shielding portion S It is preferably 1.9 or more. S It is preferably 2.8 or less.

[0120] From the perspective of thinning the light-shielding film 2, the attenuation coefficient k of the light-shielding portion is S It is preferably 2.8 or more, and more preferably 2.9 or more. In addition, from the viewpoint of reducing the back reflectivity of the light-shielding film 2, the attenuation coefficient k of the light-shielding portion is S It is preferably 3.5 or less, and more preferably 3.4 or less.

[0121] Furthermore, as the mask substrate 10, as described later Figure 2 As shown in (a), the photoresist film 3 may be in contact with the surface of the light-shielding film 2 to form a photoresist film. In order to obtain high resolution, the material of the photoresist film 3 is preferably formed by a material that is sensitive to exposure light in the wavelength region. There is no particular limitation on the photoresist material, and it may be a positive photoresist material, a negative photoresist material, a non-chemically amplified photoresist, or a chemically amplified photoresist. The refractive index n of the photoresist film 3 relative to light in the wavelength region of 350 nm or more and 520 nm or less is preferably 0. R The refractive index n of the photoresist film 3 with respect to light in the above wavelength range is 1.90 or less, and more preferably 1.80 or less. R It is preferably 1.50 or more, more preferably 1.60 or more, and even more preferably 1.67 or more. On the other hand, the attenuation coefficient k of the photoresist film 3 with respect to light in the above wavelength range is R It is preferably 0.01 or more, and more preferably 0.02 or more. Furthermore, the attenuation coefficient k of the photoresist film 3 with respect to light in the above wavelength range is RIt is preferably 0.06 or less, and more preferably 0.05 or less.

[0122] The reflectivity of the photoresist film 3 with respect to the laser drawing light is preferably 5% or less, and more preferably 4% or less. This is because reducing the reflectivity improves the photosensitivity of the photoresist film 3. It should be noted that, as long as the aforementioned reflectivity with respect to the laser drawing light is met, another layer may be present between the light-shielding film 2 and the photoresist film 3. For example, the other layer may function to improve the adhesion between the light-shielding film 2 and the photoresist film 3.

[0123] It should be noted that a phase shift film can be provided between the light-transmitting substrate 1 and the light-shielding film 2 in the mask substrate 10. The transfer mask (phase shift mask) manufactured from this mask substrate has a transfer pattern on the phase shift film, but the light-shielding film 2 is limited to a relatively sparse pattern, such as light-shielding stripes. However, even with this mask substrate, when a laser is used to expose and draw a pattern corresponding to the transfer pattern formed on the phase shift film on the photoresist film, the light-shielding film 2 exists directly beneath the photoresist film. Therefore, in order to form a transfer pattern on the photoresist film with a line width smaller than the wavelength of the laser light, the light-shielding film 2 is required to possess the aforementioned optical properties.

[0124] Next, the use of Figure 1 1 and 2. A method for manufacturing a transfer mask 20 using the mask substrate 10 shown in FIG. The method for manufacturing the transfer mask 20 using the mask substrate 10 includes: exposing the photoresist film 3 to a transfer pattern with exposure light having a wavelength range of 350 nm to 520 nm, followed by developing the photoresist film 3 to form a photoresist film (photoresist pattern 3 a) having the transfer pattern; and forming the transfer pattern on the light-shielding film 2 by etching using the photoresist pattern 3 a as a mask.

[0125] Figure 2 Schematic diagrams sequentially showing the steps of manufacturing the transfer mask 20 using the mask blank 10 .

[0126] Figure 2 (a) means that Figure 1 The photoresist film 3 is formed on the light shielding film 2 of the mask substrate 10.

[0127] then, Figure 2 (b) shows an exposure step of performing a desired pattern exposure on the photoresist film 3 formed on the mask substrate 10. The pattern exposure is performed using a laser drawing device or the like. The photoresist material used is a material having photosensitivity corresponding to the laser exposure light.

[0128] then, Figure 2(c) shows a development step of developing the photoresist film 3 according to a desired pattern exposure to form a photoresist pattern 3a. In this development step, after the desired pattern exposure is performed on the photoresist film 3 formed on the mask substrate 10, a developer is supplied to dissolve the soluble portions of the photoresist film in the developer, thereby forming the photoresist pattern 3a.

[0129] then, Figure 2 (d) represents an etching step for etching the light-shielding film 2 along the photoresist pattern 3a. Dry etching is preferably used in the present invention. In this etching step, the photoresist pattern 3a is used as a mask, and the exposed portions of the light-shielding film 2 where the photoresist pattern 3a is not formed are dissolved by dry etching. This forms a light-shielding film 2 (light-shielding pattern 2a) having the desired transfer pattern on the transparent substrate 1.

[0130] The process of forming the light-shielding pattern 2a on the light-shielding film 2 is preferably performed by dry etching using a chlorine-containing gas. By using the above-mentioned dry etching gas for dry etching, the dry etching speed can be increased, and the dry etching time can be shortened, so that the light-shielding pattern 2a with a good cross-sectional shape can be formed. As chlorine-based gases used for dry etching gases, for example, Cl2, SiCl4, HCl, CCl4, CHCl3, etc. can be cited. In addition to chlorine-based gases, dry etching gases composed of mixed gases containing oxygen and the like can also be used in dry etching.

[0131] Figure 2 (e) shows a transfer mask 20 obtained by peeling off and removing the remaining photoresist pattern 3a. In this way, a transfer mask on which the light-shielding pattern 2a having a good cross-sectional shape is formed with high precision can be realized.

[0132] It should be noted that the present invention is not limited to the embodiments described above. Specifically, it is not limited to mask substrates for so-called binary masks, in which a light-shielding film is formed on a translucent substrate. For example, the present invention may also be a mask substrate used in the manufacture of halftone phase shift masks or Levinson phase shift masks. In this case, the light-shielding film is formed on a halftone phase shift film on a translucent substrate. Since the combination of the halftone phase shift film and the light-shielding film can achieve the desired optical density (preferably 3.0 or greater), the optical density of the light-shielding film itself can be, for example, less than 3.0.

[0133] On the other hand, the transfer mask of the present invention has the same features as the mask substrate of the present invention. Specifically, the transfer mask of the present invention is characterized in that a light-shielding film 2 (light-shielding pattern 2a) having a transfer pattern is provided on a substrate 1, the light-shielding film 2 is composed of a material containing a metal element, and the light-shielding film 2 is a composition gradient film in which the content of the metal element varies in the thickness direction. When the light-shielding film is divided into a light-shielding portion and an anti-reflection portion in order from the side closest to the substrate, the refractive index n of the anti-reflection portion with respect to light in the wavelength range of 350 nm to 520 nm is A The phase difference of the light in the wavelength range is 28 degrees or more when the light in the wavelength range passes through the anti-reflection portion. Other matters related to the transfer mask of the present invention (substrate, light-shielding film, etc.) are the same as those of the mask substrate of the present invention.

[0134] In the mask substrate and transfer mask of the present invention, the light-shielding film 2 (or light-shielding pattern 2a) is preferably provided on the substrate 1 in a manner in contact with the main surface of the substrate 1, but is not limited thereto and may also be provided on the substrate 1 via other films. For example, in the case of a mask substrate in which a phase shift film and a light-shielding film are sequentially stacked on a light-transmitting substrate, the light-shielding film of the present invention may be applied to the light-shielding film and can also function effectively. The phase shift mask (transfer mask) manufactured from the mask substrate basically has a transfer pattern provided on the phase shift film, and no transfer pattern is provided on the light-shielding film. However, in the process of manufacturing the phase shift mask from the mask substrate, a photoresist film is provided on the light-shielding film. By using the light-shielding film of the present invention, when the pattern (transfer pattern) formed on the phase shift film is exposed on the photoresist film by a laser drawing device, the resolution of the photoresist pattern is greatly improved. As a result, a transfer pattern can be formed on the phase shift film with high precision.

[0135] That is, the phase shift mask (transfer mask) in this case is characterized in that it has a structure in which a phase shift film (phase shift pattern) having a transfer pattern and a light shielding film (light shielding pattern) having a pattern including light shielding bands are stacked on a substrate 1, the light shielding film is composed of a material containing a metal element, the light shielding film 2 is a composition gradient film in which the content of the metal element varies in the thickness direction, and when the light shielding film is divided into a light shielding portion and an anti-reflection portion in sequence from the side closest to the substrate, the refractive index n of the anti-reflection portion with respect to light in a wavelength range of 350 nm to 520 nm is A is 2.1 or less, and the phase difference generated by light in the above-mentioned wavelength range when light in the above-mentioned wavelength range passes through the antireflection portion is 28 degrees or more.

[0136] The method for manufacturing a semiconductor device of the present invention is characterized by comprising a step of exposing and transferring a transfer pattern onto a photoresist film on a semiconductor substrate using the transfer mask 20 manufactured by the method for manufacturing the transfer mask 20. Furthermore, the method for manufacturing a semiconductor device of the present invention is characterized by comprising a step of exposing and transferring a transfer pattern onto a photoresist film on a semiconductor substrate using the transfer mask 20. Therefore, even if the transfer mask 20 is placed in an exposure device and a transfer object (such as a photoresist film on a semiconductor wafer) is exposed and transferred by irradiating the transfer mask 20 with KrF excimer laser light or i-rays from the light-transmitting substrate 1 side of the transfer mask 20, a desired pattern can be transferred onto the transfer object with high precision.

[0137] [Example]

[0138] Hereinafter, embodiments of the present invention will be described in more detail with reference to examples.

[0139] (Example 1)

[0140] [Manufacturing of Mask Substrates]

[0141] A translucent substrate 1 made of synthetic quartz glass having a main surface size of approximately 152 mm x 152 mm and a thickness of approximately 6.35 mm is prepared. The end faces and main surface of the translucent substrate 1 are polished to a predetermined surface roughness, and then subjected to predetermined cleaning and drying processes.

[0142] A continuous sputtering device is used on the translucent substrate 1 to form a light-shielding film 2 having a component-inclined structure. Cr targets are respectively arranged in each space (sputtering chamber) that is continuously arranged relative to the substrate conveying direction in the continuous sputtering device. While the translucent substrate 1 is transported in each space, reactive sputtering is performed to form the light-shielding film 2. Specifically, first, Ar gas and N2 gas are used as sputtering gases to form the lower region of the light-shielding film 2 whose main component is CrN with a thickness of 16 nm. Then, Ar gas and CH4 gas are used as sputtering gases to form the middle region whose main component is CrC with a thickness of 63 nm. In addition, Ar gas and NO gas are used as sputtering gases to form the upper region whose main component is CrON with a thickness of 24 nm. Through the above process, a light-shielding film 2 with a thickness of 103 nm is formed on the translucent substrate 1.

[0143] The middle region of the light-shielding film 2 contains nitrogen (N) due to the N2 gas and NO gas used during film formation in the lower and upper regions. These lower, middle, and upper regions all contain Cr and N. The chromium content of the three regions of the light-shielding film 2 increases in the order of the upper region, lower region, and middle region. It should be noted that the average content of the lower region of the light-shielding film 2 is approximately 60 atomic percent chromium, approximately 34 atomic percent nitrogen, and approximately 6 atomic percent carbon. The average content of the middle region of the light-shielding film 2 is approximately 70 atomic percent chromium, approximately 10 atomic percent carbon, and approximately 20 atomic percent nitrogen. The average content of the upper region of the light-shielding film 2 is approximately 36 atomic percent chromium, approximately 40 atomic percent oxygen, approximately 22 atomic percent nitrogen, and approximately 2 atomic percent carbon.

[0144] Furthermore, the transmittance, surface reflectance R, and back reflectance of the light-shielding film 2 were measured using a spectroscopic ellipsometer (M-2000D manufactured by JA Woollam) for light in the wavelength range of 350 nm to 520 nm. Multiple wavelengths WL (355 nm, 403 nm, 413 nm, 442 nm, 488 nm, 500 nm, and 514 nm) were selected from the aforementioned wavelength range, and simulations were performed to determine the film thickness, refractive index, and attenuation coefficient of the light-shielding portion and the anti-reflection portion at each wavelength that corresponded to the measured refractive index and attenuation coefficient. The results showed that the thickness d of the anti-reflection portion was 1. A is 40nm, and the thickness of the light shielding part d S Furthermore, the refractive index n in the anti-reflection portion is calculated relative to the above-mentioned multiple wavelengths. A , attenuation coefficient k A , phase difference [degrees], and calculate the refractive index n in the light-shielding portion S , attenuation coefficient k S The results are shown in Table 1. It should be noted that the phase difference φ [degrees] is calculated by φ = 360 × d A ×(n A -1) / λ.

[0145] [Table 1]

[0146]

[0147] As shown in Table 1, the phase difference of the antireflection portion exceeded 28 degrees at any of the aforementioned wavelengths, and the surface reflectivity of the antireflection portion was less than 15%.

[0148] Next, a photoresist film 3 made of a positive photoresist (THMR-iP3500, manufactured by Tokyo Ohka Kogyo) was formed by spin coating to a target thickness of 290 nm in contact with the surface of the light shielding film 2, thereby manufacturing the mask blank 10 of Example 1.

[0149] [Manufacturing of transfer mask]

[0150] Next, the mask blank 10 of Example 1 was separately manufactured by the same steps, and the transfer mask 20 of Example 1 was manufactured by the following steps using this mask blank 10. Note that the reflectivity of the photoresist film 3 to exposure light of a wavelength of 413 nm in the separately manufactured mask blank 10 was 2.814%.

[0151] First, laser lithography is performed on the photoresist film 3 using exposure light having a wavelength of 413 nm, corresponding to the transfer pattern formed on the light-shielding film 2. The laser-lithography transfer pattern includes a pattern of lines and spaces with a line width of 300 nm. Then, a predetermined development process is performed on the laser-lithography-treated photoresist film 3 on the mask substrate 10 to form a photoresist pattern 3a. Observation of the formed photoresist pattern 3a using a CD-SEM (Critical Dimension-Scanning Electron Microscope; scanning electron microscope for feature dimension measurement) reveals that a pattern 3a having a line width smaller than the wavelength of the laser light from the laser lithography device can be formed on the photoresist film 3. Then, dry etching is performed on the light-shielding film 2 using the photoresist pattern 3a formed on the mask substrate 10 as a mask. A mixed gas of Cl2 and O2 (Cl2:O2 = 4:1) is used as the dry etching gas. After the pattern 2 a of the light shielding film 2 is formed on the substrate 1 by dry etching, the remaining photoresist pattern 3 a is peeled off using hot concentrated sulfuric acid to obtain the transfer mask 20 of Example 1.

[0152] The pattern 2a of the light-shielding film in the transfer mask 20 of Example 1 was observed using a CD-SEM. The positional deviation from the designed pattern remained within the acceptable range within the plane. Next, the transfer mask 20 of Example 1 was placed on the mask stage of an exposure apparatus using a KrF excimer laser as the exposure light source. The KrF exposure light was irradiated from the transparent substrate 1 side of the transfer mask 20, and the pattern was transferred onto the photoresist film on the semiconductor device. The transferred photoresist film was then subjected to prescribed processing to form a photoresist pattern, which was then observed using a CD-SEM. The results showed that the positional deviation from the designed pattern remained within the acceptable range within the plane. These results indicate that circuit patterns can be formed on semiconductor devices with high precision using this photoresist pattern as a mask.

[0153] (Comparative Example 1)

[0154] [Manufacturing of Mask Substrates]

[0155] The mask substrate of Comparative Example 1 was manufactured using the same steps as in Example 1 except for the light-shielding film. The light-shielding film of Comparative Example 1 was formed using the same continuous sputtering device as that used in Example 1, and also had a composition-inclined structure. Specifically, first, Ar gas and N2 gas were used as sputtering gases to form a lower region of the light-shielding film whose main component was CrN with a thickness of 41 nm. Then, Ar gas and CH4 gas were used as sputtering gases to form a middle region whose main component was CrC with a thickness of 18 nm. In addition, Ar gas and NO gas were used as sputtering gases to form an upper region whose main component was CrON with a thickness of 11 nm. Through the above steps, a light-shielding film was formed on a translucent substrate with a thickness of 70 nm, thereby manufacturing the mask substrate of Comparative Example 1. The middle region of the light-shielding film contains N (nitrogen) due to the N2 gas and NO gas used when forming the film in the lower and upper regions, and the above-mentioned lower region, middle region, and upper region all contain Cr and N. The chromium content of the three regions of the light-shielding film increases in the order of the upper region, the lower region, and the middle region.

[0156] It should be noted that the average content of the lower region of the light-shielding film in Comparative Example 1 was approximately 50 atomic percent chromium, approximately 45 atomic percent nitrogen, and approximately 5 atomic percent carbon. The average content of the middle region of the light-shielding film was approximately 42 atomic percent chromium, approximately 20 atomic percent oxygen, approximately 27 atomic percent nitrogen, and approximately 11 atomic percent carbon. The average content of the upper region of the light-shielding film was approximately 34 atomic percent chromium, approximately 44 atomic percent oxygen, approximately 19 atomic percent nitrogen, and approximately 3 atomic percent carbon.

[0157] As in Example 1, the transmittance, surface reflectance R, and back reflectance of the light-shielding film 2 were measured using a spectroscopic ellipsometer (M-2000D manufactured by JA Woollam) for light in the wavelength range of 350 nm to 520 nm. Next, multiple wavelengths WL (355 nm, 403 nm, 413 nm, 442 nm, 488 nm, 500 nm, and 514 nm) were selected from the wavelength range of 350 nm to 520 nm. Simulations were performed to determine the film thickness, refractive index, and attenuation coefficient of the light-shielding portion and the anti-reflection portion at each wavelength that corresponded to the measured refractive index and attenuation coefficient. The results showed that the thickness d of the anti-reflection portion was 1.34 nm. A is 20 nm, and the thickness of the light shielding portion d S Furthermore, the refractive index n in the anti-reflection portion is calculated relative to the above-mentioned multiple wavelengths. A , attenuation coefficient k A , phase difference [degrees], and calculate the refractive index n in the light-shielding portion S , attenuation coefficient k S The results are shown in Table 2.

[0158] [Table 2]

[0159]

[0160] As shown in Table 2, the phase difference of the antireflection portion is less than 28 degrees at any of the aforementioned wavelengths, and the surface reflectivity of the antireflection portion exceeds 15%.

[0161] Next, a photoresist film made of a positive photoresist was formed in contact with the surface of the light-shielding film by spin coating in the same manner as in Example 1 to a target film thickness of 290 nm, thereby manufacturing a mask blank of Comparative Example 1.

[0162] [Manufacturing of transfer mask]

[0163] Next, using the mask blank of Comparative Example 1, a transfer mask for Comparative Example 1 was manufactured using the same procedures as in Example 1. Inspection of the resulting photoresist pattern using a CD-SEM revealed that it was impossible to form a pattern on the photoresist film with a line width smaller than the wavelength of the laser beam used by the laser drawing apparatus. Consequently, even when dry etching was performed on the light-shielding film using the resulting photoresist pattern as a mask, as in Example 1, the desired light-shielding pattern could not be formed. Thus, the mask blank of Comparative Example 1 could not be used to manufacture a transfer mask having a light-shielding pattern with a line width smaller than the wavelength of the laser beam used by the laser drawing apparatus, and circuit patterns could not be formed on semiconductor devices.

[0164] (Comparative Example 2)

[0165] [Manufacturing of Mask Substrates]

[0166] The mask substrate of Comparative Example 2 was manufactured using the same steps as Example 1 except for the light-shielding film. The light-shielding film of Comparative Example 1 was formed using the same continuous sputtering device as that used in Example 1, and also had a composition-inclined structure. Specifically, Ar gas and N2 gas were used as sputtering gases to form a lower region of the light-shielding film with CrN as the main component at a thickness of 20 nm. Then, Ar gas and CH4 gas were used as sputtering gases to form a middle region with CrC as the main component at a thickness of 38 nm. In addition, Ar gas and NO gas were used as sputtering gases to form an upper region with CrON as the main component at a thickness of 15 nm. Through the above steps, a light-shielding film was formed on a translucent substrate with a thickness of 73 nm, thereby manufacturing the mask substrate of Comparative Example 1. The middle region of the light-shielding film contains N (nitrogen) due to the N2 gas and NO gas used when forming the film in the lower and upper regions, and the above-mentioned lower region, middle region, and upper region all contain Cr and N. The chromium content of the three regions of the light-shielding film increases in the order of the upper region, the lower region, and the middle region.

[0167] It should be noted that the average content of the lower region of the light-shielding film in Comparative Example 2 was approximately 61 atomic % chromium, approximately 32 atomic % nitrogen, and approximately 7 atomic % carbon. The average content of the middle region of the light-shielding film was approximately 71 atomic % chromium, approximately 11 atomic % carbon, and approximately 18 atomic % nitrogen. The average content of the upper region of the light-shielding film was approximately 37 atomic % chromium, approximately 41 atomic % oxygen, approximately 21 atomic % nitrogen, and approximately 1 atomic % carbon.

[0168] As in Example 1, the transmittance, surface reflectance R, and back reflectance of the light-shielding film 2 were measured using a spectroscopic ellipsometer (M-2000D manufactured by JA Woollam) for light in the wavelength range of 350 nm to 520 nm. Next, multiple wavelengths WL (355 nm, 403 nm, 413 nm, 442 nm, 488 nm, 500 nm, and 514 nm) were selected from the wavelength range of 350 nm to 520 nm. Simulations were performed to determine the film thickness, refractive index, and attenuation coefficient of the light-shielding portion and the anti-reflection portion at each wavelength that corresponded to the measured refractive index and attenuation coefficient. The results showed that the thickness d of the anti-reflection portion was 1.34 nm. A is 18nm, and the thickness of the light shielding part d S Furthermore, the refractive index n in the anti-reflection part is calculated with respect to the above-mentioned multiple wavelengths. A , attenuation coefficient k A , phase difference [degrees], and calculate the refractive index n in the light-shielding portion S , attenuation coefficient k S The results are shown in Table 3.

[0169] [Table 3]

[0170]

[0171] As shown in Table 3, the phase difference of the antireflection portion was less than 28 degrees at any of the aforementioned wavelengths, and the surface reflectivity of the antireflection portion exceeded 15%.

[0172] Next, a photoresist film composed of a positive photoresist was formed in contact with the surface of the light-shielding film by spin coating in the same manner as in Example 1 to a target film thickness of 290 nm, thereby producing a mask blank for Comparative Example 2. The reflectivity of the transfer pattern formation region of the photoresist film was measured using a reflectometer in the same procedure as in Example 1, exposed to light having a wavelength of 413 nm. The measured reflectivity was 1.494%.

[0173] [Manufacturing of transfer mask]

[0174] Next, using the mask blank of Comparative Example 2, a transfer mask of Comparative Example 2 was manufactured using the same steps as in Example 1. Inspection of the resulting photoresist pattern using a CD-SEM revealed that it was impossible to form a pattern on the photoresist film with a line width smaller than the wavelength of the laser beam used by the laser drawing apparatus. Consequently, even when dry etching was performed on the light-shielding film using the resulting photoresist pattern as a mask, as in Example 1, the desired light-shielding pattern could not be formed. Thus, the mask blank of Comparative Example 2 could not be used to manufacture a transfer mask having a light-shielding pattern with a line width smaller than the wavelength of the laser beam used by the laser drawing apparatus, and circuit patterns could not be formed on the semiconductor device.

[0175] and, Figure 3 This is a graph showing the relationship between the phase difference and the surface reflectivity in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention, as well as a curve calculated based on the relationship. Figure 3 As shown, in the wavelength range of 350 nm to 520 nm, if the phase difference of the antireflection portion is 28 degrees or more, the surface reflectivity of the antireflection portion can be suppressed to 15% or less.

[0176] On the other hand, multiple light-transmitting substrates different from Example 1 were prepared, and a light-shielding film was formed under the same film-forming conditions as in Example 1, with only the thickness of the photoresist film being varied. Similarly, multiple light-transmitting substrates different from Comparative Examples 1 and 2 were prepared, and a light-shielding film was formed under the same film-forming conditions as in Comparative Examples 1 and 2, with only the thickness of the photoresist film being varied. Then, laser drawing was performed at a predetermined exposure wavelength (413 nm) on the multiple mask substrates corresponding to Example 1, Comparative Examples 1, and 2, respectively, to produce transfer masks. As a result, the desired light-shielding pattern could be formed on the mask substrate corresponding to Example 1 at any film thickness, but the desired light-shielding pattern could not be formed on the mask substrates corresponding to Comparative Examples 1 and 2. Similarly, multiple light-transmitting substrates different from those in Comparative Examples 1 and 2 were prepared. A light-shielding film was formed using the same film-forming conditions as in Comparative Examples 1 and 2. The photoresist film thickness was varied and film-forming was performed on multiple mask substrates. Laser drawing was performed using varying exposure wavelengths to produce transfer masks. The results showed that the desired light-shielding pattern could be formed on the mask substrate corresponding to Example 1 at any exposure wavelength, but could not be formed on the mask substrates corresponding to Comparative Examples 1 and 2. Thus, even with varying the thickness and exposure wavelength of the photoresist film 3, the mask substrate 10 of Example 1 could form a pattern with a line width smaller than the wavelength of the laser light used in the laser drawing apparatus. On the other hand, with varying the thickness and exposure wavelength of the photoresist film, the mask substrate of Comparative Example 1 could not form a pattern with a line width smaller than the wavelength of the laser light used in the laser drawing apparatus.

[0177] As mentioned above, although the present invention has been described by taking the preferred embodiments as examples, the present invention is not limited to the above-mentioned embodiments.

Claims

1. A mask substrate comprising a light-shielding film on a substrate, characterized in that: The light-shielding film is made of a material containing a metal element. The light shielding film is a composition gradient film in which the content of the metal element varies in the thickness direction. When the light-shielding film is divided into the light-shielding portion and the anti-reflection portion in order from the side close to the substrate, The refractive index n of the antireflection portion with respect to light in the wavelength range of 350 nm to 520 nm is A is below 2.1, When light in the wavelength range passes through the anti-reflection portion, the phase difference between the light in the wavelength range generated by the light in the wavelength range and the light transmitted through the air at a distance equal to the thickness of the anti-reflection portion is 28 degrees or more. The antireflection portion has a thickness of 20 nm to 60 nm.

2. The mask substrate according to claim 1, wherein: The phase difference is less than 42 degrees.

3. The mask substrate according to claim 1 or 2, wherein: The refractive index n of the anti-reflection portion A It is above 1.

9.

4. The mask substrate according to claim 1 or 2, wherein: The refractive index n of the light shielding portion S It is above 1.

9.

5. The mask substrate according to claim 1 or 2, wherein: The refractive index n of the light shielding portion S Below 2.

8.

6. The mask substrate according to claim 1 or 2, wherein: The attenuation coefficient k of the light shielding portion for light in the wavelength range S It is above 2.

8.

7. The mask substrate according to claim 1 or 2, wherein: The attenuation coefficient k of the anti-reflection portion for light in the wavelength range A Below 1.

0.

8. The mask substrate according to claim 1 or 2, wherein: The light-shielding film is formed of a material containing chromium.

9. The mask substrate according to claim 1 or 2, wherein: The light-shielding film has an optical density of 3 or more with respect to exposure light.

10. The mask substrate according to claim 1 or 2, wherein: A photoresist film is formed in contact with a surface of the light-shielding film.

11. The mask substrate according to claim 10, wherein: The refractive index n of the photoresist film with respect to light in the wavelength range R Above 1.

50.

12. The mask substrate according to claim 10, wherein: The photoresist film is formed of a material that is photosensitized by exposure light in a wavelength range of 350 nm to 520 nm.

13. A transfer mask comprising a light-shielding film having a transfer pattern on a substrate, wherein: The light-shielding film is made of a material containing a metal element. The light shielding film is a composition gradient film in which the content of the metal element varies in the thickness direction. When the light-shielding film is divided into the light-shielding portion and the anti-reflection portion in order from the side close to the substrate, The refractive index n of the antireflection portion with respect to light in the wavelength range of 350 nm to 520 nm is A is below 2.1, When light in the wavelength range passes through the anti-reflection portion, the phase difference between the light in the wavelength range generated by the light in the wavelength range and the light transmitted through the air at a distance equal to the thickness of the anti-reflection portion is 28 degrees or more. The antireflection portion has a thickness of 20 nm to 60 nm.

14. The transfer mask according to claim 13, wherein The phase difference is less than 42 degrees.

15. The transfer mask according to claim 13 or 14, wherein: The refractive index n of the anti-reflection portion A It is above 1.

9.

16. The transfer mask according to claim 13 or 14, wherein: The refractive index n of the light shielding portion S It is above 1.

9.

17. The transfer mask according to claim 13 or 14, wherein: The refractive index n of the light shielding portion S Below 2.

8.

18. The transfer mask according to claim 13 or 14, wherein: The attenuation coefficient k of the light shielding portion for light in the wavelength range S It is above 2.

8.

19. The transfer mask according to claim 13 or 14, wherein: The attenuation coefficient k of the anti-reflection portion for light in the wavelength range A Below 1.

0.

20. The transfer mask according to claim 13 or 14, wherein: The light-shielding film is formed of a material containing chromium.

21. The transfer mask according to claim 13 or 14, wherein: The light-shielding film has an optical density of 3 or more with respect to exposure light.

22. A method for manufacturing a transfer mask, using the mask substrate according to any one of claims 10 to 12, characterized in that: have: After exposing the photoresist film to a transfer pattern by exposure light having a wavelength of 350 nm to 520 nm, the photoresist film is developed to form a photoresist film having the transfer pattern; A step of forming a transfer pattern on the light shielding film by etching using a photoresist film having the transfer pattern as a mask.

23. The method for manufacturing a transfer mask according to claim 22, wherein: In the step of forming the transfer pattern on the light-shielding film, the transfer pattern is formed on the light-shielding film by dry etching using a chlorine-containing gas.

24. A method for manufacturing a semiconductor device, characterized in that: The method comprises the step of transferring a transfer pattern by exposure to a photoresist film on a semiconductor substrate using the transfer mask according to any one of claims 13 to 21.

25. A method for manufacturing a semiconductor device, characterized in that: The method comprises the step of transferring a transfer pattern by exposure to a photoresist film on a semiconductor substrate using the transfer mask manufactured by the method for manufacturing a transfer mask according to claim 22 or 23.

Images