Method for manufacturing photomask, and photomask

Abstract

The present invention aims to provide a method for manufacturing a photomask and a photomask that can further realize high-resolution photomask compared to conventional methods for manufacturing photomasks. As a means to solve these problems, a first functional film (4) formed on a transparent substrate (2) and a second functional film (3) formed on the transparent substrate (2) so as to follow the edge of at least a portion of the first functional film (4) are provided, and a method for manufacturing a photomask having a pattern composed of a first region of the first functional film (4) and a second region of the second functional film (3) is provided, wherein in the functional film formation process, the first functional film (4) is formed in such a single-layer state that the second portion (4b) does not come into contact with each of the first portion (4a) and the third portion (4c).

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a photomask and a photomask. Background Technology

[0002] As a photolithography technique, a photomask is known to have two different types of functional parts in contact with each other, for example, a light-blocking part and a translucent part (a translucent part such as a phase shift part or a halftone part).

[0003] There are two types of photomasks of this kind: the photomasks described in FIGS. 5 to 7 of Patent Document 1 or Patent Document 2, and the photomasks described in FIGS. 1 to 4 of Patent Document 1. The former photomasks are provided with a second functional film and a first functional film formed on the second functional film such that at least a portion of the peripheral area of ​​the second functional film is exposed, and are provided with a first functional part (e.g., a light-blocking part) composed of a laminated portion of the first functional film and the second functional film, and a second functional part (e.g., a phase-shifting part) composed of the second functional film. The latter photomasks are provided with a first functional film and a second functional film formed to follow at least a portion of the edge of the first functional film, and are provided with a first functional part (e.g., a light-blocking part) composed of the first functional film and a second functional part (e.g., a phase-shifting part) composed of the second functional film. Prior art literature

[0004] Japanese Patent Publication No. 2003-5344 and Japanese Patent Publication No. 7-128840 The problem to be solved

[0005] However, when manufacturing any of the above photomasks, at least two drawing processes are required: a drawing process (exposure process) for a pattern constituting a first functional part and a drawing process for a pattern constituting a second functional part. And, if the drawing process is performed multiple times, misalignment of the pattern formed in each process is likely to occur.

[0006] One countermeasure is the use of alignment marks. During subsequent drawing processes, the alignment marks created during the first drawing process are read, and alignment is performed based on these marks. However, even with the use of alignment marks, it is impossible to completely eliminate pattern misalignment, and alignment misalignment still occurs. Consequently, as photomasks become more detailed, the impact of this is increasing.

[0007] Therefore, the present invention has been made in consideration of these circumstances, and aims to provide a method for manufacturing a photomask and a photomask that can further realize high-resolution photomask compared to conventional methods for manufacturing photomasks. means of solving the problem

[0008] A method for manufacturing a photomask according to the first present invention comprises a first functional film formed on a transparent substrate and a second functional film formed on a transparent substrate so as to be in contact along the edge of at least a portion of the first functional film, and a pattern comprising a first region of the first functional film and a second region of the second functional film, wherein, for a photomask blank having the second functional film formed on a transparent substrate, a portion corresponding to the second region of the second functional film is left and the other portions are removed, and a functional film forming process for forming a first functional film on the portion where the second functional film has been removed and on the second functional film, wherein in the first functional film, the portion corresponding to the first region is the first portion, the portion on the second functional film is the second portion, and the portion not of the first portion and the second portion is the third portion, such that the second portion is in a single-layer state that does not contact the first portion and the third portion, respectively, and at least among the first portion of the first functional film and the second portion of the first functional film A method for manufacturing a photomask comprising: a resist pattern forming process that forms a resist pattern that covers a portion including an edge of a first portion side and exposes at least a portion of another portion of a second portion of a first functional film and at least a portion of a third portion of a first functional film, and a removal process that removes the second portion and the third portion of a first functional film.

[0009] In addition, specific examples of such a configuration include the embodiments 1 and 2 described below.

[0010] A method for manufacturing a photomask according to the second present invention comprises a first functional film formed on a transparent substrate and a second functional film formed on a transparent substrate so as to be in contact along the edge of at least a portion of the first functional film, and a pattern comprising a first region of the first functional film and a second region of the second functional film, wherein, for a photomask blank having a second functional film and a third functional film laminated on a transparent substrate, a portion corresponding to the second region among the second functional film and the third functional film is left and the other portion is removed, and a functional film forming process for forming a first functional film on the portion where the second functional film and the third functional film have been removed and on the third functional film, wherein in the first functional film, the portion corresponding to the first region is the first portion, the portion on the third functional film is the second portion, and the portion not of the first portion and the second portion is the third portion, such that the second portion is in a single-layer state that does not contact the first portion and the third portion, respectively, and a first A method for manufacturing a photomask comprising: a resist pattern forming process for forming a resist pattern that covers a portion including an edge on the side of at least the first portion of a first functional film and a portion of the second portion of a first functional film, while exposing at least a portion of another portion of the second portion of a first functional film and at least a portion of the third portion of a first functional film; and a removal process for removing the second portion and the third portion of a first functional film and the third functional film.

[0011] In addition, specific examples of such a configuration include embodiments 3 and 4 described below.

[0012] A method for manufacturing a photomask according to the third invention comprises a first functional film formed on a transparent substrate, a second functional film formed on a transparent substrate so as to follow the edge of at least a portion of the first functional film, and a third functional film formed on the second functional film, and a pattern comprising a first region of the first functional film and a second region of the stacked portion of the second functional film and the third functional film, wherein for a photomask blank having the second functional film and the third functional film stacked on a transparent substrate, a portion corresponding to the second region among the second functional film and the third functional film is left and the other portion is removed, and a functional film forming process for forming the first functional film on the portion where the second functional film and the third functional film have been removed and on the third functional film, wherein in the first functional film, the portion corresponding to the first region is the first portion, the portion on the third functional film is the second portion, and the portion not of the first portion and the second portion is the third portion, such that the second portion does not come into contact with each of the first portion and the third portion. A method for manufacturing a photomask comprising: a functional film forming process for forming a first functional film so as to be in a monolayer state; a resist pattern forming process for forming a resist pattern that covers a portion including an edge on the side of at least the first portion of the first functional film and a portion of the second portion of the first functional film, while exposing at least a portion of another portion of the second portion of the first functional film and at least a portion of the third portion of the first functional film; and a removal process for removing the second portion and the third portion of the first functional film.

[0013] In addition, specific examples of such a configuration include embodiments 5 and 6 described below.

[0014] The photomask according to the first present invention comprises a first functional film formed on a transparent substrate and a second functional film formed on a transparent substrate so as to follow at least a portion of the edge of the first functional film, and is a photomask having a pattern composed of a first region of the first functional film and a second region of the second functional film, wherein the thickness of the first functional film is less than or equal to the thickness of the second functional film or greater than the thickness of the second functional film.

[0015] In addition, as specific examples of the configuration prior to "or" of this configuration, embodiments 1 and 2 described below may be cited, and as specific examples of the configuration following "or", embodiments 3 and 4 described below may be cited.

[0016] A photomask according to the second present invention comprises a first functional film formed on a transparent substrate, a second functional film formed on a transparent substrate so as to follow at least a portion of the edge of the first functional film, and a third functional film formed on the second functional film, and is a photomask having a pattern composed of a first region of the first functional film and a second region of the stacked portion of the second functional film and the third functional film, wherein the film thickness of the first functional film is greater than the film thickness of the second functional film and is also less than or equal to the total film thickness of the second functional film and the third functional film, or less than or equal to the film thickness of the second functional film.

[0017] In addition, as specific examples of the configuration preceding "or" of this configuration, embodiments 5 and 6 described below may be cited. Effects of the invention

[0018] According to the present invention, except for the drawing process where the positional precision of the pattern is not important, the drawing process is sufficient in a single step. For this reason, according to the present invention, there is no alignment misalignment, and thus, the high precision of the photomask can be further realized compared to the conventional method of manufacturing a photomask. Brief explanation of the drawing

[0019] FIG. 1(a) is an enlarged plan view of a key part of a photomask according to embodiment 1. FIG. 1(b) is a cross-sectional view along line AA of FIG. 1(a). Figures 2 (a) to (d) are explanatory diagrams of a method for manufacturing a photomask according to Embodiment 1. Figures 3 (a) to (d) are explanatory diagrams following Figure 2. Figures 4 (a) to (d) are explanatory diagrams following Figure 3. FIG. 5(a) is an enlarged plan view of a key part of a photomask according to embodiment 2. FIG. 5(b) is a cross-sectional view along line BB of FIG. 5(a). Figures 6 (a) to (d) are explanatory diagrams of a method for manufacturing a photomask according to embodiment 2. Figures 7 (a) to (d) are explanatory diagrams following Figure 6. Figures 8 (a) to (d) are explanatory diagrams following Figure 7. FIG. 9(a) is an enlarged plan view of a key part of a photomask according to embodiment 3. FIG. 9(b) is a cross-sectional view along the CC line of FIG. 9(a). Figures 10 (a) to (d) are explanatory diagrams of a method for manufacturing a photomask according to Embodiment 3. Figures 11 (a) to (c) are explanatory diagrams following Figure 10. Figures 12 (a) to (d) are explanatory diagrams following Figure 11. Figures 13 (a) to (c) are explanatory diagrams following Figure 12. FIG. 14 (a) is an enlarged plan view of a key part of a photomask according to embodiment 4. FIG. 14 (b) is a cross-sectional view along line DD of FIG. 14 (a). Figures 15 (a) to (d) are explanatory diagrams of a method for manufacturing a photomask according to embodiment 4. Figures 16 (a) to (c) are explanatory diagrams following Figure 15. Figures 17 (a) to (d) are explanatory diagrams following Figure 16. Figures 18 (a) to (c) are explanatory diagrams following Figure 17. FIG. 19 (a) is an enlarged plan view of a key part of a photomask according to embodiment 5. FIG. 19 (b) is a cross-sectional view along the EE line of FIG. 19 (a). FIG. 20(a) is an enlarged plan view of a key part of a photomask according to embodiment 6. FIG. 20(b) is a cross-sectional view along the FF line of FIG. 20(a). Figures (a-1) to (c-1) of FIG. 21 are explanatory diagrams of the effects of the method for manufacturing a photomask according to embodiments 1 and 2, taking into account the location of part X of FIG. 3 (c). Figures (a-2) to (c-2) of FIG. 21 are explanatory diagrams of comparative examples. Figures (a-1) to (c-1) of FIG. 22 are explanatory diagrams of the effects of the photomask manufacturing method according to embodiments 3 to 6, taking into account the location of the Y portion of FIG. 12 (a). Figures (a-2) to (c-2) of FIG. 22 are explanatory diagrams of comparative examples. Figures 23 (a) to (d) are enlarged plan views of key parts of photomasks according to other embodiments 1 to 4. Specific details for implementing the invention

[0020] <Composition of photomask according to Embodiment 1>

[0021] As shown in FIG. 1, the photomask (1) is a three-gradation multi-gradation photomask having a transparent portion (white portion) (10), a light-blocking portion (black portion) (11), and a semi-transparent portion (hatched portion) (12). The transparent portion (10) is composed of a transparent substrate (2). The light-blocking portion (11) is composed of a light-blocking film (4) as a first functional film. The semi-transparent portion (12) is composed of a semi-transparent film (3) as a second functional film. That is, the exposed portion of the transparent substrate (2) where the semi-transparent film (3) and the light-blocking film (4) are not formed becomes the transparent portion (10), the portion where the light-blocking film (4) is formed on the transparent substrate (2) becomes the light-blocking portion (11), and the portion where the semi-transparent film (3) is formed on the transparent substrate (2) becomes the semi-transparent portion (12).

[0022] The light-blocking portion (11) and the semi-transparent portion (12) constitute the pattern of the photomask (1). The pattern consists of a first region (11) and a second region (12). The first region (11) is a single layer of the light-blocking film (4) and functions as the light-blocking portion (11). The second region (12) is a single layer of the semi-transparent film (3) and functions as the semi-transparent portion (12).

[0023] In this embodiment, lines (light-blocking portions (11)) with a width in the μm range and spaces (transmitting portions (10)) with a width in the μm range are parallel (in some cases, they are repeated alternately), and the pattern of the photomask (1) is a line and space pattern. As an example, the pattern is used as a pattern for forming source and drain electrodes in a substrate to be transferred, which is manufactured by photolithography using the photomask (1). In this case, the transmitting portion (10) functions as a channel portion, the light-blocking portion (11) functions as an electrode portion, and the semi-transmitting portion (12) functions as a rim portion of the light-blocking portion (11).

[0024] Providing a rim portion (12) is a measure to improve process margin on the panel side. For example, a rim portion (12) is provided to make the edge of the resist pattern corresponding to the source and drain electrodes on the substrate to be transferred steeply sloped. The width of the rim portion (12) is, for example, 0.1 μm or more or 0.5 μm or more, and is in the range of 2.0 μm or less or 3.0 μm or less. Preferably, it is in the range of 0.5 μm or more or 2.0 μm or less. Also, the width of the rim portion (12) is not limited to these. In addition, the rim portion (12) is not limited to the source and drain electrodes, and can be provided to refine layers of transparent electrodes, indium oxide (ITO) films, source wiring, or gate wiring in response to the request for high-resolution photomask.

[0025] The transparent substrate (2) is a substrate such as synthetic quartz glass. The transparent substrate (2) has a transmittance of 95% or more for a representative wavelength (e.g., i-line, h-line, or g-line) included in the exposure light used in the photolithography exposure process. In addition, the exposure light may be, for example, i-line, h-line, or g-line, or a mixed light containing at least two of these lights. Alternatively, the exposure light may have a wavelength band shifted or expanded toward the short wavelength side and / or the long wavelength side with respect to these lights. As an example, the wavelength band of the exposure light may be applied as expanded from a broadband of 365 nm to 436 nm to 300 nm to 450 nm. However, the exposure light is not limited to these.

[0026] The semi-transparent film (3) is a type of functional film that has the function of adjusting the optical characteristics of the exposure light, and is a functional film that has the function of changing the phase of the exposure light, that is, a phase shift film. The phase shift film is set so that the amount of phase shift for a representative wavelength is approximately 180°. Approximately 180° means a value within the range of 180±20°, and more preferably, a value within the range of 180°±10°. In addition, the phase shift film is set so that, with respect to a representative wavelength included in the exposure light, it has a transmittance lower than that of the transparent substrate (2) and higher than that of the light-blocking film (4), and has a transmittance within the range of 2% or more and 90% or less with respect to the representative wavelength.

[0027] The semipermeable membrane (3) is made of a metal silicide-based material among known materials such as Cr or Cr-based compounds (Cr oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), Ni or Ni-based compounds (Ni oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), Ti or Ti-based compounds (Ti oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), Si-based compounds (Si oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), Zr or Zr-based compounds (Zr oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), and metal silicide-based compounds (molybdenum silicide, tungsten silicide, tantalum silicide, zirconium silicide, or their nitrides, oxynitrides, etc., hereinafter the same). In this embodiment, the semipermeable membrane (3) is made of a molybdenum silicide compound.

[0028] The light-blocking film (4) is a type of functional film having the function of adjusting the optical characteristics of the exposure light, and is a functional film having the function of blocking the exposure light. The light-blocking film (4) has a transmittance of 1% or less for a representative wavelength included in the exposure light. Alternatively, the optical density (OD value) in the light-blocking part (11) must satisfy 2.7 or more. As an example, the light-blocking film (4) is a laminated structure having a first film layer and a second film layer. The first film layer is composed of a metal film and is intended for light-blocking properties. The second film layer is composed of a metal oxide film and is intended for reflection suppression. In this case, even if the transmittance of the first film layer is higher than 1%, the laminated transmittance of the first film layer and the second film layer must be 1% or less. In addition, if the second film layer is formed below the first film layer, scattered light during transfer is prevented, allowing the phase effect to be fully exerted and further realization of high-resolution photomask is possible. However, the second film layer may be formed on the first film layer.

[0029] The light-blocking film (4) is made of a Cr-based material among known materials such as Cr or Cr-based compounds, Ni or Ni-based compounds, Ti or Ti-based compounds, Si-based compounds, Zr or Zr-based compounds, and metal silicide-based compounds. In this embodiment, the light-blocking film (4) is made of a Cr-based compound. Furthermore, the reason for using a Cr-based compound is that a thin film made of a Cr-based compound has desirable resistance to cleaning treatment performed when there is contamination, foreign matter, etc. attached to the photomask during the manufacturing process of the transfer substrate.

[0030] The semi-permeable film (3) and the light-blocking film (4) have different etching characteristics as their materials are different. That is, the semi-permeable film (3) has etching selectivity with respect to the light-blocking film (4), and the light-blocking film (4) has etching selectivity with respect to the semi-permeable film (3).

[0031] The semi-transparent film (3) and the light-blocking film (4) are formed so as to be aligned on the same plane on the transparent substrate (2) with their edges in contact with each other. The film thickness of the light-blocking film (4) is less than or equal to the film thickness of the semi-transparent film (3). For example, the (average) film thickness of the light-blocking film (4) is 0.09 μm (900 Å), and the (average) film thickness of the semi-transparent film (3) is 0.12 μm (1200 Å). Of course, the width of the semi-transparent film (3) is smaller than the width of the light-blocking film (4).

[0032] <Method for manufacturing a photomask according to Embodiment 1>

[0033] The method for manufacturing the photomask (1) according to embodiment 1 is as shown in FIGS. 2 to 4, and

[0034] i) Photomask blank preparation process (Process 1)

[0035] ii) First resist film formation process (Process 2)

[0036] iii) First drawing process (Process 3)

[0037] iv) First development process (Process 4)

[0038] v) Semipermeable film etching process (Process 5)

[0039] vi) First resist film removal process (Process 6)

[0040] vii) Shading film formation process (Process 7)

[0041] viii) Secondary resist film formation process (Process 8)

[0042] ix) Second drawing process (Process 9)

[0043] x) Second development process (Process 10)

[0044] xi) Light-blocking film etching process (Process 11)

[0045] xii) Second resist film removal process (Process 12)

[0046] Equipped with

[0047] Additionally, the process from the first resist film formation process to the first resist film removal process, and the process from the second resist film formation process to the second resist film removal process are each referred to as patterning processes. In the former patterning process, the semi-transparent film (3) of the photomask blank is patterned, and in the latter patterning process, the light-blocking film (4) newly formed during the intermediate process is patterned.

[0048] In the photomask blank preparation process, a photomask blank is prepared as shown in FIG. 2(a). The photomask blank is formed by a semi-transparent film (3) on a transparent substrate (2). The semi-transparent film (3) is formed by a physical vapor deposition (PVD) method, such as sputtering or deposition.

[0049] In the first resist film formation process, as shown in FIG. 2(b), a resist is uniformly applied onto a semipermeable film (3) to form a resist film (5). The resist is applied by a coating method, a spray method, etc. The resist may be of a positive type or a negative type, but in this example, it is of a positive type.

[0050] In the first drawing process, as shown in (c) of FIG. 2, exposure light is irradiated onto the resist film (5) using an electron beam or laser of a drawing device to draw a first resist pattern. At this time, two regions with different exposure amounts are formed on the resist film (5). The first region (5a) is an unexposed region. The second region (5b) is an area exposed to a predetermined amount of exposure. In the case of a negative type resist, the relationship of exposure amounts is opposite to that of a positive type. In addition, in the first drawing process, in addition to drawing the resist pattern, a mark (alignment mark) is drawn to align the position of the drawing in the second drawing process. Although not shown, the alignment mark is formed at, for example, three or four appropriate locations in the outer area surrounding the resist pattern.

[0051] In the first development process, as shown in (d) of FIG. 2, an unnecessary resist film (5) (second region (5b)) is removed by development to form a first resist pattern. The first resist pattern is a pattern corresponding to the second region (12) of the pattern of the photomask (1). Development is performed by the immersion method, spin method, paddle method, spray method, etc. Also, the first resist film formation process, the first drawing process, and the first development process are combined and referred to as the first resist pattern formation process.

[0052] In the semi-transparent film etching process, as shown in FIG. 3 (a), the first resist pattern is used as a mask for etching treatment, and the exposed portion of the semi-transparent film (3) is removed by etching. Etching can be either dry etching or wet etching, but wet etching is preferred in the case of a large-sized photomask. An etchant or an etching gas is used. Regardless of which etchant is used, an etchant having etching selectivity for the semi-transparent film (3) is used. Also, during etching, the semi-transparent film (3) undergoes side etching. This is why the position of the edge of the semi-transparent film (3) in the drawing is offset inward compared to the position of the edge of the first resist pattern. However, depending on the film thickness of the semi-transparent film (3), the material of the semi-transparent film (3), or the type of etchant, side etching may not occur. In addition, the etching rate of the semipermeable film (3) can be adjusted by adjusting the concentration, temperature, etching time, and other conditions for using the etchant. Also, by adjusting the etching rate of the semipermeable film (3), it becomes possible to adjust it to the desired offset dimension.

[0053] In the first resist film removal process, the remaining resist film (5) (first resist pattern) is removed as shown in Fig. 3(b). The removal of the resist film (5) is performed by an ashing method, an immersion method, etc. As a result, a second region (12) of the pattern of the photomask (1) is formed on the transparent substrate (2).

[0054] In the process of forming a light-shielding film, a light-shielding film (4) is formed to cover the entire surface as shown in (c) of FIG. 3. That is, a light-shielding film (4) is formed on the exposed portion of the transparent substrate (2) from which the semi-transparent film (3) has been removed, and on the semi-transparent film (3). The light-shielding film (4) is formed such that the film thickness t4 of the light-shielding film (4) is equal to or smaller than the film thickness t3 of the semi-transparent film (3). That is, the light-shielding film (4) is formed such that the film thickness t4 of the light-shielding film (4) is less than or equal to the film thickness t3 of the semi-transparent film (3). Accordingly, the light-blocking film (4) is provided with a first portion (4a) corresponding to a first region (11) of the pattern of the photomask (1), a second portion (4b) on the semi-transparent film (3), and a third portion (4c) that is not the first portion (4a) and the second portion (4b), and is formed in a single-layer state such that the second portion (4b) does not come into contact with or is not connected to each of the first portion (4a) and the third portion (4c). The light-blocking film (4) is formed by a physical vapor phase growth method such as sputtering or deposition.

[0055] In the second resist film formation process, as shown in (d) of FIG. 3, a resist is applied on the light-shielding film (4) to form a resist film (5). The method itself is the same as the first resist film formation process.

[0056] In the second drawing process, a second resist pattern is drawn on the resist film (5) as shown in FIG. 4 (a). The method itself is the same as the first drawing process, and the drawing device is the same device as the drawing device used in the first drawing process. In the second drawing process, the drawing device detects the alignment mark formed in the preceding process and performs position alignment of the transparent substrate (2).

[0057] However, the second resist pattern only needs to cover and protect the necessary areas, so positional precision is not required. For this reason, strict alignment is not necessary in the second drawing process.

[0058] Even so, alignment misalignment inevitably occurs during the second drawing process. Therefore, in the second drawing process, a second resist pattern is established that takes into account the alignment misalignment. Specifically, the second resist pattern is designed to overlap the laminated portion of the semi-transparent film (3) and the light-blocking film (4) by a predetermined amount of wrap from the edge of the laminated portion. The amount of wrap is, for example, a value of 0.3㎛ or more and 0.5㎛ or less.

[0059] In the second development process, as shown in FIG. 4(b), an unnecessary resist film (5) (second region (5b)) is removed by development to form a second resist pattern. The second resist pattern is a pattern that covers the portion including the edge on the side of at least the first portion (4a) of the first portion (4a) and the second portion (4b) of the light-shielding film (4), while exposing at least a portion of the other portion of the second portion (4b) of the light-shielding film (4) and at least a portion of the third portion (4c) of the light-shielding film (4). The method itself is the same as the first development process. Also, the second resist film formation process, the second drawing process, and the second development process are combined and referred to as the second resist pattern formation process.

[0060] In the light-shielding film etching process, as shown in FIG. 4(c), the exposed portions of the light-shielding film (4), namely the second portion (4b) and the third portion (4c) of the light-shielding film (4), are removed by etching. The first portion (4a) of the light-shielding film (4) is not in contact with the second portion (4b) and is separated from the second portion (4b). Furthermore, it is not etched because it is completely covered by the second resist pattern and the semi-transparent film (3), making it an unexposed portion. Through the light-shielding film etching process, not only the third portion (4c) of the light-shielding film (4) but also the second portion (4b) of the light-shielding film (4) are finally side-etched and completely removed. Etching can be either dry etching or wet etching, but wet etching is preferred for large-sized photomasks. An etchant such as an etching solution or an etching gas is used. Any etchant that has etching selectivity for the light-shielding film (4) (an etchant that does not etch the semi-permeable film (3)) is used. Also, the etching rate of the light-shielding film (4) can be adjusted by adjusting the concentration of the etchant, temperature, etching time, and other conditions for using the etchant.

[0061] In the second resist film removal process, the remaining resist film (5) (second resist pattern) is removed as shown in (d) of FIG. 4. The method itself is the same as the first resist film removal process. As a result, a first region (11) of the pattern of the photomask (1) is formed on the transparent substrate (2), and combined with the previously formed second region (12), the entire pattern of the photomask (1) is formed.

[0062] <Composition of photomask according to Embodiment 2>

[0063] As shown in FIG. 5, the pattern of the photomask (1) according to embodiment 2 is a hole pattern having holes (transmittance portions (10)) of μm size (in some cases, these are arranged in a one-dimensional or two-dimensional array with a predetermined spacing). Accordingly, in the photomask (1) according to embodiment 2, a hole-shaped transmittance portion (10) is formed, and a second region (12) is formed around it. The configuration of the photomask (1) according to embodiment 2 is substantially the same as the configuration of the photomask (1) according to embodiment 1, except that the shape of the pattern is different. Therefore, the description of the configuration of the photomask (1) according to embodiment 2 is omitted as it is identical to the description above.

[0064] <Method for manufacturing a photomask according to Embodiment 2>

[0065] The method for manufacturing the photomask (1) according to embodiment 2 is as shown in FIGS. 6 to 8, and

[0066] i) Photomask blank preparation process (Process 1)

[0067] ii) First resist film formation process (Process 2)

[0068] iii) First drawing process (Process 3)

[0069] iv) First development process (Process 4)

[0070] v) Semipermeable film etching process (Process 5)

[0071] vi) First resist film removal process (Process 6)

[0072] vii) Shading film formation process (Process 7)

[0073] viii) Secondary resist film formation process (Process 8)

[0074] ix) Second drawing process (Process 9)

[0075] x) Second development process (Process 10)

[0076] xi) Light-blocking film etching process (Process 11)

[0077] xii) Second resist film removal process (Process 12)

[0078] Equipped with

[0079] The method of manufacturing the photomask (1) according to Embodiment 2 is substantially the same as the method of manufacturing the photomask (1) according to Embodiment 1, except that the shape of the pattern is different. Therefore, the description of the method of manufacturing the photomask (1) according to Embodiment 2 is omitted as it is identical to the description above.

[0080] <Composition of photomask according to embodiment 3>

[0081] As shown in FIG. 9, the configuration of the photomask (1) according to Embodiment 3 is substantially the same as the configuration of the photomask (1) according to Embodiment 1, except that the film thickness of the light-blocking film (4) is greater than the film thickness of the semi-transparent film (3). Therefore, the description of the configuration of the photomask (1) according to Embodiment 3 is omitted as it is identical to the description above.

[0082] <Method for manufacturing a photomask according to Embodiment 3>

[0083] The method for manufacturing the photomask (1) according to embodiment 3 is as shown in FIGS. 10 to 13, and

[0084] i) Photomask blank preparation process (Process 1)

[0085] ii) First resist film formation process (Process 2)

[0086] iii) First drawing process (Process 3)

[0087] iv) First development process (Process 4)

[0088] v) 1st etching stopper film etching process (Process 5)

[0089] vi) Semipermeable film etching process (Process 6)

[0090] vii) 1st resist film removal process (Process 7)

[0091] viii) Shading film formation process (Process 8)

[0092] ix) Second resist film formation process (Process 9)

[0093] x) Second drawing process (Process 10)

[0094] xi) Second development process (Process 11)

[0095] xii) Light-blocking film etching process (Process 12)

[0096] xiii) Second etching stopper film etching process (Process 13)

[0097] xiv) Second resist film removal process (Process 14)

[0098] Equipped with

[0099] The method of manufacturing the photomask (1) according to Embodiment 3 is substantially the same as the method of manufacturing the photomask (1) according to Embodiment 1, except that the photomask blank has an etching stopper film (6) as a third functional film and two etching stopper film etching processes are added. Therefore, the description of the method of manufacturing the photomask (1) according to Embodiment 3 is omitted as it is identical to the description above, except for the differences described below.

[0100] In the photomask blank preparation process, as shown in FIG. 10 (a), a semi-transparent film (3) is formed on a transparent substrate (2), and an etching stopper film (6) is formed on the semi-transparent film (3), and accordingly, the semi-transparent film (3) and the etching stopper film (6) are laminated on the transparent substrate (2). The semi-transparent film (3) and the etching stopper film (6) are each formed by a physical vapor phase growth method such as sputtering or deposition.

[0101] The etching stopper film (6) is a film interposed between the semi-transparent film (3) and the light-blocking film (4) to block both films (3, 4). The etching stopper film (6) is a type of functional film that has the function of adjusting the optical characteristics of the exposure light, is a type of semi-transparent film, and is a functional film that has the function of adjusting the transmittance of the exposure light, that is, a halftone film. With respect to a representative wavelength included in the exposure light, the halftone film has a transmittance lower than that of the transparent substrate (2) and higher than that of the light-blocking film (4), and is set to have a transmittance within the range of 10% or more and 75% or less with respect to the representative wavelength. In addition, the halftone film is set so that the amount of phase shift with respect to the representative wavelength is less than 20°, more preferably less than 5°. In addition, the halftone film may be a semi-transparent metal film that improves the transmittance distribution within the plane of the photomask by adjusting the nitrogen content. In addition, it is also possible to change the optical concentration (OD value) in the semi-transparent portion (12) by including other elements in the halftone film.

[0102] The etching stopper film (6) is made of a suitable material among known materials such as Cr or Cr-based compounds, Ni or Ni-based compounds, Ti or Ti-based compounds, Si-based compounds, Zr or Zr-based compounds, and metal silicide-based compounds.

[0103] The semi-permeable film (3), the etching stopper film (6), and the light-blocking film (4) each have different etching characteristics as their materials are different. That is, the semi-permeable film (3) has etching selectivity for each of the etching stopper film (6) and the light-blocking film (4), the etching stopper film (6) has etching selectivity for each of the semi-permeable film (3) and the light-blocking film (4), and the light-blocking film (4) has etching selectivity for each of the semi-permeable film (3) and the etching stopper film (6).

[0104] The film thickness of the etching stopper film (6) is smaller than the film thickness of the semipermeable film (3). For example, the film thickness of the etching stopper film (6) is 0.01 μm (100 Å) or more and 0.10 μm (1000 Å) or less. In order to perform etching preferably, a range of 0.03 μm (300 Å) or more and 0.05 μm (500 Å) or less is preferred. Also, the film thickness is not limited to these.

[0105] In the first etching stopper film etching process, as shown in FIG. 11 (a), the first resist pattern is used as a mask for etching treatment, and the exposed portion of the etching stopper film (6) is removed by etching. Etching can be either dry etching or wet etching, but wet etching is preferred in the case of a large-sized photomask. An etching solution or an etching gas is used as the etchant. Regardless of which etchant is used, an etchant having etching selectivity for the etching stopper film (6) (an etchant that does not etch the semi-transparent film (3)) is used. Also, in the etching process, the etching stopper film (6) undergoes side etching. This is why the position of the edge of the etching stopper film (6) in the drawing is offset inward compared to the position of the edge of the first resist pattern. However, depending on the thickness of the etching stopper film (6), the material of the etching stopper film (6), or the type of etchant, side etching may not occur. Also, the etching rate of the etching stopper film (6) can be adjusted by adjusting the concentration, temperature, etching time, and other conditions for using the etchant. And, by adjusting the etching rate of the etching stopper film (6), it becomes possible to adjust it to the desired offset dimension.

[0106] In the process of forming a light-shielding film, a light-shielding film (4) is formed to cover the entire surface as shown in FIG. 12 (a). That is, a light-shielding film (4) is formed on the exposed portion of the transparent substrate (2) from which the semi-transparent film (3) and the etching stopper film (6) have been removed, and on the etching stopper film (6). The light-shielding film (4) is formed such that the film thickness t4 of the light-shielding film (4) is equal to the total film thickness t3+t6 of the semi-transparent film (3) and the etching stopper film (6), or is smaller than the total film thickness t3+t6 of the semi-transparent film (3) and the etching stopper film (6). That is, the light-shielding film (4) is formed such that the film thickness t4 of the light-shielding film (4) is less than or equal to the total film thickness t3+t6 of the semi-transparent film (3) and the etching stopper film (6). Accordingly, the light-shielding film (4) is provided with a first portion (4a) corresponding to a first region (11) of the pattern of the photomask (1), a second portion (4b) on the etching stopper film (6), and a third portion (4c) that is not the first portion (4a) and the second portion (4b), and is formed such that the second portion (4b) is not in contact with or connected to each of the first portion (4a) and the third portion (4c), and is formed in a single-layer state. The light-shielding film (4) is formed by a physical vapor phase growth method such as sputtering or deposition.

[0107] In the second etching stopper film etching process, the etching stopper film (6) is removed by etching as shown in (b) of FIG. 13. The method itself is the same as the first etching stopper film etching process. By the second etching stopper film etching process, the etching stopper film (6) is finally side-etched and completely removed. Also, in the previous process (light-shielding film etching process), depending on the relationship of the etching rate of the light-shielding film (4), the second part (4b) of the light-shielding film (4) is not completely removed by side-etching, and a part (partially the inner part of the undercut portion of the second resist pattern) may remain on the etching stopper film (6). Even in such cases, the second part (4b) of the remaining light-blocking film (4) is removed together with the etching stopper film (6) in the second etching stopper film etching process (removal by lift-off), so there is no problem.

[0108] Among the descriptions of the method for manufacturing a photomask (1) according to embodiment 1,

[0109] i) In the first resist film formation process, the substrate of the "semipermeable film (3)" is replaced with the "etching stopper film (6)", and

[0110] ii) In the semipermeable film etching process, the description of "first resist pattern" in "using the first resist pattern as a mask for etching treatment" is replaced with "etching stopper film (6)", and the description of "etchant having etching selectivity for the semipermeable film (3)" is replaced with "etchant having etching selectivity for the semipermeable film (3) (etchant that does not etch the etching stopper film (6))",

[0111] iii) In the light-shielding film etching process, the description “completely covered with the second resist pattern and the semi-transparent film (3)” is replaced with “completely covered with the second resist pattern, the semi-transparent film (3), and the etching stopper film (6),” and the description “etchant having etching selectivity for the light-shielding film (4) (etchant that does not etch the semi-transparent film (3))” is replaced with “etchant having etching selectivity for the light-shielding film (4) (etchant that does not etch the semi-transparent film (3) and the etching stopper film (6)),”

[0112] iv) Process numbers and drawing numbers shall be read by appropriately replacing them with their corresponding numbers.

[0113] <Composition of photomask according to embodiment 4>

[0114] As shown in FIG. 14, the configuration of the photomask (1) according to Embodiment 4 is substantially the same as the configuration of the photomask (1) according to Embodiment 2, except that the film thickness of the light-blocking film (4) is greater than the film thickness of the semi-transparent film (3). In addition, the configuration of the photomask (1) according to Embodiment 4 is substantially the same as the configuration of the photomask (1) according to Embodiment 3, except that the shape of the pattern is different. Therefore, the description of the configuration of the photomask (1) according to Embodiment 4 is omitted as it is identical to the description above.

[0115] <Method for manufacturing a photomask according to Embodiment 4>

[0116] The method for manufacturing the photomask (1) according to embodiment 4 is as shown in FIGS. 15 to 18, and

[0117] i) Photomask blank preparation process (Process 1)

[0118] ii) First resist film formation process (Process 2)

[0119] iii) First drawing process (Process 3)

[0120] iv) First development process (Process 4)

[0121] v) 1st etching stopper film etching process (Process 5)

[0122] vi) Semipermeable film etching process (Process 6)

[0123] vii) 1st resist film removal process (Process 7)

[0124] viii) Shading film formation process (Process 8)

[0125] ix) Second resist film formation process (Process 9)

[0126] x) Second drawing process (Process 10)

[0127] xi) Second development process (Process 11)

[0128] xii) Light-blocking film etching process (Process 12)

[0129] xiii) Second etching stopper film etching process (Process 13)

[0130] xiv) Second resist film removal process (Process 14)

[0131] Equipped with

[0132] The method of manufacturing the photomask (1) according to Embodiment 4 is substantially the same as the method of manufacturing the photomask (1) according to Embodiment 2, except that the photomask blank has an etching stopper film (6) as a third functional film and two etching stopper film etching processes are added. In addition, the method of manufacturing the photomask (1) according to Embodiment 4 is substantially the same as the method of manufacturing the photomask (1) according to Embodiment 3, except that the shape of the pattern is different. Therefore, the description of the method of manufacturing the photomask (1) according to Embodiment 4 is omitted as it is identical to the description above.

[0133] <Composition of photomask according to embodiment 5>

[0134] As shown in FIG. 19, the pattern of the photomask (1) according to embodiment 5 is a line and space pattern in which an etching stopper film (upper layer) (6) is formed to overlap a semi-transparent film (lower layer) (3), the semi-transparent portion (12) is composed of the lower layer (3) and the upper layer (6), and the second region (12) is a stacked portion of the lower layer (3) and the upper layer (6). The configuration of the photomask (1) according to embodiment 5 is substantially the same as the configuration of the photomask (1) according to embodiment 1, except that the shape of the pattern is different. Therefore, the description of the configuration of the photomask (1) according to embodiment 5 is omitted as it is identical to the description above.

[0135] For example, the lower layer (3) is a phase shift film and the upper layer (6) is a halftone film, the transmittance of the lower layer (3) is high transmittance (10 to 90%) and the transmittance of the upper layer (6) is high transmittance (10 to 75%), the light-blocking film (4) is a film in which the optical density (OD value) in the light-blocking part (11) is 2.7 or higher, and the phase angle of the semi-transparent part (12) which functions as the rim part of the light-blocking part (11) is approximately 180° (for example, the phase angle of the lower layer (3) is 160 to 180°, and the phase angle of the upper layer (6) is greater than 0° and less than or equal to 20° (low phase)).

[0136] <Method for manufacturing a photomask according to Embodiment 5>

[0137] The method for manufacturing the photomask (1) according to embodiment 5

[0138] i) Photomask blank preparation process (Process 1)

[0139] ii) First resist film formation process (Process 2)

[0140] iii) First drawing process (Process 3)

[0141] iv) First development process (Process 4)

[0142] v) Etching stopper film etching process (Process 5)

[0143] vi) Semipermeable film etching process (Process 6)

[0144] vii) 1st resist film removal process (Process 7)

[0145] viii) Shading film formation process (Process 8)

[0146] ix) Second resist film formation process (Process 9)

[0147] x) Second drawing process (Process 10)

[0148] xi) Second development process (Process 11)

[0149] xii) Light-blocking film etching process (Process 12)

[0150] xiii) Second resist film removal process (Process 13)

[0151] Equipped with

[0152] The method for manufacturing a photomask (1) according to Embodiment 5 is the same as steps 1 to 12 and step 14 of the method for manufacturing a photomask (1) according to Embodiment 3. That is, the method for manufacturing a photomask (1) according to Embodiment 5 is the same as the method for manufacturing a photomask (1) according to Embodiment 3, but without performing step 13 and performing step 14. Therefore, the description of the method for manufacturing a photomask (1) according to Embodiment 5 is omitted as it is identical to the description above.

[0153] <Composition of photomask according to embodiment 6>

[0154] As shown in FIG. 20, the pattern of the photomask (1) according to embodiment 6 is formed such that an etching stopper film (upper layer) (6) overlaps on a semi-transparent film (lower layer) (3), the semi-transparent portion (12) is composed of the lower layer (3) and the upper layer (6), and the second region (12) is a hole pattern in which the lower layer (3) and the upper layer (6) are stacked. The configuration of the photomask (1) according to embodiment 6 is substantially the same as the configuration of the photomask (1) according to embodiment 2, except that the shape of the pattern is different. Therefore, the description of the configuration of the photomask (1) according to embodiment 6 is omitted as it is identical to the description above.

[0155] <Method for manufacturing a photomask according to Embodiment 6>

[0156] The method for manufacturing the photomask (1) according to embodiment 6

[0157] i) Photomask blank preparation process (Process 1)

[0158] ii) First resist film formation process (Process 2)

[0159] iii) First drawing process (Process 3)

[0160] iv) First development process (Process 4)

[0161] v) Etching stopper film etching process (Process 5)

[0162] vi) Semipermeable film etching process (Process 6)

[0163] vii) 1st resist film removal process (Process 7)

[0164] viii) Shading film formation process (Process 8)

[0165] ix) Second resist film formation process (Process 9)

[0166] x) Second drawing process (Process 10)

[0167] xi) Second development process (Process 11)

[0168] xii) Light-blocking film etching process (Process 12)

[0169] xiii) Second resist film removal process (Process 13)

[0170] Equipped with

[0171] The method for manufacturing a photomask (1) according to Embodiment 6 is the same as steps 1 to 12 and step 14 of the method for manufacturing a photomask (1) according to Embodiment 4. That is, the method for manufacturing a photomask (1) according to Embodiment 6 is the same as the method for manufacturing a photomask (1) according to Embodiment 4, but without performing step 13 and performing step 14. Therefore, the description of the method for manufacturing a photomask (1) according to Embodiment 6 is omitted as it is identical to the description above.

[0172] <Effects according to the method of manufacturing the photomask according to each embodiment>

[0173] According to the manufacturing method of the photomask (1) according to each embodiment, the drawing process (second drawing process) in which the positional precision of the pattern is not important can be excluded, and the drawing process can determine the final required pattern dimensions in only one step (first drawing process). Accordingly, in the manufacturing process of the photomask (1), it is not necessary to require excessive precision of alignment. For this reason, according to the manufacturing method of the photomask (1) according to each embodiment, there is no alignment misalignment, and high precision of the photomask (1) can be realized.

[0174] According to the manufacturing method of the photomask (1) according to each embodiment, the translucent portion (second region) (12) of the pattern of the photomask (1) is not formed as a gap between adjacent patterns in the resist pattern, but is formed as the first resist pattern itself formed in the first resist pattern formation process. That is, the translucent portion (second region) (12) is formed as a line pattern. Because of this, according to the manufacturing method of the photomask (1) according to each embodiment, a rim portion (12) with a width of ultra-fine (submicron) below the resolution limit of the drawing device used in the drawing process can be formed.

[0175] According to the method of manufacturing the photomask (1) according to each embodiment, as shown in (a-1) of FIG. 21 and (a-1) of FIG. 22, in the process of forming the light-shielding film, the light-shielding film (4) is formed such that the film thickness t4 of the light-shielding film (4) is less than or equal to the film thickness t3 of the semi-transparent film (3) or less than or equal to the total film thickness t3+t6 of the semi-transparent film (3) and the etching stopper film (6), so that the second part (4b) is in a single-layer state that is not in contact with or connected to each of the first part (4a) and the third part (4c), and thus becomes an insulated state. Accordingly, as shown in (b-1) and (c-1) of FIG. 21 and (b-1) and (c-1) of FIG. 22, in the light-blocking film etching process, only the second part (4b) and the third part (4c) can be removed by etching, and the first part (4a) can be left in its original state. The state refers to a state in which the cross-section of the edge of the semi-transparent film (3) side of the first part (4a) is in close contact with the cross-section of the edge of the first part (4a) side of the semi-transparent film (3) (and the etching stopper film (6)), and the first part (4a) and the semi-transparent film (3) are aligned on the same plane on the transparent substrate (2) with their edges in contact with each other. For this reason, according to the manufacturing method of the photomask (1) according to each embodiment, a clear photomask (1) pattern can be formed in which the light-blocking portion (first region) (11) and the translucent portion (second region) (12) of the pattern of the photomask (1) are closely connected.

[0176] In this regard, as shown in (a-2) of FIG. 21 and (a-2) of FIG. 22, if the light-shielding film (4) is formed such that the film thickness t4' of the light-shielding film (4) is greater than the film thickness t3' of the semi-permeable film (3) or the film thickness t4' of the light-shielding film (4) is greater than the total film thickness t3'+t6' of the semi-permeable film (3) and the etching stopper film (6), the second part (4b) is connected in contact with each of the first part (4a) and the third part (4c), and thus is connected in a partial state. In this case, as shown in (b-2) and (c-2) of FIG. 21 and (b-2) and (c-2) of FIG. 22, in the light-blocking film etching process, the first part (4a) is etched by the permeated etchant, and depending on the degree, the etching reaches the surface of the transparent substrate (2) and a defect (7) occurs. Because of this, a problem arises in that the yield is reduced because a repair operation for the defect (7) is required.

[0177] According to the manufacturing method of the photomask (1) according to each embodiment, the first portion (4a) of the semi-transparent film (3) and the light-blocking film (4) are formed so as to be aligned on the same plane on the transparent substrate (2) with their edges touching each other. Because of this, according to the manufacturing method of the photomask (1) according to each embodiment, the line width of the semi-transparent film (3) (rim portion) can be measured with high precision. In the case of a photomask in which the light-blocking portion is composed of a laminated portion of a semi-transparent film and a light-blocking film, as described in FIGS. 5 to 7 of the aforementioned Patent Document 1 and Patent Document 2, and the rim portion is composed of a semi-transparent film, the line width of the rim portion is measured using a line width measuring instrument after the photomask is manufactured. A line width measuring instrument uses a measurement principle in which the line width is measured by defining a boundary where the amount of transmitted light of the measurement light for the pattern changes significantly. However, if the light-blocking part is a layered part, the change in the amount of transmitted light at the boundary between the light-blocking part and the rim part becomes gradual, making it difficult to accurately determine the position of the boundary, which has the drawback of lowering the measurement precision. However, according to the manufacturing method of the photomask (1) according to each embodiment, the line width can be measured with high precision by measuring it at the step in which the pattern of the semi-transparent film (3) is formed (Fig. 3 (b), Fig. 7 (b), Fig. 11 (c), Fig. 16 (c)). As a result, the high precision of the photomask can be further realized. In addition, the measurement time can be shortened, which can lead to cost reduction. Furthermore, if a defect occurs in the pattern of the semi-transparent film (3) at the step in which the pattern of the semi-transparent film (3) is formed, the defect can be corrected at this stage, which has the advantage of making it easier to correct the defect.

[0178] In addition, according to the manufacturing method of the photomask (1) according to each embodiment, the width or shape of the semi-transparent film (3) (rim portion (12)) can be arbitrarily set by changing the width or shape of the first resist pattern as shown in FIG. 23. For this reason, according to the manufacturing method of the photomask (1) according to each embodiment, the rim portion (12) can be designed and formed with a high degree of freedom.

[0179] For example, if adjacent openings are close together and the rim portions become connected, a reduction in film may occur in the central part of the semi-transparent portion due to the influence of phase. In that case, as shown in FIG. 23 (b), this problem can be prevented by misaligning the rim portions so that they do not become connected to other rim portions.

[0180] In addition, for example, at the four corners of the opening in FIG. 20 (a), the transfer pattern may be deformed by light diffraction. In that case, as shown in FIG. 23 (c), a desired pattern can be formed by applying corrections to the pattern at the four corners in advance so that the transfer pattern after exposure becomes the intended pattern (OPC technology).

[0181] <Other embodiments>

[0182] Furthermore, the present invention is not limited to the above embodiments, and various modifications are possible within the scope of not departing from the gist of the invention.

[0183] In the above embodiment 1, etc., the semi-transparent film (3) (and etching stopper film (6)) and the light-blocking film (4) are formed so that their cross-sections are in close contact with each other. However, as long as it is within a range that does not affect the transfer pattern during the manufacture of the substrate to be transferred, a small gap (for example, a gap below the resolution limit) may be formed. The term "in contact" in claims 1 to 3 means "substantially in contact."

[0184] In the above embodiment 1, etc., in the process of forming the light-shielding film, the light-shielding film (4) is formed such that the second part (4b) does not come into contact with or is not connected to each of the first part (4a) and the third part (4c). However, if it is within a range where adverse effects caused by the etchant seeping in do not occur, it may come into contact to some extent. The term "not coming into contact" in claims 1 to 3 means "substantially not coming into contact."

[0185] In the above embodiment 1, etc., in the first patterning process, the semi-transparent film (3) and the etching stopper film (6) are formed such that their cross-sectional shape is rectangular, and the cross-sections of both edges follow a plane that is orthogonal to the surface of the transparent substrate (2). This is to ensure that, in the light-shielding film formation process, the second part (4b) of the light-shielding film (4) does not come into contact with or connect to each of the first part (4a) and the third part (4c), resulting in a single-layer state. However, the present invention is not limited to this. The semi-transparent film (3) and the etching stopper film (6) may be formed such that their cross-sectional shape is inversely tapered. The same objective can be achieved by this as well.

[0186] In the above embodiment 1, etc., the second region (12) of the pattern of the photomask (1) is a rim portion. However, the present invention is not limited to this. The second region may be given other functions.

[0187] In the above embodiment 1, etc., the rim portion (12) is formed on both sides of the light-blocking portion (11). However, the present invention is not limited to this. The rim portion may be formed on only one side of the light-blocking portion.

[0188] In the three-layer type of the above embodiment 3, etc., in the process of forming a light-shielding film, the light-shielding film (4) is formed such that the film thickness t4 of the light-shielding film (4) is greater than the film thickness t3 of the semi-transparent film (3) and the total film thickness of the semi-transparent film (3) and the etching stopper film (6) is t3+t6 or less. However, the present invention is not limited to this. In the three-layer type, the light-shielding film (4) may be formed such that the film thickness t4 of the light-shielding film (4) is less than or equal to the film thickness t3 of the semi-transparent film (3).

[0189] In the three-layer type of the above embodiment 3, the semi-permeable film (3) and the light-blocking film (4) have different etching characteristics. However, the present invention is not limited to this. In the three-layer type, the semi-permeable film (3) and the light-blocking film (4) may have the same etching characteristics as the same material (e.g., a Cr-based material) is used. In this case, since the film thickness t3 of the semi-permeable film (3) is smaller than the film thickness t4 of the light-blocking film (4), side etching of the semi-permeable film (3) can be suppressed during the light-blocking film etching process. Also, when the etching characteristics are "same" and the film material is "same," this includes the concept of "approximation."

[0190] In the above embodiment 1, etc., the films used are of two types (in the case of a two-layer type) or three types (in the case of a three-layer type). However, the present invention is not limited to this. As long as the layer configuration is applicable to the method of manufacturing a photomask according to the present invention, cases in which other films are formed are not excluded. For example, other films may be formed between the pattern layer of the semi-transparent film (3) and the light-blocking film (4) and the transparent substrate (2).

[0191] In the above embodiment 1, etc., the first functional film is a light-blocking film (4), and the second and third functional films are semi-transparent films (3, 6). However, the present invention is not limited thereto. The first, second, and third functional films may be selected from any of the various functional films having the function of adjusting the optical characteristics of exposure light, such as light-blocking films, phase shift films, and halftone films. In particular, in the above embodiments 3 and 4, the third functional film is eventually eliminated, so it may be any of them.

[0192] The first functional film, the second functional film, and the third functional film are not limited to the materials exemplified in the above embodiments, and can be selected from any one of Cr-based materials, Ni-based materials, Ti-based materials, Si-based materials, Zr-based materials, or metal silicide-based materials, or from other materials, according to the corresponding transfer shape and area.

[0193] In the above embodiment 1, etc., the pattern of the photomask (1) is a line and space pattern. Or in the above embodiment 2, etc., the pattern of the photomask (1) is a hole pattern. However, the present invention is not limited to this. The pattern of the photomask may be a dot pattern having dots (light-blocking parts) of a size in μm units in at least a part of the area (in some cases, these are arranged in a one-dimensional or two-dimensional array with a predetermined spacing). Of course, it may be a pattern other than these. In short, the type of pattern is not limited as long as it is a pattern that can be implemented by the method of the present invention.

[0194] In the above embodiment 2, etc., the shape of the hole (boundary line between the transparent part (10) and the semi-transparent part (12)) is rectangular, and the shape of the rim part (12) (boundary line between the semi-transparent part (12) and the light-blocking part (11)) is rectangular. However, the present invention is not limited to this. The shape of the hole and the shape of the rim part may be other shapes such as circular or polygonal. In addition, the shape of the hole and the shape of the rim part may be different from each other. Explanation of the symbols

[0195] 1 : Photomask 10 : Transmissive part 11 : Light-blocking section (1st area) 12 : Semi-transparent section (2nd region) 2 : Transparent substrate 3 : Semipermeable membrane (secondary functional membrane) 4: Shade screen (1st functional screen) 4a : Part 1 4b : Part 2 4c : Part 3 5 : Resist film 5a : First region 5b : Second area 6 : Etching stopper film (third functional film) 7 : Defect (White defect)

Claims

Claim 1 A method for manufacturing a photomask comprising a first functional film formed on a transparent substrate and a second functional film formed on a transparent substrate so as to be in contact along the edge of at least a portion of the first functional film, and a pattern comprising a first region of the first functional film and a second region of the second functional film, wherein, for a photomask blank having the second functional film formed on a transparent substrate, a portion corresponding to the second region of the second functional film is left and the other portions are removed; a functional film forming process for forming a first functional film on the portion where the second functional film has been removed and on the second functional film, wherein in the first functional film, the portion corresponding to the first region is the first portion, the portion on the second functional film is the second portion, and the portion not of the first portion and the second portion is the third portion, such that the second portion is in a single-layer state that does not contact the first portion and the third portion, respectively; and at least the first portion side of the first portion of the first functional film and the second portion of the first functional film. A method for manufacturing a photomask having a resist pattern forming process that covers a portion including an edge and exposes at least a portion of another portion of a second portion of a first functional film and at least a portion of a third portion of a first functional film, and a removal process that removes the second portion and the third portion of a first functional film by etching while the resist pattern is present, wherein the resist pattern remains even after the second portion and the third portion of the first functional film are removed by etching in the removal process. Claim 2 A method for manufacturing a photomask comprising a first functional film formed on a transparent substrate and a second functional film formed on a transparent substrate so as to be in contact along the edge of at least a portion of the first functional film, and a pattern comprising a first region of the first functional film and a second region of the second functional film, wherein, for a photomask blank having a second functional film and a third functional film laminated on a transparent substrate, a portion corresponding to the second region among the second functional film and the third functional film is left and the other portion is removed; a functional film forming process for forming a first functional film on the portion where the second functional film and the third functional film have been removed and on the third functional film, wherein in the first functional film, the portion corresponding to the first region is the first portion, the portion on the third functional film is the second portion, and the portion not of the first portion and the second portion is the third portion, such that the second portion is in a single-layer state that does not contact the first portion and the third portion, respectively; and the first portion of the first functional film and the first functional film A method for manufacturing a photomask having a resist pattern forming process that covers a portion including an edge on the side of at least the first portion of a second portion, while exposing at least a portion of another portion of the second portion of a first functional film and at least a portion of the third portion of a first functional film, and a removal process that removes the second portion and third portion of the first functional film and the third functional film by etching while the resist pattern is present, wherein the resist pattern remains even after the second portion and third portion of the first functional film and the third functional film are removed by etching in the removal process. Claim 3 A method for manufacturing a photomask comprising a first functional film formed on a transparent substrate, a second functional film formed on a transparent substrate so as to follow the edge of at least a portion of the first functional film, and a third functional film formed on the second functional film, and a pattern comprising a first region of the first functional film and a second region of the stacked portion of the second functional film and the third functional film, wherein, for a photomask blank having the second functional film and the third functional film stacked on a transparent substrate, a portion corresponding to the second region among the second functional film and the third functional film is left and the other portion is removed, and a functional film forming process for forming a first functional film on the portion where the second functional film and the third functional film have been removed and on the third functional film, wherein in the first functional film, the portion corresponding to the first region is the first portion, the portion on the third functional film is the second portion, and the portion not of the first portion and the second portion is the third portion, such that the second portion is formed in a single-layer state that does not contact the first portion and the third portion, respectively. A method for manufacturing a photomask having a functional film forming process, a resist pattern forming process that covers a portion including an edge on the side of at least the first portion of a first functional film and a second portion of a first functional film, while exposing at least a portion of another portion of the second portion of a first functional film and at least a portion of the third portion of a first functional film, and a removal process that removes the second portion and the third portion of a first functional film by etching while the resist pattern is present, wherein the resist pattern remains even after the second portion and the third portion of the first functional film are removed by etching in the removal process. Claim 4 A method for manufacturing a photomask according to claim 1, wherein the removal process is a process of removing a second portion of a first functional film by etching including side etching so that it does not remain on a second functional film while a resist pattern exists, and simultaneously removing a third portion of the first functional film by etching. Claim 5 A method for manufacturing a photomask according to claim 2, wherein the removal process is a process of removing the second portion of the first functional film and the third functional film by etching including side etching so that they do not remain on the second functional film while the resist pattern is present, and simultaneously removing the third portion of the first functional film by etching. Claim 6 A method for manufacturing a photomask according to claim 3, wherein the removal process is a process of removing a second portion of a first functional film by etching including side etching so that it does not remain on a third functional film while a resist pattern is present, and simultaneously removing a third portion of a first functional film by etching. Claim 7 A method for manufacturing a photomask according to any one of claims 1 to 6, wherein in a functional film formation process, the thickness of the first functional film is less than or equal to the thickness of the second functional film. Claim 8 A method for manufacturing a photomask according to any one of claims 2, 3, 5 and 6, wherein the third functional film is a film having etching selectivity with respect to the second functional film. Claim 9 A method for manufacturing a photomask according to any one of claims 2, 3, 5 and 6, wherein in a functional film formation process, the thickness of the first functional film is greater than the thickness of the second functional film and is less than or equal to the total thickness of the second and third functional films. Claim 10 A method for manufacturing a photomask according to any one of claims 1 to 6, wherein, as a first functional film, a film in which a first region functions as a light-blocking portion, and as a second functional film, a film in which a second region functions as a phase-shifting portion. Claim 11 In claim 10, the second region functions as the rim of the light-blocking portion. A method for manufacturing a photomask. Claim 12 A method for manufacturing a photomask according to claim 11, wherein a patterning process is performed such that the rim portion has a width of 0.1㎛ or more and 3.0㎛ or less. Claim 13 A method for manufacturing a photomask according to claim 11, wherein the rim part is patterned such that the width is less than or equal to the resolution limit of the drawing device used in the patterning process of the photomask. Claim 14 A method for manufacturing a photomask according to any one of claims 1 to 6, wherein the pattern of the photomask is one of a line and space pattern, a hole pattern, or a dot pattern. Claim 15 delete

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