Photomask manufacturing method and photomask

Abstract

To provide a method of manufacturing a photomask capable of achieving higher definition of the photomask as compared with a conventional method of manufacturing the photomask, and to provide the photomask.SOLUTION: The method for producing a photomask includes 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 be in contact with and along at least a part of an edge of the first functional film 4, and has a pattern composed of a first region of the first functional film 4 and a second region of the second functional film 3, wherein in a functional film forming step, the first functional film 4 is formed so as to be in a fault state in which a second partial 4b is not in contact with each of a first partial 4a and a third partial 4c.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] 2. Description of the Related Art Photomasks are known as photolithography techniques that have two different types of functional portions, for example, a light-shielding portion and a semi-transparent portion (a semi-transparent portion such as a phase shift portion or a halftone portion), in contact with each other.

[0003] There are two types of photomasks of this type: the photomask shown in Figures 5 to 7 of Patent Document 1 and Patent Document 2, and the photomask shown in Figures 1 to 4 of Patent Document 1. The former photomask includes a second functional film and a first functional film formed on the second functional film so that at least a portion of the peripheral region of the second functional film is exposed, and is a photomask that includes a first functional portion (e.g., a light-shielding portion) formed by a laminated portion of the first functional film and the second functional film, and a second functional portion (e.g., a phase-shifting portion) formed by the second functional film. The latter photomask includes a first functional film and a second functional film formed in contact with and along at least a portion of the edge of the first functional film, and is a photomask that includes a first functional portion (e.g., a light-shielding portion) formed by the first functional film, and a second functional portion (e.g., a phase-shifting portion) formed by the second functional film. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-5344 [Patent Document 2] Japanese Patent Application Publication No. 7-128840 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the manufacture of any of the above photomasks, at least two drawing steps are required: a drawing step (exposure step) of the pattern that constitutes the first functional part, and a drawing step of the pattern that constitutes the second functional part. Furthermore, when the drawing steps are performed multiple times, misalignment of the patterns formed in each step is likely to occur.

[0006] One solution to this problem is to use alignment marks. When performing the second or subsequent drawing process, the alignment marks created in the first drawing process are read and alignment (positioning) is performed using these alignment marks as a reference. However, even when using alignment marks, it is impossible to completely eliminate pattern misalignment (misalignment), and misalignment will occur. For this reason, the impact of this problem is becoming greater as photomasks become more highly precise.

[0007] Therefore, the present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a photomask manufacturing method and a photomask that can achieve even higher resolution than conventional photomask manufacturing methods. [Means for solving the problem]

[0008] The first method for manufacturing a photomask according to the present invention includes: A method for manufacturing a photomask comprising: a first functional film formed on a transparent substrate; and a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; the photomask having a pattern constituted by a first region of the first functional film and a second region of the second functional film, a patterning step of removing a portion of the second functional film corresponding to the second region from a photomask blank having a second functional film formed on a transparent substrate, while leaving the remaining portion; a functional film forming step of forming a first functional film on the portion from which the second functional film has been removed and on the second functional film, in which, assuming that the portion of the first functional film corresponding to the first region is a first portion, the portion on the second functional film is a second portion, and the portion other than the first and second portions is a third portion, the first functional film is formed in a disconnected state in which the second portion is not in contact with either the first portion or the third portion; a resist pattern forming step of forming a resist pattern that covers at least a portion of the first portion of the first functional film and a portion of the second portion of the first functional film that includes an edge on the first portion side, and exposes at least a portion of the other portion of the second portion of the first functional film and at least a portion of the third portion of the first functional film; a removing step of removing the second portion and the third portion of the first functional film. This is a method for manufacturing a photomask.

[0009] Specific examples of such a configuration include the following embodiments 1 and 2.

[0010] The second method of manufacturing a photomask according to the present invention includes: A method for manufacturing a photomask comprising: a first functional film formed on a transparent substrate; and a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; the photomask having a pattern constituted by a first region of the first functional film and a second region of the second functional film, a patterning step of removing the second and third functional films from a photomask blank having a second functional film and a third functional film laminated on a transparent substrate, while leaving portions of the second and third functional films corresponding to the second region; a functional film forming step of forming a first functional film on the portion from which the second functional film and the third functional film have been removed and on the third functional film, in which, assuming that the portion of the first functional film corresponding to the first region is the first portion, the portion above the third functional film is the second portion, and the portion other than the first and second portions is the third portion, the first functional film is formed in a disconnected state in which the second portion is not in contact with either the first portion or the third portion; a resist pattern forming step of forming a resist pattern that covers at least a portion of the first portion of the first functional film and a portion of the second portion of the first functional film that includes an edge on the first portion side, and exposes at least a portion of the other 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 step of removing the second and third portions of the first functional film and the third functional film. This is a method for manufacturing a photomask.

[0011] Specific examples of such a configuration include the third and fourth embodiments described below.

[0012] A third method for manufacturing a photomask according to the present invention includes: A method for manufacturing a photomask comprising: a first functional film formed on a transparent substrate; a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; and a third functional film formed on the second functional film, the photomask having a pattern constituted by a first region of the first functional film and a second region of a laminated portion of the second functional film and the third functional film, a patterning step of removing the second and third functional films from a photomask blank having a second functional film and a third functional film laminated on a transparent substrate, while leaving portions of the second and third functional films corresponding to the second region; a functional film forming step of forming a first functional film on the portion from which the second functional film and the third functional film have been removed and on the third functional film, in which, assuming that the portion of the first functional film corresponding to the first region is the first portion, the portion above the third functional film is the second portion, and the portion other than the first and second portions is the third portion, the first functional film is formed in a disconnected state in which the second portion is not in contact with either the first portion or the third portion; a resist pattern forming step of forming a resist pattern that covers at least a portion of the first portion of the first functional film and a portion of the second portion of the first functional film that includes an edge on the first portion side, and exposes at least a portion of the other portion of the second portion of the first functional film and at least a portion of the third portion of the first functional film; a removing step of removing the second portion and the third portion of the first functional film. This is a method for manufacturing a photomask.

[0013] Specific examples of such a configuration include the fifth and sixth embodiments described below.

[0014] The photomask according to the first aspect of the present invention is A photomask comprising: a first functional film formed on a transparent substrate; and a second functional film formed on the transparent substrate so as to contact and follow at least a part of an edge of the first functional film; the photomask having a pattern constituted by a first region of the first functional film and a second region of the second functional film, The thickness of the first functional film is equal to or less than the thickness of the second functional film, or is greater than the thickness of the second functional film. It is a photomask.

[0015] Specific examples of the configuration before "or" in such a configuration include embodiment 1 and embodiment 2 described below, and specific examples of the configuration after "or" include embodiment 3 and embodiment 4 described below.

[0016] The photomask according to the second aspect of the present invention is A photomask comprising: a first functional film formed on a transparent substrate; a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; and a third functional film formed on the second functional film, the photomask having a pattern constituted by a first region of the first functional film and a second region of a laminated portion of the second functional film and the third functional film, The thickness of the first functional film is greater than the thickness of the second functional film and is equal to or less than the total thickness of the second and third functional films, or equal to or less than the thickness of the second functional film. It is a photomask.

[0017] Specific examples of the configuration before "or" in such a configuration include the fifth and sixth embodiments described below. [Effects of the Invention]

[0018] According to the present invention, except for the drawing process where the positional accuracy of the pattern is not important, the drawing process is performed only once. Therefore, according to the present invention, there is no alignment error and it is possible to realize a photomask with higher resolution than the conventional photomask manufacturing method. [Brief explanation of the drawings]

[0019] [Figure 1] Fig. 1(a) is an enlarged plan view of a main part of a photomask according to embodiment 1. Fig. 1(b) is a cross-sectional view taken along line AA in Fig. 1(a). [Figure 2] 2(a) to 2(d) are explanatory diagrams of the method for manufacturing a photomask according to the first embodiment. [Figure 3] 3(a) to 3(d) are explanatory diagrams continuing from FIG. [Figure 4] 4(a) to 4(d) are explanatory diagrams continuing from FIG. [Figure 5] Fig. 5(a) is an enlarged plan view of a main part of a photomask according to embodiment 2. Fig. 5(b) is a cross-sectional view taken along line BB in Fig. 5(a). [Figure 6] 6(a) to 6(d) are explanatory diagrams of a method for manufacturing a photomask according to the second embodiment. [Figure 7] 7(a) to 7(d) are explanatory diagrams continuing from FIG. [Figure 8] 8(a) to 8(d) are explanatory diagrams continuing from FIG. [Figure 9] Fig. 9(a) is an enlarged plan view of a main part of a photomask according to embodiment 3. Fig. 9(b) is a cross-sectional view taken along line CC in Fig. 9(a). [Figure 10] 10(a) to 10(d) are explanatory diagrams of a method for manufacturing a photomask according to the third embodiment. [Figure 11] 11(a) to 11(c) are explanatory diagrams continuing from FIG. [Figure 12] 12(a) to 12(d) are explanatory diagrams continuing from FIG. [Figure 13] 13(a) to 13(c) are explanatory diagrams continuing from FIG. [Figure 14] Fig. 14(a) is an enlarged plan view of a main part of a photomask according to embodiment 4. Fig. 14(b) is a cross-sectional view taken along line DD in Fig. 14(a). [Figure 15] 15(a) to 15(d) are explanatory diagrams of a method for manufacturing a photomask according to the fourth embodiment. [Figure 16] 16(a) to 16(c) are explanatory diagrams continuing from FIG. [Figure 17] 17(a) to 17(d) are explanatory diagrams continuing from FIG. [Figure 18] 18(a) to 18(c) are explanatory diagrams continuing from FIG. [Figure 19] Fig. 19(a) is an enlarged plan view of a main part of a photomask according to embodiment 5. Fig. 19(b) is a cross-sectional view taken along line EE in Fig. 19(a). [Figure 20] Fig. 20(a) is an enlarged plan view of a main part of a photomask according to embodiment 6. Fig. 20(b) is a cross-sectional view taken along line FF in Fig. 20(a). [Figure 21] 21(a-1) to 21(c-1) are explanatory diagrams illustrating the effects of the photomask manufacturing methods according to the first and second embodiments, taking into consideration the portion X in FIG. 3(c). FIGS. 21(a-2) to 21(c-2) are explanatory diagrams for comparison with a comparative example. [Figure 22] 22(a-1) to 22(c-1) are explanatory diagrams illustrating the effects of the photomask manufacturing methods according to embodiments 3 to 6, with reference to part Y in FIG. 12(a). FIGS. 22(a-2) to 22(c-2) are explanatory diagrams for comparison with a comparative example. [Figure 23] 23(a) to 23(d) are enlarged plan views of essential parts of photomasks according to other embodiments 1 to 4. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] <Configuration of the Photomask According to the First Embodiment> As shown in FIG. 1, photomask 1 is a three-tone multi-tone photomask having transparent portions (white portions) 10, light-shielding portions (black portions) 11, and semi-transparent portions (hatched portions) 12. Transparent portion 10 is made up of a transparent substrate 2. Light-shielding portion 11 is made up of a light-shielding film 4 as a first functional film. Semi-transparent portion 12 is made up of a semi-transparent film 3 as a second functional film. That is, exposed portions of transparent substrate 2 where semi-transparent film 3 and light-shielding film 4 are not formed constitute transparent portion 10, portions of transparent substrate 2 where light-shielding film 4 is formed constitute light-shielding portion 11, and portions of transparent substrate 2 where semi-transparent film 3 is formed constitute semi-transparent portion 12.

[0021] The light-shielding portion 11 and the semi-transmitting portion 12 constitute the pattern of the photomask 1. The pattern is composed of a first region 11 and a second region 12. The first region 11 is a single layer portion of the light-shielding film 4 and functions as the light-shielding portion 11. The second region 12 is a single layer portion of the semi-transmitting film 3 and functions as the semi-transmitting portion 12.

[0022] In this embodiment, lines (light-shielding portions 11) with widths in the micrometer range and spaces (transmitting portions 10) with widths in the micrometer range are arranged in parallel (and in some cases, these 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 / drain electrodes on a transfer substrate manufactured by photolithography using the photomask 1. In this case, the transmitting portions 10 function as channel portions, the light-shielding portions 11 function as electrode portions, and the semi-transmitting portions 12 function as rim portions of the light-shielding portions 11.

[0023] The rim portion 12 is provided to improve the process tolerance on the panel side. For example, the rim portion 12 is provided to make the edges of the resist pattern corresponding to the source / drain electrodes on the transfer substrate steeper. The width of the rim portion 12 is, for example, in the range of 0.1 μm or more, or 0.5 μm or more, and 2.0 μm or less, or 3.0 μm or less. Preferably, it is in the range of 0.5 μm or more and 2.0 μm or less. Note that the width of the rim portion 12 is not limited to these. Furthermore, the rim portion 12 can be provided not only for source / drain electrodes, but also for miniaturizing transparent electrode / indium oxide (ITO) film layers, source wiring layers, and gate wiring layers, in response to demands for higher definition photomasks.

[0024] The transparent substrate 2 is a substrate made of synthetic quartz glass or the like. The transparent substrate 2 has a transmittance of 95% or more for a representative wavelength (for example, i-line, h-line, or g-line) contained in the exposure light used in the exposure step of photolithography. The exposure light may be, for example, i-line, h-line, or g-line, or may be a mixed light containing at least two of these light. Alternatively, the exposure light may have a wavelength band shifted or expanded to the shorter and / or longer wavelength side compared to these lights. As an example, the wavelength band of the exposure light may be 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.

[0025] The semi-transparent film 3 is a type of functional film that adjusts the optical properties of the exposure light and changes the phase of the exposure light, i.e., a phase shift film. The phase shift film is set so that the phase shift amount relative to the 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°. The phase shift film has a transmittance for the representative wavelength contained in the exposure light that is lower than that of the transparent substrate 2 and higher than that of the light-shielding film 4, and is set so that the transmittance for the representative wavelength is within the range of 2% to 90%.

[0026] The semi-transparent film 3 is made of a metal silicide-based material selected from known materials such as Cr or Cr-based compounds (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Cr, the same applies hereinafter), Ni or Ni-based compounds (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Ni, the same applies hereinafter), Ti or Ti-based compounds (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Ti, the same applies hereinafter), Si-based compounds (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Si, the same applies hereinafter), Zr or Zr-based compounds (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Zr, the same applies hereinafter), and metal silicide-based compounds (molybdenum silicide, tungsten silicide, tantalum silicide, zirconium silicide, or nitrides, oxynitrides, etc. of these, the same applies hereinafter). In this embodiment, the semi-transparent film 3 is made of a molybdenum silicide compound.

[0027] The light-shielding film 4 is a type of functional film that adjusts the optical characteristics of the exposure light and blocks the exposure light. The light-shielding film 4 has a transmittance of 1% or less for the representative wavelength contained in the exposure light. Alternatively, the optical density (OD value) of the light-shielding portion 11 may be 2.7 or more. As an example, the light-shielding film 4 has a laminated structure including a first film layer and a second film layer. The first film layer is made of a metal film and has the purpose of light-shielding. The second film layer is made of a metal oxide film and has the purpose of anti-reflection. In this case, even if the transmittance of the first film layer is higher than 1%, it is sufficient as long as the laminated transmittance of the first and second film layers is 1% or less. Note that when the second film layer is formed below the first film layer, stray light during transfer can be prevented, the phase effect can be fully utilized, and even higher resolution photomasks can be achieved. However, the second film layer may be formed on the first film layer.

[0028] The light-shielding film 4 is made of a Cr-based material among known materials such as Cr or a Cr-based compound, Ni or a Ni-based compound, Ti or a Ti-based compound, a Si-based compound, Zr or a Zr-based compound, and a metal silicide-based compound. In this embodiment, a Cr-based compound is used for the light-shielding film 4. The reason for using a Cr-based compound is that a thin film made of a Cr-based compound has favorable resistance to a cleaning process that is performed when a photomask is contaminated, has foreign matter attached, or the like, during the manufacturing process of the transfer substrate.

[0029] The semi-transmitting film 3 and the light-shielding film 4 are made of different materials and therefore have different etching characteristics. That is, the semi-transmitting film 3 has etching selectivity relative to the light-shielding film 4, and the light-shielding film 4 has etching selectivity relative to the semi-transmitting film 3.

[0030] The semi-transmitting film 3 and the light-shielding film 4 are formed on the transparent substrate 2 so that their edges are in contact with each other and aligned on the same plane. The film thickness of the light-shielding film 4 is equal to or less than the film thickness of the semi-transmitting film 3. As an example, the (average) film thickness of the light-shielding film 4 is 0.09 μm (900 Å), and the (average) film thickness of the semi-transmitting film 3 is 0.12 μm (1200 Å). Of course, the width of the semi-transmitting film 3 is smaller than the width of the light-shielding film 4.

[0031] <Method of manufacturing a photomask according to embodiment 1> The method for manufacturing the photomask 1 according to the first embodiment is as shown in FIGS. 2 to 4. i) Photomask blank preparation process (process 1) ii) First resist film formation process (process 2) iii) First drawing process (process 3) iv) First development process (process 4) v) Semi-transparent film etching process (process 5) vi) First resist film removal process (process 6) vii) Light shielding film formation process (process 7) viii) Second resist film formation process (process 8) ix) Second drawing process (process 9) x) Second development process (Step 10) xi) Light-shielding film etching process (process 11) xii) Second resist film removal process (process 12) Equipped with.

[0032] The steps from the first resist film formation process to the first resist film removal process, and the steps from the second resist film formation process to the second resist film removal process are called patterning processes, respectively. In the former patterning process, the semi-transparent film 3 of the photomask blank is patterned, and in the latter patterning process, the light-shielding film 4, which is newly formed in the middle of the process, is patterned.

[0033] In the photomask blank preparation step, photomask blanks are prepared as shown in Fig. 2(a). The photomask blanks have a semi-transparent film 3 formed on a transparent substrate 2. The semi-transparent film 3 is formed by physical vapor deposition (PVD) such as sputtering or evaporation.

[0034] In the first resist film formation step, as shown in FIG. 2(b), a resist is uniformly applied onto the semi-transparent film 3 to form a resist film 5. The resist is applied by a coating method, a spraying method, or the like. The resist may be either positive or negative, but in this example, a positive resist is used.

[0035] In the first writing step, as shown in FIG. 2(c), exposure light is irradiated onto the resist film 5 using an electron beam or laser of a writing device, and a first resist pattern is written. At this time, two regions with different exposure amounts are formed in the resist film 5. The first region 5a is an unexposed region. The second region 5b is an exposed region with a predetermined exposure amount. In the case of a negative resist, the relationship between the exposure amounts is opposite to that of a positive resist. In addition to writing the resist pattern, in the first writing step, marks (alignment marks) are written to align the writing position in the second writing step. Although not shown, alignment marks are formed, for example, in three or four appropriate locations in the surrounding region surrounding the resist pattern.

[0036] In the first developing step, as shown in FIG. 2(d), the unnecessary resist film 5 (second region 5b) is removed by development to form a first resist pattern. The first resist pattern is a pattern that corresponds to the second region 12 of the pattern of the photomask 1. Development is carried out by a dipping method, a spin method, a puddle method, a spray method, or the like. The first resist film forming step, the first writing step, and the first developing step are collectively referred to as the first resist pattern forming step.

[0037] In the semi-transparent film etching process, as shown in FIG. 3(a), the exposed portions of the semi-transparent film 3 are etched away using the primary resist pattern as an etching mask. While either dry etching or wet etching is acceptable, wet etching is preferred for large-sized photomasks. An etching solution or etching gas is used as the etchant. Regardless of the etchant, an etchant with etching selectivity to the semi-transparent film 3 is used. During etching, the semi-transparent film 3 also undergoes side etching. This is why the edge of the semi-transparent film 3 is offset inward from the edge of the primary resist pattern. However, depending on the film thickness, material, or type of etchant, side etching may not occur. The etching rate of the semi-transparent film 3 can be adjusted by adjusting the etchant concentration, temperature, etching time, and other conditions for using the etchant. Adjusting the etching rate of the semi-transparent film 3 allows for the desired offset dimension to be achieved.

[0038] 3(b), the remaining resist film 5 (first resist pattern) is removed. The resist film 5 is removed by an ashing method, a dipping method, or the like. As a result, a second region 12 of the pattern of the photomask 1 is formed on the transparent substrate 2.

[0039] In the light-shielding film forming process, as shown in FIG. 3(c), the light-shielding film 4 is formed to cover the entire surface. That is, the 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 so that its thickness t4 is the same as or smaller than the thickness t3 of the semi-transparent film 3. That is, the light-shielding film 4 is formed so that its thickness t4 is equal to or smaller than the thickness t3 of the semi-transparent film 3. As a result, the light-shielding film 4 includes a first portion 4a corresponding to the 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 different from the first portion 4a and the second portion 4b, and is formed so that the second portion 4b is not in contact with or connected to the first portion 4a or the third portion 4c. The light-shielding film 4 is formed by physical vapor deposition, such as sputtering or evaporation.

[0040] 3(d), in the second resist film forming step, a resist is applied onto the light-shielding film 4 to form a resist film 5. The method itself is the same as in the first resist film forming step.

[0041] In the second writing step, as shown in Figure 4(a), a second resist pattern is written on the resist film 5. The method itself is the same as in the first writing step, and the writing device is the same as the writing device used in the first writing step. In the second writing step, the writing device detects the alignment marks formed in the previous step and aligns the transparent substrate 2.

[0042] However, the second resist pattern only needs to cover and protect the necessary areas, and does not require high pattern position accuracy, so strict alignment is not required in the second drawing process.

[0043] However, misalignment inevitably occurs in the second writing process. Therefore, in the second writing process, a second resist pattern is set that takes misalignment into consideration. Specifically, the second resist pattern is designed to overlap (lap) the laminated portion of the semi-transparent film 3 and the light-shielding film 4 by a predetermined amount from the edge of the laminated portion. The amount of overlap is, for example, 0.3 μm or more and 0.5 μm or less.

[0044] In the second developing step, as shown in FIG. 4(b), unnecessary resist film 5 (second region 5b) is removed by development to form a second resist pattern. The second resist pattern covers the first portion 4a of the light-shielding film 4 and at least the portion of the second portion 4b of the light-shielding film 4, including the edge on the first portion 4a side, and exposes 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 in the first developing step. The second resist film forming step, second writing step, and second developing step are collectively referred to as the second resist pattern forming step.

[0045] In the light-shielding film etching process, as shown in FIG. 4(c), the exposed portions of the light-shielding film 4, i.e., 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, is separated from the second portion 4b, and is completely covered by the second resist pattern and the semi-transparent film 3, making it an unexposed portion, and is therefore not etched. In 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 ultimately side-etched and completely removed. While either dry etching or wet etching may be used for etching, wet etching is preferred for large-sized photomasks. An etching solution or etching gas is used as the etchant. Regardless of the etchant, an etchant with etching selectivity to the light-shielding film 4 (an etchant that does not etch the semi-transparent film 3) is used. The etching rate of the light-shielding film 4 can be adjusted by adjusting the concentration of the etchant, the temperature, the etching time, and other conditions under which the etchant is used.

[0046] In the second resist film removal step, the remaining resist film 5 (second resist pattern) is removed as shown in Figure 4(d). The method itself is the same as in the first resist film removal step. As a result, a first region 11 of the pattern of the photomask 1 is formed on the transparent substrate 2, and together with the previously formed second region 12, the entire pattern of the photomask 1 is formed.

[0047] <Configuration of the Photomask According to the Second Embodiment> As shown in FIG. 5, the pattern of the photomask 1 according to the second embodiment is a hole pattern having holes (transmitting portions 10) of μm size (in some cases, these are arranged one-dimensionally or two-dimensionally at predetermined intervals). Therefore, in the photomask 1 according to the second embodiment, hole-shaped transmitting portions 10 are formed, and second regions 12 are formed around them. The configuration of the photomask 1 according to the second embodiment is substantially the same as the configuration of the photomask 1 according to the first embodiment, except for the different pattern shape. Therefore, a description of the configuration of the photomask 1 according to the second embodiment will be omitted, as it is the same as the corresponding description above.

[0048] <Method of manufacturing a photomask according to embodiment 2> The method for manufacturing the photomask 1 according to the second embodiment is as shown in FIGS. 6 to 8. i) Photomask blank preparation process (process 1) ii) First resist film formation process (process 2) iii) First drawing process (process 3) iv) First development process (process 4) v) Semi-transparent film etching process (process 5) vi) First resist film removal process (process 6) vii) Light shielding film formation process (process 7) viii) Second resist film formation process (process 8) ix) Second drawing process (process 9) x) Second development process (Step 10) xi) Light-shielding film etching process (process 11) xii) Second resist film removal process (process 12) Equipped with.

[0049] The method for manufacturing the photomask 1 according to the second embodiment is substantially the same as the method for manufacturing the photomask 1 according to the first embodiment, except for the shape of the pattern. Therefore, the description of the method for manufacturing the photomask 1 according to the second embodiment is omitted, as it is the same as the corresponding description above.

[0050] <Configuration of the Photomask According to the Third Embodiment> 9, the configuration of the photomask 1 according to the third embodiment is substantially the same as that of the photomask 1 according to the first embodiment, except that the thickness of the light-shielding film 4 is greater than the thickness of the semi-transparent film 3. Therefore, a description of the configuration of the photomask 1 according to the third embodiment will be omitted, as it is the same as the corresponding description above.

[0051] <Method of manufacturing a photomask according to the third embodiment> The method for manufacturing the photomask 1 according to the third embodiment is as shown in FIGS. 10 to 13. i) Photomask blank preparation process (process 1) ii) First resist film formation process (process 2) iii) First drawing process (process 3) iv) First development process (process 4) v) First etching stopper film etching process (process 5) vi) Semi-transparent film etching process (process 6) vii) First resist film removal process (process 7) viii) Light shielding film formation process (process 8) ix) Second resist film formation process (process 9) x) Second drawing process (process 10) xi) Second development process (Step 11) xii) Light-shielding film etching step (step 12) xiii) Second etching stopper film etching step (step 13) xiv) Second resist film removal process (process 14) Equipped with.

[0052] The method for manufacturing the photomask 1 according to the third embodiment is substantially the same as the method for manufacturing the photomask 1 according to the first embodiment, except that the photomask blank has an etching stopper film 6 as a third functional film and that two etching stopper film etching steps are added. Therefore, the description of the method for manufacturing the photomask 1 according to the third embodiment will be omitted, as it is the same as the corresponding description above, except for the differences described below.

[0053] 10(a), in the photomask blank preparation step, 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, so that 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 deposition method such as a sputtering method or an evaporation method.

[0054] The etching stopper film 6 is interposed between the semi-transmitting film 3 and the light-shielding film 4, blocking the passage of both films 3 and 4. The etching stopper film 6 is a type of functional film that adjusts the optical characteristics of the exposure light, i.e., a half-tone film. The half-tone film has a transmittance for the representative wavelength of the exposure light that is lower than that of the transparent substrate 2 and higher than that of the light-shielding film 4, and is set to have a transmittance of 10% to 75% for the representative wavelength. The half-tone film is set so that the phase shift for the representative wavelength is less than 20°, more preferably less than 5°. The half-tone film may be a semi-transmitting metal film that improves the transmittance distribution within the plane of the photomask by adjusting the nitrogen content. The half-tone film can also change the optical density (OD value) of the semi-transmitting portion 12 by adding other elements.

[0055] The etching stopper film 6 is made of an appropriate material selected from 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.

[0056] The semi-transparent film 3, the etching stopper film 6, and the light-shielding film 4 are made of different materials and therefore have different etching characteristics. That is, the semi-transparent film 3 has etching selectivity with respect to each of the etching stopper film 6 and the light-shielding film 4, the etching stopper film 6 has etching selectivity with respect to each of the semi-transparent film 3 and the light-shielding film 4, and the light-shielding film 4 has etching selectivity with respect to each of the semi-transparent film 3 and the etching stopper film 6.

[0057] The thickness of the etching stopper film 6 is smaller than the thickness of the semi-transparent film 3. For example, the thickness of the etching stopper film 6 is 0.01 μm (100 Å) or more and 0.10 μm (1000 Å) or less. To perform etching effectively, the thickness is preferably in the range of 0.03 μm (300 Å) or more and 0.05 μm (500 Å) or less. However, the thickness is not limited to these values.

[0058] In the first etching stopper film etching process, as shown in FIG. 11(a), the exposed portions of the etching stopper film 6 are removed by etching using the primary resist pattern as an etching mask. While either dry etching or wet etching is acceptable, wet etching is preferred for large-sized photomasks. An etching solution or etching gas is used as the etchant. Regardless of the etchant, an etchant that has etching selectivity for the etching stopper film 6 (an etchant that does not etch the semi-transparent film 3) is used. Note that the etching stopper film 6 also undergoes side etching during etching. This is why the edge of the etching stopper film 6 is offset inward from the edge of the primary resist pattern in the figure. 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. Note that the etching rate of the etching stopper film 6 can be adjusted by adjusting the etchant concentration, temperature, etching time, and other conditions for using the etchant. By adjusting the etching rate of the etching stopper film 6, it is possible to adjust the offset dimension to a desired value.

[0059] 12(a), in the light-shielding film forming step, the light-shielding film 4 is formed to cover the entire surface. That is, the 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 so that its thickness t4 is the same as the total thickness t3+t6 of the semi-transparent film 3 and the etching stopper film 6, or is smaller than the total thickness t3+t6 of the semi-transparent film 3 and the etching stopper film 6. That is, the light-shielding film 4 is formed so that its thickness t4 is equal to or smaller than the total thickness t3+t6 of the semi-transparent film 3 and the etching stopper film 6. As a result, the light-shielding film 4 is formed to include a first portion 4a corresponding to the 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 neither the first portion 4a nor the second portion 4b, and to be in a disconnected state in which the second portion 4b is not in contact with or connected to either the first portion 4a or the third portion 4c. The light-shielding film 4 is formed by physical vapor deposition such as sputtering or evaporation.

[0060] In the second etching stopper film etching step, the etching stopper film 6 is removed by etching, as shown in FIG. 13(b). The method itself is the same as in the first etching stopper film etching step. In the second etching stopper film etching step, the etching stopper film 6 is finally side-etched and completely removed. Note that in the previous step (light-shielding film etching step), depending on the etching rate of the light-shielding film 4, the second portion 4b of the light-shielding film 4 may not be completely removed by side etching, and a portion (especially the portion deep inside the undercut portion of the second resist pattern) may remain on the etching stopper film 6. Even in such a case, the remaining second portion 4b of the light-shielding film 4 is removed together with the etching stopper film 6 in the second etching stopper film etching step (removal by lift-off), so there is no problem.

[0061] In the description of the method for manufacturing the photomask 1 according to the first embodiment, i) In the first resist film formation process, the term "semi-transparent film 3" is replaced with "etching stopper film 6." ii) In the semi-transparent film etching process, the description of "first resist pattern" in "using the first resist pattern as an etching process mask" is replaced with "etching stopper film 6", and the description of "etchant having etching selectivity for the semi-transparent film 3" is replaced with "etchant having etching selectivity for the semi-transparent film 3 (etchant that does not etch the etching stopper film 6)". iii) In the light-shielding film etching process, the phrase "completely covered by the second resist pattern and the semi-transparent film 3" should be read as "completely covered by the second resist pattern, the semi-transparent film 3, and the etching stopper film 6," and the phrase "an etchant having etching selectivity for the light-shielding film 4 (an etchant that does not etch the semi-transparent film 3)" should be read as "an etchant having etching selectivity for the light-shielding film 4 (an etchant that does not etch the semi-transparent film 3 and the etching stopper film 6)." iv) Process numbers and diagram numbers shall be replaced with the corresponding numbers as appropriate.

[0062] <Configuration of Photomask According to Embodiment 4> 14, the configuration of the photomask 1 according to the fourth embodiment is substantially the same as the configuration of the photomask 1 according to the second embodiment, except that the thickness of the light-shielding film 4 is greater than the thickness of the semi-transparent film 3. Moreover, the configuration of the photomask 1 according to the fourth embodiment is substantially the same as the configuration of the photomask 1 according to the third embodiment, except that the shape of the pattern is different. Therefore, a description of the configuration of the photomask 1 according to the fourth embodiment will be omitted, as it is the same as the corresponding description above.

[0063] <Method of manufacturing a photomask according to the fourth embodiment> The method for manufacturing the photomask 1 according to the fourth embodiment is as shown in FIGS. 15 to 18. i) Photomask blank preparation process (process 1) ii) First resist film formation process (process 2) iii) First drawing process (process 3) iv) First development process (process 4) v) First etching stopper film etching process (process 5) vi) Semi-transparent film etching process (process 6) vii) First resist film removal process (process 7) viii) Light shielding film formation process (process 8) ix) Second resist film formation process (process 9) x) Second drawing process (process 10) xi) Second development process (Step 11) xii) Light-shielding film etching step (step 12) xiii) Second etching stopper film etching step (step 13) xiv) Second resist film removal process (process 14) Equipped with.

[0064] The method for manufacturing the photomask 1 according to the fourth embodiment is substantially the same as the method for manufacturing the photomask 1 according to the second embodiment, except that the photomask blank has an etching stopper film 6 as a third functional film and two etching stopper film etching steps are added. The method for manufacturing the photomask 1 according to the fourth embodiment is substantially the same as the method for manufacturing the photomask 1 according to the third embodiment, except that the shape of the pattern is different. Therefore, the description of the method for manufacturing the photomask 1 according to the fourth embodiment is omitted, as it is the same as the corresponding description above.

[0065] <Configuration of the Photomask According to the Fifth Embodiment> 19, the pattern of the photomask 1 according to the fifth embodiment is a line-and-space pattern in which an etching stopper film (upper layer film) 6 is formed so as to overlap a semi-transparent film (lower layer film) 3, a semi-transparent portion 12 is composed of the lower layer film 3 and the upper layer film 6, and a second region 12 is a laminated portion of the lower layer film 3 and the upper layer film 6. The configuration of the photomask 1 according to the fifth embodiment is substantially the same as the configuration of the photomask 1 according to the first embodiment, except for the different pattern shape. Therefore, a description of the configuration of the photomask 1 according to the fifth embodiment will be omitted as it is the same as the corresponding description above.

[0066] As an example, the lower layer film 3 is a phase shift film, the upper layer film 6 is a half-tone film, the transmittance of the lower layer film 3 is high (10 to 90%), the transmittance of the upper layer film 6 is high (10 to 75%), the light-shielding film 4 is a film in which the optical density (OD value) of the light-shielding portion 11 is 2.7 or more, and the phase angle of the semi-transmitting portion 12 that functions as the rim portion of the light-shielding portion 11 is approximately 180° (for example, the phase angle of the lower layer film 3 is 160 to 180°, and the phase angle of the upper layer film 6 is greater than 0° and less than 20° (low phase)).

[0067] <Method of manufacturing a photomask according to embodiment 5> The method for manufacturing the photomask 1 according to the fifth embodiment includes the steps of: i) Photomask blank preparation process (process 1) ii) First resist film formation process (process 2) iii) First drawing process (process 3) iv) First development process (process 4) v) Etching stopper film etching step (step 5) vi) Semi-transparent film etching process (process 6) vii) First resist film removal process (process 7) viii) Light shielding film formation process (process 8) ix) Second resist film formation process (process 9) x) Second drawing process (process 10) xi) Second development process (Step 11) xii) Light-shielding film etching step (step 12) xiii) Second resist film removal process (process 13) Equipped with.

[0068] The method for manufacturing the photomask 1 according to the fifth embodiment is the same as steps 1 to 12 and 14 of the method for manufacturing the photomask 1 according to the third embodiment. That is, the method for manufacturing the photomask 1 according to the fifth embodiment is the same as the method for manufacturing the photomask 1 according to the third embodiment, except that steps 11 to 12 are performed, step 13 is not performed, and step 14 is performed. Therefore, the description of the method for manufacturing the photomask 1 according to the fifth embodiment is omitted, as it is the same as the corresponding description above.

[0069] <Configuration of the Photomask According to the Sixth Embodiment> 20, the pattern of the photomask 1 according to the sixth embodiment is a hole pattern in which an etching stopper film (upper layer film) 6 is formed so as to overlap a semi-transparent film (lower layer film) 3, a semi-transparent portion 12 is composed of the lower layer film 3 and the upper layer film 6, and a second region 12 is a laminated portion of the lower layer film 3 and the upper layer film 6. The configuration of the photomask 1 according to the sixth embodiment is substantially the same as that of the photomask 1 according to the second embodiment, except for the shape of the pattern. Therefore, a description of the configuration of the photomask 1 according to the sixth embodiment will be omitted as it is the same as the corresponding description above.

[0070] <Method of manufacturing a photomask according to the sixth embodiment> The method for manufacturing the photomask 1 according to the sixth embodiment includes the steps of: i) Photomask blank preparation process (process 1) ii) First resist film formation process (process 2) iii) First drawing process (process 3) iv) First development process (process 4) v) Etching stopper film etching step (step 5) vi) Semi-transparent film etching process (process 6) vii) First resist film removal process (process 7) viii) Light shielding film formation process (process 8) ix) Second resist film formation process (process 9) x) Second drawing process (process 10) xi) Second development process (Step 11) xii) Light-shielding film etching step (step 12) xiii) Second resist film removal process (process 13) Equipped with.

[0071] The method for manufacturing the photomask 1 according to the sixth embodiment is the same as steps 1 to 12 and 14 of the method for manufacturing the photomask 1 according to the fourth embodiment. That is, the method for manufacturing the photomask 1 according to the sixth embodiment is the same as the method for manufacturing the photomask 1 according to the fourth embodiment, except that steps 11 to 12 are performed, step 13 is not performed, and step 14 is performed. Therefore, the description of the method for manufacturing the photomask 1 according to the sixth embodiment is omitted, as it is the same as the corresponding description above.

[0072] <Effects of the photomask manufacturing method according to each embodiment> According to the manufacturing method of the photomask 1 of each embodiment, except for the writing step (secondary writing step) in which the positional accuracy of the pattern is not important, the final required pattern dimensions can be determined in one writing step (primary writing step). This eliminates the need for excessive alignment accuracy in the manufacturing process of the photomask 1. Therefore, according to the manufacturing method of the photomask 1 of each embodiment, there is no alignment misalignment and it is possible to achieve high-definition photomasks 1.

[0073] According to the manufacturing method of the photomask 1 of each embodiment, the semi-transparent portion (second region) 12 of the pattern of the photomask 1 is not formed by the gap between adjacent patterns in the resist pattern, but is formed by the first resist pattern itself formed in the first resist pattern forming step. That is, the semi-transparent portion (second region) 12 is formed as a line pattern. Therefore, according to the manufacturing method of the photomask 1 of each embodiment, it is possible to form the rim portion 12 having an extremely thin (submicron) width below the resolution limit of the drawing device used in the drawing step.

[0074] 21(a-1) and 22(a-1), in the light-shielding film forming step, the light-shielding film 4 is formed so that its thickness t4 is equal to or less than the thickness t3 of the semi-transparent film 3, or equal to or less than the total thickness t3+t6 of the semi-transparent film 3 and the etching stopper film 6. This causes the second portion 4b to be in a disconnected state, being not in contact with or connected to the first portion 4a and the third portion 4c, and thus to be cut off. As a result, in the light-shielding film etching step, as shown in FIGS. 21(b-1), (c-1) and 22(b-1), (c-1), only the second portion 4b and the third portion 4c can be removed by etching, while the first portion 4a remains in its original state. This state refers to a state in which the edge face of the first portion 4a on the semi-transparent film 3 side is in close contact with the edge face of the semi-transparent film 3 (and etching stopper film 6) on the first portion 4a side, and the first portion 4a and the semi-transparent film 3 are in contact with each other at their edges and are arranged on the same plane on the transparent substrate 2. Therefore, according to the method for manufacturing the photomask 1 according to each embodiment, it is possible to form a clear photomask 1 pattern in which the light-shielding portions (first regions) 11 and semi-transparent portions (second regions) 12 of the photomask 1 pattern are in close contact with each other.

[0075] 21(a-2) and 22(a-2), if the light-shielding film 4 is formed so that its thickness t4' is greater than the thickness t3' of the semi-transparent film 3 or so that its thickness t4' is greater than the total thickness t3'+t6' of the semi-transparent film 3 and the etching stopper film 6, the second portion 4b will be in contact with and connected to the first portion 4a and the third portion 4c, respectively, and will be partially connected. In this case, as shown in FIGS. 21(b-2), (c-2) and 22(b-2), (c-2), the first portion 4a will be etched by the seeped etchant in the light-shielding film etching process. Depending on the extent of the etching, the etching may reach the surface of the transparent substrate 2, causing defects 7. This requires repair of the defects 7, resulting in a problem of reduced yield.

[0076] According to the manufacturing method of the photomask 1 of each embodiment, the semi-transmitting film 3 and the first portion 4a of the light-shielding film 4 are formed so that their edges are in contact with each other and aligned on the same plane on the transparent substrate 2. Therefore, according to the manufacturing method of the photomask 1 of each embodiment, the line width of the semi-transmitting film 3 (rim portion) can be measured with high accuracy. In the case of a photomask in which the light-shielding portion is formed by a laminated portion of a semi-transmitting film and a light-shielding film and the rim portion is formed by the semi-transmitting film, such as the photomasks described in FIGS. 5 to 7 of Patent Document 1 and Patent Document 2, the line width of the rim portion is measured using a line width measuring instrument after the photomask is manufactured. The line width measuring instrument measures the line width by defining the boundary where the amount of transmitted light of the measurement light for the pattern changes significantly. However, if the light-shielding portion is a laminated portion, the change in the amount of transmitted light at the boundary between the light-shielding portion and the rim portion becomes gradual, making it difficult to accurately determine the position of the boundary, resulting in a disadvantage of reduced measurement accuracy. However, according to the method for manufacturing the photomask 1 of each embodiment, the line width can be measured at the stage when the pattern of the semi-transparent film 3 is formed (FIGS. 3(b), 7(b), 11(c), and 16(c)), thereby enabling highly accurate measurement. As a result, it is possible to achieve even higher resolution photomasks. It is also possible to shorten the measurement time, which can lead to cost reductions. Furthermore, if a defect occurs in the pattern of the semi-transparent film 3 at the stage when the pattern of the semi-transparent film 3 is formed, the defect can be corrected at this stage, which has the advantage of making defect correction easier.

[0077] Furthermore, according to the method for manufacturing the photomask 1 of each embodiment, by changing the width and shape of the primary resist pattern, the width and shape of the semi-transparent film 3 (rim portion 12) can be set as desired, as shown in Fig. 23. Therefore, according to the method for manufacturing the photomask 1 of each embodiment, the rim portion 12 can be designed and formed with a high degree of freedom.

[0078] For example, if the rims of adjacent openings are close together, the film thickness may be reduced in the center of the semi-transparent section due to phase effects. In this case, as shown in Figure 23(b), this problem can be avoided by shifting the rims so that they do not join with other rims.

[0079] Furthermore, for example, the transfer pattern may be deformed due to diffraction of light at the four corners of the opening in Figure 20(a). In such cases, as shown in Figure 23(c), the desired pattern can be formed by correcting the patterns at the four corners in advance so that the transfer pattern after exposure becomes the intended pattern (OPC technology).

[0080] <Other embodiments> The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0081] In the above-mentioned first embodiment and the like, the semi-transparent film 3 (and etching stopper film 6) and the light-shielding film 4 are formed so that their end faces are in close contact with each other. However, in manufacturing the transfer substrate, a small gap (for example, a gap below the resolution limit) may be formed as long as it does not affect the transfer pattern. In claims 1 to 3, "in contact" means "substantially in contact with each other."

[0082] In the above-described first embodiment and the like, in the light-shielding film forming step, the light-shielding film 4 is formed so that the second portion 4b is not in contact with the first portion 4a and the third portion 4c at all, and is in a disconnected state. However, there may be some contact therebetween as long as there is no adverse effect due to seepage of the etchant. In claims 1 to 3, "not in contact" means "not substantially in contact."

[0083] In the first embodiment and the like, in the first patterning step, the semi-transparent film 3 and the etching stopper film 6 are formed so that their cross-sectional shape is rectangular and the end faces of both edges are along a plane perpendicular to the surface of the transparent substrate 2. This is to ensure that, in the light-shielding film formation step, the second portion 4b of the light-shielding film 4 is in a disconnected state, not in contact with or connected to the first portion 4a and the third portion 4c. However, the present invention is not limited to this. The semi-transparent film 3 and the etching stopper film 6 may also be formed so that their cross-sectional shape is inversely tapered. This also achieves the same purpose.

[0084] In the above-described first embodiment and the like, 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 another functional portion.

[0085] In the above-described first embodiment and the like, the rim portion 12 is formed on both sides of the light-shielding portion 11. However, the present invention is not limited to this. The rim portion may be formed on only one side of the light-shielding portion.

[0086] In the three-layer type of the third embodiment and the like, in the light-shielding film formation step, the light-shielding film 4 is formed so that its thickness t4 is greater than the thickness t3 of the semi-transparent film 3 and is equal to or less than the total thickness t3+t6 of the semi-transparent film 3 and the etching stopper film 6. However, the present invention is not limited to this. In the three-layer type, the light-shielding film 4 may be formed so that its thickness t4 is equal to or less than the thickness t3 of the semi-transparent film 3.

[0087] In the three-layer type such as the third embodiment, the semi-transparent film 3 and the light-shielding film 4 have different etching characteristics. However, the present invention is not limited to this. In the three-layer type, the semi-transparent film 3 and the light-shielding film 4 may have the same etching characteristics by using the same material (for example, a Cr-based material). In this case, the thickness t3 of the semi-transparent film 3 is smaller than the thickness t4 of the light-shielding film 4, thereby suppressing side etching of the semi-transparent film 3 in the light-shielding film etching step. Note that when the etching characteristics are "same" and the film materials are "same," this also includes the concept of "approximation."

[0088] In the above-described first embodiment, two types of films (in the case of a two-layer type) or three types (in the case of a three-layer type) are used. However, the present invention is not limited to this. As long as the layer configuration is applicable to the photomask manufacturing method of the present invention, other films may be formed. For example, other films may be formed between the pattern layers of the semi-transparent film 3 and the light-shielding film 4 and the transparent substrate 2.

[0089] In the above-mentioned embodiment 1 and the like, the first functional film is a light-shielding film 4, and the second functional film and the third functional film are semi-transparent films 3 and 6. However, the present invention is not limited to this. The first functional film, the second functional film, and the third functional film can be selected from various functional films that have the function of adjusting the optical properties of the exposure light, such as a light-shielding film, a phase shift film, and a halftone film. In particular, in the above-mentioned embodiment 3 and embodiment 4, the third functional film is ultimately eliminated, so it may be any film.

[0090] 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 Cr-based materials, Ni-based materials, Ti-based materials, Si-based materials, Zr-based materials, or metal silicide-based materials, or from other materials, depending on the corresponding transferred shape and portion.

[0091] In the above-mentioned first embodiment and the like, the pattern of the photomask 1 is a line and space pattern. Alternatively, in the above-mentioned second embodiment and the like, the pattern of the photomask 1 is a hole pattern. However, the present invention is not limited to this. The photomask pattern may be a dot pattern having dots (light-shielding portions) of μm size in at least a partial area (in some cases, these are arranged one-dimensionally or two-dimensionally at predetermined intervals). Of course, patterns other than these may also be used. In short, there are no limitations on the type of pattern as long as it can be implemented by the method of the present invention.

[0092] In the above-described second embodiment and the like, the shape of the hole (the boundary between the transmissive portion 10 and the semi-transmissive portion 12) is rectangular, and the shape of the rim portion 12 (the boundary between the semi-transmissive portion 12 and the light-shielding portion 11) is rectangular. However, the present invention is not limited to this. The shape of the hole and the shape of the rim portion may be other shapes such as a circle or a polygon. Furthermore, the shape of the hole and the shape of the rim portion may be different. [Explanation of symbols]

[0093] 1...photomask, 10...transmitting portion, 11...light-shielding portion (first region), 12...semi-transmitting portion (second region), 2...transparent substrate, 3...semi-transmitting film (second functional film), 4...light-shielding film (first functional film), 4a...first portion, 4b...second portion, 4c...third portion, 5...resist film, 5a...first region, 5b...second region, 6...etching stopper film (third functional film), 7...defect (white defect)

Claims

1. A method for manufacturing a photomask comprising: a first functional film formed on a transparent substrate; and a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; the photomask having a pattern constituted by a first region of the first functional film and a second region of the second functional film, a patterning step of removing a portion of the second functional film corresponding to the second region from a photomask blank having a second functional film formed on a transparent substrate, while leaving the remaining portion; a functional film forming step of forming a first functional film on the portion from which the second functional film has been removed and on the second functional film, in which, assuming that the portion of the first functional film corresponding to the first region is a first portion, the portion on the second functional film is a second portion, and the portion other than the first and second portions is a third portion, the first functional film is formed in a disconnected state in which the second portion is not in contact with either the first portion or the third portion; a resist pattern forming step of forming a resist pattern that covers at least a portion of the first portion of the first functional film and a portion of the second portion of the first functional film that includes an edge on the first portion side, and exposes at least a portion of the other portion of the second portion of the first functional film and at least a portion of the third portion of the first functional film; a removing step of removing the second portion and the third portion of the first functional film. A method for manufacturing a photomask.

2. A method for manufacturing a photomask comprising: a first functional film formed on a transparent substrate; and a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; the photomask having a pattern constituted by a first region of the first functional film and a second region of the second functional film, a patterning step of removing portions of the second functional film and the third functional film from a photomask blank having a second functional film and a third functional film laminated on a transparent substrate, while leaving portions of the second functional film and the third functional film corresponding to the second region; a functional film forming step of forming a first functional film on the portion from which the second functional film and the third functional film have been removed and on the third functional film, in which, when the portion of the first functional film corresponding to the first region is defined as a first portion, the portion above the third functional film is defined as a second portion, and the portion other than the first and second portions is defined as a third portion, the first functional film is formed in a disconnected state in which the second portion is not in contact with either the first portion or the third portion; a resist pattern forming step of forming a resist pattern that covers at least a portion of the first portion of the first functional film and a portion of the second portion of the first functional film that includes an edge on the first portion side, and exposes at least a portion of the other portion of the second portion of the first functional film and at least a portion of the third portion of the first functional film; a removing step of removing the second and third portions of the first functional film and the third functional film. A method for manufacturing a photomask.

3. A method for manufacturing a photomask comprising: a first functional film formed on a transparent substrate; a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; and a third functional film formed on the second functional film, the photomask having a pattern constituted by a first region of the first functional film and a second region of a laminated portion of the second functional film and the third functional film, a patterning step of removing portions of the second functional film and the third functional film from a photomask blank having a second functional film and a third functional film laminated on a transparent substrate, while leaving portions of the second functional film and the third functional film corresponding to the second region; a functional film forming step of forming a first functional film on the portion from which the second functional film and the third functional film have been removed and on the third functional film, in which, when the portion of the first functional film corresponding to the first region is defined as a first portion, the portion above the third functional film is defined as a second portion, and the portion other than the first and second portions is defined as a third portion, the first functional film is formed in a disconnected state in which the second portion is not in contact with either the first portion or the third portion; a resist pattern forming step of forming a resist pattern that covers at least a portion of the first portion of the first functional film and a portion of the second portion of the first functional film that includes an edge on the first portion side, and exposes at least a portion of the other portion of the second portion of the first functional film and at least a portion of the third portion of the first functional film; a removing step of removing the second portion and the third portion of the first functional film. A method for manufacturing a photomask.

4. In the functional film forming step, the first functional film is formed so that the film thickness of the first functional film is equal to or less than the film thickness of the second functional film. The method for manufacturing a photomask according to any one of claims 1 to 3.

5. In the functional film forming step, the first functional film is formed so that the film thickness of the first functional film is greater than the film thickness of the second functional film and is equal to or less than the total film thickness of the second functional film and the third functional film. The method for manufacturing a photomask according to claim 2 or 3.

6. As the first functional film, a film in which the first region functions as a light-shielding portion is used, As the second functional film, a film is used in which the second region functions as a phase shift portion. The method for manufacturing a photomask according to any one of claims 1 to 3.

7. The second region functions as a rim portion of the light blocking portion. The method for manufacturing a photomask according to claim 6 .

8. The photomask pattern is either a line and space pattern, a hole pattern, or a dot pattern. The method for manufacturing a photomask according to any one of claims 1 to 3.

9. A photomask comprising: a first functional film formed on a transparent substrate; and a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; the photomask having a pattern constituted by a first region of the first functional film and a second region of the second functional film, The thickness of the first functional film is equal to or less than the thickness of the second functional film, or is greater than the thickness of the second functional film. Photomask.

10. A photomask comprising: a first functional film formed on a transparent substrate; a second functional film formed on the transparent substrate so as to contact and follow at least a portion of an edge of the first functional film; and a third functional film formed on the second functional film, the photomask having a pattern constituted by a first region of the first functional film and a second region of a laminated portion of the second functional film and the third functional film, The thickness of the first functional film is greater than the thickness of the second functional film and is equal to or less than the total thickness of the second and third functional films, or equal to or less than the thickness of the second functional film. Photomask.

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