Photomask manufacturing method

Abstract

To provide a photomask manufacturing method that can achieve even higher resolution of photomasks than conventional photomask manufacturing methods.SOLUTION: The edge position of a second area of a photomask pattern (the edge position of a semi-transparent film 3) is defined based not on the edge position of a second pattern 4B of an upper layer film pattern on the side opposite a first pattern 4A, but on the edge position of the second pattern 4B of the upper layer film pattern on the first pattern 4A side. Accordingly, the width of the second pattern 4B of the upper layer pattern is not a factor in setting the width of the second area (the width of an exposed portion of the semi-transparent film 3). Therefore, the present invention can achieve even higher resolution of photomasks than conventional photomask manufacturing methods.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Phase shift masks and halftone masks are known as photolithography techniques. A phase shift mask is a photomask that has a phase shift film on part of a transparent substrate and has the function of improving resolution and depth of focus (DOF) by changing the phase and intensity of light passing through this part. A halftone mask is a photomask that has a halftone film on part of a transparent substrate and has the function of realizing multiple gradations of three or more levels by changing the intensity of light passing through this part.

[0003] In the conventional photomask manufacturing method, at least two drawing steps are required: a drawing step (exposure step) of a pattern constituting a light-shielding portion and a drawing step of a pattern constituting a semi-transmitting portion. When the drawing steps are performed multiple times, positional deviation of the patterns formed in each step is likely to occur.

[0004] One solution to this problem is to use alignment marks. When performing the second or subsequent drawing process, the alignment mark created in the first drawing process is read, and alignment (positioning) is performed using this alignment mark as a reference. However, even when using alignment marks, it is impossible to completely eliminate pattern position shifts (alignment deviations), and alignment deviations of up to 0.5 μm can occur. For this reason, the impact of this problem is becoming greater as photomasks become more fine.

[0005] Therefore, a method for manufacturing a photomask that can perform the drawing process in one step has been considered. For example, the method for manufacturing a photomask described in Patent Document 1 is as follows: A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; and an upper layer film formed on the underlayer film so that at least a part of a peripheral region of the underlayer film is exposed; the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film and the upper layer film and a second region of the underlayer film, i) a photomask blanks preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are laminated on a transparent substrate; ii) a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the opposite side to the first pattern set at a position corresponding to the position of the edge of the second region; iii) a first upper layer film etching process, in which an exposed portion of the upper layer film is removed by etching using the first resist pattern as a mask, to form an upper layer film pattern including a first pattern corresponding to the first region and a second pattern (temporary pattern) spaced apart from the first pattern and having an edge on the opposite side to the first pattern set at a position corresponding to the position of the edge of the second region; iv) a second resist pattern formation process for forming a second resist pattern that covers the first pattern of the upper layer film pattern, the exposed portion of the lower layer film between the first pattern and the second pattern (temporary pattern) of the upper layer film pattern, and a portion of the second pattern (temporary pattern) of the upper layer film pattern excluding a portion including an edge on the opposite side to the first pattern; v) an underlayer film etching step of removing exposed portions of the underlayer film by etching using the second resist pattern and the second pattern (temporary pattern) of the overlayer film pattern as a mask; vi) A second upper layer film etching process for removing the second pattern (temporary pattern) of the upper layer film pattern by etching.

[0006] According to the photomask manufacturing method described in Patent Document 1, except for the drawing process in which the positional accuracy of the pattern is not important (secondary resist pattern forming process), the drawing process can determine the final required pattern dimensions in one step (first resist pattern forming process). This eliminates the need for excessive alignment accuracy in the photomask manufacturing process. Since so-called self-aligned pattern formation is performed, the photomask manufacturing method described in Patent Document 1 can achieve high-definition photomasks without misalignment. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2014-2255 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the photomask manufacturing method described in Patent Document 1, the second pattern (temporary pattern) of the upper layer film pattern needs to be formed to have a width greater than an alignment misalignment of up to 0.5 μm so that the second resist pattern reliably covers the relevant portion of the second pattern (temporary pattern) of the upper layer film pattern and so that the exposed portion of the lower layer film between the first pattern and the second pattern (temporary pattern) of the upper layer film pattern is not exposed from the second resist pattern.

[0009] For this reason, when manufacturing a photomask in which the first region is a light-shielding portion, the second region is a phase shift portion, and the second region functions as a rim portion of the light-shielding portion, and in which a line-and-space pattern in which lines (light-shielding portion) with a width in μm units and spaces (transmitting portion) with a width in μm units are arranged in parallel, or in which a hole pattern in which holes (transmitting portion) with a size in μm units are arranged, the width of the second region (rim portion) becomes large by the amount including the width of the second pattern (provisional pattern) of the upper layer film pattern, and cannot be formed smaller than the sum of the width of the second pattern (provisional pattern) and the beam diameter of the drawing device. This results in restrictions on the size of the second region (rim portion).

[0010] 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 that can achieve even higher resolution photomasks compared to conventional photomask manufacturing methods. [Means for solving the problem]

[0011] The method for producing a photomask according to the present invention includes the steps of: A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; and an upper layer film formed on the underlayer film so that at least a part of a peripheral region of the underlayer film is exposed; the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film and the upper layer film and a second region of the underlayer film, a photomask blanks preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are laminated on a transparent substrate; a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region; a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask; a surface layer film forming step of forming a surface layer film so as to cover at least an exposed portion of the lower layer film between the first pattern and the second pattern of the upper layer film pattern; a second resist pattern forming process for forming a second resist pattern that covers at least a portion of the first pattern of the upper layer film pattern, a surface layer film between the first pattern and the second pattern of the upper layer film pattern, including an edge on the first pattern side, and exposes at least a portion of the other portion of the second pattern of the upper layer film pattern; a second upper layer film etching process for removing the second pattern of the upper layer film pattern by etching; an underlayer film etching step of removing exposed portions of the underlayer film by etching using the second resist pattern or the surface film as a mask; and a surface film etching step of removing the surface film by etching. A method for manufacturing a photomask.

[0012] Specific examples of such a configuration include embodiment 1, another example of embodiment 1, embodiment 2, and embodiment 3, which will be described later.

[0013] Another method for producing a photomask according to the present invention includes the steps of: A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; and an upper layer film formed on the underlayer film so that at least a part of a peripheral region of the underlayer film is exposed; the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film and the upper layer film and a second region of the underlayer film, a photomask blanks preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are laminated on a transparent substrate; a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region; a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask; a surface layer film forming step of forming a surface layer film so as to cover at least an exposed portion of the lower layer film between the first pattern and the second pattern of the upper layer film pattern; a second resist pattern forming process for forming a second resist pattern that covers at least a portion of the first pattern of the upper layer film pattern, a surface layer film between the first pattern and the second pattern of the upper layer film pattern, including an edge on the first pattern side, and exposes at least a portion of the other portion of the second pattern of the upper layer film pattern; a second upper layer film etching process for removing the second pattern of the upper layer film pattern by etching; and an underlayer film etching step of etching and removing exposed portions of the underlayer film using the second resist pattern or the surface film as a mask. A method for manufacturing a photomask.

[0014] Specific examples of such a configuration include a fourth embodiment, another example of the fourth embodiment, a fifth embodiment, and a sixth embodiment, which will be described later.

[0015] Furthermore, another method for producing a photomask according to the present invention includes the steps of: A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; an upper layer film formed on the underlayer film so that at least a portion of a peripheral region of the underlayer film is exposed; and a surface layer film formed so as to overlap at least the exposed portion of the underlayer film, the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film and the upper layer film and a second region of the laminated portion of the underlayer film and the surface layer film, a photomask blanks preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are laminated on a transparent substrate; a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region; a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask; a surface layer film forming step of forming a surface layer film so as to cover at least an exposed portion of the lower layer film between the first pattern and the second pattern of the upper layer film pattern; a second resist pattern forming process for forming a second resist pattern that covers at least a portion of the first pattern of the upper layer film pattern, a surface layer film between the first pattern and the second pattern of the upper layer film pattern, including an edge on the first pattern side, and exposes at least a portion of the other portion of the second pattern of the upper layer film pattern; a second upper layer film etching process for removing the second pattern of the upper layer film pattern by etching; and an underlayer film etching step of etching and removing exposed portions of the underlayer film using the second resist pattern or the surface film as a mask. A method for manufacturing a photomask.

[0016] Specific examples of such a configuration include the seventh and eighth embodiments described below.

[0017] Here, as one aspect of the method for producing a photomask according to the present invention, The lower and upper layers are formed of a film in which the first region functions as a light shielding portion and the second region functions as a phase shift portion. The above configuration can be adopted.

[0018] Also, in this case, A phase shift film is used as the underlayer film. A light-shielding film is used as the upper layer. The above configuration can be adopted.

[0019] In another aspect of the method for producing a photomask according to the present invention, The second region functions as a rim portion of the light blocking portion. The above configuration can be adopted.

[0020] In another aspect of the method for producing a photomask according to the present invention, The photomask pattern is either a line and space pattern, a hole pattern or a dot pattern. The above configuration can be adopted. Effect of the Invention

[0021] According to the present invention, the position of the edge of the second region of the photomask pattern is determined based on the position of the edge of the second pattern of the upper layer film pattern on the side of the first pattern, not the position of the edge of the second pattern of the upper layer film pattern on the side opposite to the first pattern. As a result, the width of the second pattern of the upper layer film pattern is not a factor in setting the width of the second region. Therefore, according to the present invention, it is possible to realize a photomask with even higher resolution than the conventional photomask manufacturing method. [Brief description of the drawings]

[0022] [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 II in Fig. 1(a). [Diagram 2] 2(a) to (d) are explanatory diagrams of the method for producing a photomask according to the first embodiment. [Diagram 3] 3(a) to (d) are explanatory diagrams continuing from FIG. [Figure 4] 4(a) to (d) are explanatory diagrams continuing from FIG. [Diagram 5] 5(a) to (c) are explanatory diagrams continuing from FIG. [Figure 6] 6(a) to (d) are explanatory diagrams of a method for producing a photomask according to another example of the first embodiment. [Figure 7] 7(a) to (d) are explanatory diagrams continuing from FIG. [Figure 8] 8(a) to (d) are explanatory diagrams continuing from FIG. [Figure 9] 9(a) to (c) are explanatory diagrams continuing from FIG. [Figure 10] Fig. 10(a) is an enlarged plan view of a main part of a photomask according to embodiment 2. Fig. 10(b) is a cross-sectional view taken along line JJ in Fig. 10(a). [Figure 11] 11(a) to (d) are explanatory diagrams of a method for producing a photomask according to the second embodiment. [Figure 12] 12(a) to (d) are explanatory diagrams continuing from FIG. [Figure 13] 13(a) to (d) are explanatory diagrams continuing from FIG. [Figure 14] 14(a) to (c) are explanatory diagrams continuing from FIG. [Figure 15] Fig. 15(a) is an enlarged plan view of a main part of a photomask according to embodiment 3. Fig. 15(b) is a cross-sectional view taken along line KK in Fig. 15(a). [Figure 16] 16(a) to (d) are explanatory diagrams of a method for producing a photomask according to the third embodiment. [Figure 17] 17(a) to (d) are explanatory diagrams continuing from FIG. [Figure 18] 18(a) to (d) are explanatory diagrams continuing from FIG. [Figure 19] 19(a) to (c) are explanatory diagrams continuing from FIG. [Figure 20] Fig. 20(a) is an enlarged plan view of a main part of a photomask according to embodiment 4. Fig. 20(b) is a cross-sectional view taken along line LL in Fig. 20(a). [Figure 21] 21(a) to (d) are explanatory diagrams of a method for producing a photomask according to the fourth embodiment. [Figure 22] 22(a) to (d) are explanatory diagrams continuing from FIG. [Diagram 23] 23(a) to (d) are explanatory diagrams continuing from FIG. [Figure 24] FIG. 24(a) is a continuation of FIG. [Diagram 25] 25(a) to (d) are explanatory diagrams of a method for producing a photomask according to another example of the fourth embodiment. [Figure 26] 26(a) to (d) are explanatory diagrams continuing from FIG. [Figure 27] 27(a) to (d) are explanatory diagrams continuing from FIG. [Figure 28] FIG. 28(a) is a continuation of FIG. [Figure 29] Fig. 29(a) is an enlarged plan view of a main part of a photomask according to embodiment 5. Fig. 29(b) is a cross-sectional view taken along line MM in Fig. 29(a). [Diagram 30] 30(a) to (d) are explanatory diagrams of a method for producing a photomask according to the fifth embodiment. [Diagram 31] 31(a) to (d) are explanatory diagrams continuing from FIG. [Diagram 32] 32(a) to (d) are explanatory diagrams continuing from FIG. [Diagram 33] FIG. 33(a) is a continuation of FIG. [Diagram 34]Fig. 34(a) is an enlarged plan view of a main part of a photomask according to embodiment 6. Fig. 34(b) is a cross-sectional view taken along line NN in Fig. 34(a). [Diagram 35] 35(a) to (d) are explanatory diagrams of a method for producing a photomask according to the sixth embodiment. [Diagram 36] 36(a) to (d) are explanatory diagrams continuing from FIG. [Figure 37] 37(a) to (d) are explanatory diagrams continuing from FIG. [Figure 38] FIG. 38(a) is a continuation of FIG. [Figure 39] Fig. 39(a) is an enlarged plan view of a main part of a photomask according to embodiment 7. Fig. 39(b) is a cross-sectional view taken along line OO in Fig. 39(a). [Diagram 40] Fig. 40(a) is an enlarged plan view of a main part of a photomask according to embodiment 8. Fig. 40(b) is a cross-sectional view taken along line PP in Fig. 40(a). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] <Configuration of the Photomask According to the First Embodiment> As shown in FIG. 1, the photomask 1 is a three-tone multi-tone photomask having a transparent portion (white portion) 10, a light-shielding portion (black portion) 11, and a semi-transmitting portion (hatched portion) 12. The transparent portion 10 is composed of a transparent substrate 2. The light-shielding portion 11 is composed of a semi-transmitting film 3 as a lower layer film and a light-shielding film 4 as an upper layer film. The semi-transmitting portion 12 is composed of the semi-transmitting film 3. That is, the exposed portion of the transparent substrate 2 on which the semi-transmitting film 3 and the light-shielding film 4 are not laminated becomes the transparent portion 10, the portion on which the semi-transmitting film 3 and the light-shielding film 4 are laminated on the transparent substrate 2 becomes the light-shielding portion 11, and the portion on which only the semi-transmitting film 3 is formed on the transparent substrate 2 becomes the semi-transmitting portion 12.

[0024] 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 laminated portion of the semi-transmitting film 3 and 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.

[0025] In this embodiment, lines (light-shielding portions 11) having widths in the order of μm and spaces (light-transmitting portions 10) having widths in the order of μm 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 in a transfer substrate manufactured by photolithography using the photomask 1. In this case, the light-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.

[0026] The rim portion 12 is provided in order to improve the process tolerance on the panel side. For example, the rim portion 12 is provided in order 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 3.0 μm or less.

[0027] 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 (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 lights. Alternatively, the exposure light may have a wavelength band shifted or expanded to the short wavelength side and / or long 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.

[0028] The semi-transparent film 3 is a kind of functional film having a function of adjusting the optical characteristics of the exposure light, and is a functional film having a function of changing the phase of the exposure light, that is, a phase shift film. The phase shift film is set so that the phase shift amount for 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°. In addition, the phase shift film has a transmittance for the representative wavelength contained in the exposure light that is lower than the transmittance of the transparent substrate 2 and higher than the transmittance 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%.

[0029] The semi-transparent film 3 is made of a metal silicide-based material selected from known materials such as Cr or a Cr-based compound (Cr oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), Ni or a Ni-based compound (Ni oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), Ti or a Ti-based compound (Ti oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), a Si-based compound (Si oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), Zr or a Zr-based compound (Zr oxide, nitride, carbide, oxynitride, oxynitride carbide, etc., hereinafter the same), a metal silicide-based compound (molybdenum silicide, tungsten silicide, tantalum silicide, zirconium silicide, or nitrides or oxynitrides thereof, hereinafter the same), etc. In this embodiment, the semi-transparent film 3 is made of a molybdenum silicide compound.

[0030] The light-shielding film 4 is a type of functional film having a function of adjusting the optical characteristics of the exposure light, and is a functional film having a function of blocking the exposure light. The light-shielding film 4 has a transmittance of 1% or less for a representative wavelength contained in the exposure light. Alternatively, the optical density (OD value) in 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-forming layer and a second film-forming layer. The first film-forming layer is made of a metal film and has a purpose of blocking light. The second film-forming layer is made of a metal oxide film and has a purpose of suppressing reflection. In this case, even if the transmittance of the first film-forming layer is higher than 1%, it is sufficient that the laminated transmittance of the first film-forming layer and the second film-forming layer is 1% or less.

[0031] 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 the present 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 a suitable resistance to a cleaning process that is performed when a photomask is contaminated or has foreign matter attached thereto during the manufacturing process of the transfer substrate.

[0032] The semi-transmitting film 3, the light-shielding film 4, and the semi-transmitting film 7 as a surface layer, which will be described later, are made of different materials and therefore have different etching characteristics. That is, the semi-transmitting film 3 has etching selectivity with respect to each of the light-shielding film 4 and the semi-transmitting film 7, the light-shielding film 4 has etching selectivity with respect to each of the semi-transmitting film 3 and the semi-transmitting film 7, and the semi-transmitting film 7 has etching selectivity with respect to each of the semi-transmitting film 3 and the light-shielding film 4.

[0033] The semi-transmitting film 7 is a kind of functional film having a function of adjusting the optical characteristics of the exposure light, and is a functional film having a function of adjusting the transmittance of the exposure light, that is, a halftone film. The halftone film has a transmittance lower than the transmittance of the transparent substrate 2 and higher than the transmittance of the light-shielding film 4 for the representative wavelength contained in the exposure light, and is set to have a transmittance within a range of 10% to 75% for the representative wavelength. The halftone film is set so that the phase shift amount for the representative wavelength is less than 20°, more preferably less than 5°. The halftone film may be a semi-transmitting metal film in which the transmittance distribution in the plane of the photomask is improved by adjusting the nitrogen content. The halftone film can also change the optical density (OD value) in the semi-transmitting part 12 by containing other elements. The advantage of using such a semi-transmitting film is that it has an effect of improving the process margin on the panel side.

[0034] The semi-transparent film 7 is made of an appropriate material selected from known materials such as Cr or a Cr-based compound, Ni or a Ni-based compound, Ti or a Ti-based compound, Si-based compound, Zr or a Zr-based compound, and a metal silicide-based compound.

[0035] <Method of Manufacturing Photomask According to Embodiment 1> The method for producing the photomask 1 according to the first embodiment is as shown in FIGS. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) First surface layer etching process (process 11) xii) Second upper layer etching process (process 12) xiii) Underlayer film etching step (step 13) xiv) Secondary resist film removal process (process 14) xv) Second surface layer etching process (process 15) Equipped with.

[0036] 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 upper layer film (light-shielding film) 4 of the photomask blank is patterned, and in the latter patterning process, the lower layer film (phase shift film) 3 of the photomask blank is patterned.

[0037] In the photomask blanks preparation step (step 1), a photomask blank is prepared as shown in Fig. 2(a). In the photomask blanks, a lower layer film 3 is formed on a transparent substrate 2, and an upper layer film 4 is formed on the lower layer film 3, so that the lower layer film 3 and the upper layer film 4, which have different etching properties, are laminated on the transparent substrate 2. The lower layer film 3 and the upper layer film 4 are each formed by a physical vapor deposition (PVD) method such as a sputtering method or a deposition method.

[0038] In the first resist film formation step (step 2), as shown in FIG. 2(b), a resist is uniformly applied onto the upper layer film 4 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 type or negative type, but in this example, a positive type is used.

[0039] In the first writing step (step 3), as shown in FIG. 2(c), the resist film 5 is irradiated with exposure light 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 of the exposure amounts is opposite to that of a positive resist. In addition to writing the resist pattern, in the first writing step, a mark (alignment mark) for aligning the position of writing in the second writing step is written. Although not shown, the alignment marks are formed, for example, at appropriate three or four places in the surrounding region surrounding the resist pattern.

[0040] In the first developing step (step 4), as shown in FIG. 2(d), unnecessary resist film 5 (second region 5b) is removed by development to form first resist patterns 5A and 5B. The first resist patterns 5A and 5B are patterns including a first pattern 5A corresponding to a first region 11 of the pattern of the photomask 1, and a second pattern 5B separated from the first pattern 5A and set at a position where the edge of the first pattern 5A side corresponds to the position of the edge of the second region 12 of the pattern of the photomask 1. Development is performed by a dipping method, a spin method, a paddle method, a spray method, or the like. The first resist film forming step, the first drawing step, and the first developing step are collectively referred to as a first resist pattern forming step.

[0041] In the first upper layer film etching step (step 5), as shown in FIG. 3(a), the exposed portion of the upper layer film 4 is removed by etching using the first resist patterns 5A and 5B as an etching mask. The etching may be either dry etching or wet etching, but wet etching is preferable for a large-sized photomask. An etching solution or an etching gas is used as the etchant. Regardless of the etchant, an etchant having etching selectivity for the upper layer film 4 (an etchant that does not etch the lower layer film 3) is used. During etching, the upper layer film 4 is also side-etched. This is why the edge position of the upper layer film 4 is offset inward from the edge position of the first resist patterns 5A and 5B in the figure. However, depending on the film thickness of the upper layer film 4, the material of the upper layer film 4, or the type of etchant, side etching may not occur. The etching rate of the upper layer film 4 can be adjusted by adjusting the concentration, temperature, etching time, and other conditions under which the etchant is used. By adjusting the etching rate of the upper layer 4, it is possible to adjust the offset dimension to a desired value.

[0042] In the first resist film removal step (step 6), the remaining resist film 5 (first resist patterns 5A, 5B) is removed as shown in FIG. 3(b). The resist film 5 is removed by an ashing method, a dipping method, or the like. As a result, upper layer film patterns 4A, 4B are formed on the semipermeable membrane 3. The upper layer film patterns 4A, 4B are patterns including a first pattern 4A corresponding to a first region 11 of the pattern of the photomask 1, and a second pattern 4B spaced apart from the first pattern 4A and set at a position where an edge on the first pattern 4A side corresponds to the position of an edge of a second region 12 of the pattern of the photomask 1.

[0043] 3(c), in the surface layer film formation step (step 7), a surface layer film (halftone film) 7 is formed to cover the entire surface, and thus the lower layer film 3, the upper layer film 4, and the surface layer film 7, which have different etching characteristics from each other, are laminated on the transparent substrate 2. The surface layer film 7 is formed by a physical vapor deposition method such as a sputtering method or a deposition method.

[0044] In the second resist film forming step (step 8), as shown in Fig. 3(d), a resist is applied onto the surface film 7 to form a resist film 5. The method itself is the same as in the first resist film forming step.

[0045] In the second drawing process (step 9), as shown in Fig. 4(a), a second resist pattern is drawn on the resist film 5. The method itself is the same as in the first drawing process, and the drawing device is the same as the drawing device used in the first drawing process. In the second drawing process, the drawing device detects the alignment marks formed in the surrounding area surrounding the pattern formation area of ​​the lower film in the first drawing process, and aligns the transparent substrate 2.

[0046] However, the second resist pattern only needs to cover and protect the necessary areas, and does not require high positional accuracy, so strict alignment is not required in the second drawing process.

[0047] However, in the second drawing process, misalignment inevitably occurs. Therefore, in the second drawing process, a second resist pattern is set taking misalignment into consideration. Specifically, the second resist pattern is designed to lap (overlap) the laminated portion of the lower layer film 3, the upper layer film 4, and the surface layer film 7 by a predetermined lap amount from the edge of the laminated portion. The lap amount is, for example, a value of 0.3 μm or more and 0.5 μm or less.

[0048] In the second development step (step 10), as shown in FIG. 4(b), unnecessary resist film 5 (part 5b) is removed by development to form a second resist pattern 5C. The second resist pattern 5C is a pattern that covers the first pattern 4A (and the surface layer 7 laminated thereon) of the upper layer film pattern, the surface layer 7A (exposed part of the lower layer film 3 and laminated thereon) between the first pattern 4A and the second pattern 4B of the upper layer film pattern, and at least a part including the edge on the first pattern 4A side (and the surface layer 7 laminated thereon) of the second pattern 4B of the upper layer film pattern, and exposes at least a part of the other part (and the surface layer 7 laminated thereon) of the second pattern 4B of the upper layer film pattern. The method itself is the same as that of the first development step. According to the second resist pattern 5C, the end face of the edge of the first pattern 4A of the upper layer film pattern (and the end face of the edge of the surface layer film 7 laminated thereon) and at least the end face of the edge of the second pattern 4B of the upper layer film pattern on the first pattern 4A side (and the end face of the edge of the surface layer film 7 laminated thereon) are also covered with resist. Note that the meaning of "covering" includes not only covering the upper layer film patterns 4A and 4B with the second resist pattern 5C in contact with the upper layer film patterns 4A and 4B, but also covering the upper layer film patterns 4A and 4B with the second resist pattern 5C in contact with the surface layer film 7 laminated on the upper layer film patterns 4A and 4B as described above, and the meaning of "exposing" includes not only exposing the upper layer film pattern 4B from the second resist pattern 5C with the surface of the upper layer film pattern 4B in contact with the outside air, but also exposing the upper layer film pattern 4B from the second resist pattern 5C with the surface layer film 7 laminated thereon as described above. The second resist film forming process, the second drawing process, and the second developing process are collectively referred to as a second resist pattern forming process.

[0049] In the first surface layer film etching step (step 11), as shown in FIG. 4(c), the surface layer film 7 laminated on the second pattern 4B of the upper layer film pattern is removed by etching. The etching may be either dry etching or wet etching, but wet etching is preferred for a large-sized photomask. An etching solution or an etching gas is used as the etchant. Regardless of the etchant, an etchant having etching selectivity for the surface layer film 7 (an etchant that does not etch the lower layer film 3 and the upper layer film 4) is used. In the first surface layer film etching step, the surface layer film 7 laminated on the second pattern 4B of the upper layer film pattern is finally side-etched and completely removed. Depending on the etching rate of the surface layer film 7, the surface layer film 7 may not be completely removed by side etching, and a part of the surface layer film 7 (especially the part behind the undercut part of the second resist pattern 5C) may remain. Even in such a case, the remaining surface layer 7 is removed (by lift-off) together with the second pattern 4B of the upper layer film pattern in the next step (second upper layer film etching step), so no problem occurs.

[0050] In the second upper layer film etching process (step 12), as shown in FIG. 4(d), the second pattern 4B of the upper layer film pattern is removed by etching. The method itself is the same as the first upper layer film etching process. In the second upper layer film etching process, the second pattern 4B of the upper layer film pattern is finally side-etched and completely removed. As a result, an edge (lower edge) that coincides with the position of the edge of the second pattern 4B of the upper layer film pattern on the first pattern 4A side is formed at the bottom of the second resist pattern 5C, and an edge that coincides with the position of the edge of the second pattern 4B of the upper layer film pattern on the first pattern 4A side is formed at the surface film 7A.

[0051] In the underlayer film etching step (step 13), as shown in FIG. 5(a), the exposed portion of the underlayer film 3 is removed by etching using the second resist pattern 5C (its lower edge) or the surface film 7A as an etching mask. Note that "the second resist pattern 5C (its lower edge) or the surface film 7A" means that either of them can be used depending on the situation. In the figure, the surface film 7A is the etching mask. The etching may be either dry etching or wet etching, but wet etching is preferable for a large-sized photomask. An etchant is an etching solution or an etching gas. Regardless of which etchant is used, an etchant that has etching selectivity for the underlayer film 3 (an etchant that does not etch the upper layer film 4 and the surface film 7A) is used. Note that during etching, the underlayer film 3 is also side-etched. This is why the position of the edge of the underlayer film 3 is offset inward from the position of the lower edge of the second resist pattern 5C and the edge of the surface film 7A in the figure. However, depending on the film thickness of the underlayer film 3, the material of the underlayer film 3, or the type of etchant, side etching may not occur. The etching rate of the underlayer film 3 can be adjusted by adjusting the concentration of the etchant, temperature, etching time, and other conditions for using the etchant. By adjusting the etching rate of the underlayer film 3, it is possible to adjust the offset dimension to a desired value.

[0052] In the second resist film removal step (step 14), the remaining resist film 5 (second resist pattern 5C) is removed as shown in Fig. 5(b) in the same manner as in the first resist film removal step.

[0053] In the second surface layer etching step (step 15), as shown in Fig. 5(c), the surface layer 7 (the surface layer 7 laminated on the upper layer 4 and the surface layer 7A laminated on the exposed portion of the lower layer 3) is removed by etching. The method itself is the same as that of the first surface layer etching step.

[0054] <Method of manufacturing a photomask according to another example of the first embodiment> A method for producing a photomask according to another embodiment of the present invention is as shown in FIGS. 6 to 9. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) First surface layer etching process (process 11) xii) Second upper layer etching process (process 12) xiii) Underlayer film etching step (step 13) xiv) Secondary resist film removal process (process 14) xv) Second surface layer etching process (process 15) Equipped with.

[0055] The method for manufacturing a photomask according to another example of embodiment 1 is substantially the same as the method for manufacturing photomask 1 according to embodiment 1, except that the width of second pattern 4B of the upper layer film pattern is reduced within a range that is not affected by misalignment (see FIG. 7(b)). Therefore, the description of the method for manufacturing photomask 1 according to another example of embodiment 1 will be omitted, since it is the same as the description of the method for manufacturing photomask 1 according to embodiment 1.

[0056] It goes without saying that the method for manufacturing the photomask 1 according to the modified example of the first embodiment can also be applied to the second, third, seventh, and eighth embodiments described below.

[0057] <Configuration of the Photomask According to the Second Embodiment> As shown in Fig. 10, the pattern of the photomask 1 according to the second embodiment is a hole pattern having holes (transmitting portions 10) of a size in the order of µm (in some cases, these are arranged one-dimensionally or two-dimensionally at a predetermined interval). Therefore, in the photomask 1 according to the second embodiment, the transmitting portions 10 that become the hole pattern are formed in the underlayer film 3, and the second regions 12 are formed around them. The configuration of the photomask 1 according to the second embodiment is substantially the same as that of the photomask 1 according to the first embodiment, except for the difference in the shape of the pattern. Therefore, the description of the configuration of the photomask 1 according to the second embodiment will be omitted, since it is the same as the description of the configuration of the photomask 1 according to the first embodiment.

[0058] <Method of Manufacturing Photomask According to Second Embodiment> The method for producing the photomask 1 according to the second embodiment is as shown in FIGS. 11 to 14. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) First surface layer etching process (process 11) xii) Second upper layer etching process (process 12) xiii) Underlayer film etching step (step 13) xiv) Secondary resist film removal process (process 14) xv) Second surface layer etching process (process 15) Equipped with.

[0059] 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 since it is the same as the description of the method for manufacturing the photomask 1 according to the first embodiment.

[0060] Supplementally, in the photomask 1 according to the first embodiment, the first region 11 and the second region 12 are defined in the first writing step, and the first region 11 functions as the light-shielding portion 11. In contrast, in the photomask 1 according to the second embodiment, the second pattern 4B of the upper layer film pattern is for defining the dimensions of a resist pattern for forming a hole pattern to be formed in the lower layer film 3, and is finally removed, and then the lower layer film 3 is removed using the resist pattern for forming the hole pattern as a mask, and the hole pattern is formed.

[0061] <Configuration of the Photomask According to the Third Embodiment> 15, the configuration of the photomask 1 according to embodiment 3 is substantially the same as that of the photomask 1 according to embodiment 1, except that the widths of the second regions (rim portions) 12, 12 on both sides are different (width A on the left side > width B on the right side). Therefore, a description of the configuration of the photomask 1 according to embodiment 3 will be omitted since it is the same as the description of the configuration of the photomask 1 according to embodiment 1.

[0062] <Method of Manufacturing Photomask According to Third Embodiment> The method for manufacturing the photomask 1 according to the third embodiment is as shown in FIGS. 16 to 19. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) First surface layer etching process (process 11) xii) Second upper layer etching process (process 12) xiii) Underlayer film etching step (step 13) xiv) Secondary resist film removal process (process 14) xv) Second surface layer etching process (process 15) Equipped with.

[0063] 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 widths of the resist removed portions on both sides are different (width a on the left side in FIG. 16(d) > width b on the right side). 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 description of the method for manufacturing the photomask 1 according to the first embodiment.

[0064] The asymmetric pattern of the photomask 1 according to the third embodiment and the manufacturing method thereof are not limited to the line-and-space pattern of the first embodiment, but can be applied to various patterns. For example, the third embodiment can also be applied to the hole pattern of the second embodiment. In this case, the width of the resist-removed portions on both sides can be made different in FIG. 11(d). Also, the width of the second region (rim portion) 12 can be made different not only in the left-right direction, but also in the up-down direction in FIG. 10(a). That is, the widths of the four sides of the hole can be set individually and arbitrarily.

[0065] <Configuration of the Photomask According to the Fourth Embodiment> 20, the configuration of the photomask 1 according to the embodiment 4 is the same as the configuration of the photomask 1 according to the embodiment 1. Therefore, the description of the configuration of the photomask 1 according to the embodiment 4 will be omitted since it is the same as the description of the configuration of the photomask 1 according to the embodiment 1.

[0066] <Method of Manufacturing Photomask According to Embodiment 4> The method for manufacturing the photomask 1 according to the fourth embodiment is as shown in FIGS. 21 to 24. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) Second upper layer etching process (process 11) xii) Underlayer film etching process (process 12) xiii) Second resist film removal process (process 13) Equipped with.

[0067] The method for producing the photomask 1 according to the fourth embodiment is substantially the same as the method for producing the photomask 1 according to the first embodiment, except that the surface film 8 in the surface film forming step is a chemical agent, and this chemical agent is integrated with the resist film in the second resist film forming step (constituting the lower layer of the resist film) and is removed integrally with the resist film, making the surface film etching steps (first surface film etching step and second surface film etching step) in the method for producing the photomask 1 according to the first embodiment unnecessary. Therefore, the description of the method for producing the photomask 1 according to the fourth embodiment will be omitted, since it is the same as the description of the method for producing the photomask 1 according to the first embodiment, except for the differences described below.

[0068] In the surface layer film forming step (step 7), as shown in FIG. 22(c), a chemical is uniformly applied to cover the entire surface, and a surface layer film 8 made of a chemical film is formed. The chemical is dissolved by development together with the resist, and an example of the chemical is HMDS (hexamethyldisilazane). The chemical is applied by a coating method, a spray method, or the like.

[0069] In the description of the manufacturing method of the photomask 1 of embodiment 1, the terms "surface film 7" and "surface film 7A" shall be read as "surface film 8" and "surface film 8A," and the process numbers and figure numbers shall be read as corresponding numbers as appropriate.

[0070] <Method of manufacturing a photomask according to another example of the fourth embodiment> A method for producing a photomask according to another embodiment of the present invention is as shown in FIGS. 25 to 28. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) Second upper layer etching process (process 11) xii) Underlayer film etching process (process 12) xiii) Second resist film removal process (process 13) Equipped with.

[0071] The method for manufacturing a photomask according to another example of embodiment 4 is substantially the same as the method for manufacturing the photomask 1 according to embodiment 4, except that the width of the second pattern 4B of the upper layer film pattern is reduced within a range that is not affected by misalignment (see FIG. 26(b)). Therefore, the description of the method for manufacturing the photomask 1 according to another example of embodiment 4 will be omitted, as it is the same as the description of the method for manufacturing the photomask 1 according to embodiments 1 and 4.

[0072] It goes without saying that the method for manufacturing the photomask 1 according to the modified example of the fourth embodiment can also be applied to the fifth and sixth embodiments described below.

[0073] <Configuration of the Photomask According to the Fifth Embodiment> 29, the pattern of the photomask 1 according to the fifth embodiment is a hole pattern. 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 fourth embodiment, except for the difference in the form of the pattern. The configuration of the photomask 1 according to the fifth embodiment is also the same as the configuration of the photomask 1 according to the second embodiment. Therefore, the description of the configuration of the photomask 1 according to the fifth embodiment will be omitted since it is the same as the description of the configuration of the photomask 1 according to the first embodiment.

[0074] <Method of Manufacturing Photomask According to Embodiment 5> The method for manufacturing the photomask 1 according to the fifth embodiment is as shown in FIGS. 30 to 33. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) Second upper layer etching process (process 11) xii) Underlayer film etching process (process 12) xiii) Second resist film removal process (process 13) Equipped with.

[0075] The method for manufacturing the photomask 1 according to the fifth embodiment is substantially the same as the method for manufacturing the photomask 1 according to the fourth embodiment, except for the difference in the shape of the pattern. Therefore, the description of the method for manufacturing the photomask 1 according to the fifth embodiment will be omitted since it is the same as the description of the method for manufacturing the photomask 1 according to the first and fourth embodiments.

[0076] <Configuration of the Photomask According to the Sixth Embodiment> 34, the configuration of the photomask 1 according to embodiment 6 is substantially the same as the configuration of the photomask 1 according to embodiment 4, except that the widths of the second regions (rim portions) 12, 12 on both sides are different (width A on the left side > width B on the right side). The configuration of the photomask 1 according to embodiment 6 is also the same as the configuration of the photomask 1 according to embodiment 3. Therefore, a description of the configuration of the photomask 1 according to embodiment 6 will be omitted, as it is the same as the description of the configuration of the photomask 1 according to embodiment 1.

[0077] <Method of Manufacturing Photomask According to Sixth Embodiment> The method for manufacturing the photomask 1 according to the sixth embodiment is as shown in FIGS. 35 to 38. i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) Second upper layer etching process (process 11) xii) Underlayer film etching process (process 12) xiii) Second resist film removal process (process 13) Equipped with.

[0078] The method for manufacturing the photomask 1 according to the sixth embodiment is substantially the same as the method for manufacturing the photomask 1 according to the fourth embodiment, except that the widths of the resist removed portions on both sides are different (width a on the left side in FIG. 35(d) > width b on the right side). Therefore, the description of the method for manufacturing the photomask 1 according to the sixth embodiment will be omitted, as it is the same as the description of the method for manufacturing the photomask 1 according to the first and fourth embodiments.

[0079] The asymmetric pattern of the photomask 1 according to the sixth embodiment and the manufacturing method thereof are not limited to the line-and-space pattern of the fourth embodiment, but can be applied to various patterns. For example, the sixth embodiment can also be applied to the hole pattern of the fifth embodiment. In this case, the width of the resist-removed portions on both sides can be made different in FIG. 30(d). Also, the width of the second region (rim portion) 12 can be made different not only in the left-right direction, but also in the up-down direction in FIG. 29(a). That is, the widths of the four sides of the hole can be set individually and arbitrarily.

[0080] <Configuration of the Photomask According to the Seventh Embodiment> As shown in FIG. 39, the pattern of the photomask 1 according to the seventh embodiment is a line-and-space pattern in which the upper layer 4 is formed on the lower layer 3 so that at least a part of the peripheral region of the lower layer 3 is exposed, the surface layer 7 is formed so as to overlap the exposed part of the lower layer 3 and the upper layer 4, the semi-transparent part 12 is composed of the lower layer 3 and the surface layer 7, and the second region 12 is a laminated part of the lower layer 3 and the surface layer 7. The configuration of the photomask 1 according to the seventh embodiment is substantially the same as that of the photomask 1 according to the first embodiment, except that the pattern form is different. Therefore, the description of the configuration of the photomask 1 according to the seventh embodiment is omitted since it is the same as the description of the configuration of the photomask 1 according to the first embodiment. In FIG. 39, the position of the edge of the lower layer 3 is offset inward from the position of the edge of the surface layer 7, and the edge part of the surface layer 7 protrudes (overhangs), but this is due to an exaggerated description in the drawing, and an excessive overhang part is not formed in the actual product.

[0081] As an example, the lower layer film 3 is a phase shift film, the surface layer film 7 is a half-tone film, the lower layer film 3 has a high transmittance (10 to 90%), the surface layer film 7 has a high transmittance (10 to 75%), the upper layer film 4 is a light-shielding film or 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 functioning as a 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 surface layer film 7 is greater than 0° and less than 20° (low phase)).

[0082] <Method of Manufacturing Photomask According to Seventh Embodiment> A method for producing the photomask 1 according to the seventh embodiment includes the steps of: i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) First surface layer etching process (process 11) xii) Second upper layer etching process (process 12) xiii) Underlayer film etching step (step 13) xiv) Secondary resist film removal process (process 14) Equipped with.

[0083] The method for manufacturing the photomask 1 according to the seventh embodiment is the same as steps 1 to 14 of the method for manufacturing the photomask 1 according to the first embodiment. That is, the method for manufacturing the photomask 1 according to the seventh embodiment is the same as the method for manufacturing the photomask 1 according to the first embodiment, except that steps up to 14 are performed but step 15 is not performed. Therefore, the description of the method for manufacturing the photomask 1 according to the seventh embodiment will be omitted since it is the same as the description of the method for manufacturing the photomask 1 according to the first embodiment.

[0084] It goes without saying that the asymmetric pattern of the photomask 1 according to the third embodiment and the manufacturing method thereof are also applicable to the seventh embodiment.

[0085] <Configuration of the Photomask According to the Eighth Embodiment> As shown in FIG. 40, the pattern of the photomask 1 according to the eighth embodiment is a hole pattern in which the upper layer 4 is formed on the lower layer 3 so that at least a part of the peripheral region of the lower layer 3 is exposed, the surface layer 7 is formed so as to overlap the exposed part of the lower layer 3 and the upper layer 4, the semi-transparent part 12 is composed of the lower layer 3 and the surface layer 7, and the second region 12 is a laminated part of the lower layer 3 and the surface layer 7. The configuration of the photomask 1 according to the eighth embodiment is substantially the same as that of the photomask 1 according to the second and seventh embodiments, except that the pattern form is different. Therefore, the description of the configuration of the photomask 1 according to the eighth embodiment is omitted since it is the same as the description of the configuration of the photomask 1 according to the first and seventh embodiments. In FIG. 40, the position of the edge of the lower layer 3 is offset inward from the position of the edge of the surface layer 7, and the edge part of the surface layer 7 protrudes (overhangs), but this is due to an exaggerated description in the drawing, and an excessive overhang part is not formed in the actual product.

[0086] <Method of Manufacturing Photomask According to Embodiment 8> A method for producing the photomask 1 according to the eighth embodiment includes the steps of: i) Photomask blanks 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 upper layer etching process (process 5) vi) First resist film removal process (process 6) vii) Surface 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) First surface layer etching process (process 11) xii) Second upper layer etching process (process 12) xiii) Underlayer film etching step (step 13) xiv) Secondary resist film removal process (process 14) Equipped with.

[0087] The method for manufacturing the photomask 1 according to the embodiment 8 is the same as steps 1 to 14 of the method for manufacturing the photomask 1 according to the embodiment 2. That is, the method for manufacturing the photomask 1 according to the embodiment 8 is the same as the method for manufacturing the photomask 1 according to the embodiment 2, except that steps up to step 14 are performed but step 15 is not performed. Therefore, the description of the method for manufacturing the photomask 1 according to the embodiment 8 will be omitted since it is the same as the description of the method for manufacturing the photomask 1 according to the embodiment 1.

[0088] It goes without saying that the asymmetric pattern of the photomask 1 according to the third embodiment and the manufacturing method thereof can also be applied to the eighth embodiment.

[0089] <Effects of the photomask manufacturing method according to each embodiment>

[0090] According to the method for manufacturing the photomask 1 of the above embodiment, except for the drawing process in which the positional accuracy of the pattern is not important (secondary drawing process), the final required pattern dimensions can be determined in one drawing process (first drawing process). This eliminates the need for excessive alignment accuracy in the manufacturing process of the photomask 1. Therefore, according to the method for manufacturing the photomask 1 of the above embodiment, there is no alignment deviation, and high definition of the photomask 1 can be achieved.

[0091] Moreover, according to the manufacturing method of the photomask 1 of the above embodiment, the position of the edge of the second region 12 of the pattern of the photomask 1 is determined based on the position of the edge of the second pattern 4B of the upper layer film pattern on the first pattern 4A side, not the position of the edge of the second pattern 4B of the upper layer film pattern on the opposite side to the first pattern 4A. As a result, the width of the second pattern 4B of the upper layer film pattern is not a factor in setting the width of the second region 12. Therefore, according to the manufacturing method of the photomask 1 of the above embodiment, it is possible to realize a photomask with even higher resolution than the conventional manufacturing method of a photomask.

[0092] According to the manufacturing method of the photomask 1 of the first to third, seventh and eighth embodiments, for example, the lower layer 3 is a metal silicide-based film, and the surface layer 7 is a film other than the metal silicide-based film, and has different etching characteristics from the lower layer 3 and the upper layer 4. The metal silicide-based film has an advantage of having high characteristics as a phase shift film, but has a disadvantage of poor adhesion to the resist (this is the current understanding of the applicant). When the surface layer 7 is provided, the resist in the second resist film formation step is in contact with the surface layer 7 (adhesion auxiliary film) that has better adhesion to the resist than the lower layer 3, not with the lower layer 3. Therefore, according to the manufacturing method of the photomask 1 of the first to third, seventh and eighth embodiments, a high-definition photomask can be manufactured with a good yield.

[0093] According to the manufacturing method of the photomask 1 of the fourth to sixth embodiments, the lower layer film 3 is a metal silicide-based film, and the surface layer film 8 is a chemical film, for example. The metal silicide-based film has the advantage of being highly characteristic as a phase shift film, but has the disadvantage of being poor in adhesion to the resist (this is the current understanding of the applicant). When the surface layer film 8 is provided, the resist in the second resist film formation step comes into contact not with the lower layer film 3, but with the surface layer film 8 (adhesion assistant) which has better adhesion to the resist than the lower layer film 3. Therefore, according to the manufacturing method of the photomask 1 of the fourth to sixth embodiments, a high-definition photomask can be manufactured with a good yield.

[0094] Furthermore, according to the manufacturing method of the photomask 1 of the third and sixth embodiments, the width of each of the second regions (rim portions) 12, 12 on both sides can be set individually and arbitrarily by changing the positions of the second patterns 5B, 5B on both sides of the primary resist pattern (the second patterns 4B, 4B on both sides of the upper layer film pattern). Therefore, according to the manufacturing method of the photomask 1 of the third and sixth embodiments, it is also possible to form an asymmetric pattern in which one second region (rim portion) 12 is wider and the other second region (rim portion) 12 is narrower.

[0095] Moreover, according to the manufacturing method of the photomask 1 of the seventh and eighth embodiments, a step (secondary surface layer etching step in the manufacturing method of the photomask 1 of the first and second embodiments) can be omitted. Moreover, according to the manufacturing method of the photomask 1 of the seventh and eighth embodiments, various gradations can be adjusted later, for example, by removing the surface layer 7 of only one of the second regions (rim portions) 12, 12 on both sides by additional processing, thereby improving the degree of freedom in design.

[0096] <Other embodiments> The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0097] In each drawing, the lower layer film (semi-transparent film) 3, upper layer film (light-shielding film) 4, surface layer film (semi-transparent film) 7, and surface layer film (drug film) 8 are depicted as being exaggeratedly thick. However, this is for convenience, and the thickness of each film is set individually as appropriate. As an example, the thickness of the light-shielding film 4 is approximately the same as or thicker than the thickness of the semi-transparent film 3. The thickness of the semi-transparent film 7 is thinner than the thickness of the semi-transparent film 3. The drug film 8 is even thinner.

[0098] In the above embodiment, the second region 12 of the photomask pattern is a rim portion. However, the present invention is not limited to this. The second region may be another functional portion.

[0099] In the above embodiment, 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.

[0100] In the above embodiment, the lower layer is a phase shift film, and the upper layer is a light-shielding film. However, the present invention is not limited to this. The lower layer may be a halftone film, and the upper layer may be a phase shift film. Alternatively, the lower layer may be a phase shift film, and the upper layer may be a halftone film. In these cases, the laminated portion of the lower layer and the upper layer may function as a light-shielding portion. In short, the lower layer and the upper layer (and the surface layer) are each selected from various functional films having 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, and a laminated structure of any combination of the lower layer and the upper layer (and the surface layer) can be adopted.

[0101] Furthermore, the materials of the lower layer film and the upper layer film (and the surface layer film) are not limited to those exemplified in the above embodiment, and in essence, on the premise that the etching characteristics are different from each other, they can be selected from any of Cr-based materials, Ni-based materials, Ti-based materials, Si-based materials, Zr-based materials, and metal silicide-based materials, or even other materials, according to the corresponding transferred shape and portion.

[0102] In the above embodiment, the surface layer film is provided to compensate for poor adhesion between the underlayer film and the resist. However, the present invention is not limited to this. The surface layer film may be provided not for the purpose of improving adhesion with the resist, or in addition to this purpose, for the purpose of additionally providing a functional film having a function of adjusting the optical properties of the exposure light.

[0103] In the above embodiment, the structure has two layers, a lower layer and an upper layer. However, the present invention is not limited to this. As long as the layer structure is applicable to the photomask manufacturing method according to the present invention, other films may be formed in addition to the lower layer and upper layer. For example, i) an intermediate film such as an etching stopper film may be formed at the interface between the upper layer and the lower layer. Alternatively, ii) another film may be formed on the upper surface of the upper layer. Alternatively, iii) another film may be formed on the lower surface of the lower layer.

[0104] In the above embodiment, the photomask pattern is a line and space pattern in which lines (light-shielding portion 11) with a width in the μm unit and spaces (transmitting portion 10) with a width in the μm unit are arranged in parallel in at least a part of the region (sometimes these are alternately repeated). Alternatively, in the above embodiment, the photomask 1 pattern is a hole pattern having holes (transmitting portion 10) with a size in the μm unit in at least a part of the region (sometimes these are arranged one-dimensionally or two-dimensionally with a predetermined interval). However, the present invention is not limited to this. The photomask pattern may be a dot pattern having dots (light-shielding portion) with a size in the μm unit in at least a part of the region (sometimes these are arranged one-dimensionally or two-dimensionally with a predetermined interval). Of course, other patterns may be used. In short, the type of pattern is not limited as long as it can be implemented by the method of the present invention.

[0105] In addition, in the above embodiments 2, 5 and 8, the shape of the hole (transmissive portion 10) (boundary line with the rim portion (semi-transmissive portion 12)) is rectangular, and the shape of the rim portion (semi-transmissive portion 12) (boundary line with 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. Also, the shape of the hole and the shape of the rim portion may be different. [Explanation of symbols]

[0106] 1...photomask, 10...transmitting portion, 11...light-shielding portion (first region), 12...semi-transmitting portion (second region), 2...transparent substrate, 3...underlayer film (semi-transmitting film), 4...upperlayer film (light-shielding film), 4A...first pattern of upper layer film pattern, 4B...second pattern of upper layer film pattern, 5...resist film, 5a...first region, 5b...second region, 5A...first pattern of primary resist pattern, 5B...second pattern of primary resist pattern, 5C...second resist pattern, 7...surface film (semi-transmitting film), 8...surface film (drug film)

Claims

1. A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; and an upper layer film formed on the underlayer film so that at least a part of a peripheral region of the underlayer film is exposed; the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film and the upper layer film and a second region of the underlayer film, a photomask blanks preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are laminated on a transparent substrate; a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region; a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask; a surface layer film forming step of forming a surface layer film so as to cover an exposed portion of the lower layer film between at least the first pattern and the second pattern of the upper layer film pattern; a second resist pattern forming process for forming a second resist pattern that covers at least a portion of the first pattern of the upper layer film pattern, a surface layer film between the first pattern and the second pattern of the upper layer film pattern, and a portion of the second pattern of the upper layer film pattern that includes an edge on the first pattern side, and exposes at least a portion of the other portion of the second pattern of the upper layer film pattern; a second upper layer film etching process for removing the second pattern of the upper layer film pattern by etching; an underlayer film etching step of removing exposed portions of the underlayer film by etching using the second resist pattern or the surface film as a mask; and a surface film etching step of removing the surface film by etching. A method for manufacturing a photomask.

2. A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; and an upper layer film formed on the underlayer film so that at least a part of a peripheral region of the underlayer film is exposed; the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film and the upper layer film and a second region of the underlayer film, a photomask blanks preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are laminated on a transparent substrate; a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region; a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask; a surface layer film forming step of forming a surface layer film so as to cover an exposed portion of the lower layer film between at least the first pattern and the second pattern of the upper layer film pattern; a second resist pattern forming process for forming a second resist pattern that covers at least a portion of the first pattern of the upper layer film pattern, a surface layer film between the first pattern and the second pattern of the upper layer film pattern, and a portion of the second pattern of the upper layer film pattern that includes an edge on the first pattern side, and exposes at least a portion of the other portion of the second pattern of the upper layer film pattern; a second upper layer film etching process for removing the second pattern of the upper layer film pattern by etching; and an underlayer film etching step of removing exposed portions of the underlayer film by etching using the second resist pattern or the surface film as a mask. A method for manufacturing a photomask.

3. A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; an upper layer film formed on the underlayer film so that at least a portion of a peripheral region of the underlayer film is exposed; and a surface layer film formed so as to overlap at least the exposed portion of the underlayer film, the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film and the upper layer film and a second region of the laminated portion of the underlayer film and the surface layer film, a photomask blanks preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are laminated on a transparent substrate; a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region; a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask; a surface layer film forming step of forming a surface layer film so as to cover an exposed portion of the lower layer film between at least the first pattern and the second pattern of the upper layer film pattern; a second resist pattern forming process for forming a second resist pattern that covers at least a portion of the first pattern of the upper layer film pattern, a surface layer film between the first pattern and the second pattern of the upper layer film pattern, and a portion of the second pattern of the upper layer film pattern that includes an edge on the first pattern side, and exposes at least a portion of the other portion of the second pattern of the upper layer film pattern; a second upper layer film etching process for removing the second pattern of the upper layer film pattern by etching; and an underlayer film etching step of removing exposed portions of the underlayer film by etching using the second resist pattern or the surface film as a mask. A method for manufacturing a photomask.

4. The lower and upper layers are formed of a film having a first region functioning as a light shielding portion and a second region functioning as a phase shift portion. The method for manufacturing a photomask according to any one of claims 1 to 3.

5. A phase shift film is used as the underlayer film. A light-shielding film is used as the upper layer. The method for producing a photomask according to claim 4 .

6. The second region functions as a rim portion of the light blocking portion. The method for producing a photomask according to claim 4 .

7. 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.

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