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 Art

[0002] As photolithography techniques, a phase shift mask and a halftone mask are known. A phase shift mask includes a phase shift film on a part of a transparent substrate, and is a photomask having functions of improving resolution and improving depth of focus (DOF) by changing the phase and intensity of light passing through this part. A halftone mask includes a halftone film on a part of a transparent substrate, and is a photomask having a function of realizing multi-tone of three or more tones by changing the intensity of light passing through this part.

[0003] In a conventional method for manufacturing a photomask, at least two drawing steps (exposure steps), that is, a drawing step (exposure step) of a pattern constituting a light-shielding portion and a drawing step of a pattern constituting a semi-transmissive portion are required. And when there are a plurality of drawing steps, misregistration of the patterns formed in each step is likely to occur.

[0004] As a countermeasure against this, the use of an alignment mark is available. In the second and subsequent drawing steps, the alignment mark created in the first drawing step is read, and alignment (positioning) is performed based on this alignment mark. However, even when using an alignment mark, it is impossible to completely eliminate pattern misregistration (alignment misalignment), and an alignment misalignment of up to 0.5 μm occurs. For this reason, with the increase in the definition of photomasks, the influence is becoming significant.

[0005] Therefore, a method for manufacturing a photomask that can complete the drawing step in one time has been studied. For example, the method for manufacturing a photomask described in Patent Document 1 is A method for manufacturing a photomask including a lower layer film formed on a transparent substrate and an upper layer film formed on the lower layer film such that at least a part of a peripheral region of the lower layer film is exposed, the photomask including a pattern composed of a first region of a stacked portion of the lower layer film and the upper layer film and a second region of the lower layer film, i) a photomask blank preparation step of preparing a photomask blank on which the lower layer film and the upper layer film are stacked on the transparent substrate; ii) a first resist pattern formation step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern that is separated from the first pattern and is set at a position where an edge on the side opposite to the first pattern corresponds to the position of the edge of the second region; iii) a first upper layer film etching step of removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask, thereby forming an upper layer film pattern including a first pattern corresponding to the first region, a second pattern (temporary pattern) that is separated from the first pattern and is set at a position where an edge on the side opposite to the first pattern corresponds to the position of the edge of the second region; iv) a second resist pattern formation step of forming a second resist pattern that covers a portion of the first pattern of the upper layer film pattern, an 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 side opposite to the first pattern; v) a lower layer film etching step of removing an exposed portion of the lower layer film by etching using the second resist pattern and the second pattern (temporary pattern) of the upper layer film pattern as masks; vi) a second upper layer film etching step of removing the second pattern (temporary pattern) of the upper layer film pattern by etching.

[0006] According to the method for manufacturing a photomask described in Patent Document 1, except for the drawing process (secondary resist pattern formation process) in which the positional accuracy of the pattern is not emphasized, the drawing process can define the pattern dimensions finally required in one time (primary resist pattern formation process). As a result, in the manufacturing process of the photomask, it is not necessary to excessively require the alignment accuracy. That is, so-called self-aligned pattern formation is performed. Therefore, according to the method for manufacturing a photomask described in Patent Document 1, there is no alignment deviation, and high definition of the photomask can be realized.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in the method for manufacturing a photomask described in Patent Document 1, in order for the secondary resist pattern to surely cover the corresponding portion of the second pattern (provisional pattern) of the upper layer film pattern and prevent the exposed portion of the lower layer film between the first pattern and the second pattern (provisional pattern) of the upper layer film pattern from being exposed from the secondary resist pattern, the second pattern (provisional pattern) of the upper layer film pattern needs to be formed with a width larger than the alignment deviation of up to 0.5 μm.

[0009] Therefore, in a photomask where the first region is a light-shielding portion, the second region is a phase-shifting portion, and the second region functions as a rim portion of the light-shielding portion, in the case of manufacturing a photomask in the form of a line-and-space pattern in which lines (light-shielding portions) with a width in μm units and spaces (transmission portions) with a width in μm units are arranged in parallel, or a photomask in the form of a hole pattern having holes (transmission portions) with a size in μm units, the width of the second region (rim portion) becomes larger by an amount including the width of the second pattern (temporary pattern) of the upper layer film pattern, and it cannot be formed smaller than the total value of the width of the second pattern (temporary pattern) and the beam diameter of the drawing apparatus. This results in a constraint on the dimensions of the second region (rim portion).

[0010] Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide a method for manufacturing a photomask capable of achieving further high definition of the photomask as compared with a conventional method for manufacturing a photomask.

Means for Solving the Problem

[0011] The method for manufacturing a photomask according to the present invention is as follows. A method for manufacturing a photomask including a pattern composed of a first region of a stacked portion of a lower layer film and an upper layer film and a second region of the lower layer film, the method comprising a lower layer film formed on a transparent substrate and an upper layer film formed on the lower layer film so that at least a part of a peripheral region of the lower layer film is exposed. A photomask blank preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are stacked 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 that is separated from the first pattern and is set at a position where an edge on the first pattern side corresponds to a position of an edge of the second region. Using the first resist pattern as a mask, by removing the exposed portion of the upper layer film by etching, a first pattern corresponding to the first region and a second pattern that is separated from the first pattern and whose edge on the first pattern side is set at a position corresponding to the edge of the second region are formed. A first upper layer film etching step for forming an upper layer film pattern including: A surface layer film forming step of forming a surface layer film so as to cover at least the exposed portion of the lower layer film between the first pattern and the second pattern of the upper layer film pattern; Among the first pattern of the upper layer film pattern, the surface layer film between the first pattern and the second pattern of the upper layer film pattern, and the second pattern of the upper layer film pattern, covering at least the portion including the edge on the first pattern side, and exposing at least a part of the other portion of the second pattern of the upper layer film pattern. A second resist pattern forming step of forming a second resist pattern; A second upper layer film etching step of removing the second pattern of the upper layer film pattern by etching; Using the second resist pattern or the surface layer film as a mask, while removing the outer edge portion in contact with the edge of the second region of the exposed portion of the lower layer film by etching, and using the second resist pattern or the surface layer film or the first pattern of the upper layer film pattern as a mask, while removing the outer edge portion not in contact with the edge of the second region of the exposed portion of the lower layer film by etching, a lower layer film etching step of removing the exposed portion of the lower layer film by etching; A surface layer film etching step of removing the surface layer film by etching. It is a method for manufacturing a photomask.

[0012] As a specific example of such a configuration, Embodiment 1 and Embodiment 2 described later can be cited.

[0013] Another method for manufacturing a photomask according to the present invention is A method for manufacturing a photomask including a lower layer film formed on a transparent substrate and an upper layer film formed on the lower layer film such that at least a part of a peripheral region of the lower layer film is exposed, the method comprising a pattern composed of a first region of a stacked portion of the lower layer film and the upper layer film and a second region of the lower layer film, A photomask blank preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are stacked 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 edge of the second region, A first upper layer film etching step of removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask, thereby forming an upper layer film pattern including a first pattern corresponding to the first region, 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 edge of the second region, 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 step of forming a second resist pattern that covers at least a portion including an edge on the first pattern side among the first pattern of the upper layer film pattern, the surface layer film between the first pattern and the second pattern of the upper layer film pattern, and the second pattern of the upper layer film pattern, and exposes at least a part of another part of the second pattern of the upper layer film pattern, A second upper layer film etching step of removing the second pattern of the upper layer film pattern by etching, A lower layer film etching step of removing an outer edge portion of the exposed portion of the lower layer film that is in contact with the edge of the second region by etching using the second resist pattern or the surface layer film as a mask, and removing an outer edge portion of the exposed portion of the lower layer film that is not in contact with the edge of the second region by etching using the second resist pattern or the surface layer film or the first pattern of the upper layer film pattern as a mask, while removing the exposed portion of the lower layer film by etching, A method for manufacturing a photomask.

[0014] As specific examples of such a configuration, Embodiment 3 and Embodiment 4 described later can be cited.

[0015] Furthermore, another method for manufacturing a photomask according to the present invention is A method for manufacturing a photomask including a lower layer film formed on a transparent substrate and an upper layer film formed on the lower layer film so that at least a part of the peripheral region of the lower layer film is exposed, the method comprising a pattern composed of a first region of a stacked portion of the lower layer film and the upper layer film and a second region of the lower layer film, A photomask blank preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are stacked 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 edge of the second region, A first upper layer film etching step of removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask, thereby forming an upper layer film pattern including a first pattern corresponding to the first region, 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 edge of the second region, A second resist pattern forming step of forming a second resist pattern that covers at least a portion including the edge on the first pattern side among 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 of the upper layer film pattern, and the second pattern of the upper layer film pattern, and exposes at least a part of another portion of the second pattern of the upper layer film pattern, A second upper layer film etching step of removing the second pattern of the upper layer film pattern by etching, Using the second resist pattern as a mask, while removing, by etching, the outer edge portion of the exposed portion of the lower layer film that contacts the edge of the second region, and using the first pattern of the second resist pattern or the upper layer film pattern as a mask, while removing, by etching, the outer edge portion of the exposed portion of the lower layer film that does not contact the edge of the second region, a lower layer film etching step of removing the exposed portion of the lower layer film by etching is provided. It is a method for manufacturing a photomask.

[0016] As a specific example of such a configuration, Embodiment 5 and Embodiment 6 described later can be cited.

[0017] Furthermore, another method for manufacturing a photomask according to the present invention is A lower layer film formed on a transparent substrate, an upper layer film formed on the lower layer film so that at least a part of the peripheral region of the lower layer film is exposed, and a surface layer film formed so as to overlap at least the exposed portion of the lower layer film, and a pattern composed of a first region of the laminated portion of the lower layer film and the upper layer film and a second region of the laminated portion of the lower layer film and the surface layer film. A method for manufacturing a photomask, comprising: A photomask blank 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 that is separated from the first pattern and whose edge on the first pattern side is set at a position corresponding to the edge of the second region; A first upper layer film etching step of forming an upper layer film pattern including a first pattern corresponding to the first region and a second pattern that is separated from the first pattern and whose edge on the first pattern side is set at a position corresponding to the edge of the second region by removing the 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 the exposed portion of the lower layer film between the first pattern and the second pattern of the upper layer film pattern; A secondary resist pattern forming step of forming a secondary resist pattern that covers at least a portion including the edge on the first pattern side among the first pattern of the upper layer film pattern, the surface layer film between the first pattern and the second pattern of the upper layer film pattern, and the second pattern of the upper layer film pattern, and exposes at least a part of the other part of the second pattern of the upper layer film pattern; A secondary upper layer film etching step of removing the second pattern of the upper layer film by etching; Using the secondary resist pattern or the surface layer film as a mask, while removing the outer edge portion in contact with the edge of the second region among the exposed portions of the lower layer film by etching, and using the secondary resist pattern or the surface layer film or the first pattern of the upper layer film pattern as a mask, while removing the outer edge portion not in contact with the edge of the second region among the exposed portions of the lower layer film by etching, a lower layer film etching step of removing the exposed portion of the lower layer film by etching. It is a method for manufacturing a photomask.

[0018] As a specific example of such a configuration, Embodiment 7 and Embodiment 8 described later can be cited.

[0019] Here, as an aspect of the method for manufacturing a photomask according to the present invention, As the lower layer film and the upper layer film, a film is used in which the first region functions as a phase shift portion with a first transmittance portion having a transmittance higher than that of the light-shielding portion, and the second region functions as a phase shift portion with a second transmittance portion having a transmittance higher than that of the first transmittance portion. A configuration such as this can be adopted.

[0020] Also, in this case, As the lower layer film, a phase shift film is used, As the upper layer film, a halftone film is used. A configuration such as this can be adopted.

[0021] Also, as another aspect of the method for manufacturing a photomask according to the present invention, As the lower layer film, a phase shift film having a phase shift amount of approximately 180° is used. As the upper layer film, a halftone film with a phase shift amount of less than 20° is used, The total phase shift amount of the lower layer film and the laminated portion of the upper layer film is set to be approximately 180°. A configuration as described above can be adopted.

[0022] Also, as another aspect of the method for manufacturing a photomask according to the present invention, As the lower layer film, a phase shift film with a transmittance of 2% or more and 90% or less is used, As the upper layer film, a halftone film with a transmittance of 10% or more and 75% or less is used, The transmittance of the laminated portion of the lower layer film and the upper layer film is set to be 0.5% or more and 70% or less. A configuration as described above can be adopted.

[0023] Also, as yet another aspect of the method for manufacturing a photomask according to the present invention, The second region functions as a rim portion of the first transmittance portion. A configuration as described above can be adopted.

[0024] Also, as yet another aspect of the method for manufacturing a photomask according to the present invention, The pattern of the photomask is any one of a line and space pattern, a hole pattern, or a dot pattern. A configuration as described above can be adopted.

Advantages of the Invention

[0025] According to the present invention, the position of the edge of the second region of the pattern of the photomask is defined based on the position of the edge of the second pattern of the upper layer film on the side of the first pattern, rather than the position of the edge of the second pattern of the upper layer film on the side opposite to the first pattern. Thereby, when setting the width of the second region, the width of the second pattern of the upper layer film does not become a factor. For this reason, according to the present invention, further high definition of the photomask can be realized as compared with the conventional method for manufacturing a photomask.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22

Figure 23

Figure 24

Figure 25

Figure 26

Figure 27

Figure 28

Figure 29

Figure 30

Mode for Carrying Out the Invention

[0027] <Configuration of Photomask According to Embodiment 1> As shown in FIG. 1, the photomask 1 is a three - tone multi - tone photomask including a transmissive portion (white - blanked portion) 10, a first transmittance portion (dense - hatched portion) 11, and a second transmittance portion (sparse - hatched portion) 12. The transmissive portion 10 is composed of a transparent substrate 2. The first transmittance portion 11 is composed of a semi - transparent film 3 as a lower layer film and a semi - transparent film 4 as an upper layer film. The second transmittance portion 12 is composed of the semi - transparent film 3. That is, the exposed portion of the transparent substrate 2 where the semi - transparent film 3 and the semi - transparent film 4 are not laminated becomes the transmissive portion 10, the portion where the semi - transparent film 3 and the semi - transparent film 4 are laminated on the transparent substrate 2 becomes the first transmittance portion 11, and the portion where only the semi - transparent film 3 is formed on the transparent substrate 2 becomes the second transmittance portion 12.

[0028] The first transmittance portion 11 and the second transmittance 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 the laminated portion of the semi - transparent film 3 and the semi - transparent film 4 and functions as the first transmittance portion 11. The second region 12 is the single - layer portion of the semi - transparent film 3 and functions as the second transmittance portion 12.

[0029] In this embodiment, lines (first transmittance portion 11) with a width in μm units and spaces (transmissive portion 10) with a width in μm units are arranged in parallel (in some cases, these are alternately repeated), and the pattern of the photomask 1 is a line - and - space pattern. As an example, the pattern is used as a pattern for forming source and drain electrodes in a substrate to be transferred manufactured by photolithography using the photomask 1. In this case, the transmissive portion 10 functions as a channel portion, the first transmittance portion 11 functions as an electrode portion, and the second transmittance portion 12 functions as a rim portion of the first transmittance portion 11.

[0030] Providing the rim portion 12 is a measure for improving the process margin on the panel side. For example, the rim portion 12 is provided to steepen the edge of the resist pattern corresponding to the source / drain electrodes on the substrate to be transferred. 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.

[0031] The transparent substrate 2 is a substrate such as synthetic quartz glass. The transparent substrate 2 has a transmittance of 95% or more with respect to the representative wavelength (for example, i-line, h-line or g-line) included in the exposure light used in the exposure process of photolithography. Note that the exposure light may be, for example, i-line, h-line or g-line, or may be 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 the long wavelength side with respect to these lights. As an example, an expanded wavelength band of the exposure light from the broadband of 365 nm to 436 nm to 300 nm to 450 nm is applicable. However, the exposure light is not limited to these.

[0032] The semi-transmissive 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 with respect 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°. Further, the phase shift film has a transmittance lower than that of the transparent substrate 2 with respect to the representative wavelength included in the exposure light, and is set to have a transmittance within the range of 2% or more and 90% or less with respect to the representative wavelength.

[0033] The semi-permeable membrane 3 is made of a known material such as Cr or a Cr-based compound (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Cr, the same hereinafter), Ni or a Ni-based compound (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Ni, the same hereinafter), Ti or a Ti-based compound (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Ti, the same hereinafter), an Si-based compound (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Si, the same hereinafter), Zr or a Zr-based compound (oxides, nitrides, carbides, oxynitrides, oxynitride carbides, etc. of Zr, the same hereinafter), a metal silicide-based compound (molybdenum silicide, tungsten silicide, tantalum silicide, zirconium silicide or their nitrides, oxynitrides, etc., the same hereinafter), etc. Among these, a metal silicide-based material is used. In this embodiment, the semi-permeable membrane 3 is made of a molybdenum silicide compound.

[0034] The semi-permeable membrane 4 is a type of functional membrane having a function of adjusting the optical characteristics of the exposure light, and is a functional membrane having a function of adjusting the transmittance of the exposure light, that is, a halftone membrane. The halftone membrane has a transmittance lower than that of the transparent substrate 2 with respect to the representative wavelength included in the exposure light, and is set to have a transmittance within the range of 10% or more and 75% or less with respect to the representative wavelength. The semi-permeable membrane 4 is set to have a transmittance higher than that of the semi-permeable membrane 3. Alternatively, the semi-permeable membrane 4 is set to have the same transmittance as that of the semi-permeable membrane 3. Alternatively, the semi-permeable membrane 4 is set to have a transmittance lower than that of the semi-permeable membrane 3. Also, the halftone membrane is set so that the phase shift amount with respect to the representative wavelength is less than 20°, more preferably less than 5°. Note that the halftone membrane may be a semi-transmissive metal membrane in which the transmittance distribution in the plane of the photomask is improved by adjusting the nitrogen content. Also, the halftone membrane can change the optical density (OD value) in the second transmittance portion 12 by containing other elements. As an advantage of using such a semi-permeable membrane, there is an effect of improving the process margin on the panel side.

[0035] The semi-permeable membrane 4 is made of a known material 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, or a metal silicide-based compound. Among these, a Cr-based material is used. In this embodiment, a Cr-based compound is used for the semi-permeable membrane 4. The reason for using a Cr-based compound is that a thin film made of a Cr-based compound has suitable resistance to the cleaning process performed when there is dirt, adhesion of foreign substances, etc. on the photomask during the manufacturing process of the substrate to be transferred.

[0036] Since the semi-permeable membrane 3 and the semi-permeable membrane 4 are these membranes, the laminated portion (first transmittance portion 11) of the semi-permeable membrane 3 and the semi-permeable membrane 4 has a transmittance lower than that of the single-layer portion (second transmittance portion 12) of the semi-permeable membrane 3, and is set to have a transmittance within the range of 0.5% or more and 70% or less with respect to the representative wavelength. Also, the first transmittance portion 11 is set so that the phase shift amount with respect to the representative wavelength is approximately 180°.

[0037] The semi-permeable membrane 3, the semi-permeable membrane 4, and the semi-permeable membrane 7 as the surface layer film described later have different etching characteristics because their materials are different. That is, the semi-permeable membrane 3 has etching selectivity with respect to each of the semi-permeable membrane 4 and the semi-permeable membrane 7, the semi-permeable membrane 4 has etching selectivity with respect to each of the semi-permeable membrane 3 and the semi-permeable membrane 7, and the semi-permeable membrane 7 has etching selectivity with respect to each of the semi-permeable membrane 3 and the semi-permeable membrane 4.

[0038] The semi-transmissive film 7 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 adjusting the transmittance of the exposure light, that is, a halftone film. The halftone film has a transmittance lower than that of the transparent substrate 2 with respect to the representative wavelength included in the exposure light, and is set to have a transmittance within the range of 10% or more and 75% or less with respect to the representative wavelength. The semi-transmissive film 7 is set to have a transmittance higher than that of the semi-transmissive film 3 or the semi-transmissive film 4. Alternatively, the semi-transmissive film 7 is set to have the same transmittance as that of the semi-transmissive film 3 or the semi-transmissive film 4. Alternatively, the semi-transmissive film 7 is set to have a transmittance lower than that of the semi-transmissive film 3 or the semi-transmissive film 4. Further, the halftone film is set such that the amount of phase shift with respect to the representative wavelength is less than 20°, more preferably less than 5°. Note that the halftone film may be a semi-transmissive metal film in which the transmittance distribution in the plane of the photomask is improved by adjusting the nitrogen content. Further, the halftone film can also change the optical density (OD value) in the second transmittance portion 12 by containing other elements. As an advantage of using such a semi-transmissive film, there is an effect of improving the process margin on the panel side.

[0039] For the semi-transmissive film 7, an appropriate material is used 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.

[0040] <Method for manufacturing a photomask according to Embodiment 1> The method for manufacturing the photomask 1 according to Embodiment 1 is as shown in FIGS. 2 to 5. i) Photomask blank preparation step (Step 1) ii) First resist film formation step (Step 2) iii) First drawing step (Step 3) iv) First development step (Step 4) v) First upper layer film etching step (Step 5) vi) First resist film removal step (Step 6) vii) Surface layer film formation step (Step 7) viii) Second resist film formation step (Step 8) ix) Second exposure step (Step 9) x) Second development step (Step 10) xi) First surface layer film etching step (Step 11) xii) Second upper layer film etching step (Step 12) xiii) Lower layer film etching step (Step 13) xiv) Second resist film removal step (Step 14) xv) Second surface layer film etching step (Step 15) It includes the following steps.

[0041] Note that, from the first resist film formation step to the first resist film removal step, and from the second resist film formation step to the second resist film removal step are each referred to as a patterning step. In the former patterning step, the upper layer film (halftone film) 4 of the photomask blank is patterned, and in the latter patterning step, the lower layer film (phase shift film) 3 of the photomask blank is patterned.

[0042] In the photomask blank preparation step (Step 1), as shown in Fig. 2(a), a photomask blank is prepared. The photomask blank has a lower layer film 3 formed on a transparent substrate 2, and an upper layer film 4 formed on the lower layer film 3. Thus, on the transparent substrate 2, the lower layer film 3 and the upper layer film 4 with different etching characteristics are laminated. The lower layer film 3 and the upper layer film 4 are each formed by a physical vapor deposition method (PVD: Physical Vapor Deposition) such as sputtering or evaporation.

[0043] In the first resist film formation step (Step 2), as shown in Fig. 2(b), a resist is uniformly coated on the upper layer film 4 to form a resist film 5. The resist is coated by a coating method, a spray method, etc. The resist can be either positive or negative, but in this example, it is positive.

[0044] In the first drawing process (Process 3), as shown in FIG. 2(c), the resist film 5 is irradiated with exposure light using an electron beam or a laser of a drawing apparatus, and a first resist pattern is drawn. 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 a region exposed with a predetermined exposure amount. In the case of a negative resist, the relationship of the exposure amount is opposite to that of a positive resist. In addition, in the first drawing process, in addition to drawing the resist pattern, a mark (alignment mark) for aligning the drawing position in the second drawing process is drawn. Although not shown, the alignment mark is formed, for example, at three or four appropriate positions in the outer peripheral region surrounding the resist pattern.

[0045] In the first development process (Process 4), as shown in FIG. 2(d), the unnecessary resist film 5 (second region 5b) is removed by development, and the first resist patterns 5A and 5B are formed. The first resist patterns 5A and 5B include a first pattern 5A corresponding to the first region 11 of the pattern of the photomask 1, and a second pattern 5B that is separated from the first pattern 5A and is set at a position corresponding to the position of the edge of the second region 12 of the pattern of the photomask 1 on the side of the first pattern 5A. The development is performed by an immersion method, a spin method, a paddle method, a spray method, or the like. In addition, the first resist film formation process, the first drawing process, and the first development process are collectively referred to as the first resist pattern formation process.

[0046] In the first upper layer film etching step (step 5), as shown in FIG. 3(a), using the first resist patterns 5A and 5B as masks for etching, the exposed portions of the upper layer film 4 are removed by etching. The etching can be either dry etching or wet etching. However, for a large-sized photomask, wet etching is preferred. An etchant, such as an etching solution or an etching gas, is used. Whichever etchant is used, an etchant having etching selectivity with respect to the upper layer film 4 (an etchant that does not etch the lower layer film 3) is used. Note that during etching, the upper layer film 4 also undergoes side etching. In the figure, the reason why the position of the edge of the upper layer film 4 is offset inward from the positions of the edges of the first resist patterns 5A and 5B is for this reason. 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. Note that the etching rate of the upper layer film 4 can be adjusted by adjusting the concentration, temperature, etching time, and other conditions for using the etchant. By adjusting the etching rate of the upper layer film 4, it is possible to adjust to a desired offset dimension.

[0047] In the first resist film removal step (step 6), as shown in FIG. 3(b), the remaining resist film 5 (the first resist patterns 5A and 5B) is removed. The removal of the resist film 5 is performed by an ashing method, a dipping method, or the like. As a result, upper layer film patterns 4A and 4B are formed on the semipermeable film 3. The upper layer film patterns 4A and 4B include a first pattern 4A corresponding to the first region 11 of the pattern of the photomask 1, and a second pattern 4B that is separated from the first pattern 4A and is set at a position where the edge on the first pattern 4A side corresponds to the position of the edge of the second region 12 of the pattern of the photomask 1.

[0048] In the surface film formation step (Step 7), as shown in FIG. 3(c), a surface film (halftone film) 7 is formed so as to cover the entire surface, whereby a lower layer film 3, an upper layer film 4, and a surface film 7 having different etching characteristics from each other are laminated on the transparent substrate 2. The surface film 7 is formed by a physical vapor deposition method such as a sputtering method or an evaporation method.

[0049] In the second resist film formation step (Step 8), as shown in FIG. 3(d), a resist is applied on the surface film 7 to form a resist film 5. The method itself is the same as that in the first resist film formation step.

[0050] In the second drawing step (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 that in the first drawing step, and the drawing apparatus is the same apparatus as that used in the first drawing step. In the second drawing step, the drawing apparatus detects an alignment mark formed in an outer peripheral region surrounding the pattern formation region of the lower layer film in the first drawing step, and aligns the transparent substrate 2.

[0051] However, the second resist pattern only needs to cover and protect the necessary portions, and positional accuracy of the pattern is not required. Therefore, strict alignment is not necessary in the second drawing step.

[0052] Nevertheless, alignment deviation inevitably occurs in the second drawing step. Therefore, in the second drawing step, a second resist pattern considering the alignment deviation is set. Specifically, the second resist pattern wraps (overlaps) from the edge of the laminated portion to a predetermined wrap amount in the laminated portion of the lower layer film 3, the upper layer film 4, and the surface film 7. The wrap amount is, for example, a value of 0.3 μm or more and 0.5 μm or less.

[0053] In the second development process (process 10), as shown in FIG. 4(b), an unnecessary resist film 5 (portion 5b) is removed by development, and a second resist pattern 5C is formed. The second resist pattern 5C covers at least a portion including the edge on the first pattern 4A side of the upper layer film pattern (and the surface layer film 7 laminated thereon), and the surface layer film 7A (exposed portion of the lower layer film 3 and the surface layer film laminated thereon) between the first pattern 4A and the second pattern 4B of the upper layer film pattern, and the second pattern 4B of the upper layer film pattern, and exposes at least a part of the other portion of the second pattern 4B of the upper layer film pattern (and the surface layer film 7 laminated thereon). The method itself is the same as the first development process. According to the second resist pattern 5C, the end faces of the edges of the first pattern 4A of the upper layer film pattern (and the end faces of the edges of the surface layer film 7 laminated thereon), and at least the end faces of the edges on the first pattern 4A side of the second pattern 4B of the upper layer film pattern (and the end faces of the edges of the surface layer film 7 laminated thereon) are also covered with the resist. Note that "cover" means that in addition to the second resist pattern 5C covering the upper layer film patterns 4A and 4B in a state of being in contact with the upper layer film patterns 4A and 4B, as described above, it also includes the meaning that the second resist pattern 5C covers the upper layer film patterns 4A and 4B in a state of being in contact with the surface layer film 7 laminated on the upper layer film patterns 4A and 4B. "Expose" means that in addition to the upper layer film pattern 4B being exposed from the second resist pattern 5C in a state where the surface is in contact with the outside air, as described above, it also includes the meaning that the upper layer film pattern 4B is exposed from the second resist pattern 5C in a state where the surface layer film 7 is laminated thereon. Note that the second resist film formation process, the second drawing process, and the second development process are collectively referred to as the second resist pattern formation process.

[0054] In the first surface film etching step (Step 11), as shown in FIG. 4(c), the surface 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 etchant, such as an etching solution or an etching gas, is used. Whichever etchant is used, an etchant having etching selectivity with respect to the surface film 7 (an etchant that does not etch the lower layer film 3 and the upper layer film 4) is used. By the first surface film etching step, the surface 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 relationship of the surface film 7, the surface film 7 may not be completely removed by side etching, and a part of the surface film 7 (especially the part on the back side of the undercut portion of the second resist pattern 5C) may remain. Even in such a case, the remaining surface film 7 is removed together with the second pattern 4B of the upper layer film pattern in the next step (the second upper layer film etching step) (removal by lift-off), so there is no problem.

[0055] In the second upper layer film etching step (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 that of the first upper layer film etching step. By the second upper layer film etching step, the second pattern 4B of the upper layer film pattern is finally side-etched and completely removed. As a result, at the lower part of the second resist pattern 5C, an edge (lower edge) that coincides with the position of the edge on the first pattern 4A side of the second pattern 4B of the upper layer film pattern is formed, and on the surface film 7A, an edge that coincides with the position of the edge on the first pattern 4A side of the second pattern 4B of the upper layer film pattern is formed.

[0056] In the lower layer film etching process (Process 13), as shown in FIG. 5(a), using the second resist pattern 5C (lower edge thereof) or the surface layer film 7A as an etching mask, while the outer edge portions (two locations on the left side in the figure) of the exposed portion of the lower layer film 3 that are in contact with the edge of the second region 12 are being removed by etching, and using the second resist pattern 5C (lower edge thereof) or the surface layer film 7A or the first pattern 4A of the upper layer film pattern as an etching mask, the outer edge portions (two locations on the right side in the figure) of the exposed portion of the lower layer film 3 that are not in contact with the edge of the second region 12 are being removed by etching, the exposed portion of the lower layer film 3 is removed by etching. Note that "the second resist pattern 5C (lower edge thereof) or the surface layer film 7A" and "the second resist pattern 5C (lower edge thereof) or the surface layer film 7A or the first pattern 4A of the upper layer film pattern" mean that either one of them is applicable depending on the situation. In the figure, at the two locations on the left side, the surface layer film 7A serves as the etching mask, and at the two locations on the right side, the first pattern 4A of the upper layer film pattern serves as the etching mask. The etching may be either dry etching or wet etching, but for a large-sized photomask, wet etching is preferred. An etchant, such as an etching solution or an etching gas, is used. Whichever etchant is used, an etchant having etching selectivity with respect to the lower layer film 3 (an etchant that does not etch the upper layer film 4 and the surface layer film 7A) is used. Note that during etching, the lower layer film 3 also undergoes side etching. In the figure, the reason why the position of the edge of the lower layer film 3 is offset inward from the positions of the lower edge of the second resist pattern 5C and the edge of the surface layer film 7A is for this purpose. However, depending on the film thickness of the lower layer film 3, the material of the lower layer film 3, or the type of etchant, side etching may not occur. Note that the etching rate of the lower layer film 3 can be adjusted by adjusting the concentration, temperature, etching time of the etchant, and other conditions for using the etchant. And by adjusting the etching rate of the lower layer film 3, it is possible to adjust to obtain a desired offset dimension.

[0057] In the second resist film removal step (step 14), as shown in FIG. 5(b), the remaining resist film 5 (second resist pattern 5C) is removed. The method itself is the same as that of the first resist film removal step.

[0058] In the second surface layer film etching step (step 15), as shown in FIG. 5(c), the surface layer film 7 (the surface layer film 7 laminated on the upper layer film 4 and the surface layer film 7A laminated on the exposed portion of the lower layer film 3) is removed by etching. The method itself is the same as that of the first surface layer film etching step.

[0059] <Configuration of the photomask according to Embodiment 2> As shown in FIG. 6, the pattern of the photomask 1 according to Embodiment 2 is a hole pattern having holes (transmission portions 10) with a size in the unit of μm (in some cases, these are arranged in a one-dimensional or two-dimensional array at a predetermined interval). Therefore, in the photomask 1 according to Embodiment 2, transmission portions 10 that form a hole pattern are formed in the lower layer film 3, and a second region 12 is formed around them. The configuration of the photomask 1 according to Embodiment 2 is substantially the same as the configuration of the photomask 1 according to Embodiment 1, except that the form of the pattern is different. Therefore, the description of the configuration of the photomask 1 according to Embodiment 2 is omitted on the assumption that it is the same as the description of the configuration of the photomask 1 according to Embodiment 1.

[0060] <Manufacturing method of the photomask according to Embodiment 2> The manufacturing method of the photomask 1 according to Embodiment 2 is as shown in FIGS. 7 to 10, i) Photomask blank preparation step (step 1) ii) First resist film formation step (step 2) iii) First drawing step (step 3) iv) First development step (step 4) v) First upper layer film etching step (step 5) vi) First resist film removal step (step 6) vii) Surface layer film formation step (step 7) viii) Second resist film formation step (step 8) ix) Second drawing process (Process 9) x) Second development process (Process 10) xi) First surface layer film etching process (Process 11) xii) Second upper layer film etching process (Process 12) xiii) Lower layer film etching process (Process 13) xiv) Second resist film removal process (Process 14) xv) Second surface layer film etching process (Process 15) comprises the following.

[0061] The method for manufacturing the photomask 1 according to Embodiment 2 is substantially the same as the method for manufacturing the photomask 1 according to Embodiment 1, except for the difference in the pattern form. Therefore, the description of the method for manufacturing the photomask 1 according to Embodiment 2 is omitted on the assumption that it is the same as the description of the method for manufacturing the photomask 1 according to Embodiment 1.

[0062] Supplementary note: In the photomask 1 according to Embodiment 1, the first region 11 and the second region 12 are defined in the first drawing process, and the first region 11 functions as the first transmittance portion 11. On the other hand, in the photomask 1 according to Embodiment 2, the second pattern 4B of the upper layer film pattern defines the dimensions of the resist pattern for forming the hole pattern formed in the lower layer film 3, and is finally removed. After that, 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.

[0063] <Configuration of the photomask according to Embodiment 3> As shown in FIG. 11, the configuration of the photomask 1 according to Embodiment 3 is the same as the configuration of the photomask 1 according to Embodiment 1. Therefore, the description of the configuration of the photomask 1 according to Embodiment 3 is omitted on the assumption that it is the same as the description of the configuration of the photomask 1 according to Embodiment 1.

[0064] <Method for manufacturing the photomask according to Embodiment 3> The manufacturing method of the photomask 1 according to Embodiment 3 is as shown in FIGS. 12 to 15, i) Photomask blank preparation step (Step 1) ii) First resist film formation step (Step 2) iii) First drawing step (Step 3) iv) First development step (Step 4) v) First upper layer film etching step (Step 5) vi) First resist film removal step (Step 6) vii) Surface layer film formation step (Step 7) viii) Second resist film formation step (Step 8) ix) Second drawing step (Step 9) x) Second development step (Step 10) xi) Second upper layer film etching step (Step 11) xii) Lower layer film etching step (Step 12) xiii) Second resist film removal step (Step 13) and includes the following steps.

[0065] The manufacturing method of the photomask 1 according to Embodiment 3 is substantially the same as the manufacturing method of the photomask 1 according to Embodiment 1, except that the surface layer film 8 related to the surface layer film formation step is a chemical agent, and this chemical agent is integrated with the resist film related to the second resist film formation step (constituting the lower layer of the resist film) and is removed integrally with the resist film. Therefore, the surface layer film etching steps (the first surface layer film etching step and the second surface layer film etching step) of the manufacturing method of the photomask 1 according to Embodiment 1 are not required. Therefore, the description of the manufacturing method of the photomask 1 according to Embodiment 3 is omitted as being the same as the description of the manufacturing method of the photomask 1 according to Embodiment 1, except for the different points described below.

[0066] In the surface layer film formation step (Step 7), as shown in FIG. 13(c), the chemical agent is uniformly applied so as to cover the entire surface, and the surface layer film 8 made of the chemical agent film is formed. The chemical agent is dissolved by development together with the resist. As an example, it is HMDS (hexamethyldisilazane). The chemical agent is applied by a coating method, a spray method, or the like.

[0067] Regarding the description of the method for manufacturing the photomask 1 according to Embodiment 1, the descriptions of "surface layer film 7" and "surface layer film 7A" shall be read as "surface layer film 8" and "surface layer film 8A", respectively, and the process numbers and figure numbers shall be read as the corresponding numbers as appropriate.

[0068] <Configuration of the photomask according to Embodiment 4> As shown in FIG. 16, the pattern of the photomask 1 according to Embodiment 4 is a hole pattern. The configuration of the photomask 1 according to Embodiment 4 is substantially the same as the configuration of the photomask 1 according to Embodiment 3, except that the form of the pattern is different. Also, the configuration of the photomask 1 according to Embodiment 4 is the same as the configuration of the photomask 1 according to Embodiment 2. Therefore, the description of the configuration of the photomask 1 according to Embodiment 4 is omitted as being the same as the description of the configuration of the photomask 1 according to Embodiment 1.

[0069] <Method for manufacturing the photomask according to Embodiment 4> The method for manufacturing the photomask 1 according to Embodiment 4 is as shown in FIGS. 17 to 20, i) Photomask blank preparation step (Step 1) ii) First resist film formation step (Step 2) iii) First exposure step (Step 3) iv) First development step (Step 4) v) First upper layer film etching step (Step 5) vi) First resist film removal step (Step 6) vii) Surface layer film formation step (Step 7) viii) Second resist film formation step (Step 8) ix) Second exposure step (Step 9) x) Second development step (Step 10) xi) Second upper layer film etching step (Step 11) xii) Lower layer film etching step (Step 12) xiii) Second resist film removal step (Step 13) and includes.

[0070] The manufacturing method of the photomask 1 according to Embodiment 4 is substantially the same as the manufacturing method of the photomask 1 according to Embodiment 3, except for the difference in the pattern form. Therefore, the description of the manufacturing method of the photomask 1 according to Embodiment 4 is omitted on the assumption that it is the same as the description of the manufacturing method of the photomask 1 according to Embodiments 1 and 3.

[0071] <Configuration of the photomask according to Embodiment 5> As shown in FIG. 21, the configuration of the photomask 1 according to Embodiment 5 is the same as the configuration of the photomask 1 according to Embodiment 1. Therefore, the description of the configuration of the photomask 1 according to Embodiment 5 is omitted on the assumption that it is the same as the description of the configuration of the photomask 1 according to Embodiment 1.

[0072] <Manufacturing method of the photomask according to Embodiment 5> The manufacturing method of the photomask 1 according to Embodiment 5 is as shown in FIGS. 22 to 24, i) Photomask blank preparation step (Step 1) ii) First resist film formation step (Step 2) iii) First drawing step (Step 3) iv) First development step (Step 4) v) First upper layer film etching step (Step 5) vi) First resist film removal step (Step 6) vii) Second resist film formation step (Step 7) viii) Second drawing step (Step 8) ix) Second development step (Step 9) x) Second upper layer film etching step (Step 10) xi) Lower layer film etching step (Step 11) xii) Second resist film removal step (Step 12) and includes.

[0073] The manufacturing method of the photomask 1 according to Embodiment 5 is substantially the same as the manufacturing method of the photomask 1 according to Embodiment 1, except that it does not include the surface layer film forming step and the surface layer film etching step of the manufacturing method of the photomask 1 according to Embodiment 1. Therefore, the description of the manufacturing method of the photomask 1 according to Embodiment 5 is omitted, assuming that it is the same as the description of the manufacturing method of the photomask 1 according to Embodiment 1, except for the different points described below.

[0074] Among the descriptions of the manufacturing method of the photomask 1 according to Embodiment 1, · The description of "surface layer film 7" in the second resist film forming step is replaced with "lower layer film 3 and upper layer film 4", · The description of "lower layer film 3, upper layer film 4 and surface layer film 7" in the second drawing step is replaced with "lower layer film 3 and upper layer film 4", · The description of "the surface layer film 7 laminated thereon" and the description of "In addition,... the gist is as follows." in the second development step are deleted, and the description of "the surface layer film 7A between the first pattern 4A and the second pattern 4B of the upper layer film pattern" is replaced with "the exposed portion of the lower layer film 3 between the first pattern 4A and the second pattern 4B of the upper layer film pattern", · The description of "In the surface layer film 7A,... an edge is formed" in the second upper layer film etching step is deleted, · The descriptions of "the second resist pattern 5C (lower edge) or the surface layer film 7A", "the upper layer film 4 and the surface layer film 7A", and "the lower edge of the second resist pattern 5C and the edge of the surface layer film 7A" in the lower layer film etching step are replaced with "the second resist pattern 5C (lower edge)", "the upper layer film 4", and "the lower edge of the second resist pattern 5C", · The process numbers and figure numbers shall be appropriately replaced with corresponding numbers.

[0075] <Configuration of the photomask according to Embodiment 6> As shown in FIG. 25, the pattern of the photomask 1 according to Embodiment 6 is a hole pattern. The configuration of the photomask 1 according to Embodiment 6 is substantially the same as the configuration of the photomask 1 according to Embodiment 5, except that the form of the pattern is different. Also, the configuration of the photomask 1 according to Embodiment 6 is the same as the configuration of the photomask 1 according to Embodiment 2. Therefore, the description of the configuration of the photomask 1 according to Embodiment 5 is omitted on the assumption that it is the same as the description of the configuration of the photomask 1 according to Embodiment 1.

[0076] <Method for manufacturing a photomask according to Embodiment 6> The method for manufacturing the photomask 1 according to Embodiment 6 is as shown in FIGS. 26 to 28, i) Photomask blank preparation step (Step 1) ii) First resist film formation step (Step 2) iii) First drawing step (Step 3) iv) First development step (Step 4) v) First upper layer film etching step (Step 5) vi) First resist film removal step (Step 6) vii) Second resist film formation step (Step 7) viii) Second drawing step (Step 8) ix) Second development step (Step 9) x) Second upper layer film etching step (Step 10) xi) Lower layer film etching step (Step 11) xii) Second resist film removal step (Step 12) and includes.

[0077] The method for manufacturing the photomask 1 according to Embodiment 6 is substantially the same as the method for manufacturing the photomask 1 according to Embodiment 5, except that the form of the pattern is different. Therefore, the description of the method for manufacturing the photomask 1 according to Embodiment 4 is omitted on the assumption that it is the same as the description of the methods for manufacturing the photomask 1 according to Embodiments 1 and 5.

[0078] <Configuration of a photomask according to Embodiment 7> As shown in FIG. 29, the pattern of the photomask 1 according to Embodiment 7 is formed on the lower layer film 3 such that at least a part of the peripheral region of the lower layer film 4 is exposed, and the surface layer film 7 is formed so as to overlap the exposed portion of the lower layer film 3 and the upper layer film 4. The second transmittance portion 12 is composed of the lower layer film 3 and the surface layer film 7, and the second region 12 is a line-and-space pattern that is a stacked portion of the lower layer film 3 and the surface layer film 7. The configuration of the photomask 1 according to Embodiment 7 is substantially the same as the configuration of the photomask 1 according to Embodiment 1, except that the form of the pattern is different. Therefore, the description of the configuration of the photomask 1 according to Embodiment 7 is omitted on the assumption that it is the same as the description of the configuration of the photomask 1 according to Embodiment 1. In FIG. 29, the position of the edge of the lower layer film 3 is offset inward from the position of the edge of the surface layer film 7, and the edge portion of the surface layer film 7 protrudes (overhangs). However, this is due to an exaggerated description on the drawing, and an excessive overhang portion is not formed in the actual product.

[0079] As an example, the lower layer film 3 is a phase shift film, the upper layer film 4 is a halftone film, the surface layer film 7 is a halftone film, the transmittance of the lower layer film 3 is high transmittance (10 to 90%), the transmittance of the upper layer film 4 is high transmittance (10 to 75%), the transmittance of the surface layer film 7 is high transmittance (10 to 75%), and the phase angle of the second transmittance portion 12 that functions as the rim portion of the first transmittance portion 11 is approximately 180° (for example, the phase angle of the lower layer film 3 is 160 to 180°, the phase angle of the upper layer film 4 is more than 0° and 20° or less (low phase), and the phase angle of the surface layer film 7 is more than 0° and 20° or less (low phase)).

[0080] <Method for manufacturing a photomask according to Embodiment 7> The method for manufacturing the photomask 1 according to Embodiment 7 is i) Photomask blank preparation step (Step 1) ii) First resist film formation step (Step 2) iii) First drawing step (Step 3) iv) First development step (Step 4) v) First upper layer film etching step (Step 5) vi) First resist film removal step (Step 6) vii) Surface film formation step (Step 7) viii) Second resist film formation step (Step 8) ix) Second drawing step (Step 9) x) Second development step (Step 10) xi) First surface film etching step (Step 11) xii) Second upper layer film etching step (Step 12) xiii) Lower layer film etching step (Step 13) xiv) Second resist film removal step (Step 14) It includes the following steps.

[0081] The method for manufacturing the photomask 1 according to Embodiment 7 is the same as Steps 1 to 14 of the method for manufacturing the photomask 1 according to Embodiment 1. That is, the method for manufacturing the photomask 1 according to Embodiment 7 is the same as the method for manufacturing the photomask 1 according to Embodiment 1 in that it performs up to Step 14 and does not perform Step 15. Therefore, the description of the method for manufacturing the photomask 1 according to Embodiment 7 is omitted on the assumption that it is the same as the description of the method for manufacturing the photomask 1 according to Embodiment 1.

[0082] <Configuration of the photomask according to Embodiment 8> As shown in FIG. 30, the pattern of the photomask 1 according to Embodiment 8 is formed on the lower layer film 3 such that at least a part of the peripheral region of the upper layer film 4 is exposed, and the surface layer film 7 is formed so as to overlap the exposed portion of the lower layer film 3 and the upper layer film 4. The second transmittance portion 12 is composed of the lower layer film 3 and the surface layer film 7, and the second region 12 is a hole pattern that is a laminated portion of the lower layer film 3 and the surface layer film 7. The configuration of the photomask 1 according to Embodiment 8 is substantially the same as the configuration of the photomask 1 according to Embodiments 2 and 7, except for the difference in the form of the pattern. Therefore, the description of the configuration of the photomask 1 according to Embodiment 8 is omitted on the assumption that it is the same as the description of the configuration of the photomask 1 according to Embodiments 1 and 7. In FIG. 30, the position of the edge of the lower layer film 3 is offset inward from the position of the edge of the surface layer film 7, and the edge portion of the surface layer film 7 protrudes (overhangs). However, this is due to an exaggerated description on the drawing, and an excessive overhang portion is not formed in the actual product.

[0083] <Method for manufacturing a photomask according to Embodiment 8> The method for manufacturing the photomask 1 according to Embodiment 8 is as follows. i) Photomask blank preparation step (Step 1) ii) First resist film formation step (Step 2) iii) First drawing step (Step 3) iv) First development step (Step 4) v) First upper layer film etching step (Step 5) vi) First resist film removal step (Step 6) vii) Surface layer film formation step (Step 7) viii) Second resist film formation step (Step 8) ix) Second drawing step (Step 9) x) Second development step (Step 10) xi) First surface layer film etching step (Step 11) xii) Second upper layer film etching step (Step 12) xiii) Lower layer film etching step (Step 13) xiv) Second resist film removal step (Step 14) It includes.

[0084] The manufacturing method of the photomask 1 according to Embodiment 8 is the same as Steps 1 to 14 of the manufacturing method of the photomask 1 according to Embodiment 2. That is, the manufacturing method of the photomask 1 according to Embodiment 8 is the same as the manufacturing method of the photomask 1 according to Embodiment 2 in that Steps 1 to 14 are performed and Step 15 is not performed. Therefore, the description of the manufacturing method of the photomask 1 according to Embodiment 8 is omitted on the assumption that it is the same as the description of the manufacturing method of the photomask 1 according to Embodiment 1.

[0085] <Effects of the manufacturing method of the photomask according to each embodiment>

[0086] According to the manufacturing method of the photomask 1 according to the above embodiment, except for the drawing process (second drawing process) in which the positional accuracy of the pattern is not emphasized, the drawing process can define the pattern dimensions finally required in one time (first drawing process). Thereby, in the manufacturing process of the photomask 1, it is not necessary to excessively require the alignment accuracy. Therefore, according to the manufacturing method of the photomask 1 according to the above embodiment, there is no alignment deviation, and high definition of the photomask 1 can be realized.

[0087] Also, according to the manufacturing method of the photomask 1 according to the above embodiment, the position of the edge of the second region 12 of the pattern of the photomask 1 is not the position of the edge on the side opposite to the first pattern 4A of the second pattern 4B of the upper layer film pattern, but is defined based on the position of the edge of the second pattern 4B of the upper layer film pattern on the first pattern 4A side. Thereby, when setting the width of the second region 12, the width of the second pattern 4B of the upper layer film pattern does not become a factor. Therefore, according to the manufacturing method of the photomask 1 according to the above embodiment, further high definition of the photomask can be realized as compared with the conventional manufacturing method of the photomask.

[0088] Further, according to the method for manufacturing the photomask 1 according to Embodiments 1, 2, 7, and 8, as an example, the lower layer film 3 is a metal silicide film, the surface layer film 7 is a film other than the metal silicide film, and the etching characteristics of each of the lower layer film 3 and the upper layer film 4 are different. The metal silicide film has the advantage of high characteristics as a phase shift film, but has the disadvantage of poor adhesion to the resist (this is the applicant's recognition at the current time). When the surface layer film 7 is provided, the resist in the second resist film forming step comes into contact with the surface layer film 7 (adhesion assisting film) having better adhesion to the resist than the lower layer film 3, rather than the lower layer film 3. Therefore, according to the method for manufacturing the photomask 1 according to Embodiments 1 to 3, 7, and 8, a high-definition photomask can be manufactured with good yield.

[0089] Further, according to the method for manufacturing the photomask 1 according to Embodiments 3 and 4, as an example, the lower layer film 3 is a metal silicide film, and the surface layer film 8 is a drug film. The metal silicide film has the advantage of high characteristics as a phase shift film, but has the disadvantage of poor adhesion to the resist (this is the applicant's recognition at the current time). When the surface layer film 8 is provided, the resist in the second resist film forming step comes into contact with the surface layer film 8 (adhesion assisting agent) having better adhesion to the resist than the lower layer film 3, rather than the lower layer film 3. Therefore, according to the method for manufacturing the photomask 1 according to Embodiments 4 to 6, a high-definition photomask can be manufactured with good yield.

[0090] Further, in the method for manufacturing the photomask 1 according to the above embodiment, by changing the positions of the second patterns 5B, 5B (the second patterns 4B, 4B on both sides of the upper layer film pattern) on both sides of the first resist pattern, the widths of the second regions (rim portions) 12, 12 on both sides can be individually and arbitrarily set. In this case, it is also possible to form an asymmetric pattern in which the width of one second region (rim portion) 12 is large and the width of the other second region (rim portion) 12 is small.

[0091] Further, according to the method for manufacturing the photomask 1 according to Embodiments 7 and 8, the step (the secondary surface layer film etching step of the method for manufacturing the photomask 1 according to Embodiments 1 and 2) can be omitted. Further, according to the method for manufacturing the photomask 1 according to Embodiments 7 and 8, various gradations can be adjusted later, such as removing the surface layer film 7 from only one of the second regions (rim portions) 12, 12 on both sides by additional processing, and the degree of freedom in design can be improved.

[0092] <Other Embodiments> Note that the present invention is not limited to the above embodiments, and various modifications are possible without departing from the gist of the present invention.

[0093] In each drawing, the lower layer film (semi-transmissive film) 3, the upper layer film (semi-transmissive film) 4, the surface layer film (semi-transmissive film) 7, and the surface layer film (drug film) 8 are depicted exaggeratedly thick. However, this is for convenience, and the respective film thicknesses of the films are appropriately set individually. As an example, the film thickness of the semi-transmissive film 4 is about the same as the film thickness of the semi-transmissive film 3, thicker than the film thickness of the semi-transmissive film 3, or thinner than the film thickness of the semi-transmissive film 3. The film thickness of the semi-transmissive film 7 is thinner than the film thickness of the semi-transmissive film 3. The drug film 8 is even thinner.

[0094] Further, in the above embodiment, the second region 12 of the pattern of the photomask is the rim portion. However, the present invention is not limited to this. The second region may be another functional portion.

[0095] Further, in the above embodiment, the rim portions 12 are formed on both sides of the first transmittance portion 11. However, the present invention is not limited to this. The rim portion may be formed on only one side of the first transmittance portion.

[0096] Further, in the above embodiment, the lower layer film is a phase shift film and the upper layer film is a halftone film. However, the present invention is not limited to this. The lower layer film may be a halftone film and the upper layer film may be a phase shift film. Alternatively, the lower layer film may be a phase shift film and the upper layer film may be a light shielding film. Also, in these cases, the laminated portion of the lower layer film and the upper layer film may function as a light shielding portion. In short, each of the lower layer film and the upper layer film (and the surface layer film) can be arbitrarily selected from various functional films having a function of adjusting the optical characteristics of the exposure light, such as a light shielding film, a phase shift film, and a halftone film, and an arbitrary combination of the lower layer film and the upper layer film (and the surface layer film) can be adopted. The light shielding film 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 shielding the exposure light. The light shielding film has a transmittance of 1% or less with respect to the representative wavelength included in the exposure light. Alternatively, it is sufficient that the optical density (OD value) in the light shielding portion satisfies 2.7 or more. As an example, the light shielding film has a laminated structure including a first film forming layer and a second film forming layer. The first film forming layer is composed of a metal film and is for the purpose of light shielding property. The second film forming layer is composed of a metal oxide film and is for the 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.

[0097] Also, the lower layer film and the upper layer film (and the surface layer film) are not limited to the materials exemplified in the above embodiment. In short, on the premise that their etching characteristics are different from each other, each can be selected from any of Cr-based materials, Ni-based materials, Ti-based materials, Si-based materials, Zr-based materials, or metal silicide-based materials, or even from other materials, according to the corresponding transfer shape and site.

[0098] Further, in the above embodiment, the surface layer film is provided to compensate for the poor adhesion between the lower layer 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 the adhesion with the resist, or may be provided for the purpose of additionally providing a functional film having a function of adjusting the optical characteristics of the exposure light in addition to this purpose.

[0099] Also, in the above embodiment, it has a two-layer structure of a lower layer film and an upper layer film. However, the present invention is not limited thereto. As long as it is a layer structure to which the method for manufacturing a photomask according to the present invention can be applied, the case where other films are formed in addition to the above lower layer film and upper layer film is not excluded. For example, i) an intermediate film such as an etching stopper film may be formed at the interface between the upper layer film and the lower layer film. Alternatively, ii) another film may be formed on the upper surface of the upper layer film. Alternatively, iii) another film may be formed on the lower surface of the lower layer film.

[0100] Also, in the above embodiment, the pattern of the photomask is a line and space pattern in which lines (first transmittance portions 11) with a width in μm units and spaces (transmittance portions 10) with a width in μm units are arranged in parallel (in some cases, these are alternately repeated) in at least a part of the region. Alternatively, in the above embodiment, the pattern of the photomask 1 has holes (transmittance portions 10) with a size in μm units in at least a part of the region (in some cases, these are one-dimensionally or two-dimensionally arranged at a predetermined interval), which is a hole pattern. However, the present invention is not limited thereto. The pattern of the photomask may be a dot pattern having dots (first transmittance portions) with a size in μm units in at least a part of the region (in some cases, these are one-dimensionally or two-dimensionally arranged at a predetermined interval). Of course, patterns other than these may also be used. In short, as long as it is a pattern that can be implemented by the method of the present invention, the type of the pattern is not limited.

[0101] Also, in the above Embodiments 2, 4, 6, and 8, the shape of the hole (transmittance portion 10) (the boundary line with the rim portion (second transmittance portion 12)) is rectangular, and the shape of the rim portion (second transmittance portion 12) (the boundary line with the first transmittance portion 11) is rectangular. However, the present invention is not limited thereto. The shape of the hole and the shape of the rim portion may be other shapes such as circular or polygonal. Also, the shape of the hole and the shape of the rim portion may be different.

Explanation of Reference Numerals

[0102] 1… photomask, 10… transmissive portion, 11… first transmittance portion (first region), 12… second transmittance portion (second region), 2… transparent substrate, 3… lower layer film (semi-transmissive film), 4… upper layer film (semi-transmissive 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 first resist pattern, 5B… second pattern of first resist pattern, 5C… second resist pattern, 7… surface layer film (semi-transmissive film), 8… surface layer film (agent film)

Claims

1. A method for manufacturing a photomask including a lower layer film formed on a transparent substrate and an upper layer film formed on the lower layer film such that at least a part of a peripheral region of the lower layer film is exposed, the method comprising a pattern composed of a first region of a stacked portion of the lower layer film and the upper layer film and a second region of the lower layer film, a photomask blank preparation step of preparing a photomask blank having the lower layer film and the upper layer film stacked on the 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 an edge of the second region, a first upper layer film etching step of removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask, thereby forming an upper layer film pattern including a first pattern corresponding to the first region, a second pattern spaced apart from the first pattern, and having an edge on the first pattern side set at a position corresponding to an edge of the second region, 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 step of forming a second resist pattern that covers at least a portion including an edge on the first pattern side among the first pattern of the upper layer film pattern, the surface layer film between the first pattern and the second pattern of the upper layer film pattern, and the second pattern of the upper layer film pattern, and exposes at least a part of another portion of the second pattern of the upper layer film pattern, a second upper layer film etching step of removing the second pattern of the upper layer film pattern by etching, a lower layer film etching step of removing an exposed portion of the lower layer film by etching while removing an outer edge portion in contact with the edge of the second region among the exposed portions of the lower layer film using the second resist pattern or the surface layer film as a mask, and while removing an outer edge portion not in contact with the edge of the second region among the exposed portions of the lower layer film using the second resist pattern or the surface layer film or the first pattern of the upper layer film pattern as a mask, and a surface layer film etching step of removing the surface layer film by etching. A method for manufacturing a photomask.

2. A method for manufacturing a photomask including a lower layer film formed on a transparent substrate and an upper layer film formed on the lower layer film such that at least a part of a peripheral region of the lower layer film is exposed, the method comprising a pattern composed of a first region of a stacked portion of the lower layer film and the upper layer film and a second region of the lower layer film, a photomask blank preparation step of preparing a photomask blank in which the lower layer film and the upper layer film are stacked on the transparent substrate, a first resist pattern formation 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 edge of the second region, a first upper layer film etching step of removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask, thereby forming an upper layer film pattern including a first pattern corresponding to the first region, 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 edge of the second region, a surface layer film formation 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 formation step of forming a second resist pattern that covers at least a portion including the edge on the first pattern side among the first pattern of the upper layer film pattern, the surface layer film between the first pattern and the second pattern of the upper layer film pattern, and the second pattern of the upper layer film pattern, and exposes at least a part of another part of the second pattern of the upper layer film pattern, a second upper layer film etching step of removing the second pattern of the upper layer film pattern by etching, a lower layer film etching step of removing an outer edge portion of the exposed portion of the lower layer film that is in contact with the edge of the second region by etching using the second resist pattern or the surface layer film as a mask, and removing an outer edge portion of the exposed portion of the lower layer film that is not in contact with the edge of the second region by etching using the second resist pattern or the surface layer film or the first pattern of the upper layer film pattern as a mask, while removing the exposed portion of the lower layer film by etching, a method for manufacturing a photomask.

3. A method for manufacturing a photomask, comprising a lower layer film formed on a transparent substrate and an upper layer film formed on the lower layer film such that at least a part of the peripheral region of the lower layer film is exposed, and comprising a pattern composed of a first region of the stacked portion of the lower layer film and the upper layer film and a second region of the lower layer film. A photomask blank preparation step of preparing a photomask blank in which a lower layer film and an upper layer film are stacked 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 edge of the second region. A first upper layer film etching step of removing the exposed portion of the upper layer film by etching using the first resist pattern as a mask, thereby forming an upper layer film pattern including a first pattern corresponding to the first region, 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 edge of the second region. A second resist pattern forming step of forming a second resist pattern that covers at least a portion including the edge on the first pattern side among 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 of the upper layer film pattern, and the second pattern of the upper layer film pattern, and exposes at least a part of the other portion of the second pattern of the upper layer film pattern. A second upper layer film etching step of removing the second pattern of the upper layer film pattern by etching. A lower layer film etching step of removing the exposed portion of the lower layer film by etching while removing the outer edge portion in contact with the edge of the second region among the exposed portions of the lower layer film using the second resist pattern as a mask, and while removing the outer edge portion not in contact with the edge of the second region among the exposed portions of the lower layer film using the second resist pattern or the first pattern of the upper layer film pattern as a mask. A method for manufacturing a photomask.

4. A method for manufacturing a photomask, comprising: a lower layer film formed on a transparent substrate; an upper layer film formed on the lower layer film such that at least a part of the peripheral region of the lower layer film is exposed; and a surface layer film formed so as to overlap at least the exposed portion of the lower layer film, the method including a pattern composed of a first region of a stacked portion of the lower layer film and the upper layer film and a second region of a stacked portion of the lower layer film and the surface layer film. A photomask blank preparation step of preparing a photomask blank on which a lower layer film and an upper layer film are stacked 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 edge of the second region. A first upper layer film etching step of removing the exposed portion of the upper layer film by etching using the first resist pattern as a mask, thereby forming an upper layer film pattern including a first pattern corresponding to the first region, 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 edge of the second region. A surface layer film forming step of forming a surface layer film so as to cover at least the 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 step of forming a second resist pattern that covers at least a portion including the edge on the first pattern side among the first pattern of the upper layer film pattern, the surface layer film between the first pattern and the second pattern of the upper layer film pattern, and the second pattern of the upper layer film pattern, and exposes at least a part of another portion of the second pattern of the upper layer film pattern. A second upper layer film etching step of removing the second pattern of the upper layer film pattern by etching. A lower layer film etching step of removing the exposed portion of the lower layer film by etching while removing, by etching, an outer edge portion in contact with the edge of the second region among the exposed portions of the lower layer film using the second resist pattern or the surface layer film as a mask, and while removing, by etching, an outer edge portion not in contact with the edge of the second region among the exposed portions of the lower layer film using the second resist pattern or the surface layer film or the first pattern of the upper layer film pattern as a mask. A method for manufacturing a photomask.

5. As the lower layer film and the upper layer film, use a film in which the first region is a first transmittance portion having a transmittance higher than that of the light-shielding portion, and the second region functions as a phase shift portion with a second transmittance portion having a transmittance higher than that of the first transmittance portion. The method for manufacturing a photomask according to any one of claims 1 to 4.

6. Use a phase shift film as the lower layer film. Use a halftone film as the upper layer film. The method for manufacturing a photomask according to claim 5.

7. Use a phase shift film with a phase shift amount of approximately 180° as the lower layer film. Use a halftone film with a phase shift amount of less than 20° as the upper layer film. Set so that the total phase shift amount of the laminated portion of the lower layer film and the upper layer film is approximately 180°. The method for manufacturing a photomask according to claim 5.

8. Use a phase shift film with a transmittance of 2% or more and 90% or less as the lower layer film. Use a halftone film with a transmittance of 10% or more and 75% or less as the upper layer film. Set so that the transmittance of the laminated portion of the lower layer film and the upper layer film is 0.5% or more and 70% or less. The method for manufacturing a photomask according to claim 5.

9. The second region functions as a rim portion of the first transmittance portion. The method for manufacturing a photomask according to claim 5.

10. The pattern of the photomask is any one of 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 4.

Images