JP7545791B1 - Photomask manufacturing method - Google Patents

Abstract

[Problem] To provide a photomask manufacturing method and a photomask that can realize a photomask with higher resolution than conventional photomask manufacturing methods. [Solution] The position of the edge of the second region of the photomask pattern (the position of the edge of the semi-transparent film 3) is determined based on the position of the edge of the second pattern 4B of the upper layer film pattern on the first pattern 4A side, not the position of the edge of the second pattern 4B of the upper layer film pattern on the opposite side to the first pattern 4A. As a result, the width of the second pattern 4B of the upper layer film pattern is not a factor in setting the width of the second region (the width of the exposed portion of the semi-transparent film 3). Therefore, according to the present invention, a photomask with higher resolution can be realized compared to conventional photomask manufacturing methods. [Selected Figure] Figure 4

Description

The present invention relates to a method for manufacturing a photomask.

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

Conventional photomask manufacturing methods require at least two drawing steps: a drawing step (exposure step) for the pattern that constitutes the light-shielding portion, and a drawing step for the pattern that constitutes the semi-transmitting portion. Furthermore, when multiple drawing steps are required, the patterns formed in each step are more likely to become misaligned.

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

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

According to the photomask manufacturing method 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 important, the final required pattern dimensions can be determined in one drawing process (first resist pattern formation process). This means that excessive alignment accuracy is not required in the photomask manufacturing process. Since so-called self-aligned pattern formation is performed, the photomask manufacturing method described in Patent Document 1 can achieve high-definition photomasks without misalignment.

JP 2014-2255 A

However, in the photomask manufacturing method described in Patent Document 1, the second resist pattern must be formed to a width greater than the maximum alignment deviation of 0.5 μm so that the second resist pattern reliably covers the corresponding portion of the second pattern (temporary pattern) of the upper layer film pattern and the exposed portion of the lower layer film between the first and second patterns (temporary patterns) of the upper layer film pattern is not exposed from the second resist pattern.

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

Therefore, the present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a photomask manufacturing method that can achieve even higher resolution photomasks compared to conventional photomask manufacturing methods.

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

Specific examples of such a configuration include embodiment 1, variation 2 of embodiment 1, embodiment 2, and embodiment 3, which will be described later.

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

Specific examples of such a configuration include Alternative Example 1 and Alternative Example 3 of the first embodiment described below.

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

Specific examples of such a configuration include embodiment 4 and embodiment 5, which will be described later.

Here, as one aspect of the method for producing a photomask according to the present invention,
It is possible to adopt a configuration in which the lower layer, intermediate layer and upper layer are made of films whose first region functions as a light shielding portion and whose second region functions as a phase shift portion.

Also, in this case,
A phase shift film is used as the underlayer film.
A light-shielding film may be used as the upper layer.

In another aspect of the method for producing a photomask according to the present invention,
The second region may be configured to function as a rim portion of the light blocking portion.

In another aspect of the method for producing a photomask according to the present invention,
The photomask pattern may be any one of a line and space pattern, a hole pattern, and a dot pattern.

Further, the photomask according to the present invention comprises:
A photomask comprising: an underlayer film formed on a transparent substrate; an intermediate film formed on the underlayer film so that at least a portion of a peripheral region of the underlayer film is exposed; and an upper layer film formed so as to overlap the intermediate film, the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film, the intermediate film, and the upper layer film, and a second region of the underlayer film,
The underlayer film is a metal silicide film,
The intermediate film is a photomask having etching characteristics different from those of the lower and upper films.

Specific examples of such a configuration include embodiment 1, alternative examples 1 to 3 of embodiment 1, embodiment 2, and embodiment 3, which will be described later.

Another photomask according to the present invention comprises:
A photomask comprising: a lower layer film formed on a transparent substrate; an intermediate film formed so as to overlap the lower layer film; and an upper layer film formed on the intermediate film so that at least a part of a peripheral region of the intermediate film is exposed, the photomask having a pattern constituted by a first region of a laminated portion of the lower layer film, the intermediate film, and the upper layer film, and a second region of the laminated portion of the lower layer film and the intermediate film,
The underlayer film is a metal silicide film,
The intermediate film is a photomask having etching characteristics different from those of the lower and upper films.

Specific examples of such a configuration include embodiment 4 and embodiment 5, which will be described later.

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

Fig. 1(a) is an enlarged plan view of a main part of a photomask according to embodiment 1. Fig. 1(b) is a cross-sectional view taken along line DD of Fig. 1(a). 2A to 2D are explanatory diagrams of the method for manufacturing a photomask according to the first embodiment. 3(a) to (d) are explanatory diagrams continuing from FIG. 2. 4(a) to (d) are explanatory diagrams continuing from FIG. 5(a) and (b) are explanatory diagrams continuing from FIG. 6A to 6D are explanatory diagrams of a method for manufacturing a photomask according to a first modified example of the first embodiment. 7(a) to (d) are explanatory diagrams continuing from FIG. 8(a) to (d) are explanatory diagrams continuing from FIG. 9(a) and (b) are explanatory diagrams continuing from FIG. 10A to 10D are explanatory diagrams of a method for manufacturing a photomask according to a second modification of the first embodiment. 11(a) to (d) are explanatory diagrams continuing from FIG. 12(a) to (d) are explanatory diagrams continuing from FIG. 13A and 13B are explanatory diagrams continuing from FIG. 14A to 14D are explanatory diagrams of a method for manufacturing a photomask according to a third modification of the first embodiment. 15(a) to (d) are explanatory diagrams continuing from FIG. 14. 16(a) to (d) are explanatory diagrams continuing from FIG. 15. 17(a) and (b) are explanatory diagrams continuing from FIG. 16. Fig. 18(a) is an enlarged plan view of a main part of a photomask according to embodiment 2. Fig. 18(b) is a cross-sectional view taken along line E-E in Fig. 18(a). 19A to 19D are explanatory diagrams of a method for manufacturing a photomask according to the second embodiment. 20(a) to (d) are explanatory diagrams continuing from FIG. 19. 21(a) to (d) are explanatory diagrams continuing from FIG. 20. 22(a) and (b) are explanatory diagrams continuing from FIG. 21. Fig. 23(a) is an enlarged plan view of a main part of a photomask according to embodiment 3. Fig. 23(b) is a cross-sectional view taken along line FF of Fig. 23(a). 24A to 24D are explanatory diagrams of a method for manufacturing a photomask according to the third embodiment. 25(a) to (d) are explanatory diagrams continuing from FIG. 24. 26(a) to (d) are explanatory diagrams continuing from FIG. 25. 27(a) and (b) are explanatory diagrams continuing from FIG. 26. Fig. 28(a) is an enlarged plan view of a main part of a photomask according to embodiment 4. Fig. 28(b) is a cross-sectional view taken along line GG in Fig. 28(a). Fig. 29(a) is an enlarged plan view of a main part of a photomask according to embodiment 5. Fig. 29(b) is a cross-sectional view taken along line HH in Fig. 29(a).

<Configuration of the Photomask According to the First Embodiment>
The configuration of the photomask according to the first embodiment will be described below.

As shown in FIG. 1, the photomask 1 is a three-tone multi-tone photomask having a transparent portion (white portion) 10, a light-shielding portion (black portion) 11, and a semi-transparent portion (hatched portion) 12. The transparent portion 10 is composed of a transparent substrate 2. The light-shielding portion 11 is composed of a semi-transparent film 3 as a lower layer film, an etching stopper film 6 as an intermediate film, and a light-shielding film 4 as an upper layer film. The semi-transparent portion 12 is composed of a semi-transparent film 3. That is, the exposed portion of the transparent substrate 2 where the semi-transparent film 3, the etching stopper film 6, and the light-shielding film 4 are not laminated becomes the transparent portion 10, the portion where the semi-transparent film 3, the etching stopper film 6, and the light-shielding film 4 are laminated on the transparent substrate 2 becomes the light-shielding portion 11, and the portion where only the semi-transparent film 3 is formed on the transparent substrate 2 becomes the semi-transparent portion 12.

The light-shielding portion 11 and the semi-transparent portion 12 constitute the pattern of the photomask 1. The pattern is composed of a first region 11 and a second region 12. The first region 11 is a laminated portion of the semi-transparent film 3, the etching stopper film 6, and the light-shielding film 4, and functions as the light-shielding portion 11. The second region 12 is a single layer portion of the semi-transparent film 3, and functions as the semi-transparent portion 12.

In this embodiment, lines (light-shielding portions 11) with widths in μm units and spaces (transmitting portions 10) with widths in μm units are arranged in parallel (and in some cases, these are repeated alternately), and the pattern of the photomask 1 is a line-and-space pattern. As an example, the pattern is used as a pattern for forming source and drain electrodes in a transfer substrate manufactured by photolithography using the photomask 1. In this case, the transmitting portions 10 function as channel portions, the light-shielding portions 11 function as electrode portions, and the semi-transmitting portions 12 function as rim portions of the light-shielding portions 11.

The rim portion 12 is provided to improve the process tolerance on the panel side. For example, the rim portion 12 is provided to make the edges of the resist pattern corresponding to the source and drain electrodes on the transfer substrate steeper. The width of the rim portion 12 is, for example, in the range of 0.1 μm or more, or 0.5 μm or more, and 3.0 μm or less.

In FIG. 1 and the following drawings, the semi-transparent film 3, the etching stopper film 6, and the light-shielding film 4 are exaggerated and shown as being thicker. Also, in FIG. 1 and the following drawings, the light-shielding film 4 is shown as being thicker than the semi-transparent film 3 and the etching stopper film 6, and the etching stopper film 6 is shown as being thinner than the semi-transparent film 3. However, this is for the sake of convenience, and the film thicknesses of the semi-transparent film 3, the etching stopper film 6, and the light-shielding film 4 are set individually as appropriate.

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

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

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

The etching stopper film 6 is a film that is interposed between the semi-transmitting film 3 and the light-shielding film 4 and blocks both films 3 and 4. The etching stopper film 6 is a type of functional film that has the function of adjusting the optical characteristics of the exposure light, and is a type of semi-transmitting film that has the function of adjusting the transmittance of the exposure light, that is, a half-tone film. The half-tone film has a transmittance lower than the transmittance of the transparent substrate and higher than the transmittance of the light-shielding film for the representative wavelength contained in the exposure light, and is set to have a transmittance of 10% to 70% for the representative wavelength. The half-tone film may be a semi-transmitting metal film that improves the transmittance distribution within the surface of the photomask by adjusting the nitrogen content. The half-tone film can also change the optical density (OD value) in the semi-transmitting part by containing other elements. The advantage of using such a semi-transmitting film is that it has the effect of improving the process tolerance on the panel side.

The etching stopper film 6 is made of an appropriate material from among known materials such as Cr or Cr-based compounds, Ni or Ni-based compounds, Ti or Ti-based compounds, Si-based compounds, Zr or Zr-based compounds, and metal silicide-based compounds.

The light-shielding film 4 is a type of functional film that has the function of adjusting the optical characteristics of the exposure light, and is a functional film that has the function of blocking the exposure light. The light-shielding film 4 has a transmittance of 1% or less for the representative wavelength contained in the exposure light. Alternatively, the optical density (OD value) in the light-shielding portion 11 may be 2.7 or more. As an example, the light-shielding film 4 has a laminated structure including a first film-forming layer and a second film-forming layer. The first film-forming layer is made of a metal film and has the purpose of blocking light. The second film-forming layer is made of a metal oxide film and has 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.

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

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

<Method of Manufacturing Photomask According to First Embodiment>
Next, a method for manufacturing the photomask 1 according to the first embodiment will be described.

The method for manufacturing the photomask 1 according to the first embodiment is as shown in FIGS.
i) Photomask blank preparation process (process 1)
ii) First resist film formation process (process 2)
iii) First drawing process (process 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 forming process (process 7)
viii) Second drawing process (process 8)
ix) Second development step (Step 9)
x) Second upper layer film etching step (step 10)
xi) First intermediate film etching step (step 11)
xii) Underlayer film etching step (step 12)
xiii) Second resist film removal step (step 13)
xiv) Second intermediate film etching step (step 14)
Equipped with.

The steps from the resist film formation step (step 2) to the resist film removal step (step 6) and from the resist film formation step (step 7) to the resist film removal step (step 13) are referred to as patterning steps. In the former patterning step, the upper layer film (light-shielding 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.

In the photomask blanks preparation step (step 1), a photomask blank is prepared as shown in FIG. 2(a). In the photomask blanks, a lower layer film 3 is formed on a transparent substrate 2, an intermediate film 6 is formed on the lower layer film 3, and an upper layer film 4 is formed on the intermediate film 6, so that the lower layer film 3, intermediate film 6, and upper layer film 4, which have different etching characteristics, are laminated on the transparent substrate 2. The lower layer film 3, intermediate film 6, and upper layer film 4 are each formed by physical vapor deposition (PVD) such as sputtering or evaporation.

In the first resist film formation process (process 2), as shown in FIG. 2(b), resist is uniformly applied onto the upper layer film 4 to form a resist film 5. The resist is applied by a coating method, a spraying method, or the like. The resist may be either positive or negative, but in this example, a positive type is used.

In the first drawing process (step 3), as shown in FIG. 2(c), the resist film 5 is irradiated with exposure light using an electron beam or laser of a drawing device, and a first resist pattern is drawn. At this time, two areas with different exposure amounts are formed in the resist film 5. The first area 5a is an unexposed area. The second area 5b is an area 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 to drawing the resist pattern, in the first drawing process (step 3), a mark (alignment mark) for aligning the position of drawing in the second drawing process (step 8) is drawn. Although not shown, the alignment marks are formed, for example, at appropriate three or four places in the surrounding area surrounding the resist pattern.

In the first development step (step 4), as shown in FIG. 2(d), the unnecessary resist film 5 (second region 5b) is removed by development to form the first resist patterns 5A and 5B. The first resist patterns 5A and 5B are patterns including a first pattern 5A corresponding to the first region 11 of the pattern of the photomask 1, and a second pattern 5B separated from the first pattern 5A and set at a position where the edge of the first pattern 5A side corresponds to the position of the edge of the second region 12 of the pattern of the photomask 1. Development is performed by a dipping method, a spin method, a paddle method, a spray method, or the like. The first resist film formation step (step 2), the first drawing step (step 3), and the first development step (step 4) are collectively referred to as the first resist pattern formation step.

In the first upper layer film etching process (step 5), as shown in FIG. 3(a), the exposed portion of the upper layer film 4 is removed by etching using the first resist patterns 5A and 5B as an etching mask. The etching may be either dry etching or wet etching, but wet etching is preferred for a large-sized photomask. An etching solution or etching gas is used as the etchant. Regardless of the etchant, an etchant that has etching selectivity for the upper layer film 4 (an etchant that does not etch the intermediate film 6) is used. During etching, the upper layer film 4 is also side-etched. This is why the edge position of the upper layer film 4 is offset inward from the edge position of the first resist patterns 5A and 5B in the figure. However, depending on the film thickness of the upper layer film 4, the material of the upper layer film 4, or the type of etchant, side etching may not occur. The etching rate of the upper layer film 4 can be adjusted by adjusting the concentration, temperature, etching time, and other conditions under which the etchant is used. By adjusting the etching rate of the upper layer film 4, it is possible to adjust the offset dimension to the desired value.

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

In the second resist film formation process (step 7), as shown in FIG. 3(c), resist is applied onto the intermediate film 6 and the upper layer film 4 to form a resist film 5. The method itself is the same as in the first resist film formation process (step 2).

In the second drawing process (step 8), as shown in FIG. 3(d), a second resist pattern is drawn on the resist film 5. The method itself is the same as in the first drawing process (step 3), and the drawing device is the same as the drawing device used in the first drawing process (step 3). In the second drawing process (step 8), the drawing device detects the alignment marks formed in the surrounding area surrounding the pattern formation area of the lower layer film in the first drawing process (step 3), and aligns the transparent substrate 2.

However, the second resist pattern only needs to cover and protect the necessary areas, and does not require high positional accuracy of the pattern. For this reason, strict alignment is not required in the second drawing process (step 8).

However, in the second drawing process (step 8), alignment errors inevitably occur. Therefore, in the second drawing process (step 8), a second resist pattern is set that takes alignment errors into consideration. Specifically, the second resist pattern is designed to lap (overlap) the laminated portion of the lower layer film 3, intermediate film 6, and upper layer film 4 by a predetermined lap amount from the edge of the laminated portion. The lap amount is, for example, a value of 0.3 μm or more and 0.5 μm or less.

In the second development step (step 9), as shown in FIG. 4(a), the unnecessary resist film 5 (part 5b) is removed by development to form a second resist pattern 5C. The second resist pattern 5C covers the first pattern 4A of the upper layer film pattern, the exposed part of the intermediate film 6 between the first pattern 4A and the second pattern 4B of the upper layer film pattern, and at least the part including the edge on the first pattern 4A side of the second pattern 4B of the upper layer film pattern, and exposes at least a part of the other part of the second pattern 4B of the upper layer film pattern. The method itself is the same as that of the first development step (step 4). The second resist film formation step (step 7), the second drawing step (step 8), and the second development step (step 9) are collectively referred to as the second resist pattern formation step.

In the second upper layer film etching process (step 10), as shown in FIG. 4(b), the second pattern 4B of the upper layer film pattern is removed by etching. The method itself is the same as the first upper layer film etching process (step 5). In the second upper layer film etching process (step 10), the second pattern 4B of the upper layer film pattern is finally side-etched and completely removed. As a result, an edge (lower edge) is formed at the bottom of the second resist pattern 5C that coincides with the position of the edge of the second pattern 4B of the upper layer film pattern on the first pattern 4A side.

In the first intermediate film etching process (step 11), as shown in FIG. 4(c), the exposed portion of the intermediate film 6 is removed by etching using the lower edge of the second resist pattern 5C as an etching mask. Either dry etching or wet etching may be used for the etching, but wet etching is preferred for a large-sized photomask. An etching solution or an etching gas is used as the etchant. Regardless of the etchant, an etchant that has etching selectivity for the intermediate film 6 (an etchant that does not etch the lower film 3 and the upper film 4) is used. During etching, the intermediate film 6 is also side-etched. This is why the position of the edge of the intermediate film 6 is offset inward from the position of the lower edge of the second resist pattern 5C in the figure. However, depending on the film thickness of the intermediate film 6, the material of the intermediate film 6, or the type of etchant, side etching may not occur. The etching rate of the intermediate film 6 can be adjusted by adjusting the concentration, temperature, etching time, and other conditions under which the etchant is used. By adjusting the etching rate of the intermediate film 6, it is possible to adjust the offset dimension to the desired value.

In the lower layer film etching step (step 12), as shown in FIG. 4(d), the exposed portion of the lower layer film 3 is removed by etching using the intermediate film 6 as an etching mask. Either dry etching or wet etching may be used for the etching, but wet etching is preferred for a large-sized photomask. An etching solution or an etching gas is used as the etchant. Regardless of the etchant, an etchant that has etching selectivity for the lower layer film 3 (an etchant that does not etch the intermediate film 6 and the upper layer film 4) is used. During etching, the lower layer film 3 is also side-etched. This is why the edge position of the lower layer film 3 is offset inward from the edge position of the intermediate film 6 in the figure. 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. The etching rate of the lower layer film 3 can be adjusted by adjusting the concentration, temperature, etching time, and other conditions under which the etchant is used. By adjusting the etching rate of the underlayer film 3, it is possible to adjust the offset dimension to the desired value.

In the second resist film removal process (step 13), as shown in FIG. 5(a), the remaining resist film 5 (second resist pattern 5C) is removed. The method itself is the same as in the first resist film removal process (step 6).

In the second intermediate film etching process (step 14), as shown in FIG. 5(b), the exposed portion of the intermediate film 6 is removed by etching using the upper film 4 as an etching mask. The method itself is the same as the first intermediate film etching process (step 11).

After going through steps 1 to 12 above, photomask 1 is completed.

As described above, according to the method for manufacturing the photomask 1 of this embodiment, except for the drawing process in which the positional accuracy of the pattern is not important (secondary drawing process (process 8)), the final required pattern dimensions can be determined in one drawing process (first drawing process (process 3)). This eliminates the need for excessive alignment accuracy in the manufacturing process of the photomask 1. Therefore, according to the method for manufacturing the photomask 1 of this embodiment, there is no alignment deviation, and a high definition photomask 1 can be achieved.

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

In addition, according to the manufacturing method of the photomask 1 of this embodiment, as an example, the lower layer 3 is a metal silicide-based film, and the intermediate film 6 is a film other than a metal silicide-based film, and has different etching characteristics from the lower layer 3 and the upper layer 4. Metal silicide-based films have the advantage of having high characteristics as a phase shift film, but have the disadvantage of poor adhesion to the resist. When the intermediate film 6 is provided, the resist in the second resist film formation process (step 7) comes into contact not with the lower layer 3, but with the intermediate film 6, which has better adhesion to the resist than the lower layer 3. Therefore, according to the manufacturing method of the photomask 1 of this embodiment, a high-definition photomask can be manufactured with a good yield.

<Method of Manufacturing a Photomask According to Alternative Example 1 of the First Embodiment>
The method for manufacturing a photomask according to the first modified example of the first embodiment is as shown in FIGS.
i) Photomask blank preparation process (process 1)
ii) First resist film formation process (process 2)
iii) First drawing process (process 3)
iv) First development step (step 4)
v) First upper layer film etching step (step 5)
vi) First intermediate film etching step (step 6)
vii) First resist film removal step (step 7)
viii) Second resist film forming step (step 8)
ix) Second drawing process (process 9)
x) Second development step (Step 10)
xi) Second upper layer film etching step (step 11)
xii) Second intermediate film etching step (step 12)
xiii) Underlayer film etching step (step 13)
xiv) Second resist film removal step (step 14)
Equipped with.

The method for manufacturing the photomask 1 according to the modified example 1 of the embodiment 1 is substantially the same as the method for manufacturing the photomask 1 according to the embodiment 1, except that the first intermediate film etching process is performed between the first upper layer film etching process and the first resist film removal process, and the second intermediate film etching process is performed between the second upper layer film etching process and the lower layer film etching process. Therefore, the description of the method for manufacturing the photomask 1 according to the modified example 1 of the embodiment 1 will be omitted, since it is the same as the description of the method for manufacturing the photomask 1 according to the embodiment 1.

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

<Method of Manufacturing a Photomask According to Alternative Example 2 of the First Embodiment>
The method for manufacturing the photomask 1 according to the second modification of the first embodiment is as shown in FIGS.
i) Photomask blank preparation process (process 1)
ii) First resist film formation process (process 2)
iii) First drawing process (process 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 forming process (process 7)
viii) Second drawing process (process 8)
ix) Second development step (step 9)
x) Second upper layer film etching step (step 10)
xi) First intermediate film etching step (step 11)
xii) Underlayer film etching step (step 12)
xiii) Second resist film removal step (step 13)
xiv) Second intermediate film etching step (step 14)
Equipped with.

The method for manufacturing a photomask according to Example 2 of Embodiment 1 is substantially the same as the method for manufacturing photomask 1 according to Embodiment 1, except that the width of the second pattern 4B of the upper layer film pattern is reduced to the extent that it is not affected by misalignment (see FIG. 11(b)). Therefore, the description of the method for manufacturing photomask 1 according to Example 2 of Embodiment 1 will be omitted, as it is the same as the description of the method for manufacturing photomask 1 according to Embodiment 1.

It goes without saying that the method for manufacturing the photomask 1 according to the modified example 2 of the first embodiment can also be applied to the second and third embodiments described below.

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

The method for manufacturing a photomask according to Example 3 of the first embodiment is substantially the same as the method for manufacturing a photomask 1 according to Example 1 of the first embodiment, except that the width of the second pattern 4B of the upper layer film pattern is reduced to the extent that it is not affected by misalignment (see FIG. 15(c)). Therefore, the description of the method for manufacturing a photomask 1 according to Example 3 of the first embodiment will be omitted, since it is the same as the description of the method for manufacturing a photomask 1 according to Example 1 of the first embodiment and Example 1 of the first embodiment.

It goes without saying that the method for manufacturing the photomask 1 according to the modified example 3 of the first embodiment can also be applied to the second and third embodiments described below.

<Configuration of Photomask According to Second Embodiment>
As shown in Fig. 18, the pattern of the photomask 1 according to the second embodiment is a hole pattern having holes (transmitting portions 10) of a size in the μm unit (in some cases, these are arranged one-dimensionally or two-dimensionally at a predetermined interval). Therefore, in the photomask 1 according to the second embodiment, the transmitting portions 10 that become the hole pattern are formed in the underlayer film 3, and the second regions 12 are formed around them. The configuration of the photomask 1 according to the second embodiment is substantially the same as that of the photomask 1 according to the first embodiment, except that the shape of the pattern is different. Therefore, the description of the configuration of the photomask 1 according to the second embodiment is omitted since it is the same as the description of the configuration of the photomask 1 according to the first embodiment.

<Method of Manufacturing a Photomask According to the Second Embodiment>
The method for manufacturing the photomask 1 according to the second embodiment is as shown in FIGS.
i) Photomask blank preparation process (process 1)
ii) First resist film formation process (process 2)
iii) First drawing process (process 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 forming process (process 7)
viii) Second drawing process (process 8)
ix) Second development step (step 9)
x) Second upper layer film etching step (step 10)
xi) First intermediate film etching step (step 11)
xii) Underlayer film etching step (step 12)
xiii) Second resist film removal step (step 13)
xiv) Second intermediate film etching step (step 14)
Equipped with.

The manufacturing method of the photomask 1 according to the second embodiment is substantially the same as the manufacturing method of the photomask 1 according to the first embodiment, except for the difference in the shape of the pattern. Therefore, the description of the manufacturing method of the photomask 1 according to the second embodiment is omitted, since it is the same as the description of the manufacturing method of the photomask 1 according to the first embodiment. To add, in the photomask 1 according to the first embodiment, the first region 11 and the second region 12 are defined in the first drawing process, and the first region 11 functions as the light shielding portion 11. In contrast, in the photomask 1 according to the second embodiment, the second pattern 4B of the upper layer film pattern is for defining the dimensions of the resist pattern for forming the hole pattern to be formed in the lower layer film 3, and is finally removed, and then the lower layer film 3 is removed using the resist pattern for forming the hole pattern as a mask, and the hole pattern is formed.

In this way, the method for manufacturing the photomask 1 according to the second embodiment also achieves the same effects as the method for manufacturing the photomask 1 according to the first embodiment.

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

<Method of Manufacturing a Photomask According to the Third Embodiment>
The method for manufacturing the photomask 1 according to the third embodiment is as shown in FIGS.
i) Photomask blank preparation process (process 1)
ii) First resist film formation process (process 2)
iii) First drawing process (process 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 forming process (process 7)
viii) Second drawing process (process 8)
ix) Second development step (step 9)
x) Second upper layer film etching step (step 10)
xi) First intermediate film etching step (step 11)
xii) Underlayer film etching step (step 12)
xiii) Second resist film removal step (step 13)
xiv) Second intermediate film etching step (step 14)
Equipped with.

The method for manufacturing the photomask 1 according to the third embodiment is substantially the same as the method for manufacturing the photomask 1 according to the first embodiment, except that the widths of the resist removed portions on both sides are different (width a on the left side in FIG. 24(d) > width b on the right side). Therefore, the description of the method for manufacturing the photomask 1 according to the third embodiment is omitted, since it is the same as the description of the method for manufacturing the photomask 1 according to the first embodiment.

In this way, the method for manufacturing the photomask 1 according to the third embodiment also achieves the same effects as the method for manufacturing the photomask 1 according to the first embodiment.

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

The asymmetric pattern of the photomask 1 according to the third embodiment and the manufacturing method thereof are not limited to the line-and-space pattern of the first embodiment, but can be applied to various patterns. For example, the third embodiment can also be applied to the hole pattern of the second embodiment. In this case, the width of the resist-removed portions on both sides can be made different in FIG. 19(d). Also, the width of the second region (rim portion) 12 can be made different not only in the left-right direction, but also in the up-down direction in FIG. 18(a). In other words, the widths of the four sides of the hole can be set individually and arbitrarily.

<Configuration of Photomask According to Fourth Embodiment>
As shown in FIG. 28, the pattern of the photomask 1 according to the fourth embodiment is a line-and-space pattern in which the intermediate film (etching stopper film) 6 is formed so as to overlap the lower film (semi-transparent film) 3, the upper film (light-shielding film) 4 is formed on the intermediate film 6 so that at least a part of the peripheral region of the intermediate film 6 is exposed, the semi-transparent portion 12 is composed of the lower film 3 and the intermediate film 6, and the second region 12 is a laminated portion of the lower film 3 and the intermediate film 6. The configuration of the photomask 1 according to the fourth embodiment is substantially the same as that of the photomask 1 according to the first embodiment, except for the difference in the form of the pattern. Therefore, the description of the configuration of the photomask 1 according to the fourth embodiment is omitted since it is the same as the description of the configuration of the photomask 1 according to the first embodiment. Note that in FIG. 28, the position of the edge of the lower film 3 is offset inward from the position of the edge of the intermediate film 6, and the edge portion of the intermediate film 6 protrudes (overhangs), but this is due to an exaggerated description in the drawing, and an excessive overhang portion is not formed in the actual product.

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

<Method of Manufacturing a Photomask According to the Fourth Embodiment>
A method for manufacturing a photomask 1 according to the fourth embodiment includes the steps of:
i) Photomask blank preparation process (process 1)
ii) First resist film formation process (process 2)
iii) First drawing process (process 3)
iv) First development step (step 4)
v) First upper layer film etching step (step 5)
vi) First resist film removal step (step 6)
vii) Second resist film forming process (process 7)
viii) Second drawing process (process 8)
ix) Second development step (step 9)
x) Second upper layer film etching step (step 10)
xi) First intermediate film etching step (step 11)
xii) Underlayer film etching step (step 12)
xiii) Second resist film removal step (step 13)
Equipped with.

The method for manufacturing the photomask 1 according to the fourth embodiment is the same as steps 1 to 13 of the method for manufacturing the photomask 1 according to the first embodiment. In other words, the method for manufacturing the photomask 1 according to the fourth embodiment is the same as the method for manufacturing the photomask 1 according to the first embodiment, except that steps 13 and 14 are not performed. Therefore, the description of the method for manufacturing the photomask 1 according to the fourth embodiment will be omitted, as it is the same as the description of the method for manufacturing the photomask 1 according to the first embodiment.

In this way, the method for manufacturing the photomask 1 according to the fourth embodiment also achieves the same effects as those achieved by the method for manufacturing the photomask 1 according to the first embodiment.

Moreover, according to the method for manufacturing the photomask 1 of the fourth embodiment, a step (step 14 in the method for manufacturing the photomask 1 of the first embodiment) can be omitted. Furthermore, according to the method for manufacturing the photomask 1 of the fourth embodiment, the intermediate film 6 can be removed from only one of the second regions (rim portions) 12, 12 on both sides by additional processing, and various gradations can be adjusted later, thereby improving the degree of freedom in design.

It goes without saying that the manufacturing method of the photomask 1 according to the modified example 2 of the first embodiment and the asymmetric pattern and manufacturing method of the photomask 1 according to the third embodiment can also be applied to the fourth embodiment.

<Configuration of Photomask According to Fifth Embodiment>
As shown in FIG. 29, the pattern of the photomask 1 according to the fifth embodiment is a hole pattern in which the intermediate film (etching stopper film) 6 is formed so as to overlap the lower film (semi-transparent film) 3, the upper film (light-shielding film) 4 is formed on the intermediate film 6 so as to expose at least a part of the peripheral region of the intermediate film 6, the semi-transparent portion 12 is composed of the lower film 3 and the intermediate film 6, and the second region 12 is a laminated portion of the lower film 3 and the intermediate film 6. The configuration of the photomask 1 according to the fifth embodiment is substantially the same as that of the photomask 1 according to the second and fourth embodiments, except for the difference in the form of the pattern. Therefore, the description of the configuration of the photomask 1 according to the fifth embodiment is omitted since it is the same as the description of the configuration of the photomask 1 according to the first, second, and fourth embodiments. In FIG. 29, the position of the edge of the lower film 3 is offset inward from the position of the edge of the intermediate film 6, and the edge portion of the intermediate film 6 protrudes (overhangs), but this is an exaggerated description in the drawing, and an excessive overhang portion is not formed in the actual product.

<Method of Manufacturing a Photomask According to the Fifth Embodiment>
A method for manufacturing a photomask 1 according to the fifth embodiment includes the steps of:
i) Photomask blank preparation process (process 1)
ii) First resist film formation process (process 2)
iii) First drawing process (process 3)
iv) First development step (step 4)
v) First upper layer film etching step (step 5)
vi) First resist film removal step (step 6)
vii) Second resist film forming process (process 7)
viii) Second drawing process (process 8)
ix) Second development step (step 9)
x) Second upper layer film etching step (step 10)
xi) First intermediate film etching step (step 11)
xii) Underlayer film etching step (step 12)
xiii) Second resist film removal step (step 13)
Equipped with.

The method for manufacturing the photomask 1 according to the fifth embodiment is the same as steps 1 to 13 of the method for manufacturing the photomask 1 according to the second embodiment. In other words, the method for manufacturing the photomask 1 according to the fifth embodiment is the same as the method for manufacturing the photomask 1 according to the second embodiment, except that steps 13 and 14 are performed. Therefore, the description of the method for manufacturing the photomask 1 according to the fifth embodiment will be omitted, as it is the same as the description of the method for manufacturing the photomask 1 according to the first and second embodiments.

In this way, the method for manufacturing the photomask 1 according to the fifth embodiment also achieves the same effects as those achieved by the method for manufacturing the photomask 1 according to the first embodiment.

In addition, the method for manufacturing the photomask 1 according to the fifth embodiment is substantially the same as the method for manufacturing the photomask 1 according to the fourth embodiment, except for the difference in the shape of the pattern, and therefore has the same effects as those of the method for manufacturing the photomask 1 according to the fourth embodiment.

It goes without saying that the manufacturing method of the photomask 1 according to the modified example 2 of the embodiment 1 and the asymmetric pattern and manufacturing method of the photomask 1 according to the embodiment 3 can also be applied to the embodiment 5.

The present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention.

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

In addition, in the above embodiment, the rim portion 12 is formed on both sides of the light-shielding portion 11. However, the present invention is not limited to this. The rim portion may be formed on only one side of the light-shielding portion.

In the above embodiment, the lower layer is a phase shift film. However, the present invention is not limited to this. The lower layer may be a half-tone film.

In the above embodiment, the lower layer is a phase shift film, the intermediate film is a halftone film, and the upper layer is a light-shielding film. However, the present invention is not limited to this. The lower layer may be a phase shift film, the intermediate film may be a phase shift film, and the upper layer may be a light-shielding film. Alternatively, the lower layer may be a halftone film, the intermediate film may be a halftone film, and the upper layer may be a phase shift film. Alternatively, the lower layer may be a phase shift film, the intermediate film may be a halftone film, and the upper layer may be a halftone film. In these cases, the laminated portion of the lower layer, intermediate film, and upper layer may function as a light-shielding portion. In short, the lower layer, intermediate film, and upper layer may be selected from various functional films that have the function of adjusting the optical properties of the exposure light, such as a light-shielding film, a phase shift film, and a halftone film, and a laminated structure of any combination of the lower layer, intermediate film, and upper layer film may be adopted.

The lower layer, intermediate layer, and upper layer are not limited to the materials exemplified in the above embodiment, and can be selected from Cr-based materials, Ni-based materials, Ti-based materials, Si-based materials, Zr-based materials, or metal silicide-based materials, or from other materials, based on the premise that the intermediate layer, the lower layer, and the upper layer have different etching characteristics, depending on the corresponding transferred shape and part.

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

In addition, in the above-mentioned second embodiment, the shape of the hole (transmissive portion 10) (boundary line with the rim portion (semi-transmissive portion 12)) is rectangular, and the shape of the rim portion (semi-transmissive portion 12) (boundary line with the light-shielding portion 11) is rectangular. However, the present invention is not limited to this. The shape of the hole and the shape of the rim portion may be other shapes such as a circle or a polygon. Furthermore, the shape of the hole and the shape of the rim portion may be different.

1...photomask, 10...transmitting portion, 11...light-shielding portion (first region), 12...semi-transmitting portion (second region), 2...transparent substrate, 3...underlayer film (semi-transmitting film), 4...upperlayer film (light-shielding film), 4A...first pattern of upper layer film pattern, 4B...second pattern of upper layer film pattern, 5...resist film, 5a...first region, 5b...second region, 5A...first pattern of primary resist pattern, 5B...second pattern of primary resist pattern, 5C...second resist pattern, 6...intermediate film (etching stopper film)

Claims (7)

A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; an intermediate film formed on the underlayer film so that at least a portion of a peripheral region of the underlayer film is exposed; and an upper layer film formed so as to overlap the intermediate film, the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film, the intermediate film, and the upper layer film, and a second region of the underlayer film,
a photomask blanks preparation step of preparing a photomask blank in which a lower layer film, an intermediate film, and an upper layer film are laminated on a transparent substrate;
a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region;
a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask;
a second resist pattern forming process for forming a second resist pattern that covers the first pattern of the upper layer film pattern, an exposed portion of the intermediate film between the first pattern and the second pattern of the upper layer film pattern, and at least a portion including an edge on the first pattern side of 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 process for removing the second pattern of the upper layer film pattern by etching;
a first intermediate film etching process for removing exposed portions of the intermediate film by etching using the second resist pattern as a mask;
an underlayer film etching step of removing exposed portions of the underlayer film by etching using the intermediate film as a mask;
and a second intermediate film etching step of removing the exposed portion of the intermediate film by etching using the upper layer film as a mask. A method for manufacturing a photomask comprising: an underlayer film formed on a transparent substrate; an intermediate film formed on the underlayer film so that at least a portion of a peripheral region of the underlayer film is exposed; and an upper layer film formed so as to overlap the intermediate film, the photomask having a pattern constituted by a first region of a laminated portion of the underlayer film, the intermediate film, and the upper layer film, and a second region of the underlayer film,
a photomask blanks preparation step of preparing a photomask blank in which a lower layer film, an intermediate film, and an upper layer film are laminated on a transparent substrate;
a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region;
a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask;
a first intermediate film etching step of etching away exposed portions of the intermediate film using the upper film as a mask;
a second resist pattern forming process for forming a second resist pattern that covers the first pattern of the upper layer film pattern, the exposed portion of the lower layer film between the first pattern and the second pattern of the upper layer film pattern, and at least a portion including an edge on the first pattern side of 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 process for removing the second pattern of the upper layer film pattern by etching;
a second intermediate film etching step of removing exposed portions of the intermediate film by etching using the second resist pattern as a mask;
and an underlayer film etching step of removing exposed portions of the underlayer film by etching using the second resist pattern as a mask. A method for manufacturing a photomask comprising: a lower layer film formed on a transparent substrate; an intermediate film formed so as to overlap the lower layer film; and an upper layer film formed on the intermediate film so that at least a part of a peripheral region of the intermediate film is exposed, the photomask having a pattern constituted by a first region of a laminated portion of the lower layer film, the intermediate film, and the upper layer film, and a second region of the laminated portion of the lower layer film and the intermediate film,
a photomask blanks preparation step of preparing a photomask blank in which a lower layer film, an intermediate film, and an upper layer film are laminated on a transparent substrate;
a first resist pattern forming step of forming a first resist pattern including a first pattern corresponding to the first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region;
a first upper layer film etching process in which an upper layer film pattern is formed including a first pattern corresponding to a first region and a second pattern spaced apart from the first pattern and having an edge on the first pattern side set at a position corresponding to the position of an edge of the second region by removing an exposed portion of the upper layer film by etching using the first resist pattern as a mask;
a second resist pattern forming process for forming a second resist pattern that covers the first pattern of the upper layer film pattern, an exposed portion of the intermediate film between the first pattern and the second pattern of the upper layer film pattern, and at least a portion including an edge on the first pattern side of the second pattern of the upper layer film pattern, and exposes at least a portion of the other portion of the second pattern of the upper layer film pattern;
a second upper layer film etching process for removing the second pattern of the upper layer film pattern by etching;
an intermediate film etching process of removing exposed portions of the intermediate film by etching using the second resist pattern as a mask;
and an underlayer film etching step of removing exposed portions of the underlayer film by etching using the intermediate film as a mask. 4. The method for manufacturing a photomask according to claim 1, wherein the lower layer, the intermediate layer and the upper layer are films each having a first region functioning as a light shielding portion and a second region functioning as a phase shift portion. A phase shift film is used as the underlayer film.
The method for producing a photomask according to claim 4, wherein the upper layer is a light-shielding film. The method for manufacturing a photomask according to claim 4 , wherein the second region functions as a rim portion of the light-shielding portion. The method for producing a photomask according to any one of claims 1 to 3, wherein the pattern of the photomask is any one of a line and space pattern, a hole pattern, and a dot pattern.

Images