Photomask blank, photomask, and manufacturing method of photomask

Abstract

To provide a photomask blank, a photomask, and a manufacturing method of a photomask, in which a region dependence of a transmittance of light in a film forming a photomask pattern can be reduced.SOLUTION: According to one embodiment, a photomask blank includes a substrate, a first transmittance adjusting film provided on the substrate, a phase shifter film provided on the first transmittance adjusting film, and a second transmittance adjusting film provided on the phase shifter film. In the photomask blank, when light having a predetermined wavelength transmits through the phase shifter film, a phase of the light transmitted through the phase shifter film and the first transmittance adjusting film is different from a phase of light passed through atmosphere with about 180 degrees, and a phase of the light transmitted through the phase shifter film and the second transmittance adjusting film is different from a phase of the light passed through the atmosphere with about 180 degrees.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE FIELD OF THE DISCLOSURE The present invention relates to photomask blanks, photomasks, and methods for making photomasks. [Background technology]

[0002] A problem that can arise in photomasks for lithography is that the light transmittance through the film forming the photomask pattern varies depending on the region of the photomask. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-91338 A Summary of the Invention [Problem to be solved by the invention]

[0004] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a photomask blank, a photomask, and a method for manufacturing a photomask, which are capable of reducing the regional dependency of light transmittance in a film forming a photomask pattern. [Means for solving the problem]

[0005] According to one embodiment, a photomask blank includes a substrate, a first transmittance adjustment film provided on the substrate, a phase shifter film provided on the first transmittance adjustment film, and a second transmittance adjustment film provided on the phase shifter film. In the photomask blank, when light having a predetermined wavelength passes through the phase shifter film, the phase of the light that has passed through the phase shifter film and the first transmittance adjustment film differs by approximately 180 degrees from the phase of the light that has passed through the atmosphere, and the phase of the light that has passed through the phase shifter film and the second transmittance adjustment film differs by approximately 180 degrees from the phase of the light that has passed through the atmosphere. [Brief description of the drawings]

[0006] [Figure 1] 1 is a cross-sectional view showing a structure of a photomask according to a first embodiment. [Diagram 2] 1 is a cross-sectional view (1 / 7) illustrating the method for manufacturing the photomask according to the first embodiment. [Diagram 3] 1 is a cross-sectional view (2 / 7) illustrating the method for manufacturing the photomask according to the first embodiment. [Figure 4] 1 is a cross-sectional view (3 / 7) illustrating the method for manufacturing the photomask according to the first embodiment. [Diagram 5] 4 is a cross-sectional view (4 / 7) illustrating the method for manufacturing the photomask according to the first embodiment. [Figure 6] 5 is a cross-sectional view (5 / 7) illustrating the method for manufacturing the photomask according to the first embodiment. [Figure 7] 6A to 6C are cross-sectional views (6 / 7) illustrating the method for manufacturing the photomask according to the first embodiment. [Figure 8] 7 is a cross-sectional view (7 / 7) showing the method for manufacturing the photomask according to the first embodiment. [Figure 9] FIG. 11 is a cross-sectional view showing the structure of a photomask according to a second embodiment. [Figure 10] 8 is a cross-sectional view (1 / 8) showing a method for manufacturing a photomask according to a second embodiment. [Figure 11] 8 is a cross-sectional view (2 / 8) showing the method for manufacturing the photomask according to the second embodiment. FIG. [Figure 12] 8 is a cross-sectional view (3 / 8) showing the method for manufacturing the photomask according to the second embodiment. FIG. [Figure 13] 8 is a cross-sectional view (4 / 8) showing the method for manufacturing the photomask according to the second embodiment. FIG. [Figure 14] 8 is a cross-sectional view (5 / 8) showing the method for manufacturing the photomask according to the second embodiment. FIG. [Figure 15] 6 is a cross-sectional view (6 / 8) showing the method for manufacturing the photomask according to the second embodiment. [Figure 16] 7 is a cross-sectional view (7 / 8) showing the method for manufacturing the photomask according to the second embodiment. [Figure 17]8 is a cross-sectional view (8 / 8) illustrating the method for manufacturing the photomask according to the second embodiment. [Figure 18] FIG. 11 is a cross-sectional view showing the structure of a photomask according to a third embodiment. [Figure 19] 13 is a cross-sectional view (1 / 8) showing a method for manufacturing a photomask according to a third embodiment. [Figure 20] 13 is a cross-sectional view (2 / 8) showing the method for manufacturing the photomask according to the third embodiment. [Figure 21] 13 is a cross-sectional view (3 / 8) showing the method for manufacturing the photomask according to the third embodiment. FIG. [Figure 22] 13 is a cross-sectional view (4 / 8) showing the method for manufacturing the photomask according to the third embodiment. FIG. [Figure 23] 8 is a cross-sectional view (5 / 8) showing the method for manufacturing the photomask according to the third embodiment. FIG. [Figure 24] 6 is a cross-sectional view (6 / 8) showing the method for manufacturing the photomask according to the third embodiment. [Diagram 25] 7 is a cross-sectional view (7 / 8) showing the method for manufacturing the photomask according to the third embodiment. [Figure 26] 8 is a cross-sectional view (8 / 8) showing the method for manufacturing the photomask according to the third embodiment. [Figure 27] 13 is a cross-sectional view (1 / 7) showing a method for manufacturing a photomask according to a fourth embodiment. [Figure 28] 13 is a cross-sectional view (2 / 7) showing the method for manufacturing the photomask according to the fourth embodiment. [Figure 29] 13 is a cross-sectional view (3 / 7) showing the method for manufacturing the photomask according to the fourth embodiment. [Diagram 30] 13 is a cross-sectional view (4 / 7) showing the method for manufacturing the photomask according to the fourth embodiment. [Diagram 31] 13 is a cross-sectional view (5 / 7) showing the method for manufacturing the photomask according to the fourth embodiment. [Diagram 32] 13 is a cross-sectional view (6 / 7) showing the method for manufacturing the photomask according to the fourth embodiment. [Diagram 33] 13 is a cross-sectional view (7 / 7) showing the method for manufacturing the photomask according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In Fig. 1 to Fig. 33, the same components are denoted by the same reference numerals, and duplicated descriptions will be omitted.

[0008] (First embodiment) 1) Photomask of the first embodiment FIG. 1 is a cross-sectional view showing the structure of a photomask according to the first embodiment.

[0009] The photomask of this embodiment includes a substrate 1, a transmittance adjustment film 2, an HT (halftone) film 3, a transmittance adjustment film 4, and a light-shielding film 5. The transmittance adjustment film 2 is an example of a first transmittance adjustment film. The HT film 3 is an example of a phase shifter film. The transmittance adjustment film 4 is an example of a second transmittance adjustment film.

[0010] The substrate 1 is, for example, a transparent substrate such as a quartz substrate or a glass substrate. FIG. 1 shows an X direction and a Y direction parallel to the surface of the substrate 1 and perpendicular to each other, and a Z direction perpendicular to the surface of the substrate 1. The X direction, the Y direction, and the Z direction intersect with each other. In this specification, the +Z direction is treated as the upward direction, and the -Z direction is treated as the downward direction. The -Z direction may or may not coincide with the direction of gravity.

[0011] The transmittance adjustment film 2 is formed on the substrate 1. The transmittance adjustment film 2 has the effect of significantly changing (reducing) the light transmittance of the photomask of this embodiment. In this embodiment, the light transmittance of the transmittance adjustment film 2 is lower than the light transmittance of the HT film 3. The transmittance adjustment film 2 of this embodiment has a thickness smaller than the thickness of the HT film 3. The transmittance adjustment film 2 is made of, for example, HfO x The transmittance adjusting film 2 is a HfO xIt may be a film other than the film, for example, a Hf film or a HfN film (hafnium nitride film), or a simple metal film, metal oxide film, or metal nitride film containing Cr (chromium), Al (aluminum), W (tungsten), Ta (tantalum), Mo (molybdenum), Y (yttrium), or Ru (ruthenium). In this embodiment, the light transmittance of the photomask is adjusted by the transmittance adjusting film 2.

[0012] The HT film 3 is formed on the transmittance adjustment film 2. The HT film 3 has the effect of greatly changing the phase of light transmitted through the photomask of this embodiment. In this embodiment, the amount of change in the phase of light transmitted through the HT film 3 is greater than the amount of change in the phase of light transmitted through the transmittance adjustment film 2 and the amount of change in the phase of light transmitted through the transmittance adjustment film 4. The HT film 3 is, for example, a SiN film (silicon nitride film). The HT film 3 may contain Mo atoms in addition to Si atoms and N atoms. The light transmittance of the HT film 3 is, for example, about 6% of the light transmittance of the substrate 1. In this embodiment, the phase of light transmitted through the photomask is shifted within the HT film 3.

[0013] The transmittance adjustment film 4 is formed on the HT film 3. The transmittance adjustment film 4, like the transmittance adjustment film 2, has the effect of significantly changing (reducing) the light transmittance of the photomask of this embodiment. In this embodiment, the light transmittance of the transmittance adjustment film 4 is lower than the light transmittance of the HT film 3. The transmittance adjustment film 4 of this embodiment has a thickness smaller than that of the HT film 3. The transmittance adjustment film 4 is made of, for example, HfO x The transmittance adjusting film 2 is HfO x For example, it may be a Hf film or a HfN film, or it may be a simple metal film, a metal oxide film, or a metal nitride film containing Cr, Al, W, Ta, Mo, Y, or Ru. In this embodiment, the light transmittance of the photomask is adjusted by the transmittance adjusting film 4.

[0014] The light-shielding film 5 is formed on the transmittance adjusting film 4. The light-shielding film 5 has a function of blocking light incident on the photomask of this embodiment. The light-shielding film 5 is, for example, a Cr film.

[0015] The above transmittance is an energy transmittance that represents the ratio of the energy of light after transmission to the energy of light before transmission. On the other hand, the amplitude transmittance represents the ratio of the amplitude of light after transmission to the amplitude of light before transmission. The energy transmittance is the square of the amplitude transmittance. In this specification, the energy transmittance is simply referred to as "transmittance".

[0016] The photomask of this embodiment includes regions R1, R2, R3, and R4, as shown in Fig. 1. Region R1 is an example of a first region. Region R2 is an example of a second region. Regions R3 and R4 are examples of a third region.

[0017] The region R1 has a structure including the substrate 1, the transmittance adjustment film 2, and the HT film 3, but does not include the transmittance adjustment film 4 and the light-shielding film 5. Specifically, the region R1 includes a pattern portion P1 including the transmittance adjustment film 2 and the HT film 3, and a recess (non-pattern portion) H1 provided in the transmittance adjustment film 2 and the HT film 3. In this manner, in the region R1, the transmittance adjustment film 2 and the HT film 3 form a photomask pattern. The recess H1 penetrates the HT film 3 and the transmittance adjustment film 2 to reach the substrate 1. Thus, the side surface of the recess H1 is formed by at least the HT film 3 and the transmittance adjustment film 2, and the bottom surface of the recess H1 is formed by the substrate 1. The recess H1 is an example of a first recess. The light transmittance of the region R1 not including the transmittance adjustment film 4 is higher than the light transmittance of the region R2 including the transmittance adjustment film 4, so the region R1 is called a bright region (bright mask).

[0018] The region R2 has a structure including the substrate 1, the transmittance adjusting film 2, the HT film 3, and the transmittance adjusting film 4, but does not include the light-shielding film 5. Specifically, the region R2 includes a pattern portion P2 including the HT film 3 and the transmittance adjusting film 4, and a recess (non-pattern portion) H2 provided in the HT film 3 and the transmittance adjusting film 4. In this manner, in the region R2, the HT film 3 and the transmittance adjusting film 4 form a photomask pattern. The recess H2 penetrates the transmittance adjusting film 4 and the HT film 3 to reach the transmittance adjusting film 2. Thus, the side surface of the recess H2 is formed by at least the transmittance adjusting film 4 and the HT film 3, and the bottom surface of the recess H2 is formed by the transmittance adjusting film 2. The recess H2 is an example of a second recess. The light transmittance of the region R2 including the transmittance adjusting film 4 is lower than the light transmittance of the region R1 not including the transmittance adjusting film 4, so the region R2 is called a dark region (dark mask). For example, the amplitude transmittance of the dark region is about 70% of the amplitude transmittance of the bright region, and the transmittance (energy transmittance) of the dark region is about 49% of the transmittance of the bright region.

[0019] The region R3 has a structure including the substrate 1, the transmittance adjusting film 2, the HT film 3, the transmittance adjusting film 4, and the light-shielding film 5. Similarly, the region R4 has a structure including the substrate 1, the transmittance adjusting film 2, the HT film 3, the transmittance adjusting film 4, and the light-shielding film 5. The regions R3 and R4 form the light-shielding frame of the photomask of this embodiment. As shown in FIG. 1, the region R3 has a pattern portion P3 including the light-shielding film 5, but does not have a recess. On the other hand, the region R4 has a pattern portion P4 including the light-shielding film 5, and a recess (non-pattern portion) H4 provided in the light-shielding film 5, the transmittance adjusting film 4, the HT film 3, and the transmittance adjusting film 2. In the regions R3 and R4, the light-shielding film 5 forms a light-shielding pattern. Note that the light-shielding frame includes the region R4 in this embodiment, but may not include the region R4. That is, the light-shielding frame may or may not include the recess H4.

[0020] The transmittance adjusting film 2, the HT film 3, and the transmittance adjusting film 4 in this embodiment are formed to have predetermined properties with respect to light having a predetermined wavelength, for example, ArF excimer laser light (hereinafter referred to as "ArF light") (Ar stands for argon, and F stands for fluorine). The wavelength of ArF excimer laser light is 193 nm.

[0021] First, the transmittance adjustment film 2 and the HT film 3 of this embodiment are formed so that the phase of the ArF light transmitted through the transmittance adjustment film 2 and the HT film 3 is approximately 180 degrees different from the phase of the ArF light that has passed through the atmosphere. Therefore, the phase of the ArF light transmitted through the transmittance adjustment film 2 and the HT film 3 is approximately the inverted phase of the ArF light that has passed through the atmosphere. In this case, the phase of the ArF light transmitted through the pattern portion P1 of the region R1 is approximately 180 degrees different from the phase of the ArF light that has passed through the recessed portion H1 of the region R1. This is because the pattern portion P1 includes the transmittance adjustment film 2 and the HT film 3, whereas the recessed portion H1 does not include the transmittance adjustment film 2 and the HT film 3. Here, the above-mentioned "ArF light that has passed through the atmosphere" refers to the ArF light that has passed through the atmosphere at a distance equal to the thickness of the transmittance adjustment film 2 and the HT film 3.

[0022] Secondly, the HT film 3 and the transmittance adjustment film 4 of this embodiment are formed so that the phase of the ArF light transmitted through the HT film 3 and the transmittance adjustment film 4 is approximately 180 degrees different from the phase of the ArF light that has passed through the atmosphere. Therefore, the phase of the ArF light transmitted through the HT film 3 and the transmittance adjustment film 4 is approximately the inverted phase of the ArF light that has passed through the atmosphere. In this case, the phase of the ArF light transmitted through the pattern portion P2 of the region R2 is approximately 180 degrees different from the phase of the ArF light that has passed through the recessed portion H2 of the region R2. This is because the pattern portion P2 includes the HT film 3 and the transmittance adjustment film 4, whereas the recessed portion H2 does not include the HT film 3 and the transmittance adjustment film 4. Here, the above-mentioned "ArF light that has passed through the atmosphere" refers to the ArF light that has passed through the atmosphere at a distance equal to the thickness of the HT film 3 and the transmittance adjustment film 4.

[0023] As described above, the photomask of this embodiment includes the transmittance adjustment film 2 provided below the HT film 3, and the transmittance adjustment film 4 provided above the HT film 3. That is, the photomask of this embodiment includes the transmittance adjustment films 2, 4 on both sides of the HT film 3 rather than on one side. The effects of the transmittance adjustment films 2, 4 of this embodiment will be described below.

[0024] In this embodiment, the pattern portion P1 in the region R1 includes an HT film 3 and a transmittance adjustment film 2, and the pattern portion P2 in the region R2 includes an HT film 3 and a transmittance adjustment film 4. Thus, although there is a difference in that the transmittance adjustment film 2 is formed below the HT film 3 and the transmittance adjustment film 4 is formed above the HT film 3, both the pattern portion P1 and the pattern portion P2 include an HT film and a transmittance adjustment film. This makes it possible to approximate the transmittance of the pattern portion P1 and the transmittance of the pattern portion P2, and to approximate the amount of phase change in the pattern portion P1 and the amount of phase change in the pattern portion P2.

[0025] In addition, in this embodiment, the region R1 includes a transmittance adjusting film 2 in the pattern portion P1, whereas the region R2 includes a transmittance adjusting film 2 below the pattern portion P2. This makes it possible to make the transmittance of the region R1 different from that of the region R2. Thus, the region R1 is a light mask, and the region R2 is a dark mask. According to this embodiment, it is possible to make the optical characteristics of the pattern portions P1 and P2 closer to each other while making the optical characteristics of the regions R1 and R2 different.

[0026] Here, it is assumed that the above photomask includes the transmittance adjustment film 4 but does not include the transmittance adjustment film 2. In this case, if the pattern portion P1 does not include the transmittance adjustment film 4 and the pattern portion P2 includes the transmittance adjustment film 4, the transmittance of the region R1 can be made different from the transmittance of the region R2. However, in this case, the optical characteristics of the pattern portions P1 and P2 also differ from each other. This is because the pattern portion P1 includes only the HT film 3, and the pattern portion P2 includes the HT film 3 and the transmittance adjustment film 4.

[0027] Also, assume that the photomask includes the transmittance adjustment film 2 but does not include the transmittance adjustment film 4. In this case, if the recess H1 penetrates the transmittance adjustment film 2 and the recess H2 does not penetrate the transmittance adjustment film 2, the transmittance of the region R1 can be made different from the transmittance of the region R2. However, in this case, the optical characteristics of the pattern portions P1 and P2 also differ from each other. This is because the pattern portion P1 includes the transmittance adjustment film 2 and the HT film 3, and the pattern portion P2 includes only the HT film 3. The transmittance adjustment film 2 in the region R2 is located below the pattern portion P2, not within the pattern portion P2.

[0028] On the other hand, according to this embodiment, the photomask includes both the transmittance adjusting films 2 and 4, so that it is possible to make the optical characteristics of the regions R1 and R2 different while making the optical characteristics of the pattern portions P1 and P2 similar to each other. This makes it possible, for example, to make both the regions R1 and R2 halftone masks, or to make the regions R1 and R2 function as halftone masks having different characteristics.

[0029] The photomask pattern of this embodiment is formed by a transmittance adjustment film 2 and an HT film 3 in region R1, and by an HT film 3 and a transmittance adjustment film 4 in region R2. As a result, although there is a difference in that the transmittance adjustment film 2 is formed below the HT film 3 and the transmittance adjustment film 4 is formed above the HT film 3, both the pattern portion P1 in region R1 and the pattern portion P2 in region R2 include an HT film and a transmittance adjustment film. Therefore, according to this embodiment, it is possible to reduce the area dependency of the light transmittance in the film forming the photomask pattern.

[0030] As described above, the photomask of this embodiment has two regions R1 and R2 having different transmittances as regions not having the light-shielding film 5. On the other hand, the photomask of this embodiment may have three or more regions having different transmittances as regions not having the light-shielding film 5. For example, the photomask of this embodiment may have, as regions not having the light-shielding film 5, a region R1 having a high transmittance, a region R2 having a low transmittance, and another region having a medium transmittance.

[0031] 2) Method for manufacturing the photomask of the first embodiment 2 to 8 are cross-sectional views showing the method for manufacturing the photomask of the first embodiment.

[0032] First, a substrate 1 is prepared, and a transmittance adjusting film 2, an HT film 3, a transmittance adjusting film 4, a light-shielding film 5, and a resist film 6 are formed in this order on the substrate 1 (FIG. 2(a)). As a result, a photomask blank including the substrate 1, the transmittance adjusting film 2, the HT film 3, the transmittance adjusting film 4, the light-shielding film 5, and the resist film 6 is manufactured. FIG. 2(a) shows regions R1 to R4 in the same manner as FIG. 1.

[0033] In this embodiment, a certain manufacturer may manufacture a photomask blank including the substrate 1, the transmittance adjusting film 2, the HT film 3, and the transmittance adjusting film 4, and another manufacturer may sequentially form the light-shielding film 5 and the resist film 6 on this photomask blank. Also, in this embodiment, a certain manufacturer may manufacture a photomask blank including the substrate 1, the transmittance adjusting film 2, the HT film 3, the transmittance adjusting film 4, and the light-shielding film 5, and another manufacturer may form the resist film 6 on this photomask blank.

[0034] Next, recesses H1, H2, and H4 are formed in the resist film 6 in the regions R1, R2, and R4, respectively, by EB (electron beam) writing and development (FIG. 2(b)).

[0035] Next, the light-shielding film 5 is processed by RIE (Reactive Ion Etching) using the resist film 6 (FIG. 3(a)). As a result, the pattern of the resist film 6 is transferred to the light-shielding film 5, and recesses H1, H2, and H4 are also formed in the light-shielding film 5. The RIE in the process of FIG. 3(a) is performed using, for example, Cl2 gas and O2 gas (Cl stands for chlorine).

[0036] Next, the transmittance adjustment film 4 is processed by RIE using the resist film 6 (FIG. 3(b)). As a result, the pattern of the resist film 6 is transferred to the transmittance adjustment film 4, and recesses H1, H2, and H4 are also formed in the transmittance adjustment film 4. The RIE in the process of FIG. 3(b) is performed using, for example, BCl3 gas (B represents boron).

[0037] Next, the HT film 3 is processed by RIE using the resist film 6 (FIG. 4(a)). As a result, the pattern of the resist film 6 is transferred to the HT film 3, and recesses H1, H2, and H4 are also formed in the HT film 3. The RIE in the process of FIG. 4(a) is performed using, for example, SF6 gas and Ar gas (S stands for sulfur).

[0038] Next, the resist film 6 is peeled off (FIG. 4(b)). In this manner, pattern portions P1, P2, P3, and P4 are formed in regions R1, R2, R3, and R4, respectively. In FIG. 4(b), the pattern portions P1 to P4 include the pattern of the light-shielding film 5.

[0039] Next, a resist film 7 is formed on the light-shielding film 5 (FIG. 5(a)). The resist film 7 is also formed in the recesses H1, H2, and H4.

[0040] Next, the resist film 7 is removed from the regions R1 and R2 by laser drawing and development (FIG. 5(b)).

[0041] Next, the light-shielding film 5 is processed by RIE using the resist film 7 (FIG. 6(a)). As a result, the pattern of the resist film 7 is transferred to the light-shielding film 5, and the light-shielding film 5 is removed from the regions R1 and R2. The RIE in the process of FIG. 6(a) is performed using, for example, Cl2 gas and O2 gas.

[0042] Next, the resist film 7 is peeled off (FIG. 6(b)). In FIG. 6(b), the pattern portions P3 and P4 include the pattern of the light-shielding film 5, and the pattern portions P1 and P2 include the patterns of the transmittance adjusting film 4 and the HT film 3.

[0043] Next, a resist film 8 is formed on the light-shielding film 5 and the transmittance adjusting film 4 (FIG. 7(a)). The resist film 8 is also formed in the recesses H1, H2, and H4.

[0044] Next, the resist film 8 is removed from the entire region R1 and part of the region R4 by laser drawing and development (FIG. 7(b)).

[0045] Next, the transmittance adjustment films 2 and 4 are simultaneously processed by RIE using the resist film 8 (FIG. 8(a)). As a result, recesses H1 and H4 are also formed in the transmittance adjustment film 2, and the transmittance adjustment film 4 is removed from the region R1. The RIE in the process of FIG. 8(a) is performed using, for example, BCl3 gas. Note that the light-shielding film 5 exposed from the resist film 8 in the region R4 acts as a hard mask film during this RIE.

[0046] Next, the resist film 8 is peeled off (FIG. 8(b)). In FIG. 8(b), the pattern portions P3 and P4 include a pattern of the light-shielding film 5, the pattern portion P2 includes a pattern of the transmittance adjusting film 4 and the HT film 3, and the pattern portion P1 includes a pattern of the HT film 3 and the transmittance adjusting film 2.

[0047] In this manner, the photomask shown in FIG. 1 is manufactured.

[0048] As described above, the photomask pattern of this embodiment is formed by the transmittance adjustment film 2 and the HT film 3 in the region R1, and by the HT film 3 and the transmittance adjustment film 4 in the region R2. As a result, although there is a difference in that the transmittance adjustment film 2 is formed below the HT film 3 and the transmittance adjustment film 4 is formed above the HT film 3, both the pattern portion P1 in the region R1 and the pattern portion P2 in the region R2 include an HT film and a transmittance adjustment film. Therefore, according to this embodiment, it is possible to reduce the region dependency of the light transmittance in the film forming the photomask pattern.

[0049] Second embodiment 1) Photomask of the second embodiment FIG. 9 is a cross-sectional view showing the structure of a photomask according to the second embodiment.

[0050] The photomask of this embodiment has the same structure as the photomask of the first embodiment. However, the transmittance adjustment film 2 of this embodiment includes transmittance adjustment films 2a and 2b. The transmittance adjustment film 2a is an example of the first film, and the transmittance adjustment film 2b is an example of the second film. Furthermore, the transmittance adjustment film 4 of this embodiment includes transmittance adjustment films 4a and 4b. The transmittance adjustment film 4b is an example of the first film, and the transmittance adjustment film 4a is an example of the second film.

[0051] The transmittance adjusting film 2a is formed on the substrate 1. The transmittance adjusting film 2a is, for example, a SiN film. The transmittance adjusting film 2b is formed on the transmittance adjusting film 2a. The transmittance adjusting film 2b is, for example, a HfO x The transmittance adjusting film 2b is HfO x For example, it may be a Hf film or a HfN film, or it may be a simple metal film, a metal oxide film, or a metal nitride film containing Cr, Al, W, Ta, Mo, Y, or Ru. In this embodiment, the light transmittance of the photomask is adjusted by the transmittance adjusting films 2a and 2b.

[0052] The transmittance adjusting film 4b is formed on the HT film 3. The transmittance adjusting film 4b is, for example, HfO x The transmittance adjusting film 4b is a HfO xThe transmittance adjusting film 4a may be a film other than the film, for example, a Hf film or a HfN film, or a simple metal film, a metal oxide film, or a metal nitride film containing Cr, Al, W, Ta, Mo, Y, or Ru. The transmittance adjusting film 4a is formed on the transmittance adjusting film 4b. The transmittance adjusting film 4a is, for example, a SiN film. In this embodiment, the transmittance of the light of the photomask is adjusted by the transmittance adjusting films 4a and 4b.

[0053] Moreover, the regions R1 to R4 of this embodiment have the same characteristics as the regions R1 to R4 of the first embodiment. For example, the transmittance adjustment film 2 and the HT film 3 of this embodiment are formed so that the phase of the ArF light transmitted through the transmittance adjustment film 2 and the HT film 3 differs from the phase of the ArF light transmitted through the atmosphere by approximately 180 degrees. Moreover, the HT film 3 and the transmittance adjustment film 4 of this embodiment are formed so that the phase of the ArF light transmitted through the HT film 3 and the transmittance adjustment film 4 differs from the phase of the ArF light transmitted through the atmosphere by approximately 180 degrees. Therefore, according to the photomask of this embodiment, it is possible to obtain the same effect as the photomask of the first embodiment.

[0054] 2) Method for manufacturing a photomask according to the second embodiment 10 to 17 are cross-sectional views showing the method for manufacturing the photomask of the second embodiment.

[0055] First, a substrate 1 is prepared, and a transmittance adjusting film 2, an HT film 3, a transmittance adjusting film 4, a light-shielding film 5, and a resist film 6 are formed in this order on the substrate 1 (FIG. 10(a)). As a result, a photomask blank is manufactured that includes the substrate 1, the transmittance adjusting film 2, the HT film 3, the transmittance adjusting film 4, the light-shielding film 5, and the resist film 6. FIG. 10(a) shows regions R1 to R4, similar to FIG. 9. The transmittance adjusting film 2 is formed by forming transmittance adjusting films 2a and 2b in this order on the substrate 1. The transmittance adjusting film 4 is formed by forming transmittance adjusting films 4b and 4a in this order on the HT film 3.

[0056] Next, recesses H1, H2, and H4 are formed in the resist film 6 in the regions R1, R2, and R4, respectively, by EB writing and development (FIG. 10(b)).

[0057] Next, the light-shielding film 5 is processed by RIE using a resist film 6 (FIG. 11(a)). As a result, recesses H1, H2, and H4 are also formed in the light-shielding film 5.

[0058] Next, the transmittance adjustment film 4a is processed by RIE using the resist film 6 (FIG. 11(b)). As a result, recesses H1, H2, and H4 are also formed in the transmittance adjustment film 4a. The RIE in the process of FIG. 11(b) is performed using, for example, SF6 gas and Ar gas.

[0059] Next, the transmittance adjustment film 4b is processed by RIE using the resist film 6 (FIG. 12(a)). As a result, recesses H1, H2, and H4 are also formed in the transmittance adjustment film 4b. The RIE in the process of FIG. 12(a) is performed using, for example, BCl3 gas.

[0060] Next, the HT film 3 is processed by RIE using the resist film 6 (FIG. 12(b)). As a result, recesses H1, H2, and H4 are also formed in the HT film 3.

[0061] Next, the resist film 6 is peeled off (FIG. 13(a)). In this manner, pattern portions P1, P2, P3, and P4 are formed in the regions R1, R2, R3, and R4, respectively.

[0062] Next, a resist film 7 is formed on the light-shielding film 5 (FIG. 13(b)). The resist film 7 is also formed in the recesses H1, H2, and H4.

[0063] Next, the resist film 7 is removed from the regions R1 and R2 by laser drawing and development (FIG. 14(a)). Next, the light-shielding film 5 is processed by RIE using the resist film 7 (FIG. 14(b)). As a result, the light-shielding film 5 is removed from the regions R1 and R2.

[0064] Next, the resist film 7 is peeled off (FIG. 15(a)). Next, a resist film 8 is formed on the light-shielding film 5 and the transmittance adjusting film 4 (FIG. 15(b)). The resist film 8 is also formed in the recesses H1, H2, and H4.

[0065] Next, the resist film 8 is removed from the entire region R1 and part of the region R4 by laser drawing and development (FIG. 16(a)).

[0066] Next, the transmittance adjustment film 2b is processed by RIE using a resist film 8 (FIG. 16(b)). As a result, recesses H1 and H4 are also formed in the transmittance adjustment film 2b. The RIE in the process of FIG. 16(b) is performed using, for example, BCl3 gas.

[0067] Next, the transmittance adjustment films 2a and 4a are simultaneously processed by RIE using a resist film 8 (FIG. 17(a)). As a result, recesses H1 and H4 are also formed in the transmittance adjustment film 2a, and the transmittance adjustment film 4a is removed from the region R1. The RIE in the process of FIG. 17(a) is performed using, for example, SF6 gas and Ar gas.

[0068] Next, the transmittance adjustment film 4b is processed by RIE using the resist film 8 (FIG. 17(b)). As a result, the transmittance adjustment film 4b is removed from the region R1. The RIE in the process of FIG. 17(b) is performed using, for example, BCl3 gas. Thereafter, the resist film 8 is peeled off.

[0069] In this manner, the photomask shown in FIG. 10 is manufactured.

[0070] As described above, the photomask pattern of this embodiment is formed by the transmittance adjusting films 2a, 2b and the HT film 3 in the region R1, and by the HT film 3 and the transmittance adjusting films 4a, 4b in the region R2. As a result, although there is a difference in that the transmittance adjusting films 2a, 2b are formed below the HT film 3, and the transmittance adjusting films 4a, 4b are formed above the HT film 3, both the pattern portion P1 in the region R1 and the pattern portion P2 in the region R2 include the HT film and the transmittance adjusting film. Therefore, according to this embodiment, it is possible to reduce the region dependency of the light transmittance in the film forming the photomask pattern.

[0071] Third embodiment 1) Photomask of the third embodiment FIG. 18 is a cross-sectional view showing the structure of a photomask according to the third embodiment.

[0072] The photomask of this embodiment has the same structure as the photomask of the second embodiment. However, the transmittance adjustment film 2 of this embodiment includes a transmittance adjustment film 2b formed on the substrate 1 and a transmittance adjustment film 2a formed on the transmittance adjustment film 2b. In this embodiment, the transmittance adjustment film 2b is an example of the first film, and the transmittance adjustment film 2a is an example of the second film. Furthermore, the photomask of this embodiment includes an etching stopper film 11.

[0073] The etching stopper film 11 is formed between the transmittance adjustment film 2 and the HT film 3. Therefore, the HT film 3 in this embodiment is formed on the transmittance adjustment film 2 with the etching stopper film 11 interposed therebetween. The etching stopper film 11 in this embodiment has a thickness smaller than that of the HT film 3. The etching stopper film 11 is made of, for example, HfO x The etching stopper film 11 is a HfO x The film may be a film other than the above film, for example, a Hf film or a HfN film, or a simple metal film containing Cr, Al, W, Ta, Mo, Y, or Ru, a metal oxide film, or a metal nitride film.

[0074] The etching stopper film 11 functions as an etching stopper when the recesses H1, H2, and H4 are formed in the HT film 3 by RIE. Therefore, the etching selectivity of the etching stopper film 11 to the HT film 3 is set to a low value (for example, 1 / 10 or less). For example, the HT film 3 is a SiN film, and the etching stopper film 11 is a HfO x Such an etching selectivity can be realized by forming a film.

[0075] If the etching stopper film 11 were not present, when forming the recess H2 in the HT film 3, the recess H2 may also be formed in the transmittance adjustment film 2. This is called a film loss of the transmittance adjustment film 2. If the recess H2 in the transmittance adjustment film 2 becomes deep, the optical characteristics of the region R2 may differ from the designed characteristics. On the other hand, according to this embodiment, by forming the etching stopper film 11 between the transmittance adjustment film 2 and the HT film 3, it is possible to suppress the film loss of the transmittance adjustment film 2.

[0076] Moreover, the regions R1 to R4 of this embodiment have the same characteristics as the regions R1 to R4 of the first embodiment. For example, the transmittance adjustment film 2, the etching stopper film 11, and the HT film 3 of this embodiment are formed so that the phase of the ArF light transmitted through the transmittance adjustment film 2, the etching stopper film 11, and the HT film 3 differs from the phase of the ArF light transmitted through the atmosphere by approximately 180 degrees. Moreover, the etching stopper film 11, the HT film 3, and the transmittance adjustment film 4 of this embodiment are formed so that the phase of the ArF light transmitted through the etching stopper film 11, the HT film 3, and the transmittance adjustment film 4 differs from the phase of the ArF light transmitted through the atmosphere by approximately 180 degrees. Therefore, according to the photomask of this embodiment, it is possible to obtain the same effects as the photomasks of the first and second embodiments.

[0077] 2) Method for manufacturing a photomask according to the third embodiment 19 to 26 are cross-sectional views showing a method for manufacturing a photomask according to the third embodiment.

[0078] First, a substrate 1 is prepared, and a transmittance adjusting film 2, an etching stopper film 11, an HT film 3, a transmittance adjusting film 4, a light-shielding film 5, and a resist film 6 are formed in this order on the substrate 1 (FIG. 19(a)). As a result, a photomask blank including the substrate 1, the transmittance adjusting film 2, the etching stopper film 11, the HT film 3, the transmittance adjusting film 4, the light-shielding film 5, and the resist film 6 is manufactured. FIG. 19(a) shows regions R1 to R4 as in FIG. 18. The transmittance adjusting film 2 is formed by forming transmittance adjusting films 2b and 2a in this order on the substrate 1. The transmittance adjusting film 4 is formed by forming transmittance adjusting films 4b and 4a in this order on the HT film 3.

[0079] Next, recesses H1, H2, and H4 are formed in the resist film 6 in the regions R1, R2, and R4, respectively, by EB writing and development (FIG. 19(b)).

[0080] Next, the light-shielding film 5 is processed by RIE using a resist film 6 (FIG. 20(a)). As a result, recesses H1, H2, and H4 are also formed in the light-shielding film 5.

[0081] Next, the transmittance adjustment film 4a is processed by RIE using a resist film 6 (FIG. 20(b)). As a result, recesses H1, H2, and H4 are also formed in the transmittance adjustment film 4a.

[0082] Next, the transmittance adjustment film 4b is processed by RIE using a resist film 6 (FIG. 21(a)). As a result, recesses H1, H2, and H4 are also formed in the transmittance adjustment film 4b.

[0083] Next, the HT film 3 is processed by RIE using the resist film 6 (FIG. 21(b)). As a result, recesses H1, H2, and H4 are also formed in the HT film 3. At this time, the etching stopper film 11 functions as an etching stopper that stops the progress of the RIE.

[0084] Next, the etching stopper film 11 is processed by RIE using the resist film 6 (FIG. 22(a)). As a result, recesses H1, H2, and H4 are also formed in the etching stopper film 11. The RIE in the process of FIG. 22(a) is performed using, for example, BCl3 gas.

[0085] Next, the resist film 6 is peeled off (FIG. 22(b)). In this manner, pattern portions P1, P2, P3, and P4 are formed in the regions R1, R2, R3, and R4, respectively.

[0086] Next, a resist film 7 is formed on the light-shielding film 5 (FIG. 23(a)). The resist film 7 is also formed in the recesses H1, H2, and H4. Next, the resist film 7 is removed from the regions R1 and R2 by laser writing and development (FIG. 23(b)).

[0087] Next, the light-shielding film 5 is processed by RIE using the resist film 7 (FIG. 24(a)). As a result, the light-shielding film 5 is removed from the regions R1 and R2. Next, the resist film 7 is peeled off (FIG. 24(b)).

[0088] Next, a resist film 8 is formed on the light-shielding film 5 and the transmittance adjusting film 4 (FIG. 25(a)). The resist film 8 is also formed in the recesses H1, H2, and H4. Next, the resist film 8 is removed from the entire region R1 and part of the region R4 by laser writing and development (FIG. 25(b)).

[0089] Next, the transmittance adjustment films 2a and 4a are simultaneously processed by RIE using a resist film 8 (FIG. 26(a)). As a result, recesses H1 and H4 are also formed in the transmittance adjustment film 2a, and the transmittance adjustment film 4a is removed from the region R1. The RIE in the process of FIG. 26(a) is performed using, for example, SF6 gas and Ar gas.

[0090] Next, the transmittance adjustment films 2b and 4b are simultaneously processed by RIE using the resist film 8 (FIG. 26(b)). As a result, recesses H1 and H4 are also formed in the transmittance adjustment film 2b, and the transmittance adjustment film 4b is removed from the region R1. The RIE in the process of FIG. 26(b) is performed using, for example, BCl3 gas. Thereafter, the resist film 8 is peeled off.

[0091] In this manner, the photomask shown in FIG. 18 is manufactured.

[0092] As described above, the photomask pattern of this embodiment is formed by the transmittance adjustment film 2, the etching stopper film 11, and the HT film 3 in the region R1, and by the etching stopper film 11, the HT film 3, and the transmittance adjustment film 4 in the region R2. As a result, although there is a difference that the transmittance adjustment film 2 is formed on the lower side of the HT film 3 and the transmittance adjustment film 4 is formed on the upper side of the HT film 3, both the pattern portion P1 in the region R1 and the pattern portion P2 in the region R2 include the HT film and the transmittance adjustment film. Therefore, according to this embodiment, it is possible to reduce the region dependency of the light transmittance in the film forming the photomask pattern. Furthermore, according to this embodiment, by forming the etching stopper film 11 between the transmittance adjustment film 2 and the HT film 3, it is possible to suppress the film loss of the transmittance adjustment film 2.

[0093] (Fourth embodiment) 27 to 33 are cross-sectional views showing a method for manufacturing a photomask according to the fourth embodiment. In this embodiment, a photomask having the structure shown in Fig. 1 (first embodiment) is manufactured using a hard mask film 21. The hard mask film 21 is, for example, a SiO2 film.

[0094] First, a substrate 1 is prepared, and a transmittance adjusting film 2, an HT film 3, a transmittance adjusting film 4, a light-shielding film 5, a hard mask film 21, and a resist film 6 are formed in this order on the substrate 1 (FIG. 27(a)). As a result, a photomask blank including the substrate 1, the transmittance adjusting film 2, the HT film 3, the transmittance adjusting film 4, the light-shielding film 5, the hard mask film 21, and the resist film 6 is manufactured. FIG. 27(a) shows regions R1 to R4 in the same manner as FIG. 1.

[0095] Next, recesses H1, H2, and H4 are formed in the resist film 6 in the regions R1, R2, and R4, respectively, by EB lithography and development (FIG. 27(b)).

[0096] Next, the hard mask film 21 is processed by RIE using the resist film 6 (FIG. 28(a)). As a result, the pattern of the resist film 6 is transferred to the hard mask film 21, and recesses H1, H2, and H4 are also formed in the hard mask film 21. The RIE in the step of FIG. 28(a) is performed using, for example, SF6 gas and Ar gas. Next, the resist film 6 is stripped (FIG. 28(b)).

[0097] Next, the light-shielding film 5 is processed by RIE using the hard mask film 21 (FIG. 29(a)). As a result, the pattern of the hard mask film 21 is transferred to the light-shielding film 5, and recesses H1, H2, and H4 are also formed in the light-shielding film 5.

[0098] Next, the transmittance adjustment film 4 is processed by RIE using the hard mask film 21 (FIG. 29(b)). As a result, the pattern of the hard mask film 21 is transferred to the transmittance adjustment film 4, and recesses H1, H2, and H4 are also formed in the transmittance adjustment film 4.

[0099] Next, the HT film 3 is processed by RIE using the hard mask film 21 (FIG. 30(a)). As a result, the pattern of the hard mask film 21 is transferred to the HT film 3, and recesses H1, H2, and H4 are also formed in the HT film 3. In the step shown in FIG. 30(a), the hard mask film 21 is also removed. In this manner, pattern portions P1, P2, P3, and P4 are formed in regions R1, R2, R3, and R4, respectively.

[0100] Next, a resist film 7 is formed on the light-shielding film 5 (FIG. 30(b)). The resist film 7 is also formed in the recesses H1, H2, and H4.

[0101] Next, the resist film 7 is removed from the regions R1 and R2 by laser drawing and development (FIG. 31(a)). Next, the light-shielding film 5 is processed by RIE using the resist film 7 (FIG. 31(b)). As a result, the light-shielding film 5 is removed from the regions R1 and R2.

[0102] Next, the resist film 7 is peeled off (FIG. 32(a)). Next, a resist film 8 is formed on the light-shielding film 5 and the transmittance adjusting film 4 (FIG. 32(b)). The resist film 8 is also formed in the recesses H1, H2, and H4.

[0103] Next, the resist film 8 is removed from the entire region R1 and part of region R4 by laser writing and development (FIG. 32(a)). Next, the transmittance adjustment films 2 and 4 are simultaneously processed by RIE using the resist film 8 (FIG. 32(b)). As a result, recesses H1 and H4 are also formed in the transmittance adjustment film 2, and the transmittance adjustment film 4 is removed from region R1. Thereafter, the resist film 8 is peeled off.

[0104] In this manner, the photomask shown in FIG. 1 is manufactured.

[0105] As described above, the photomask pattern of this embodiment is formed by the transmittance adjustment film 2 and the HT film 3 in the region R1, and by the HT film 3 and the transmittance adjustment film 4 in the region R2. As a result, although there is a difference in that the transmittance adjustment film 2 is formed below the HT film 3 and the transmittance adjustment film 4 is formed above the HT film 3, both the pattern portion P1 in the region R1 and the pattern portion P2 in the region R2 include an HT film and a transmittance adjustment film. Therefore, according to this embodiment, it is possible to reduce the region dependency of the light transmittance in the film forming the photomask pattern.

[0106] Although several embodiments have been described above, these embodiments are presented only as examples and are not intended to limit the scope of the invention. The novel blanks, masks, and methods described in this specification can be implemented in various other forms. In addition, various omissions, substitutions, and modifications can be made to the forms of the blanks, masks, and methods described in this specification without departing from the spirit of the invention. The appended claims and their equivalents are intended to include such forms and modifications that fall within the scope and spirit of the invention. [Explanation of symbols]

[0107] 1: Substrate, 2: Transmittance adjustment film, 2a: Transmittance adjustment film, 2b: Transmittance adjustment film, 3: Halftone film, 4: Transmittance adjustment film, 4a: Transmittance adjustment film, 4b: Transmittance adjustment film, 5: light shielding film, 6: resist film, 7: resist film, 8: resist film, 11: etching stopper film, 21: hard mask film

Claims

1. A substrate; A first transmittance control film provided on the substrate; a phase shifter film provided on the first transmittance adjustment film; a second transmittance adjustment film provided on the phase shifter film, when light having a predetermined wavelength is transmitted through the phase shifter film, the phase of the light transmitted through the phase shifter film and the first transmittance adjustment film differs by approximately 180 degrees from the phase of the light transmitted through the atmosphere, and the phase of the light transmitted through the phase shifter film and the second transmittance adjustment film differs by approximately 180 degrees from the phase of the light transmitted through the atmosphere. Photomask blank.

2. The photomask blank of claim 1 , wherein the light having the predetermined wavelength is ArF excimer laser light.

3. The photomask blank according to claim 1 , wherein a thickness of the first transmittance adjustment film and a thickness of the second transmittance adjustment film are thinner than a thickness of the phase shifter film.

4. The photomask blank of claim 1 , wherein the phase shifter film contains Si (silicon) and N (nitrogen).

5. 2. The photomask blank of claim 1, wherein at least the first or second transmittance adjusting film contains Hf (hafnium), Cr (chromium), Al (aluminum), W (tungsten), Ta (tantalum), Mo (molybdenum), Y (yttrium), or Ru (ruthenium).

6. The photomask blank according to claim 1 , wherein at least the first or second transmittance adjusting film includes a first film and a second film provided on the first film.

7. one of the first and second films contains Si (silicon) and N (nitrogen); the other of the first and second films contains Hf (hafnium), Cr (chromium), Al (aluminum), W (tungsten), Ta (tantalum), Mo (molybdenum), Y (yttrium), or Ru (ruthenium); The photomask blank of claim 6.

8. The photomask blank according to claim 1 , further comprising an etching stopper film provided between said first transmittance adjustment film and said phase shifter film.

9. The photomask blank according to claim 8 , wherein the etching stopper film has a thickness smaller than a thickness of the phase shifter film.

10. 9. The photomask blank of claim 8, wherein the etching stopper film comprises Hf (hafnium), Cr (chromium), Al (aluminum), W (tungsten), Ta (tantalum), Mo (molybdenum), Y (yttrium), or Ru (ruthenium).

11. a first region including a substrate, a first transmittance adjustment film provided on the substrate, and a phase shifter film provided on the first transmittance adjustment film, the first region having a first recess penetrating the phase shifter film and the first transmittance adjustment film to reach the substrate; a second region including the substrate, the first transmittance adjustment film, the phase shifter film, and a second transmittance adjustment film provided on the phase shifter film, the second region having a second recess penetrating the second transmittance adjustment film and the phase shifter film to reach the first transmittance adjustment film; A photomask comprising:

12. The photomask according to claim 11, further comprising a third region including the substrate, the first transmittance adjustment film, the phase shifter film, the second transmittance adjustment film, and a light-shielding film provided on the second transmittance adjustment film.

13. The photomask according to claim 11 , wherein at least the first or second transmittance adjusting film includes a first film and a second film provided on the first film.

14. 12. The photomask according to claim 11, wherein the first and second regions further include an etching stopper film provided between the first transmittance adjustment film and the phase shifter film.

15. forming a first region including a substrate, a first transmittance adjustment film provided on the substrate, and a phase shifter film provided on the first transmittance adjustment film; forming a first recess in the first region, the first recess penetrating the phase shifter film and the first transmittance adjustment film and reaching the substrate; forming a second region including the substrate, the first transmittance adjustment film, the phase shifter film, and a second transmittance adjustment film provided on the phase shifter film; forming a second recess in the second region, the second recess penetrating the second transmittance adjustment film and the phase shifter film to reach the first transmittance adjustment film; A method for manufacturing a photomask comprising the steps of:

16. 16. The method for manufacturing a photomask according to claim 15, further comprising forming a third region including the substrate, the first transmittance adjustment film, the phase shifter film, the second transmittance adjustment film, and a light-shielding film provided on the second transmittance adjustment film.

17. the first, second, and third regions are formed to include the substrate, the first transmittance adjustment film, the phase shifter film, the second transmittance adjustment film, and the light-shielding film; removing the light-shielding film and the second transmittance adjusting film from the first region; removing the light-shielding film from the second region; The method of claim 16 , further comprising:

18. the second recess is formed in the second transmittance adjustment film and the phase shifter film before removing the light shielding film from the second region; the first recess is formed in the second transmittance adjustment film and the phase shifter film before removing the light shielding film from the first region, and is formed in the first transmittance adjustment film when or before removing the second transmittance adjustment film from the first region. The method for producing a photomask according to claim 17 .

19. 16. The method for manufacturing a photomask according to claim 15, wherein at least the first or second transmittance adjusting film is formed to include a first film and a second film provided on the first film.

20. 16. The method for manufacturing a photomask according to claim 15, wherein the phase shifter film is formed on the first transmittance adjustment film via an etching stopper film.

Images