Photomask substrate, photomask and manufacturing method of photomask

Abstract

The invention provides a photomask substrate, a photomask, and a method for manufacturing the photomask, which can reduce the regional dependency of light transmittance in a film on which a photomask pattern is formed. According to one embodiment, a photomask base is provided with: a substrate; a first transmittance adjustment film provided on the substrate; a phase shift film provided on the first transmittance adjustment film; and a second transmittance adjustment film provided on the phase shift film. In the photomask base, when light having a predetermined wavelength passes through the phase shift film, the phase of the light passing through the phase shift film and the first transmittance adjustment film differs by approximately 180 degrees from the phase of the light passing through the atmosphere, and the phase of the light passing through the first transmittance adjustment film differs by approximately 180 degrees from the phase of the light passing through the atmosphere. The phase of the light that has passed through the phase shift film and the second transmittance adjustment film differs from the phase of the light that has passed through the atmosphere by approximately 180 degrees.

Description

[0001] Related Applications

[0002] This application claims priority based on Japanese Patent Application No. 2023-102059 (filing date: June 21, 2023), and the present application incorporates all the contents of the basic application by reference. Technical Field

[0003] Embodiments of the present invention relate to a mask base, a mask, and a method for manufacturing the mask. Background Art

[0004] In a photomask for photolithography, there is a possibility that the transmittance of light in a film forming a mask pattern varies depending on the region of the mask, which may become a problem. Summary of the invention

[0005] Embodiments of the present invention provide a mask blank, a mask, and a method for manufacturing a mask that can reduce the area dependency of light transmittance in a film forming a mask pattern.

[0006] According to one embodiment, a photomask base includes: a substrate; a first transmittance adjustment film disposed on the substrate; a phase shift film disposed on the first transmittance adjustment film; and a second transmittance adjustment film disposed on the phase shift film. In the photomask base, when light having a predetermined wavelength passes through the phase shift film, the phase of the light passing through the phase shift film and the first transmittance adjustment film differs by about 180 degrees from the phase of the light passing through the atmosphere, and the phase of the light passing through the phase shift film and the second transmittance adjustment film differs by about 180 degrees from the phase of the light passing through the atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a cross-sectional view showing the structure of the photomask according to the first embodiment.

[0008] Figure 2 (a) and (b) are cross-sectional views (1 / 7) showing the method for manufacturing the photomask according to the first embodiment.

[0009] Figure 3 (a) and (b) are cross-sectional views (2 / 7) showing the method for manufacturing the photomask according to the first embodiment.

[0010] Figure 4 (a) and (b) are cross-sectional views (3 / 7) showing the method for manufacturing the photomask according to the first embodiment.

[0011] Figure 5 (a) and (b) are cross-sectional views (4 / 7) showing the method for manufacturing the photomask according to the first embodiment.

[0012] Figure 6 (a) and (b) are cross-sectional views (5 / 7) showing the method for manufacturing the photomask according to the first embodiment.

[0013] Figure 7 (a) and (b) are cross-sectional views (6 / 7) showing the method for manufacturing the photomask according to the first embodiment.

[0014] Figure 8 (a) and (b) are cross-sectional views (7 / 7) showing the method for manufacturing the photomask according to the first embodiment.

[0015] Fig. 9 It is a cross-sectional view showing the structure of a photomask according to the second embodiment.

[0016] Fig.10 (a) and (b) are cross-sectional views (1 / 8) showing a method for manufacturing a photomask according to a second embodiment.

[0017] Fig.11 (a) and (b) are cross-sectional views (2 / 8) showing the method for manufacturing a photomask according to the second embodiment.

[0018] Fig.12 (a) and (b) are cross-sectional views (3 / 8) showing the method for manufacturing a photomask according to the second embodiment.

[0019] Fig.13 (a) and (b) are cross-sectional views (4 / 8) showing the method for manufacturing a photomask according to the second embodiment.

[0020] Fig.14 (a) and (b) are cross-sectional views (5 / 8) showing the method for manufacturing a photomask according to the second embodiment.

[0021] Fig.15 (a) and (b) are cross-sectional views (6 / 8) showing the method for manufacturing a photomask according to the second embodiment.

[0022] Fig.16 (a) and (b) are cross-sectional views (7 / 8) showing the method for manufacturing a photomask according to the second embodiment.

[0023] Fig.17 (a) and (b) are cross-sectional views (8 / 8) showing the method for manufacturing a photomask according to the second embodiment.

[0024] Fig.18 It is a cross-sectional view showing the structure of a photomask according to the third embodiment.

[0025] Fig.19(a) and (b) are cross-sectional views (1 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0026] Fig. 20 (a) and (b) are cross-sectional views (2 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0027] Fig.21 (a) and (b) are cross-sectional views (3 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0028] Fig. 22 (a) and (b) are cross-sectional views (4 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0029] Fig.23 (a) and (b) are cross-sectional views (5 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0030] Fig.24 (a) and (b) are cross-sectional views (6 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0031] Fig.25 (a) and (b) are cross-sectional views (7 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0032] Fig.26 (a) and (b) are cross-sectional views (8 / 8) showing a method for manufacturing a photomask according to a third embodiment.

[0033] Fig. 27 (a) and (b) are cross-sectional views (1 / 7) showing a method for manufacturing a photomask according to a fourth embodiment.

[0034] Fig.28 (a) and (b) are cross-sectional views (2 / 7) showing a method for manufacturing a photomask according to a fourth embodiment.

[0035] Fig.29 (a) and (b) are cross-sectional views (3 / 7) showing a method for manufacturing a photomask according to a fourth embodiment.

[0036] Fig.30 (a) and (b) are cross-sectional views (4 / 7) showing a method for manufacturing a photomask according to a fourth embodiment.

[0037] Fig.31 (a) and (b) are cross-sectional views (5 / 7) showing a method for manufacturing a photomask according to a fourth embodiment.

[0038] Fig.32(a) and (b) are cross-sectional views (6 / 7) showing a method for manufacturing a photomask according to a fourth embodiment.

[0039] Fig.33 (a) and (b) are cross-sectional views (7 / 7) showing a method for manufacturing a photomask according to a fourth embodiment. DETAILED DESCRIPTION

[0040] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 to Figure 33 In the drawings, the same symbols are used to mark the same structures, and repeated descriptions are omitted.

[0041] (First embodiment)

[0042] 1) Photomask according to the first embodiment

[0043] Figure 1 It is a cross-sectional view showing the structure of the photomask according to the first embodiment.

[0044] The photomask of this embodiment includes a substrate 1, a transmittance adjustment film 2, a HT (Half Tone) 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 shift film. The transmittance adjustment film 4 is an example of a second transmittance adjustment film.

[0045] The substrate 1 is a transparent substrate such as a quartz substrate or a glass substrate. Figure 1 The X direction and the Y direction which are parallel to the surface of the substrate 1 and perpendicular to each other, and the Z direction which is perpendicular to the surface of the substrate 1 are shown. The X direction, the Y direction, and the Z direction intersect 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 be consistent with the gravity direction, or may not be consistent with the gravity direction.

[0046] The transmittance adjustment film 2 is formed on the substrate 1. The transmittance adjustment film 2 has the function of greatly changing (reducing) the transmittance of light of the photomask of this embodiment. In this embodiment, the transmittance of light of the transmittance adjustment film 2 is lower than the transmittance of light of the HT film 3. The transmittance adjustment film 2 of this embodiment has a film thickness thinner than the film thickness of the HT film 3. The transmittance adjustment film 2 is, for example, HfO x The transmittance adjustment film 2 may be HfO x The film other than the film may be, for example, an Hf film or an HfN film (hafnium nitride film), or a single metal film containing Cr (chromium), Al (aluminum), W (tungsten), Ta (tantalum), Mo (molybdenum), Y (yttrium), or Ru (ruthenium), a metal oxide film, or a metal nitride film. In this embodiment, the transmittance of the light of the mask is adjusted by the transmittance adjustment film 2.

[0047] The HT film 3 is formed on the transmittance adjustment film 2. The HT film 3 has the function of greatly changing (reducing) the phase of the light passing through the photomask of this embodiment. In this embodiment, the amount of change in the phase of the light passing through the HT film 3 is greater than the amount of change in the phase of the light passing through the transmittance adjustment film 2 or the amount of change in the phase of the light passing through the transmittance adjustment film 4. The HT film 3 is, for example, a SiCN film (silicon carbonitride film). The HT film 3 may contain Mo atoms together with Si atoms and N atoms. The transmittance of the light of the HT film 3 is, for example, about 6% of the transmittance of the light of the substrate 1. In this embodiment, the phase of the light passing through the photomask is shifted in the HT film 3.

[0048] 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 function of greatly changing (reducing) the transmittance of light of the photomask of this embodiment. In this embodiment, the transmittance of light of the transmittance adjustment film 4 is lower than the transmittance of light of the HT film 3. The transmittance adjustment film 4 of this embodiment has a film thickness thinner than the film thickness of the HT film 3. The transmittance adjustment film 4 is, for example, HfO x The transmittance adjustment film 2 may be HfO x The film other than the film may be, for example, an Hf film or an HfN film, or a single metal film, a metal oxide film, or a metal nitride film containing Cr, Al, W, Ta, Mo, Y, or Ru. In this embodiment, the transmittance of the light of the mask is adjusted by the transmittance adjustment film 4.

[0049] The light shielding film 5 is formed on the transmittance adjustment film 4. The light shielding film 5 has a function of shielding light incident on the photomask of the present embodiment. The light shielding film 5 is, for example, a Cr film.

[0050] In addition, the transmittance is an energy transmittance that represents the ratio of the energy of the light after transmission to the energy of the light before transmission. On the other hand, the amplitude transmittance represents the ratio of the amplitude of the light after transmission to the amplitude of the light before transmission. The energy transmittance is the square of the amplitude transmittance. In this specification, the energy transmittance is simply expressed as "transmittance".

[0051] The photomask of this embodiment is as follows Figure 1 As shown, there are regions R1, R2, R3, and R4. 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.

[0052] Region R1 has a structure including a substrate 1, a transmittance adjustment film 2, and a HT film 3, but not including a transmittance adjustment film 4 and a light shielding film 5. Specifically, 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. Thus, in region R1, the transmittance adjustment film 2 and the HT film 3 form a mask pattern. The recess H1 penetrates the HT film 3 and the transmittance adjustment film 2 to reach the substrate 1. Therefore, 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. Region H1 is an example of the first recess. Since the transmittance of light in region R1 without the transmittance adjustment film 4 is higher than the transmittance of light in region R2 with the transmittance adjustment film 4, region R1 is called a bright region (bright mask).

[0053] The region R2 has a structure including a substrate 1, a transmittance adjustment film 2, a HT film 3, and a transmittance adjustment film 4, but not including a light shielding film 5. Specifically, the region R2 includes: a pattern portion P2 including the HT film 3 and the transmittance adjustment film 4; and a recess (non-pattern portion) H2 provided in the HT film 3 and the transmittance adjustment film 4. Thus, in the region R2, the HT film 3 and the transmittance adjustment film 4 form a mask pattern. The recess H2 penetrates the transmittance adjustment film 4 and the HT film 3 to reach the transmittance adjustment film 2. Therefore, the side surface of the recess H2 is formed by at least the transmittance adjustment film 4 and the HT film 3, and the bottom surface of the recess H2 is formed by the transmittance adjustment film 2. The recess H2 is an example of the second recess. Since the transmittance of light in the region R2 including the transmittance adjustment film 4 is lower than the transmittance of light in the region R1 not including the transmittance adjustment film 4, the region R2 is a dark region (dark mask). For example, the amplitude transmittance of the dark region is approximately 70% of the amplitude transmittance of the bright region, and the transmittance (energy transmittance) of the dark region is approximately 49% of the transmittance of the bright region.

[0054] Region R3 has a structure including a substrate 1, a transmittance adjustment film 2, a HT film 3, a transmittance adjustment film 4, and a light shielding film 5. Similarly, region R4 has a structure including a substrate 1, a transmittance adjustment film 2, a HT film 3, a transmittance adjustment film 4, and a light shielding film 5. Regions R3 and R4 form a light shielding frame of the photomask of this embodiment. Figure 1 As shown, region R3 has a pattern portion P3 including a light shielding film 5, but does not have a recessed portion. On the other hand, region R4 has: a pattern portion P4 including a light shielding film 5; and a recessed portion (non-patterned portion) H4, which is provided in the light shielding film 5, the transmittance adjustment film 4, the HT film 3, and the transmittance adjustment film 2. In regions R3 and R4, the light shielding film 5 is formed with a light shielding pattern. In addition, the light shielding frame has region R4 in this embodiment, but may not have region R4. That is, the light shielding frame may have a recessed portion H4, or may not have a recessed portion H4.

[0055] The transmittance adjustment film 2, HT film 3, and transmittance adjustment film 4 of this embodiment are formed to have predetermined properties for light having a predetermined wavelength, such as ArF excimer laser light (hereinafter referred to as "ArF light") (Ar represents argon and F represents fluorine). The wavelength of ArF excimer laser light is 193 nm.

[0056] First, the transmittance adjustment film 2 and the HT film 3 of the present embodiment are formed so that the phase of the ArF light passing through the transmittance adjustment film 2 and the HT film 3 is different from the phase of the ArF light passing through the atmosphere by about 180 degrees. Therefore, the phase of the ArF light passing through the transmittance adjustment film 2 and the HT film 3 becomes a phase that roughly reverses the phase of the ArF light passing through the atmosphere. In the case described above, the phase of the ArF light passing through the pattern portion P1 of the region R1 is different from the phase of the ArF light passing through the recessed portion H1 of the region R1 by about 180 degrees. The reason is that the pattern portion P1 has the transmittance adjustment film 2 and the HT film 3, while the recessed portion H1 does not have the transmittance adjustment film 2 and the HT film 3. In addition, the "ArF light passing through the atmosphere" here refers to the ArF light passing through the atmosphere at the same distance as the film thickness of the transmittance adjustment film 2 and the HT film 3.

[0057] Second, the HT film 3 and the transmittance adjustment film 4 of the present embodiment are formed so that the phase of the ArF light passing through the HT film 3 and the transmittance adjustment film 4 is different from the phase of the ArF light passing through the atmosphere by about 180 degrees. Therefore, the phase of the ArF light passing through the HT film 3 and the transmittance adjustment film 4 becomes a phase that roughly reverses the phase of the ArF light passing through the atmosphere. In the case described above, the phase of the ArF light passing through the pattern portion P2 of the region R2 is different from the phase of the ArF light passing through the recessed portion H2 of the region R2 by about 180 degrees. The reason is that the pattern portion P2 has the HT film 3 and the transmittance adjustment film 4, while the recessed portion H2 does not have the HT film 3 and the transmittance adjustment film 4. In addition, the "ArF light passing through the atmosphere" here refers to the ArF light passing through the atmosphere at the same distance as the film thickness of the HT film 3 and the transmittance adjustment film 4.

[0058] As described above, the photomask of the present embodiment includes: the transmittance adjustment film 2 provided on the lower side of the HT film 3; and the transmittance adjustment film 4 provided on the upper side of the HT film 3. That is, the photomask of the present embodiment includes the transmittance adjustment films 2 and 4 on both sides of the HT film 3 instead of on one side. The effects of the transmittance adjustment films 2 and 4 of the present embodiment will be described below.

[0059] In this embodiment, the pattern portion P1 of the region R1 includes the HT film 3 and the transmittance adjustment film 2, and the pattern portion P2 of the region R2 includes the HT film 3 and the transmittance adjustment film 4. Therefore, 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 and the pattern portion P2 include the HT film and the transmittance adjustment film. As a result, the transmittance of the pattern portion P1 can be made close to the transmittance of the pattern portion P2, or the amount of change in the phase in the pattern portion P1 can be made close to the amount of change in the phase in the pattern portion P2.

[0060] In addition, in the present embodiment, the region R1 includes the transmittance adjustment film 2 in the pattern portion P1, and the region R2 includes the transmittance adjustment film 2 under the pattern portion P2. Thus, the transmittance of the region R1 and the transmittance of the region R2 can be made different. Therefore, the region R1 becomes a bright mask and the region R2 becomes a dark mask. According to the present embodiment, the optical characteristics of the pattern portions P1 and P2 can be made close, and the optical characteristics of the regions R1 and R2 can be made different.

[0061] Here, it is assumed that the photomask has a transmittance adjustment film 4 but does not have a transmittance adjustment film 2. In the above case, if the pattern portion P1 does not have a transmittance adjustment film 4, and the pattern portion P2 has a transmittance adjustment film 4, the transmittance of the region R1 can be made different from the transmittance of the region R2. However, in the above case, the optical properties of the pattern portions P1 and P2 are also different from each other. The reason is that the pattern portion P1 only has the HT film 3, and the pattern portion P2 has the HT film 3 and the transmittance adjustment film 4.

[0062] In addition, it is assumed that the photomask has a transmittance adjustment film 2 but does not have a transmittance adjustment film 4. In the above 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 different from the transmittance of the region R2. However, in the above case, the optical properties of the pattern portions P1 and P2 are also different from each other. The reason is that the pattern portion P1 has a transmittance adjustment film 2 and a HT film 3, while the pattern portion P2 only has the HT film 3. The transmittance adjustment film 2 in the region R2 is located under the pattern portion P2 instead of being located in the pattern portion P2.

[0063] On the other hand, according to this embodiment, the optical properties of the pattern portions P1 and P2 can be made close, and the optical properties of the regions R1 and R2 can be made different, by providing the mask with two transmittance adjustment films 2 and 4. Thus, for example, the regions R1 and R2 can both be set as halftone masks, or the regions R1 and R2 can function as halftone masks with different properties.

[0064] The mask pattern of this embodiment is formed by the transmittance adjustment film 2 and the HT film 3 in the region R1, and is formed by 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 of the region R1 and the pattern portion P2 of the region R2 have the HT film and the transmittance adjustment film. Therefore, according to this embodiment, the regional dependence of the transmittance of light in the film forming the mask pattern can be reduced.

[0065] As described above, the photomask of the present embodiment includes two regions R1 and R2 having different transmittances as regions without the light-shielding film 5. On the other hand, the photomask of the present embodiment may include three or more regions having different transmittances as regions without the light-shielding film 5. For example, the photomask of the present embodiment may include a region R1 having a high transmittance, R2 having a low transmittance, and other regions having intermediate transmittances as regions without the light-shielding film 5.

[0066] 2) Method for manufacturing photomask according to first embodiment

[0067] Figure 2 to Figure 8 It is a cross-sectional view showing the method for manufacturing the photomask according to the first embodiment.

[0068] First, a substrate 1 is prepared, and a transmittance adjustment film 2, a HT film 3, a transmittance adjustment film 4, a light shielding film 5, and a photoresist film 6 are sequentially formed on the substrate 1 ( Figure 2 As a result, a mask blank including the substrate 1, the transmittance adjustment film 2, the HT film 3, the transmittance adjustment film 4, the light shielding film 5, and the photoresist film 6 is manufactured. Figure 2 (a) and Figure 1 Regions R1 to R4 are also shown.

[0069] In addition, in the present embodiment, a photomask base including a substrate 1, a transmittance adjustment film 2, a HT film 3, and a transmittance adjustment film 4 can be manufactured for a certain manufacturer, and a light shielding film 5 and a photoresist film 6 can be sequentially formed on the photomask base by another manufacturer. In addition, in the present embodiment, a photomask base including a substrate 1, a transmittance adjustment film 2, a HT film 3, a transmittance adjustment film 4, and a light shielding film 5 can be manufactured for a certain manufacturer, and a photoresist film 6 can be formed on the photomask base by another manufacturer.

[0070] Next, by EB (Electron Beam: electron beam) drawing and development, recessed portions H1, H2, H4 ( Figure 2 (b) in the figure.

[0071] Next, the light shielding film 5 ( Figure 3 As a result, the pattern of the photoresist film 6 is transferred to the light shielding film 5 , and the recessed portions H1 , H2 , and H4 are also formed in the light shielding film 5 . Figure 3 The RIE in step (a) is performed using, for example, Cl 2 gas and O 2 gas (Cl represents chlorine).

[0072] Next, the transmittance adjustment film 4 ( Figure 3 As a result, the pattern of the photoresist film 6 is transferred to the transmittance adjustment film 4 , and the recessed portions H1 , H2 , and H4 are also formed in the transmittance adjustment film 4 . Figure 3 The RIE in step (b) is performed using, for example, BCl 3 gas (B represents boron).

[0073] Next, the HT film 3 ( Figure 4 As a result, the pattern of the photoresist film 6 is transferred to the HT film 3 , and the recessed portions H1 , H2 , and H4 are also formed in the HT film 3 . Figure 4 The RIE in step (a) is performed using, for example, SF6 gas and Ar gas (S represents sulfur).

[0074] Next, the photoresist film 6 ( Figure 4 In this way, pattern parts P1, P2, P3, and P4 are formed in regions R1, R2, R3, and R4, respectively. Figure 4 In (b), the pattern portions P1 to P4 include patterns of the light shielding film 5 .

[0075] Next, a photoresist film 7 is formed on the light shielding film 5 ( Figure 5 (a) in FIG. 1 ). The photoresist film 7 is also formed in the recesses H1 , H2 , and H4 .

[0076] Next, the photoresist film 7 ( Figure 5 (b) in the figure.

[0077] Next, the light shielding film 5 ( Figure 6 As a result, the pattern of the photoresist film 7 is transferred to the light shielding film 5, and the light shielding film 5 is removed from the regions R1 and R2. Figure 6 The RIE in step (a) is performed using Cl 2 gas and O 2 gas.

[0078] Next, the photoresist film 7 ( Figure 6 (b) in the Figure 6In (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 adjustment film 4 and the HT film 3 .

[0079] Next, a photoresist film 8 is formed on the light shielding film 5 and the transmittance adjustment film 4. Figure 7 (a) in FIG. 1 ). The photoresist film 8 is also formed in the recesses H1 , H2 , and H4 .

[0080] Next, the photoresist film 8 is removed from the entire region R1 and a portion of the region R4 by laser drawing and development. Figure 7 (b) in the figure.

[0081] Next, the transmittance adjustment films 2 and 4 are processed simultaneously by RIE using the photoresist film 8. Figure 8 As a result, the recessed portions H1 and H4 are also formed in the transmittance adjusting film 2, and the transmittance adjusting film 4 is removed from the region R1. Figure 8 The RIE in step (a) is performed using, for example, BCl 3 gas. In addition, the light shielding film 5 exposed from the photoresist film 8 in the region R4 functions as a hard mask film during the RIE.

[0082] Next, the photoresist film 8 ( Figure 8 (b) in the Figure 8 In (b), the pattern portions P3 and P4 include the pattern of the light shielding film 5 , the pattern portion P2 includes the patterns of the transmittance adjustment film 4 and the HT film 3 , and the pattern portion P1 includes the patterns of the HT film 3 and the transmittance adjustment film 2 .

[0083] In this way, manufacturing Figure 1 The photomask shown.

[0084] As described above, the mask pattern of the present embodiment is formed by the transmittance adjustment film 2 and the HT film 3 in the region R1, and is formed by 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 have the HT film and the transmittance adjustment film. Therefore, according to the present embodiment, the regional dependency of the transmittance of light in the film forming the mask pattern can be reduced.

[0085] (Second embodiment)

[0086] 1) Photomask according to the second embodiment

[0087] Fig. 9 It is a cross-sectional view showing the structure of a photomask according to the second embodiment.

[0088] The photomask of this embodiment has the same structure as the photomask of the first embodiment. Among them, 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. In addition, 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 4b is an example of the second film.

[0089] The transmittance adjustment film 2a is formed on the substrate 1. The transmittance adjustment film 2a is, for example, a SiN film. The transmittance adjustment film 2b is formed on the transmittance adjustment film 2a. The transmittance adjustment film 2b is, for example, a HfO x The transmittance adjustment film 2b may be HfO x The film other than the film may be, for example, an Hf film or an HfN film, or a single metal film, a metal oxide film, or a metal nitride film containing Cr, Al, W, Ta, Mo, Y, or Ru. In this embodiment, the transmittance of the light of the mask is adjusted by the transmittance adjustment films 2a and 2b.

[0090] The transmittance adjustment film 4b is formed on the HT film 3. The transmittance adjustment film 4b is made of, for example, HfO x The transmittance adjustment film 4b may be HfO x The film other than the film may be, for example, an Hf film or an HfN film, or may be a single metal film, a metal oxide film, or a metal nitride film containing Cr, Al, W, Ta, Mo, Y, or Ru. The transmittance adjustment film 4a is formed on the transmittance adjustment film 4b. The transmittance adjustment film 4a is, for example, a SiN film. In this embodiment, the transmittance of the light of the mask is adjusted by the transmittance adjustment films 4a and 4b.

[0091] In addition, the regions R1 to R4 of the present 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 the present embodiment are formed so that the phase of the ArF light passing through the transmittance adjustment film 2 and the HT film 3 differs from the phase of the ArF light passing through the atmosphere by about 180 degrees. In addition, the HT film 3 and the transmittance adjustment film 4 of the present embodiment are formed so that the phase of the ArF light passing through the HT film 3 and the transmittance adjustment film 4 differs from the phase of the ArF light passing through the atmosphere by about 180 degrees. Therefore, according to the mask of the present embodiment, the same effect as the mask of the first embodiment can be obtained.

[0092] 2) Method for manufacturing photomask according to second embodiment

[0093] Figure 10 to Figure 17 It is a cross-sectional view showing the method for manufacturing a photomask according to the second embodiment.

[0094] First, a substrate 1 is prepared, and a transmittance adjustment film 2, a HT film 3, a transmittance adjustment film 4, a light shielding film 5, and a photoresist film 6 are sequentially formed on the substrate 1 ( Fig.10 As a result, a mask blank including the substrate 1, the transmittance adjustment film 2, the HT film 3, the transmittance adjustment film 4, the light shielding film 5, and the photoresist film 6 is manufactured. Fig.10 (a) and Fig. 9 Regions R1 to R4 are also shown. The transmittance adjusting film 2 is formed by sequentially forming transmittance adjusting films 2a and 2b on the substrate 1. The transmittance adjusting film 4 is formed by sequentially forming transmittance adjusting films 4a and 4b on the HT film 3.

[0095] Next, recesses H1, H2, H4 ( Fig.10 (b) in the figure.

[0096] Next, the light shielding film 5 ( Fig.11 As a result, recessed portions H1 , H2 , and H4 are also formed in the light shielding film 5 .

[0097] Next, the transmittance adjustment film 4a ( Fig.11 As a result, recessed portions H1, H2, and H4 are also formed in the transmittance adjusting film 4a. Fig.11 The RIE in step (b) is performed using, for example, SF6 gas and Ar gas.

[0098] Next, the transmittance adjustment film 4b ( Fig.12 As a result, recessed portions H1, H2, and H4 are also formed in the transmittance adjusting film 4b. Fig.12 The RIE in step (a) is performed using, for example, BCl 3 gas.

[0099] Next, the HT film 3 ( Fig.12 As a result, recessed portions H1 , H2 , and H4 are also formed in the HT film 3 .

[0100] Next, the photoresist film 6 ( Fig.13 In this way, pattern portions P1, P2, P3, and P4 are formed in regions R1, R2, R3, and R4, respectively.

[0101] Next, a photoresist film 7 is formed on the light shielding film 5 ( Fig.13 (b) in FIG. 1 ). The photoresist film 7 is also formed in the recesses H1 , H2 , and H4 .

[0102] Next, the photoresist film 7 ( Fig.14 Next, the light shielding film 5 ( Fig.14 As a result, the light shielding film 5 is removed from the regions R1 and R2.

[0103] Next, the photoresist film 7 ( Fig.15 Next, a photoresist film 8 is formed on the light shielding film 5 and the transmittance adjustment film 4 ( Fig.15 (b) in FIG. 1 ). The photoresist film 8 is also formed in the recesses H1 , H2 , and H4 .

[0104] Next, the photoresist film 8 is removed from the entire region R1 and a portion of the region R4 by laser drawing and development. Fig.16 (a) in the figure.

[0105] Next, the transmittance adjustment film 2b ( Fig.16 As a result, the recessed portions H1 and H4 are also formed in the transmittance adjusting film 2b. Fig.16 The RIE in step (b) is performed using, for example, BCl 3 gas.

[0106] Next, the transmittance adjustment films 2a and 4a ( Fig.17 As a result, the recessed portions H1 and H4 are also formed in the transmittance adjusting film 2a, and the transmittance adjusting film 4a is removed from the region R1. Fig.17 The RIE in step (a) is performed using, for example, SF6 gas and Ar gas.

[0107] Next, the transmittance adjustment film 4b ( Fig.17 As a result, the transmittance adjustment film 4b is removed from the region R1. Fig.17 The RIE in step (b) is performed using, for example, BCl 3 gas. Thereafter, the photoresist film 8 is peeled off.

[0108] In this way, manufacturing Fig.10 The photomask shown.

[0109] As described above, the mask pattern of the present embodiment is formed by the transmittance adjustment films 2a, 2b and the HT film 3 in the region R1, and is formed by the HT film 3 and the transmittance adjustment films 4a, 4b in the region R2. As a result, although there is a difference that the transmittance adjustment films 2a, 2b are formed on the lower side of the HT film 3, and the transmittance adjustment films 4a, 4b are 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 have the HT film and the transmittance adjustment film. Therefore, according to the present embodiment, the regional dependency of the transmittance of light in the film forming the mask pattern can be reduced.

[0110] (Third embodiment)

[0111] 1) Photomask according to the third embodiment

[0112] Fig.18 It is a cross-sectional view showing the structure of a photomask according to a third embodiment.

[0113] 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. In addition, the photomask of this embodiment includes an etching stopper film 11.

[0114] The etching stopper film 11 is formed between the transmittance adjustment film 2 and the HT film 3. Therefore, the HT film 3 of this embodiment is formed on the transmittance adjustment film 2 via the etching stopper film 11. The etching stopper film 11 of this embodiment has a film thickness thinner than that of the HT film 3. The etching stopper film 11 is, for example, HfO x The etching stopper film 11 may be HfO x The film other than the film may be, for example, an Hf film or an HfN film, or may be a single metal film containing Cr, Al, W, Ta, Mo, Y, or Ru, a metal oxide film, or a metal nitride film.

[0115] 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 with respect to the HT film 3 is set to a low value (e.g., less than 1 / 10). For example, by making the HT film 3 a SiN film and the etching stopper film 11 a HfO x film, can achieve this etching selectivity ratio.

[0116] If the etching stopper film 11 is not present, when the recess H2 is formed in the HT film 3, there is a concern that the recess H2 is also formed in the transmittance adjustment film 2. This is called film reduction of the transmittance adjustment film 2. If the recess H2 in the transmittance adjustment film 2 becomes deeper, there is a concern that the optical characteristics of the region R2 may be different from the designed characteristics. On the other hand, according to the present embodiment, by forming the etching stopper film 11 between the transmittance adjustment film 2 and the HT film 3, the film reduction of the transmittance adjustment film 2 can be suppressed.

[0117] In addition, the regions R1 to R4 of the present embodiment have the same characteristics as the regions R1 to R4 of the first embodiment. For example, the transmittance adjustment film 2, the etching stop film 11, and the HT film 3 of the present embodiment are formed so that the phase of the ArF light passing through the transmittance adjustment film 2, the etching stop film 11, and the HT film 3 is different from the phase of the ArF light passing through the atmosphere by about 180 degrees. In addition, the etching stop film 11, the HT film 3, and the transmittance adjustment film 4 of the present embodiment are formed so that the phase of the ArF light passing through the etching stop film 11, the HT film 3, and the transmittance adjustment film 4 is different from the phase of the ArF light passing through the atmosphere by about 180 degrees. Therefore, according to the mask of the present embodiment, the same effect as the mask of the first and second embodiments can be obtained.

[0118] 2) Method for manufacturing photomask according to third embodiment

[0119] Figures 19 to 26 It is a cross-sectional view showing a method for manufacturing a photomask according to a third embodiment.

[0120] First, a substrate 1 is prepared, and a transmittance adjustment film 2, an etching stopper film 11, a HT film 3, a transmittance adjustment film 4, a light shielding film 5, and a photoresist film 6 are sequentially formed on the substrate 1 ( Fig.19 As a result, a mask blank including the substrate 1, the transmittance adjustment film 2, the etching stopper film 11, the HT film 3, the transmittance adjustment film 4, the light shielding film 5, and the photoresist film 6 is manufactured. Fig.19 (a) and Fig.18 Regions R1 to R4 are shown in the same manner. The transmittance adjusting film 2 is formed by sequentially forming transmittance adjusting films 2b and 2a on the substrate 1. The transmittance adjusting film 4 is formed by sequentially forming transmittance adjusting films 4b and 4a on the HT film 3.

[0121] Next, recesses H1, H2, H4 ( Fig.19 (b) in the figure.

[0122] Next, the light shielding film 5 ( Fig. 20 As a result, recessed portions H1 , H2 , and H4 are also formed in the light shielding film 5 .

[0123] Next, the transmittance adjustment film 4a ( Fig. 20 As a result, recessed portions H1, H2, and H4 are also formed in the transmittance adjusting film 4a.

[0124] Next, the transmittance adjustment film 4b ( Fig.21 As a result, recessed portions H1, H2, and H4 are also formed in the transmittance adjusting film 4b.

[0125] Next, the HT film 3 ( Fig.21 As a result, the recessed portions 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 RIE.

[0126] Next, the etching stopper film 11 ( Fig. 22 As a result, recessed portions H1 , H2 , and H4 are also formed in the etching stopper film 11 . Fig. 22 The RIE in step (a) is performed using, for example, BCl 3 gas.

[0127] Next, the photoresist film 6 ( Fig. 22 In this way, pattern portions P1, P2, P3, and P4 are formed in regions R1, R2, R3, and R4, respectively.

[0128] Next, a photoresist film 7 is formed on the light shielding film 5 ( Fig.23 (a) in FIG. 1 ). The photoresist film 7 is also formed in the recesses H1, H2, and H4. Next, the photoresist film 7 is removed from the regions R1 and R2 by laser drawing and development. Fig.23 (b) in the figure.

[0129] Next, the light shielding film 5 ( Fig.24 As a result, the light shielding film 5 is removed from the regions R1 and R2. Next, the photoresist film 7 ( Fig.24 (b) in the figure.

[0130] Next, a photoresist film 8 is formed on the light shielding film 5 and the transmittance adjustment film 4. Fig.25 (a) in FIG. 1 ). The photoresist film 8 is also formed in the recesses H1, H2, and H4. Next, the photoresist film 8 is removed from the entire region R1 and a portion of the region R4 by laser drawing and development ( Fig.25 (b) in the figure.

[0131] Next, the transmittance adjustment films 2a and 4a ( Fig.26 As a result, the recessed portions H1 and H4 are also formed in the transmittance adjusting film 2a, and the transmittance adjusting film 4a is removed from the region R1. Fig.26 The RIE in step (a) is performed using, for example, SF6 gas and Ar gas.

[0132] Next, the transmittance adjustment films 2b and 4b ( Fig.26 As a result, the recessed portions H1 and H4 are also formed in the transmittance adjusting film 2b, and the transmittance adjusting film 4b is removed from the region R1. Fig.26 The RIE in step (b) is performed using, for example, BCl 3 gas. Thereafter, the photoresist film 8 is peeled off.

[0133] In this way, manufacturing Fig.18 The photomask shown.

[0134] As described above, the mask pattern of the present embodiment is formed by the transmittance adjustment film 2, the etching stopper film 11, and the HT film 3 in the region R1, and is formed 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 of the region R1 and the pattern portion P2 of the region R2 have the HT film and the transmittance adjustment film. Therefore, according to the present embodiment, the regional dependence of the transmittance of light in the film forming the mask pattern can be reduced. In addition, according to the present embodiment, by forming the etching stopper film 11 between the transmittance adjustment film 2 and the HT film 3, the film reduction of the transmittance adjustment film 2 can be suppressed.

[0135] (Fourth embodiment)

[0136] Figure 27 to Figure 33 2 is a cross-sectional view showing a method for manufacturing a photomask according to a fourth embodiment. Figure 1 (First Embodiment) Photomask having the structure shown in the figure. The hard mask film 21 is, for example, a SiO2 film.

[0137] First, a substrate 1 is prepared, and a transmittance adjustment film 2, a HT film 3, a transmittance adjustment film 4, a light shielding film 5, a hard mask film 21, and a photoresist film 6 are sequentially formed on the substrate 1 ( Fig. 27 As a result, a mask blank including the substrate 1, the transmittance adjustment film 2, the HT film 3, the transmittance adjustment film 4, the light shielding film 5, the hard mask film 21, and the photoresist film 6 is manufactured. Fig. 27 (a) and Figure 1 Regions R1 to R4 are also shown.

[0138] Next, recesses H1, H2, H4 ( Fig. 27 (b) in the figure.

[0139] Next, the hard mask film 21 ( Fig.28 As a result, the pattern of the photoresist film 6 is transferred to the hard mask film 21 , and the recesses H1 , H2 , and H4 are also formed in the hard mask film 21 . Fig.28 The RIE in step (a) is performed using, for example, SF6 gas and Ar gas. Next, the photoresist film 6 ( Fig.28 (b) in the figure.

[0140] Next, the light shielding film 5 ( Fig.29 As a result, the pattern of the hard mask film 21 is transferred to the light shielding film 5 , and the recessed portions H1 , H2 , and H4 are also formed in the light shielding film 5 .

[0141] Next, the transmittance adjustment film 4 ( Fig.29 As a result, the pattern of the hard mask film 21 is transferred to the transmittance adjustment film 4 , and the recessed portions H1 , H2 , and H4 are also formed in the transmittance adjustment film 4 .

[0142] Next, the HT film 3 ( Fig.30 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. Fig.30 In the step (a) of FIG. 1 , the hard mask film 21 is also removed. In this way, pattern portions P1, P2, P3, and P4 are formed in regions R1, R2, R3, and R4, respectively.

[0143] Next, a photoresist film 7 is formed on the light shielding film 5 ( Fig.30 (b) in FIG. 1 ). The photoresist film 7 is also formed in the recesses H1 , H2 , and H4 .

[0144] Next, the photoresist film 7 ( Fig.31 Next, the light shielding film 5 ( Fig.31 As a result, the light shielding film 5 is removed from the regions R1 and R2.

[0145] Next, the photoresist film 7 ( Fig.32 Next, a photoresist film 8 is formed on the light shielding film 5 and the transmittance adjustment film 4 ( Fig.32 (b) in FIG. 1 ). The photoresist film 8 is also formed in the recesses H1 , H2 , and H4 .

[0146] Next, the photoresist film 8 is removed from the entire region R1 and a portion of the region R4 by laser drawing and development. Fig.32 Next, the transmittance adjustment films 2 and 4 are processed simultaneously by RIE using the photoresist film 8 ( Fig.32 As a result, the recessed portions H1 and H4 are also formed in the transmittance adjustment film 2, and the transmittance adjustment film 4 is removed from the region R1. Thereafter, the photoresist film 8 is peeled off.

[0147] In this way, manufacturing Figure 1 The photomask shown.

[0148] As described above, the mask pattern of the present embodiment is formed by the transmittance adjustment film 2 and the HT film 3 in the region R1, and is formed by 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 have the HT film and the transmittance adjustment film. Therefore, according to the present embodiment, the regional dependency of the transmittance of light in the film forming the mask pattern can be reduced.

[0149] Although various embodiments have been described above, the embodiments are presented only as examples and are not intended to limit the scope of the invention. The novel substrates, masks, and methods described in this specification can be implemented in various other ways. In addition, various omissions, substitutions, and changes can be made to the substrates, masks, and methods described in this specification without departing from the scope of the invention. The scope of the attached claims and their equivalents are intended to include such methods or variations as included in the scope or subject matter of the invention.

[0150] [Explanation of Symbols]

[0151] 1 Substrate

[0152] 2 Transmittance adjustment membrane

[0153] 2a Transmittance adjustment membrane

[0154] 2b Transmittance adjustment membrane

[0155] 3 Halftone Film

[0156] 4 Transmittance adjustment membrane

[0157] 4a Transmittance adjustment membrane

[0158] 4b Transmittance adjustment membrane

[0159] 5 shading film

[0160] 6 Photoresist film

[0161] 7 Photoresist film

[0162] 8 Photoresist film

[0163] 11 Etching barrier film

[0164] 21 hard mask film.

Claims

1. A photomask substrate, comprising: substrate; a first transmittance adjustment film disposed on the substrate; a phase shift film disposed on the first transmittance adjustment film; and A second transmittance adjustment film is disposed on the phase shift film; and When light having a specified wavelength passes through the phase shift film, the phase of the light passing through the phase shift film and the first transmittance adjustment film differs by approximately 180 degrees from the phase of the light passing through the atmosphere, and the phase of the light passing through the phase shift film and the second transmittance adjustment film differs by approximately 180 degrees from the phase of the light passing through the atmosphere.

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

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

4. The photomask blank according to claim 1, wherein The phase shift film includes Si (silicon) and N (nitrogen).

5. The photomask blank according to claim 1, wherein At least the first or second transmittance adjustment film includes 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. The photomask blank according to claim 6, wherein One of the first and second films includes Si (silicon) and N (nitrogen), and The other of the first and second films includes Hf (hafnium), Cr (chromium), Al (aluminum), W (tungsten), Ta (tantalum), Mo (molybdenum), Y (yttrium) or Ru (ruthenium).

8. The photomask blank according to claim 1, further comprising: An etching stopper film is provided between the first transmittance adjustment film and the phase shift film.

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

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

11. A photomask comprising: The first region includes a substrate, a first transmittance adjustment film disposed on the substrate, and a phase shift film disposed on the first transmittance adjustment film, and has a first recessed portion penetrating the phase shift film and the first transmittance adjustment film to reach the substrate; and The second region includes the substrate, the first transmittance adjusting film, the phase shift film, and a second transmittance adjusting film provided on the phase shift film, and has a second recessed portion penetrating the second transmittance adjusting film and the phase shift film to reach the first transmittance adjusting film.

12. The photomask according to claim 11, further comprising: The third region includes the substrate, the first transmittance adjustment film, the phase shift 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. 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 shift film.

15. A method for manufacturing a photomask, comprising: forming a first region including a substrate, a first transmittance adjustment film disposed on the substrate, and a phase shift film disposed on the first transmittance adjustment film; forming a first concave portion in the first region, penetrating the phase shift 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 shift film, and a second transmittance adjustment film disposed on the phase shift film; and In the second region, a second recessed portion is formed which penetrates the second transmittance adjusting film and the phase shift film and reaches the first transmittance adjusting film.

16. The method for manufacturing a photomask according to claim 15, further comprising: A third region including the substrate, the first transmittance adjustment film, the phase shift film, the second transmittance adjustment film, and a light shielding film provided on the second transmittance adjustment film is formed.

17. The method for manufacturing a photomask according to claim 16, further comprising: The first, second, and third regions are formed to include the substrate, the first transmittance adjustment film, the phase shift film, the second transmittance adjustment film, and the light shielding film; removing the light shielding film and the second transmittance adjustment film from the first region; and The light shielding film is removed from the second region.

18. The method for manufacturing a photomask according to claim 17, wherein The second recess is formed in the second transmittance adjustment film and the phase shift film before the light shielding film is removed from the second region, and The first recessed portion is formed in the second transmittance adjustment film and the phase shift film before the light shielding film is removed from the first region, and is formed in the first transmittance adjustment film when or before the second transmittance adjustment film is removed from the first region.

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

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

Images