Photomask and exposure method

Abstract

The present invention aims to suppress a size conversion difference generated in exposure. An embodiment of the present invention relates to a photomask and an exposure method, and the photomask of the embodiment is a photomask including a joint area having a first end portion at one end portion and a second end portion at a position inside from the one end portion by a prescribed distance, and provided with: a substrate; a reflection layer arranged at a first surface of the substrate to reflect light; and a light-shielding pattern arranged at a second surface of the reflection layer opposite to the substrate, including a light-absorbing layer that absorbs light; and configured such that, in the joint area, the reflection intensity of light is lower at the first end portion side than at the second end portion side.

Description

Technical Field

[0001] The embodiments of the present invention relate to a photomask and an exposure method. Background Technology

[0002] In High-Numerical Aperture Extreme Ultra-Violet (HNA EUV) exposure, the mask magnification is, for example, 4 × 8 times relative to the pattern transferred onto the wafer. On the other hand, the photomask itself maintains a size based on, for example, a mask magnification of 4 × 4 times.

[0003] [Background Technical Documents]

[0004] [Non-patent literature]

[0005] [Non-Patent Literature 1] Vincent Wiauxa et al., “An experimental stitching study on the eve of High NA EUV”, Advanced Lithography, April 10, 2024, Engineering, Physics Summary of the Invention

[0006] [The problem the invention aims to solve]

[0007] One embodiment aims to provide a photomask and exposure method that can suppress size conversion differences caused by exposure.

[0008] [Technical means to solve the problem]

[0009] The photomask of the embodiment includes a splicing region having a first end at one end and a second end at a position extending inward from the first end at a predetermined distance, and comprises: a substrate; a reflective layer disposed on a first surface of the substrate to reflect light; and a light-shielding pattern disposed on a second surface of the reflective layer opposite to the substrate, including a light-absorbing layer that absorbs the light; and configured such that the light reflection intensity in the splicing region is lower than that on the first end side than on the second end side. Attached Figure Description

[0010] Figures 1A to 1C This is a schematic diagram illustrating an example of the configuration of the photomask in Embodiment 1.

[0011] Figures 2A to 2G This is a schematic diagram illustrating an example of the configuration of a light-shielding pattern prepared on the opposite side of the wafer in Embodiment 1.

[0012] Figure 3A and Figure 3B This is a cross-sectional view illustrating a portion of the sequence of exposure methods using the photomask of Embodiment 1.

[0013] Figure 4A and Figure 4B This is a cross-sectional view illustrating a portion of the sequence of exposure methods using the photomask of Embodiment 1.

[0014] Figures 5A to 5D This is a cross-sectional view showing a portion of the sequence of the wafer processing method of Embodiment 1.

[0015] Figures 6A to 6D This is a schematic diagram illustrating an example of the configuration of a light-shielding pattern prepared on the opposite side of the wafer in Embodiment 1, a variation of Embodiment 1.

[0016] Figures 7A to 7C This is a schematic diagram illustrating an example of the configuration of a photomask in variation 2 of implementation method 1.

[0017] Figure 8A and Figure 8B This is a schematic diagram illustrating an example of the configuration of the photomask in Embodiment 2.

[0018] Figures 9A to 9E This is a cross-sectional view illustrating a portion of the thin film manufacturing method according to Embodiment 2.

[0019] Figures 10A to 10F This is a cross-sectional view illustrating a portion of the thin film manufacturing method according to Embodiment 2.

[0020] Figure 11A and Figure 11B This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, exemplified sequentially.

[0021] Figure 12 This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, exemplified sequentially.

[0022] Figures 13A-13C This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, exemplified sequentially.

[0023] Figure 14A and Figure 14B This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, exemplified sequentially.

[0024] Figure 15 This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, exemplified sequentially.

[0025] Figures 16A-16CThis is a cross-sectional view of a portion of the method for manufacturing a thin film according to a variation of Embodiment 2.

[0026] Figures 17A-17C This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, Example 3.

[0027] Figures 18A-18C This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, Example 3.

[0028] Figure 19A and Figure 19B This is a cross-sectional view illustrating a portion of the method for manufacturing a thin film according to a variation of Embodiment 2, Example 3.

[0029] Figure 20A and Figure 20B This is a schematic diagram illustrating a configuration example of the photomask in variation 4 of implementation method 2. Detailed Implementation

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments. Furthermore, the constituent elements in the following embodiments include elements readily conceived by those skilled in the art or substantially the same elements.

[0031] [Implementation Method 1]

[0032] Hereinafter, Embodiment 1 will be described in detail with reference to the accompanying drawings.

[0033] (Example of photomask construction)

[0034] Figures 1A to 1C This is a schematic diagram illustrating an example of the configuration of the photomask 10 in Embodiment 1. More specifically, Figure 1A This is a cross-sectional view of the photomask 10 with the thin film 20 mounted on it. Figure 1B and Figure 1C This is a schematic diagram illustrating the general outline of the exposure method using photomask 10.

[0035] Furthermore, in the following text, even if it is only referred to as photomask 10, unless otherwise specified, it refers to photomask 10 on which the thin film 20 described in detail below is mounted.

[0036] The photomask 10 in Embodiment 1 is configured, for example, as a reflective photomask for high NA-EUV exposure.

[0037] High-NA-EUV exposure is a technique that uses lenses with a numerical aperture (NA) increased from the current 0.33 to 0.55 to expose to extreme ultraviolet (EUV) light at 13.5 nm. NA is a physical quantity that represents the performance of a lens in focusing and reducing light; by using lenses with high NA, finer patterns can be formed.

[0038] Furthermore, in high NA-EUV exposure, the mask magnification, which is currently 4×4 times, becomes 4×8 times relative to the pattern transferred onto the wafer. Therefore, in order to maintain the current mask size, for example, two photomasks 10 (10-1, 10-2) are used in pairs to expose one exposure area on the wafer. Figure 1B and Figure 1C This indicates the aforementioned situation.

[0039] like Figure 1B As shown, one of the photomasks 10-1 in a pair of photomasks 10 (10-1, 10-2) is used to expose approximately half of the exposure area SH set on the wafer.

[0040] As described above, the photomask 10 in Embodiment 1 is, for example, a reflective photomask, which allows light L2, after being reflected from EUV light L1 irradiated by the light source LS, to illuminate the exposure area SH. Furthermore, although omitted in the figures, the light L1 and L2 each reach the photomask 10 or the exposure area SH on the wafer, which serves as the destination, via multiple reflectors.

[0041] like Figure 1C As shown, the remaining approximately half of the exposure region SH on the wafer is exposed using another photomask 10-2 in the pair of photomasks 10 (10-1, 10-2).

[0042] Here, a portion of the exposure area EX1 of photomask 10-1 and a portion of the exposure area EX2 of photomask 10-2 overlap near the center of the exposure area SH. Therefore, since the overlapping exposure area Dex is a double exposure, it is preferable to make some adjustments to prevent excessive light exposure caused by the double exposure. This is because, when excessive light exposure occurs, there is a concern that the dimensional conversion difference in the exposure area Dex will increase, such as the transfer pattern on the wafer becoming thinner.

[0043] Therefore, a stitching region ST corresponding to the exposure region Dex is set in the photomask 10 to adjust the light amount transition in the exposure region Dex.

[0044] More specifically, in photomask 10-1, a splicing area ST is set at the position near the center of the exposure area SH on the left and right ends E11-1 and E12-1 of the paper, that is, at the right end E12-1 of the paper. In photomask 10-2, a splicing area ST is set at the position near the center of the exposure area SH on the left and right ends E12-2 and E11-2 of the paper, that is, at the left end E12-2 of the paper.

[0045] In the splicing area ST, the transfer patterns of the exposure areas EX1 and EX2 spanning the two photomasks 10 are joined together in a manner that matches each other within the exposure area SH.

[0046] like Figure 1A As shown, the basic structure of the photomasks 10 used in pairs can be common to each other.

[0047] The photomask 10 includes a glass substrate 12 with one side covered by a conductive layer 11, and the other side of the glass substrate 12 faces the wafer side. The conductive layer 11 is held on the electrostatic chuck 30 or the like of the exposure apparatus. The glass substrate 12 is made of, for example, low thermal expansion glass (LTEMLow-Thermal-Expansion substrate material).

[0048] In addition, the photomask 10 has a reflective layer 13, a buffer layer 14 and a light-absorbing layer 15 sequentially arranged on the side of the glass substrate 12 facing the wafer.

[0049] The reflective layer 13 has, for example, a multilayer structure in which multiple Mo layers and multiple Si layers are alternately stacked. As a result, light such as exposure light incident on the reflective layer 13 at a predetermined angle undergoes diffraction and is reflected at an angle corresponding to the incident angle. Since extremely short wavelength light such as EUV is difficult to reflect by optical mirrors, this artificial lattice structure is used to make it reflective.

[0050] The buffer layer 14, for example, is a Ru layer, and serves as the base layer for the light-absorbing layer 15. The light-absorbing layer 15, for example, is a TaBN layer, and has the property of absorbing exposure light such as EUV. In addition, the light-absorbing layer 15 and the buffer layer 14 together form a light-shielding pattern P1 with a predetermined pattern, which is dispersed on the reflective layer 13.

[0051] The light-absorbing layer 15 of the light-shielding pattern P1 absorbs light L1 from the light source LS, while the remaining light L2 is reflected toward the wafer side by the reflective layer 13 exposed from the light-shielding pattern P1, thereby transferring the light-shielding pattern P1 to the exposure area SH of the wafer.

[0052] Additionally, as described later, the photomask 10 has a light-shielding pattern in the splicing area ST that is not transferred to the wafer.

[0053] The thin film 20, for example, has a protective layer 21 and a frame 22 to protect the surface of the light mask 10, such as the light-shielding pattern P1.

[0054] The protective layer 21 can be, for example, a carbon-based layer such as carbon nanotubes or graphene, a resin layer such as polyimide, or an inorganic layer such as polycrystalline silicon or silicon carbide. When the protective layer 21 is a carbon-based layer, it is preferably composed of a material with a carbon content of 40% by mass or more. Therefore, the protective layer 21 has high transmittance to exposure light such as EUV, and hardly obstructs the incident light L1 from the light source LS onto the photomask 10, or the exit light L2 reflected in the photomask 10, thus covering and protecting the surface of the photomask 10.

[0055] The frame 22, for example, is made of aluminum alloy, and supports the protective layer 21. Figure 2A In the example, the frame 22 is held together with the photomask 10 by the electrostatic chuck 30 of the exposure apparatus, but the lower end of the frame 22 can be held directly on the surface of the photomask 10 by an adhesive or the like.

[0056] Additionally, the thin film 20 may have an oxidation suppression layer (not shown) on the side of the protective layer 21 facing the wafer to suppress oxidation of the protective layer 21. In this case, an oxidation suppression layer, such as a SiO2 layer or a SiN layer, can be used as the oxidation suppression layer.

[0057] Alternatively, the protective layer 21 not installed on the frame 22, or the protective layer 21 with an oxidation inhibition layer, can be used as a thin film.

[0058] A photomask 10 with the above configuration can be manufactured, for example, as follows.

[0059] On the glass substrate 12, a reflective layer 13 is formed by alternately depositing Mo and Si layers through chemical vapor deposition (CVD) or sputtering. Furthermore, a buffer layer 14 and a light-absorbing layer 15 are sequentially formed on the reflective layer 13 through CVD or sputtering, and then processed into a pattern shape including a light-shielding pattern P1 through reactive ion etching (RIE). Additionally, a conductive layer 11 is formed on the back side of the glass substrate 12 through CVD or sputtering.

[0060] Through the above, the photomask 10 of Embodiment 1 is manufactured.

[0061] Furthermore, the thin film 20 having the aforementioned structure can be manufactured, for example, as follows.

[0062] A protective layer 21 is formed on a support substrate using methods such as CVD. If the protective layer 21 is a resin layer, it can also be formed by immersing the support substrate in a dispersion of a resin containing the material that forms the protective layer 21. Alternatively, an oxidation inhibition layer covering the protective layer 21 can be further formed using methods such as CVD. The protective layer 21 is then attached to the frame 22.

[0063] Through the above, the thin film 20 of Embodiment 1 is manufactured.

[0064] Figures 2A to 2G This is a schematic diagram illustrating an example of the configuration of light-shielding patterns P1 and P2 prepared on the opposite side of the wafer in Embodiment 1 of the photomask 10. More specifically, Figure 2A This is a top view showing an example of the composition of the light-blocking patterns P1 and P2. Figures 2B to 2G This is a top view showing several examples of the composition of the light-blocking pattern P2.

[0065] like Figure 2A As shown, the light-shielding pattern P1 is set over approximately the entire area of ​​the photomask 10, which includes the splicing area ST, opposite to the wafer. As described above, the light-shielding pattern P1 is a pattern transferred onto the wafer, and can be any pattern based on the design pattern, selected from various patterns such as line and gap patterns, dot patterns, and hole patterns.

[0066] Like light-shielding pattern P1, light-shielding pattern P2 is a pattern composed of light-absorbing layer 15 and buffer layer 14 disposed on reflective layer 13. However, while light-shielding pattern P1 is transferred to the wafer through combination with reflective layer 13, light-shielding pattern P2, as described above, is a pattern that is not transferred to the wafer. Light-shielding pattern P2 can be, for example, an SRAF (Sub-Resolution Assist Feature) pattern.

[0067] More specifically, the light-blocking pattern P2 is configured in the splicing area ST, such that the coverage rate increases in stages from one end of the splicing area ST, namely end E31, toward the other end of the splicing area ST, namely end E32.

[0068] Here, the end E31 of the splicing region ST is the end closest to the center of the photomask 10. Additionally, the end E32 of the splicing region ST is located at the end E12 on one side of the photomask 10. That is, the end E32 of the splicing region ST coincides with the end E12 on one side of the photomask 10.

[0069] Figures 2B to 2G Several examples of shading patterns P2 with varying coverage are listed below.

[0070] exist Figures 2B to 2DIn the example shown, the light-blocking patterns P21a to P21c, which are light-blocking patterns P2, all have line and gap patterns.

[0071] like Figure 2B As shown, the light-blocking pattern P21a is composed of lines, each with a fixed width, and gaps that gradually decrease in width towards the ends E32 of the splicing area ST.

[0072] like Figure 2C As shown, the light-blocking pattern P21b is composed of lines whose width gradually increases toward the end E32 of the splicing area ST, and gaps of fixed width.

[0073] like Figure 2D As shown, the light-blocking pattern P21c consists of lines whose width gradually increases toward the end E32 of the splicing area ST, and gaps whose width gradually decreases.

[0074] exist Figures 2E to 2G In the example shown, the light-blocking patterns P22a to P22c, which are light-blocking patterns P2, all have dot patterns.

[0075] like Figure 2E As shown, the light-shielding pattern 22a has dots, each with a fixed area, arranged such that the spacing decreases toward the end E32 of the splicing area ST.

[0076] like Figure 2F As shown, the light-shielding pattern 22b has multiple points of different areas, which are arranged such that the area increases toward the end E32 of the splicing area ST.

[0077] like Figure 2G As shown, the light-blocking pattern 22c has multiple points of different areas, which are arranged such that the area increases while the spacing decreases towards the end E32 of the splicing area ST.

[0078] In this way, a light-shielding pattern P2 can be formed by combining a prescribed pattern, such as a line and a gap pattern or a dot pattern. By changing any one or two of the arrangement density (spacing) and size (width, area) of the pattern, the light-shielding pattern P2 can be formed in a way that the coverage rate increases in stages from the end E31 to the end E32 of the splicing area ST.

[0079] Within the splicing area ST, a light-shielding pattern P2 is formed in such a varying coverage manner that, closer to the end E12 on one side of the photomask 10, the amount of exposure light reflected from the photomask 10 to the wafer per unit area is weaker. Therefore, the exposure areas EX1 and EX2 of the paired photomasks 10 (see reference) can be suppressed. Figure 1B and Figure 1C The overlapping part of the exposure area (Dex) is the excessive amount of light caused by double exposure.

[0080] With this configuration, the photomask 10 of Embodiment 1 has a splicing area ST that has the function of adjusting the light-shielding patterns P1 and the like transferred to the exposure areas EX1 and EX2 to match each other within the exposure area SH.

[0081] Furthermore, in the example described, the light-shielding pattern P2 has been described as having a line and gap pattern or a dot pattern, but the light-shielding pattern P2 is not limited to these patterns. As long as the reflection intensity in the photomask 10 per unit area can be adjusted, any pattern, such as a combination of line and gap patterns and dot patterns, or other patterns, can be used.

[0082] Furthermore, the basic configuration of the paired photomasks 10 (10-1, 10-2) is common, for example, as described above. However, this does not mean that each of the paired photomasks 10 has the same light-shielding pattern P1 and the same light-shielding pattern P2.

[0083] Regarding the light-shielding pattern P1, each photomask 10 can be adjusted according to the corresponding wafer exposure area SH (reference). Figure 1B and Figure 1C The positions of the photomasks 10 can be such that one of them has a light-shielding pattern P1 corresponding to a component pattern, and the other has a light-shielding pattern P1 corresponding to a peripheral circuit pattern, so that the light-shielding patterns P1 are different from each other. On the other hand, when a repeating pattern, such as a cell array of a large capacitor, occupies most of the exposure area SH, the pair of photomasks 10 can have light-shielding patterns P1 that are equal to each other.

[0084] Furthermore, regarding the light-shielding pattern P2, the paired photomasks 10 can each adopt a light-shielding pattern P2 of arbitrary shape and arrangement, and each photomask 10 can be configured to have light-shielding patterns P2 that are equal to each other, or it can be configured to have light-shielding patterns P2 that are different from each other.

[0085] (Pattern Formation Method)

[0086] Next, use Figures 3A to 5D The pattern forming method including the exposure method using the photomask 10 of Embodiment 1 will be described.

[0087] Figures 3A to 4B This is a cross-sectional view illustrating a portion of the sequence of exposure methods using the photomask 10 of Embodiment 1.

[0088] like Figure 3A As shown, a wafer 100 is prepared to have a processing layer 110 and a photoresist layer 120 formed sequentially.

[0089] Wafer 100 is, for example, a semiconductor substrate such as a silicon wafer. The processed layer 110 is a layer that is processed into a shape such as a light-shielding pattern P1, and may be an insulating layer such as a SiO2 layer or a SiN layer, a semiconductor layer such as a polysilicon layer, or a metal layer such as a tungsten layer. Figures 3A to 5D In the example, the processed layer 110 is an insulating layer such as a SiO2 layer. The photoresist layer 120 becomes the exposure object using the photomask 10, and is the layer that serves as the mask when processing the processed layer 110.

[0090] In addition, wafer 100 is divided into multiple exposure areas SH.

[0091] like Figure 3B As shown, one of the pairs of photomasks 10 (e.g., photomask 10-1) is mounted on the electrostatic chuck 30 of the exposure apparatus, positioned at a predetermined location opposite to the wafer 100 being transported into the exposure apparatus. The light source LS of the exposure apparatus (reference LS)... Figure 1B and Figure 1C EUV light L1 is irradiated onto the photomask 10 to cause it to reflect, and the reflected light L2 is irradiated onto the photoresist layer 120 of the specified exposure area SH among the multiple exposure areas SH on the wafer 100.

[0092] As described above, in high NA-EUV exposure, the mask magnification is, for example, 4×8, and by combining pairs of photomasks 10, the entire exposure area SH corresponding to the 4×8 mask magnification is exposed. Therefore, through Figure 3B In the process, the photoresist layer 120 is exposed in approximately half of the exposure area SH. As described above, the area exposed by a photomask 10 is referred to as the exposure area EX1.

[0093] In the exposure area EX1, a pattern with a shape similar to the light-shielding pattern P1 of a photomask 10 is transferred into the photoresist layer 120. However, in the area (exposure area Dex) corresponding to the splicing area ST of the photomask 10 within the exposure area EX1, the photoresist layer 120 may be less sensitive than other parts of the exposure area EX1 because it is irradiated with attenuated exposure light (light L2).

[0094] like Figure 4A As shown, another of the paired photomasks 10 (e.g., photomask 10-2) is mounted on the electrostatic chuck 30 of the exposure apparatus, positioned at a predetermined location opposite to the wafer 100 within the exposure apparatus. The light source LS of the exposure apparatus (reference...) Figure 1B and Figure 1C EUV light L1 is irradiated onto the photomask 10 to cause it to reflect, and the reflected light L2 is irradiated onto the photoresist layer 120 of the exposure area SH.

[0095] Therefore, the photoresist layer 120 is exposed in approximately half of the remaining area of ​​the exposure region SH. As described above, the area exposed by another photomask 10 is referred to as the exposure region EX2.

[0096] In the exposure area EX2, a pattern with a shape similar to the light-shielding pattern P1 of another photomask 10 is transferred in the photoresist layer 120.

[0097] Furthermore, in the double-exposed exposure area Dex where exposure areas EX1 and EX2 overlap, the amount of light in each exposure can be suppressed by the splicing area ST of each pair of photomasks 10. Therefore, at the end of the second exposure stage, the cumulative amount of light is approximately equal to that outside the exposure areas EX1 and EX2, and the photosensitivity of the photoresist layer 120 is also approximately equal to that of other areas.

[0098] like Figure 4B As shown, by developing the photoresist layer 120 exposed using two photomasks 10, a resist pattern 120p with the light-shielding pattern P1 of the photomasks 10 transferred onto it can be obtained. Thanks to the splicing area ST function of the photomasks 10, even in the double-exposed exposure area Dex, the dimensional conversion difference of the resist pattern 120p can be reduced.

[0099] The exposure process using the photomask 10 of Embodiment 1 is now complete.

[0100] Subsequently, the resist pattern 120p obtained by heat treatment and development after exposure is used to process the processed layer 110 on the wafer 100.

[0101] Figures 5A to 5D This is a cross-sectional view showing a portion of the sequence of the processing method for the wafer 100 of Embodiment 1.

[0102] like Figure 5A As shown, the resist pattern 120p is used as a mask, and the workpiece layer 110 is processed by means of RIE, for example, to form a workpiece layer 110t having a plurality of grooves TR.

[0103] like Figure 5B As shown, the resist pattern 120p is removed by ashing with oxygen plasma, etc.

[0104] like Figure 5C As shown, a conductive layer 130, such as a Cu layer, is filled into the groove TR of the processed layer 110. The conductive layer 130 is also formed by covering the upper surface of the processed layer 110.

[0105] like Figure 5DAs shown, the conductive layer 130 covering the upper surface of the processed layer 110t is removed by chemical mechanical polishing (CMP) or similar methods. As a result, a plurality of wirings 130w filled with the conductive layer 130 are formed in the groove TR of the processed layer 110.

[0106] Through the above, the pattern formation process of the processed layer 110 and the processing of the wafer 100 in Embodiment 1 are completed.

[0107] The wiring 130W formed as described above becomes, for example, part of a semiconductor device. That is, Figures 3A to 5D The exposure method using the photomask 10 of Embodiment 1 and the patterning process for the processed layer 110 are included in the manufacturing method of a semiconductor device.

[0108] (Summary)

[0109] To maintain the exposure area on a wafer formed by photomask exposure with a low NA exposure ratio of, for example, 4×4, the mask ratio becomes, for example, 4×8 in high NA-EUV exposure. While maintaining the current photomask size, sometimes an exposure process is performed that combines two photomasks of approximately the same size using a stitching technique. In this case, to match the transfer patterns spanning the two exposure areas, a portion of the exposure areas is sometimes overlapped. In this situation, a problem arises in the double-exposure portion created at the seam between the exposure areas of the two photomasks, where the size conversion difference of the transfer patterns increases.

[0110] Therefore, proposals include, for example, not configuring fine patterns or patterns that require precise control of dimensional conversion differences in the stitching area (Stitching Band); adjusting the resolution of the stitching area to obtain appropriate resolution through double exposure (At-Resolution Stitching); or applying a gradient to the amount of light in the stitching area by controlling the on / off state of the light source during exposure (Dose-Gradient Stitching).

[0111] However, the first method requires significant design changes, the second method is prone to process changes, and the third method is difficult to obtain the positional accuracy of the on / off light source.

[0112] According to the photomask 10 of Embodiment 1, the reflection intensity of the exposure light decreases from the end E31 of the splicing region ST located inside the photomask 10 toward the other end E32 of the splicing region ST located on one side of the photomask 10, which is the end E12. This suppresses the size conversion difference caused by double exposure due to the overlap of exposure regions EX1 and EX2.

[0113] According to the photomask 10 of Embodiment 1, the coverage of the light-shielding pattern P2 increases from the end E31 of the splicing region ST located inside the photomask 10 toward the other end E32 of the splicing region ST located on one side of the photomask 10, namely the end E12. This reduces the intensity of reflected light for exposure and suppresses the size conversion difference caused by double exposure due to the overlap of exposure regions EX1 and EX2.

[0114] According to the photomask 10 of Embodiment 1, in the light-shielding pattern P22a, the number of dots per unit area increases from the end E31 of the splicing region ST located inside the photomask 10 towards the other end E32 of the splicing region ST located on one side of the photomask 10, E12. This increases the coverage of the light-shielding pattern P22a towards the end E12 of the photomask 10, reducing the intensity of light reflection for exposure.

[0115] According to the photomask 10 of Embodiment 1, in the light-shielding pattern P22b, the area of ​​each point increases from the end E31 of the splicing region ST located inside the photomask 10 toward the other end E32 of the splicing region ST located on one side of the photomask 10, E12. This allows the coverage of the light-shielding pattern P22b to increase toward the end E12 of the photomask 10, reducing the intensity of light reflection for exposure.

[0116] According to the photomask 10 of Embodiment 1, in the light-shielding pattern P22c, the number of points per unit area and the area of ​​each point increase from the end E31 of the splicing region ST located inside the photomask 10 toward the other end E32 of the splicing region ST located on one side of the photomask 10, E12. This allows the coverage of the light-shielding pattern P22c to increase toward the end E12 of the photomask 10, reducing the intensity of light reflection for exposure.

[0117] According to the photomask 10 of Embodiment 1, in the light-shielding pattern P21a, the number of lines per unit area increases from the end E31 of the splicing region ST located inside the photomask 10 toward the other end E32 of the splicing region ST located on one side of the photomask 10, E12. This allows the coverage of the light-shielding pattern P21a to increase toward the end E12 of the photomask 10, reducing the intensity of light reflection for exposure.

[0118] According to the photomask 10 of Embodiment 1, in the light-shielding pattern P21b, the width of each line increases from the end E31 of the splicing area ST located inside the photomask 10 toward the other end E32 of the splicing area ST located on one side of the photomask 10, E12. This allows the coverage of the light-shielding pattern P21b to increase toward the end E12 of the photomask 10, reducing the intensity of light reflection for exposure.

[0119] According to the photomask 10 of Embodiment 1, in the light-shielding pattern P21c, the number of lines per unit area and the width of each line increase from the end E31 of the splicing area ST located inside the photomask 10 toward the other end E32 of the splicing area ST located on one side of the photomask 10, E12. This allows the coverage of the light-shielding pattern P21c to increase toward the end E12 of the photomask 10, reducing the intensity of light reflection for exposure.

[0120] (Variation Example 1)

[0121] In embodiment 1, the coverage of the light-shielding pattern P2 changes because the reflection intensity is changed in the splicing area ST of the photomask 10. However, the method for changing the reflection intensity of the photomask is not limited to this.

[0122] The following uses Figures 6A to 6D An example of how the reflection intensity of a photomask can be changed by varying the thickness of the light-absorbing layer 15 of the light-shielding pattern P3 will be explained.

[0123] Figures 6A to 6D This is a schematic diagram illustrating an example of the configuration of light-shielding patterns P1 and P3 prepared on the opposite side of the wafer in Embodiment 1, Variation 1. More specifically, Figure 6A This is a top view showing an example of the composition of the light-blocking patterns P1 and P3. Figures 6B to 6D This is a cross-sectional view showing an example of the composition of the light-blocking patterns P1 and P3.

[0124] In addition, Figures 6A to 6D In some cases, the same symbols are used to mark the same components as in Embodiment 1, and their descriptions are omitted.

[0125] like Figures 6A to 6D As shown, the light-shielding pattern P3, like the light-shielding pattern P1, is a pattern composed of a light-absorbing layer 15 and a buffer layer 14 disposed on the reflective layer 13, and is disposed between the light-shielding patterns P1 in the splicing area STa of the photomask in Variation Example 1.

[0126] In addition, the thickness of the light-absorbing layer 15 in the light-shielding pattern P1 is fixed. In contrast, in the light-shielding pattern P3, the thickness of the light-absorbing layer 15 is configured to increase gradually from the end E31 of the splicing region ST near the center of the photomask toward the other end E32 of the splicing region ST located on one side of the photomask, E12.

[0127] The light-absorbing layer 15 has a predetermined absorptivity relative to the exposure light. The amount of exposure light that reaches the reflective layer 13 without being absorbed by the light-absorbing layer 15 varies depending on the thickness of the light-absorbing layer 15. More specifically, the thinner the light-absorbing layer 15, the easier it is for the exposure light to reach the reflective layer 13 without being absorbed; the thicker the light-absorbing layer 15, the more difficult it is for the exposure light to reach the reflective layer 13 after being absorbed. Therefore, by increasing the thickness of the light-absorbing layer 15 towards the end E12 of the photomask, the amount of exposure light reaching the reflective layer 13 is reduced, thereby reducing the reflection intensity per unit area of ​​the photomask 10.

[0128] exist Figure 6C In the example shown, the light-shielding pattern P31, which is the light-shielding pattern P3, has a gently sloping inclined surface 15t, thereby gradually thickening from one end E31 of the splicing region STa toward the other end E32. At this time, the light-shielding pattern P31 can be configured such that, in the end E31 of the splicing region STa near the center of the photomask, the thickness of the light-absorbing layer 15 is minimized or approximately zero, and at a predetermined distance from the center of the photomask, the thickness of the light-absorbing layer 15 is equal to or greater than that of the light-absorbing layer 15 of the light-shielding pattern P1.

[0129] Such light-blocking patterns P1 and P31 can be formed, for example, as follows.

[0130] A buffer layer 14 and a light-absorbing layer 15 are sequentially formed on the entire surface of the reflective layer 13. Furthermore, the portion of the light-absorbing layer 15 covered by a resist pattern, forming light-shielding patterns P1 and P31, is etched sequentially with an anisotropic shape such as a RIE (Resist Interchange). After temporarily removing the resist pattern, a further resist pattern is formed that exposes the inclined surface 15t of the light-absorbing layer 15, and the light-absorbing layer 15 is further etched with a skirt-like shape. To achieve a skirt-like shape for the light-absorbing layer 15, methods such as using conditions that easily accumulate etching byproducts or using conditions with low selectivity to the resist pattern can be employed to allow the resist pattern to recede during etching.

[0131] Through the above, a light-shielding pattern P1 with a generally vertical light-absorbing layer 15 and a buffer layer 14, and a light-shielding pattern P31 with a skirt-shaped light-absorbing layer 15 having an inclined surface 15t are formed.

[0132] exist Figure 6DIn the example shown, the light-shielding pattern P32, which is the light-shielding pattern P3, has a stepped portion 15s that is stepped instead of a gently sloping surface 15t, thereby gradually thickening in stages from one end E31 of the splicing region STa toward the other end E32. At this time, the light-shielding pattern P32 can also be configured as follows: in the end E31 of the splicing region STa near the center of the photomask, the thickness of the light-absorbing layer 15 is minimized or approximately zero, and at a position at a predetermined distance from the center of the photomask, the thickness of the light-absorbing layer 15 is equal to or greater than that of the light-absorbing layer 15 of the light-shielding pattern P1.

[0133] Such light-blocking patterns P1 and P32 can be formed, for example, as follows.

[0134] After the light-shielding pattern P1 is formed, it can be temporarily processed in the same way as the light-shielding pattern P31 until the first resist pattern is formed. After temporarily removing the resist pattern, a resist pattern is further formed that exposes part of the light-absorbing layer 15 that becomes the step portion 15s, and the thinning of the resist pattern and the etching of the light-absorbing layer 15 are repeated multiple times.

[0135] Through the above, a light-shielding pattern P1 with a generally vertical shape light-absorbing layer 15 and a buffer layer 14, and a light-shielding pattern P31 with a light-absorbing layer 15 having a stepped surface 15s are formed.

[0136] According to the photomask of Variation Example 1, in the light-shielding pattern P3, the light-absorbing layer 15 thickens from the end E31 of the splicing region STa located inside the photomask of Variation Example 1 toward the other end E32 of the splicing region STa located on one side of the photomask, E12.

[0137] Therefore, the amount of light absorbed by the light-shielding pattern P3 for exposure can be increased towards the end E12 of the photomask in Variation Example 1, thereby reducing the intensity of light reflection for exposure in the photomask of Variation Example 1. Thus, the size conversion difference caused by double exposure due to the overlap of exposure areas EX1 and EX2 can be suppressed.

[0138] According to the photomask of Variation Example 1, in the light-shielding pattern P31, the light-absorbing layer 15 has an inclined surface 15t, and the inclined surface 15t slopes gently from the end E31 of the splicing region STa located inside the photomask of Variation Example 1 toward the other end E32 of the splicing region STa located on one side of the photomask, E12. This allows the amount of light absorbed by the light-shielding pattern P31 for exposure to increase toward the end E12 of the photomask of Variation Example 1, thereby reducing the intensity of light reflection for exposure in the photomask of Variation Example 1.

[0139] According to the photomask of Variation Example 1, in the light-shielding pattern P32, the light-absorbing layer 15 gradually thickens from the end E31 of the splicing region STa located inside the photomask of Variation Example 1 toward the other end E32 of the splicing region STa located on one side of the photomask, E12. This allows the amount of light absorbed by the light-shielding pattern P32 for exposure to increase toward the end E12 of the photomask of Variation Example 1, thereby reducing the intensity of light reflection for exposure in the photomask of Variation Example 1.

[0140] The photomask of Variation Example 1, in addition to the above, also performs the same effect as in Embodiment 1.

[0141] (Variation Example 2)

[0142] Next, as another method to change the reflection intensity of the photomask, we use... Figures 7A to 7C The photomask 10b of variation example 2 will be explained.

[0143] Figures 7A to 7C This is a schematic diagram illustrating an example of the configuration of the photomask 10b in Variation 2 of Embodiment 1. More specifically, Figure 7A This is a cross-sectional view of the photomask 10b with the thin film 20 mounted on it. Figure 7B and Figure 7C This is an enlarged cross-sectional view showing several examples of the reflective layer 13b provided by the photomask 10b.

[0144] In addition, Figures 7A to 7C In some cases, the same symbols are used to mark the same components as in Embodiment 1, and their descriptions are omitted.

[0145] like Figure 7A As shown, the photomask 10b replaces the reflective layer 13 of Embodiment 1, and has a reflective layer 13b (131b, 132b) that thins towards its end E12. For example, the photomask 10b has a light-shielding pattern P1 similar to that of Embodiment 1, and the reflective layer 13b exposed from the light-shielding pattern P1 thins towards its end E12.

[0146] In the reflective layer 13b, the reflectivity of exposure light, such as EUV, varies depending on its thickness. More specifically, the reflective layer 13b is similar to the reflective layer 13 in Embodiment 1, for example, having a multilayer structure in which multiple Mo layers and multiple Si layers are alternately stacked, and the exposure light is diffracted in these layers and reflected outward from the reflective layer 13b. Therefore, the thinner the reflective layer 13b, the fewer the number of stacked layers, and the lower the reflectivity of the exposure light; the thicker the reflective layer 13b, the more stacked layers, and the higher the reflectivity of the exposure light.

[0147] As a result, the thickness of the reflective layer 13b is reduced toward the end E12 of the photomask 10b, thereby reducing the reflectivity of the light used for exposure and reducing the reflection intensity per unit area of ​​the photomask 10b.

[0148] exist Figure 7B In the example shown, the reflective layer 131b, which serves as the reflective layer 13b, has a gently sloping inclined surface 13t, thereby gradually thinning from one end E31 of the splicing region STb toward the other end E32. The reflective layer 131b can be configured such that its thickness is maximized at the end E31 of the splicing region STb near the center of the photomask 10b, i.e., a thickness sufficient to achieve sufficient reflectivity for exposure of the photoresist layer, etc., while its thickness is minimized or approximately zero at the end E12 of the photomask 10b.

[0149] This reflective layer 131b can be formed, for example, as follows.

[0150] A reflective layer 13, similar to that in Embodiment 1, is formed on the entire surface of the glass substrate 12. A resist pattern is formed that exposes a portion of the reflective layer 131b that becomes an inclined surface 13t. The reflective layer 13 is then etched under conditions that form a skirt shape. To set the reflective layer 13b to a skirt shape, methods such as using conditions that easily accumulate etching byproducts or using conditions with low selectivity for the resist pattern can be employed to cause the resist pattern to recede during etching.

[0151] Through the above, a reflective layer 131b with a skirt shape having an inclined surface 13t is formed.

[0152] exist Figure 7C In the example shown, instead of a gently sloping surface 13t, the reflective layer 132b, which serves as the reflective layer 13b, has a stepped portion 13s that is stepped in shape, thereby gradually thinning from one end E31 of the splicing region STb toward the other end E32. This shape of the reflective layer 132b is obtained, for example, by processing the Mo layer and Si layer contained in the reflective layer 132b into a stepped shape in multiple layers.

[0153] At this point, the reflective layer 132b can be configured as follows: at the end E31 of the splicing region STb near the center of the photomask 10b, the number of stacked layers of the reflective layer 132b is maximized, that is, the number of stacked layers that can obtain sufficient reflectivity for exposure of photoresist layers, etc., and at the end E12 position of the photomask 10b, the number of stacked layers of the reflective layer 132b is minimized or approximately zero.

[0154] This reflective layer 132b can be formed, for example, as follows.

[0155] On the entire surface of the glass substrate 12, a reflective layer 13 of Embodiment 1 is formed, and a resist pattern is formed to expose a portion of the reflective layer 132b that becomes a step portion 13s. The thinning of the resist pattern and the etching of the Mo layer and Si layer of the reflective layer 13 are repeated multiple times in a multi-layer manner.

[0156] Through the above, a reflective layer 132b with stepped portions 13s is formed.

[0157] In addition, when the Mo layer and Si layer of the reflective layer 132 are formed by sputtering or the like, the reflective layer 132 can also be formed in a manner that has a stepped portion 13s during the film forming stage.

[0158] In this case, a shielding plate is disposed between the glass substrate 12 on which the reflective layer 132 is formed and the sputtering target. By gradually shifting the position of the shielding plate, the range of the Mo layer and the Si layer formed by the adhesion of sputtering particles is gradually narrowed. The reflective layer 132b having the stepped portion 13s is also formed by this method.

[0159] According to the photomask 10b of Variation Example 2, the reflective layer 13b is thinned from the end E31 of the splicing region STb located inside the photomask 10b toward the other end E32 of the splicing region STb located on one side of the photomask 10b, at the end E12.

[0160] This reduces the reflectivity of the reflective layer 13b towards the end E12 of the photomask 10b, thereby decreasing the intensity of the reflected light. Consequently, it suppresses the size conversion difference caused by double exposure due to the overlap of exposure regions EX1 and EX2.

[0161] According to the photomask 10b of Variation Example 2, the reflective layer 131b has an inclined surface 13t, which slopes gently from the end E31 of the splicing region STb located inside the photomask 10b toward the other end E32 of the splicing region STb located on one side of the photomask 10b, at the end E12. This reduces the reflectivity of the reflective layer 131b to exposure light toward the end E12 of the photomask 10b, thereby reducing the intensity of the reflected exposure light.

[0162] According to the photomask 10b of Variation Example 2, the reflective layer 132b gradually thins from the end E31 of the splicing region STb located inside the photomask 10b toward the other end E32 of the splicing region STb located on one side of the photomask 10b, by gradually shortening the extension distance between the multiple Mo layers and the Si layers. This reduces the reflectivity of the reflective layer 132b to the exposure light toward the end E12 of the photomask 10b, thereby reducing the intensity of the reflected exposure light.

[0163] The photomask 10b according to Variation Example 2, in addition to the above, also performs the same effect as in Embodiment 1.

[0164] [Implementation Method 2]

[0165] In embodiment 1, the reflectivity of the photomasks 10 and 10b is varied by the configuration of their respective components, thereby adjusting the amount of light in the double-exposure exposure region Dex. However, the method for adjusting the amount of light in the double-exposure region is not limited to this.

[0166] Hereinafter, with reference to the accompanying drawings, the configuration of Embodiment 2, which adjusts the light intensity of the double-exposure area using a method different from Embodiment 1, will be described in detail. Furthermore, in the following drawings, there are instances where the same reference numerals are used for configurations identical to those in Embodiment 1, and their descriptions are omitted.

[0167] (Example of thin film composition)

[0168] Figure 8A and Figure 8B This is a schematic diagram illustrating an example of the configuration of the photomask 10c in Embodiment 2. More specifically, Figure 8A This is a cross-sectional view of the photomask 10c with the thin film 20 mounted on it. Figure 8B This is an enlarged cross-sectional view of the thin film 200.

[0169] like Figure 8A As shown, the photomask 10c includes a conductive layer 11, a glass substrate 12, a reflective layer 13, and a light-shielding pattern P1 including a buffer layer 14 and a light-absorbing layer 15. In addition, a splicing region STc is provided near the end E12 on one side of the photomask 10c.

[0170] The film 200 has a protective layer 210 and a frame 22.

[0171] The protective layer 210 is, for example, a carbon nanotube layer, and its thickness varies in the region PL corresponding to the splicing region STc and through which exposure light reflected from the splicing region STc passes. More specifically, the protective layer 210 thickens from one end E21 of the region PL corresponding to the splicing region STc toward the other end E22.

[0172] Here, the end E21 in the region PL is located at the position corresponding to the end E31 of the splicing region STc near the center of the photomask 10c, and the end E22 in the region PL is located at the position corresponding to the other end E32 of the splicing region ST located at the end E12 of the photomask 10c.

[0173] like Figure 8B As shown, the protective layer 210, whose thickness varies as described above, has a stepped portion 210s that has a stepped shape.

[0174] As described above, the protective layer 210 has high transmittance for exposure light such as EUV, but the transmittance of exposure light can be reduced by thickening the protective layer 210. Therefore, by increasing the thickness of the protective layer 210 towards the position corresponding to the end E12 of the photomask 10c, the amount of exposure light reaching the reflective layer 13 through the protective layer 210 is reduced, thereby reducing the reflection intensity per unit area of ​​the photomask 10c.

[0175] In addition, the thin film 200 of Embodiment 2 may also include an oxidation inhibition layer covering the protective layer 210 to suppress oxidation of the protective layer 210.

[0176] (Methods for manufacturing thin films)

[0177] Next, use Figures 9A to 10F The manufacturing method of the thin film 200 in Embodiment 2 will be described. Figures 9A to 10F This is a cross-sectional view illustrating a portion of the method for manufacturing the thin film 200 according to Embodiment 2.

[0178] like Figure 9A As shown, a thin layer 210b, such as a carbon nanotube layer, is formed on a support substrate 320 by means of CVD or the like.

[0179] like Figure 9B As shown, the support substrate 320 on which the thin layer 210b is formed is immersed in pure water or the like in the immersion tank BT, and the thin layer 210b is peeled off from the support substrate 320.

[0180] like Figure 9C As shown, on a support substrate 310 that is different from the support substrate 320, a thin layer 210a such as a carbon nanotube layer is formed by CVD or the like, with an extension distance longer than that of the thin layer 210b, so that the thin layer 210b peeled off as described above overlaps with the thin layer 210a.

[0181] like Figure 9D As shown, a thin layer 210c with a shorter extension distance than the thin layer 210b is formed on the support substrate 320 by CVD or the like, and then the thin layer 210c is immersed in the immersion tank BT for peeling.

[0182] like Figure 9E As shown, thin layer 210c is overlapped and attached to thin layer 210b on support substrate 310.

[0183] like Figures 10A to 10F As shown, the process is repeated so that thin layers 210d to 210h, such as carbon nanotube layers, are sequentially overlapped and attached to thin layer 210c on the supporting substrate 310. This forms a protective layer 210 with multiple thin layers 210a to 210h deposited on it.

[0184] Then, the protective layer 210 is attached to the frame 22.

[0185] Through the above, the thin film 200 of Embodiment 2 is manufactured.

[0186] (Summary)

[0187] According to the photomask 10c of embodiment 2, the protective layer 210 of the thin film 200 thickens in the region PL of the thin film 200 from the end E21 corresponding to the inner position of the photomask 10c toward the other end E22 corresponding to the end E12 on one side of the photomask 10c.

[0188] This reduces the amount of light reaching the reflective layer 13 towards the end E12 of the photomask 10c, thereby decreasing the intensity of light reflection. Consequently, it suppresses the size conversion difference caused by double exposure due to the overlap of exposure regions EX1 and EX2.

[0189] The photomask 10c according to embodiment 2, in addition to the above, also performs the same effect as that in embodiment 1.

[0190] Furthermore, in Embodiment 2, the protective layer 210 is, for example, a carbon nanotube layer. However, as described in Embodiment 1, the protective layer 210 in Embodiment 2 can be, for example, a graphene layer, a polyimide layer, a polycrystalline silicon layer, or a silicon carbide layer. Even when using a protective layer 210 made of the aforementioned material, the transmittance of light used for exposure can be changed by varying its thickness, thereby achieving the aforementioned effect.

[0191] (Variation Example 1)

[0192] In embodiment 2, a protective layer 210 is formed by layering thin layers 210a to 201h, such as carbon nanotube layers, one layer at a time. However, the method for forming the protective layer 210 with varying thickness is not limited to the method described above.

[0193] In the following variation example 1, using Figures 11A to 15 An example of a method for forming the protective layer 210 in a manner different from Embodiment 2 will be described. The difference between Variation Example 1 and Embodiment 2 is that the protective layer 210 is formed by impregnation.

[0194] Figures 11A to 15 This is a cross-sectional view illustrating a portion of the method for manufacturing the thin film 200 according to a variation of Embodiment 2, exemplified sequentially. Additionally, in Figures 11A to 15 Sometimes, the same symbols are used to mark the same components as in Embodiment 2, and their descriptions are omitted.

[0195] like Figure 11A As shown, a thin layer 210a, such as a carbon nanotube layer, is formed on the support substrate 310 by CVD or the like. However, the thin layer 210a can be formed by impregnation or the like, as detailed below.

[0196] like Figure 11B As shown, a portion of the support substrate 310, on which a thin layer 210a is formed, is immersed in a carbon nanotube dispersion DSP in an impregnation tank BT. The carbon nanotube dispersion DSP is a liquid in which the fine molecules of carbon nanotubes are dispersed in pure water or an organic solvent, and commercially available products can be used.

[0197] like Figure 12 As shown, the support substrate 310, which is immersed in a carbon nanotube dispersion DSP, is lifted from the dispersion DSP, thereby forming a new thin layer 210b, such as a carbon nanotube layer covering a portion of the thin layer 210a on the support substrate 310.

[0198] Additionally, a thin layer 210b can also be formed on the back side of the support substrate 310 at this time. The following illustrations and descriptions related to the thin layer formed on the back side of the support substrate 310 by repeating the same process are omitted.

[0199] like Figure 13A As shown, a portion of the support substrate 310, on which thin layers 210a and 210b are formed, is immersed in the dispersion liquid DSP. At this time, the support substrate 310 is immersed to a depth greater than... Figure 11B The treatment shown is shallow.

[0200] like Figure 13B As shown, a new thin layer 210c is formed by lifting the support substrate 310 from the dispersion DSP, covering a portion of the thin layer 210b.

[0201] like Figure 13C As shown, a portion of the support substrate 310, on which thin layers 210a to 210c are formed, is immersed in the dispersion liquid DSP. At this time, the support substrate 310 is immersed to a depth greater than... Figure 12 The treatment shown is shallower.

[0202] like Figure 14A As shown, a new thin layer 210d is formed by lifting the support substrate 310 from the dispersion DSP, covering a portion of the thin layer 210c.

[0203] like Figure 14B As shown, a portion of the support substrate 310, on which thin layers 210a to 210d are formed, is immersed in the dispersion liquid DSP and then lifted. This forms a new thin layer 210e covering a portion of thin layer 210d.

[0204] like Figure 15 As shown, by repeating the impregnation process, a protective layer 210 with thin layers 210a to 2120h of gradually shortening extension distance is obtained.

[0205] Then, the protective layer 210 is attached to the frame 22.

[0206] Through the above, the thin film 200 of Embodiment 2 is manufactured.

[0207] According to the manufacturing method of the thin film 200 in Variation Example 1, a thin film 200 that performs the same effect as in Embodiment 2 can be obtained.

[0208] (Variation Example 2)

[0209] In the following variation example 2, using Figures 16A-16C An example of a method for forming the protective layer 210 in a manner different from that of Embodiment 2 and Variation 1 will be described. In Variation 2, the difference from Embodiment 2, etc., is that the protective layer 210 is formed by compression.

[0210] Figures 16A-16C This is a cross-sectional view of a portion of the method for manufacturing the thin film 200, which is an example of a variation of Embodiment 2. Additionally, in Figures 16A-16C Sometimes, the same symbols are used to mark the same components as in Embodiment 2, and their descriptions are omitted.

[0211] like Figure 16A As shown, a layer 210t of the same thickness as the carbon nanotube layer is formed on a support substrate 310. This layer 210t preferably has a low layer density, for example, and can be formed by spraying a dispersion of the carbon nanotubes (DSP) onto the support substrate 310 using a sprayer (not shown). Layer 210t can also be formed through the aforementioned impregnation process.

[0212] Additionally, a mold 400 with a stepped shape is disposed opposite to the layer 210t on the support substrate 310. The mold 400 is made of a material arbitrarily selected from various materials, such as metal, ceramic, or resin.

[0213] like Figure 16B As shown, the mold 400 presses layer 210t onto the support substrate 310, compressing and shaping layer 210t. As described above, since layer 210t is formed with a low density, it can be compressed by the mold 400 and shaped into the desired shape. Furthermore, it is preferable to pre-adjust the layer density when forming layer 210t so that it becomes the desired layer density after compression.

[0214] like Figure 16C As shown, a protective layer 210 can be obtained by demolding the mold 400.

[0215] Then, the protective layer 210 is attached to the frame 22.

[0216] Through the above, the thin film 200 of Embodiment 2 is manufactured.

[0217] According to the manufacturing method of the thin film 200 in Variation 2, a thin film 200 that performs the same effect as in Embodiment 2 can be obtained.

[0218] (Variation Example 3)

[0219] In the following variation example 3, the following is used Figures 17A to 19B An example of a method for forming the protective layer 210 in a manner different from Embodiment 2 and Variations 1 and 2 will be described. In Variation 3, the difference from Embodiment 2, etc., is that the protective layer 210 is formed by spraying.

[0220] Figures 17A to 19B This is a cross-sectional view illustrating a portion of the method for manufacturing the thin film 200, as shown in Variation 3 of Embodiment 2. Additionally, in Figures 17A to 19B Sometimes, the same symbols are used to mark the same components as in Embodiment 2, and their descriptions are omitted.

[0221] like Figure 17A As shown, a dispersion of carbon nanotubes or the like, DSP, is sprayed onto a support substrate 310 by a sprayer 510, forming a thin layer 210a such as a carbon nanotube layer. In addition, a shielding plate 520 is disposed above the support substrate 310 on which the thin layer 210a is formed, shielding a portion of the support substrate 310 from the spraying of the dispersion of DSP by the sprayer 510.

[0222] The shielding plate 520 can be made of any material that will not dissolve or deteriorate in the dispersion liquid DSP, such as metal, ceramic or resin.

[0223] like Figure 17B As shown, after forming a thin layer 210b covering a portion of the thin layer 210a by shielding a portion of the support substrate 310, the dispersion liquid DSP is sprayed while the shielding area is expanded by sliding the shielding plate 520.

[0224] like Figure 17C As shown, after forming a thin layer 210c covering a portion of the thin layer 210b by expanding the shielding area of ​​the support substrate 310, the dispersion liquid DSP is sprayed while the shielding area is further expanded by further sliding the shielding plate 520.

[0225] like Figures 18A-18C As shown, thin layers 210d to 210f are sequentially formed on the support substrate 310 by repeatedly expanding the shielding area of ​​the shielding plate 520 and spraying the dispersion liquid DSP of the sprayer 510.

[0226] like Figures 19A-19BAs shown, thin layers 210g and 210h are sequentially formed on the support substrate 310 by repeatedly expanding the shielding area of ​​the shielding plate 520 and spraying the dispersion liquid DSP from the sprayer 510. Thus, a protective layer 210 is formed on the support substrate 310.

[0227] Then, the protective layer 210 is attached to the frame 22.

[0228] Through the above, the thin film 200 of Embodiment 2 is manufactured.

[0229] According to the manufacturing method of the thin film 200 in Variation 3, a thin film 200 that performs the same effect as in Embodiment 2 can be obtained.

[0230] (Variation Example 4)

[0231] In Embodiment 2 and Variations 1-3, the thickness of the protective layer 210 of the thin film 200 is varied, thereby changing the intensity of the reflected light from the photomask 10c and adjusting it to the amount of light in the double-exposure exposure region Dex. However, the method for adjusting the amount of light in the double-exposure region of the thin film is not limited to this.

[0232] In the following variation example 4, the following is used Figure 20A and Figure 20B A method for adjusting the light intensity of the thin film 200a in a manner different from that of Embodiment 2 and Variations 1 to 3 will be described.

[0233] Figure 20A and Figure 20B This is a schematic diagram illustrating a configuration example of the photomask 10c in Embodiment 2, Variation 4. More specifically, Figure 20A This is a cross-sectional view of a photomask 10c with a thin film 200a mounted on it. Figure 20B This is an enlarged cross-sectional view of film 200a.

[0234] like Figure 20A As shown, the thin film 200a has a protective layer 21, an oxidation inhibition layer 23, and a frame 22.

[0235] The oxidation suppression layer 23 is, for example, a SiO2 layer or a SiN layer, and is configured to cover the opposite side of the protective layer 21 to suppress oxidation of the protective layer 21. Furthermore, in Variation 4, the thickness of the oxidation suppression layer 23 varies in the region corresponding to the splicing region STc. More specifically, in region PL of the thin film 200a, the oxidation suppression layer 23 thickens from end E21 corresponding to the end E31 near the center of the photomask 10c in the splicing region STc, toward end E22 corresponding to the other end E32 of the splicing region STc located at end E12 of the photomask 10c.

[0236] like Figure 20BAs shown, the oxidation inhibition layer 23, whose thickness varies as described above, has a stepped portion 23s that has a stepped shape.

[0237] Like the protective layer 21, the oxidation inhibition layer 23 has a high transmittance relative to exposure light such as EUV. However, the transmittance of the exposure light can be reduced by thickening the oxidation inhibition layer 23. Therefore, by increasing the thickness of the oxidation inhibition layer 23 towards the position corresponding to the end E12 of the photomask 10c, the amount of exposure light reaching the reflective layer 13 is reduced, thereby reducing the reflection intensity per unit area of ​​the photomask 10c.

[0238] In addition, the oxidation inhibition layer 23 with this shape can also be formed by CVD and etching.

[0239] According to the photomask 10c of variation 4, the oxidation inhibition layer 23 of the thin film 200a thickens in the region PL of the thin film 200a from the end E21 corresponding to the inner position of the photomask 10c toward the other end E22 corresponding to the end E12 on one side of the photomask 10c.

[0240] This reduces the amount of light reaching the reflective layer 13 towards the end E12 of the photomask 10c, thereby decreasing the intensity of light reflection. Consequently, it suppresses the size conversion difference caused by double exposure due to the overlap of exposure regions EX1 and EX2.

[0241] The photomask 10c according to Variation Example 4, in addition to the above, also performs the same effect as in Embodiment 2.

[0242] While several embodiments of the invention have been described, these embodiments are merely illustrative and not intended to limit the scope of the invention. The novel embodiments can be implemented in various other ways, with various omissions, substitutions, and modifications possible without departing from the spirit of the invention. The embodiments or variations thereof are included within the scope or spirit of the invention, and are encompassed by the invention as described in the claims and their equivalents.

[0243] [Symbol Explanation]

[0244]

Claims

1. A photomask comprising a splicing region having a first end at one end and a second end at a position extending inwardly at a predetermined distance from said first end, and further comprising: Substrate; A reflective layer, disposed on a first surface of the substrate, reflects light; and A light-shielding pattern is disposed on the second surface of the reflective layer opposite to the substrate, and includes a light-absorbing layer that absorbs the light; and is configured such that... In the splicing area, The intensity of light reflection is lower at the first end than at the second end.

2. The photomask according to claim 1, wherein The light-blocking pattern includes: A first light-shielding pattern is disposed on the second surface of the reflective layer including the splicing area; and A second light-shielding pattern is disposed in the splicing area of ​​the second surface of the reflective layer; and Coverage of the second light-blocking pattern The first end side is larger than the second end side of the splicing region.

3. The photomask according to claim 2, wherein... Coverage of the second light-blocking pattern The joint increases in stages from the second end toward the first end of the splicing area.

4. The photomask according to claim 2, wherein The first light-shielding pattern The region disposed between one end and the other end relative to the one end.

5. The photomask according to claim 1, wherein... The light-blocking pattern includes: A first light-shielding pattern is disposed on the second surface of the reflective layer including the splicing area; and A second light-shielding pattern is disposed in the splicing area of ​​the second surface of the reflective layer; and In the second light-shielding pattern, The light-absorbing layer is thicker at the first end than at the second end of the splicing region.

6. The photomask according to claim 1, wherein The reflective layer The first end side is thinner than the second end side of the splicing area.

7. A photomask, comprising: Substrate; A reflective layer, disposed on the first surface of the substrate, reflects light. A light-shielding pattern, disposed on a second surface of the reflective layer opposite to the substrate, includes a light-absorbing layer that absorbs the light; and The thin film, disposed at a predetermined distance from the light-shielding pattern, faces the first surface; and The film includes the following regions: It has a first end facing one end of the substrate, and a second end at a position corresponding to a position extending inward from the first end of the substrate at a predetermined distance; and has: The first layer thickens from the second end toward the first end.

8. The photomask according to claim 7, wherein The first layer is a protective layer that protects the light-shielding pattern.

9. The photomask according to claim 7, wherein The film also has: The second layer covers the third surface of the first layer opposite to the light-shielding pattern; and The first layer is an oxidation inhibition layer that inhibits the oxidation of the second layer; The second layer is a protective layer that protects the light-shielding pattern.

10. An exposure method, Using the first photomask, exposure is performed on a first region from one end of the exposure area on the wafer to a position extending a first distance inward into the exposure area; and Using a second photomask, a second region is exposed from the other end of the exposure area to a position a second distance inward into the exposure area, and within the first region. This double-exposes a third region located in the center of the exposure area while simultaneously exposing the entire exposure area. The first and second photomasks include: The splicing area, corresponding to the third area, has a first end at one end of each of the first and second photomasks, and a second end at a position extending inward from the first end at a predetermined distance; and possesses: Substrate; A reflective layer, disposed on a first surface of the substrate, reflects light; and A light-shielding pattern is disposed on the second surface of the reflective layer opposite to the substrate, and includes a light-absorbing layer that absorbs the light; and is configured such that... In the splicing area, The intensity of the reflected light is lower at the first end than at the second end.

11. An exposure method, Using the first photomask, exposure is performed on a first region from one end of the exposure area on the wafer to a position extending a first distance inward into the exposure area; and Using a second photomask, a second region is exposed from the other end of the exposure area to a position a second distance inward into the exposure area, and within the first region. This results in double exposure of a third region located in the center of the exposure area, while simultaneously exposing the entire exposure area. The first and second photomasks have the following features: Substrate; A reflective layer, disposed on the first surface of the substrate, reflects light. A light-shielding pattern, disposed on a second surface of the reflective layer opposite to the substrate, includes a light-absorbing layer that absorbs the light; and The film, separated from the light-shielding pattern by a predetermined distance, faces the first surface; and The film includes the following regions: Corresponding to the third region, and having a first end at a position corresponding to one end of each of the first and second photomasks, and a second end at a position corresponding to a position extending inwards a predetermined distance from one end of each of the first and second photomasks; and having: The first layer thickens from the second end toward the first end.

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