Photomask and method for making the same

Abstract

A photomask and a method for forming the same, wherein the method comprises: providing a transparent substrate, etching the transparent substrate, forming a plurality of discrete first grooves in the transparent substrate; and filling the first grooves with opaque material to form a shielding pattern. The shielding pattern formed in the present application is located in the first groove, that is, the shielding pattern penetrates deep into the transparent substrate, and the thickness of the shielding pattern can be relatively thick. When the exposure light passes through the transparent substrate and is incident on the edge of the shielding pattern, the scattering and / or refraction of light can be prevented or reduced, and the exposure light can be prevented or reduced from entering the opaque area at the bottom of the shielding pattern, thereby improving the position and size accuracy of the photolithography pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology.

Description

Technical Field

[0001] The present application relates to the field of photomasks, and in particular to a photomask capable of preventing static electricity from being generated and a method for manufacturing the same. Background Art

[0002] The photolithography process is an indispensable and important technology in the integrated circuit manufacturing process. The photolithography process generally includes the following steps: first, a photosensitive material such as a photoresist is coated on the surface of the wafer. After the photoresist material is dried, the mask pattern on the photomask is exposed to the photoresist photosensitive material with a specific light source by an exposure machine. Subsequently, the photoresist photosensitive material is developed with a developer to form a photoresist pattern on the surface of the wafer. The photoresist pattern is used as a mask pattern in the subsequent ion implantation process or etching process.

[0003] Existing photomasks generally include: a transparent substrate; a plurality of discrete shielding patterns (or mask patterns) formed on the surface of the transparent substrate; an annular frame located on the surface of the transparent substrate, the annular frame surrounding the shielding patterns; a protective film located on the top surface of the annular frame, the protective film and the annular frame being used to seal the photomask.

[0004] However, as the limits of lithography technology are pushed to the manufacturing of devices using deep submicron node technology, photomask technology faces great challenges. The quality and performance of the photomask must be maintained in a more advanced and complex technical environment, including graphic size accuracy: absolute accuracy, CD uniformity, CD linearity, etc. However, during the photolithography process, light scattering and refraction will occur around the edges of the opaque shielding pattern in the photomask, and the light quanta will scatter and move to the defined opaque area, affecting the accuracy of the photolithography pattern formed in the photoresist layer. Summary of the invention

[0005] Some embodiments of the present application provide a method for manufacturing a photomask, including:

[0006] providing a transparent substrate;

[0007] Etching the transparent substrate to form a plurality of discrete first grooves in the transparent substrate;

[0008] The first groove is filled with an opaque material to form a shielding pattern.

[0009] In some embodiments, a top surface of the shielding pattern is flush with or higher than a surface of the transparent substrate.

[0010] In some embodiments, when the top surface of the shielding pattern is flush with the surface of the transparent substrate, the process of forming the shielding pattern includes: forming a shielding pattern film that fills the first groove and covers the surface of the transparent substrate; using a chemical mechanical polishing process to remove the shielding pattern film on the surface of the transparent substrate to form a shielding pattern in the first groove.

[0011] In some embodiments, after forming the first groove, the method further includes: continuing to etch the transparent substrate along the bottom of the first groove to form an annular second groove in the transparent substrate, wherein the annular second groove is connected to the bottom of the first groove, and the annular second groove is located below the bottom of the first groove; filling the first groove and the annular second groove with opaque material to form a shielding pattern in the first groove, and forming an annular deep groove structure connected to the bottom of the shielding pattern in the annular second groove, wherein the annular deep groove structure is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern after scattering and / or refraction at the edges of the shielding pattern.

[0012] In some embodiments, the first groove is formed before the annular second groove or after the annular second groove.

[0013] In some embodiments, before forming the first groove, a first patterned mask layer is formed on the surface of the transparent substrate, and the first patterned mask layer has a plurality of first openings exposing a portion of the surface of the transparent substrate; using the patterned first mask layer as a mask, the transparent substrate is etched along the first openings to form a plurality of discrete first grooves in the transparent substrate.

[0014] In some embodiments, before forming the annular second groove, a second patterned mask layer is formed on the surface of the transparent substrate, and the second patterned mask layer has an annular second opening exposing the surface around the bottom of the first groove; using the patterned second mask layer as a mask, the transparent substrate is etched along the second opening to form an annular second groove in the transparent substrate.

[0015] In some embodiments, the material of the opaque material is one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, platinum, chromium oxide, iron oxide, niobium oxide, chromium nitride, molybdenum trioxide, molybdenum nitride, chromium oxide, titanium nitride, zirconium nitride, titanium oxide, tantalum nitride, tantalum oxide, silicon dioxide, niobium nitride, silicon nitride, silicon oxynitride, amorphous carbon, silicon oxycarbide, neutral aluminum oxide, and aluminum oxide.

[0016] In some embodiments, the depth of the first groove is 50nm-1000nm, and the depth of the annular second groove is 1.5um-2.5um.

[0017] In some embodiments, the method further includes: forming an annular frame surrounding the shielding pattern on the surface of the edge region of the transparent substrate; and forming a protective film on the top surface of the annular frame to close the space inside the annular frame.

[0018] Some embodiments of the present application further provide a photomask, including:

[0019] Transparent substrate;

[0020] A plurality of discrete first grooves are formed in the transparent substrate;

[0021] A shielding pattern that completely fills the first groove.

[0022] In some embodiments, a top surface of the shielding pattern is flush with or higher than a surface of the transparent substrate.

[0023] In some embodiments, it also includes: an annular second groove in the transparent substrate located below the bottom of the first groove, the annular second groove is connected to the bottom of the first groove; a shielding pattern located in the first groove; an annular deep groove structure located in the annular second groove, the annular deep groove structure is connected to the bottom of the shielding pattern, and the annular deep groove structure is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern after scattering and / or refraction at the edges of the shielding pattern.

[0024] In some embodiments, the material of the shielding pattern and the deep trench structure is one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, platinum, chromium oxide, iron oxide, niobium oxide, chromium nitride, molybdenum trioxide, molybdenum nitride, chromium oxide, titanium nitride, zirconium nitride, titanium oxide, tantalum nitride, tantalum oxide, silicon dioxide, niobium nitride, silicon nitride, silicon oxynitride, amorphous carbon, silicon oxycarbide, neutral aluminum oxide, and aluminum oxide.

[0025] In some embodiments, the depth of the first groove is 50nm-1000nm, and the depth of the annular second groove is 1.5um-2.5um.

[0026] In some embodiments, it further includes: an annular frame surrounding the shielding pattern and located on the surface of the edge region of the transparent substrate; and a protective film located on the top surface of the annular frame and closing the space inside the annular frame.

[0027] In the method for forming the photomask in some of the aforementioned embodiments of the present application, after providing a transparent substrate, the transparent substrate is etched to form a plurality of discrete first grooves in the transparent substrate; the first grooves are filled with opaque materials to form a shielding pattern. The shielding pattern formed in the present application is located in the first groove, that is, the shielding pattern penetrates into the transparent substrate, and the thickness of the shielding pattern can be relatively thick. When the exposure light passes through the transparent substrate and is incident on the edge of the shielding pattern, the scattering and / or refraction of light can be prevented or reduced, and the exposure light can be prevented or reduced from entering the opaque area at the bottom of the shielding pattern, thereby improving the position and dimensional accuracy of the photolithography pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology. In addition, since the shielding pattern of the present application penetrates into the transparent substrate and has multiple contact surfaces with the transparent substrate, the shielding pattern is tightly connected to the transparent substrate, and the shielding pattern is not easy to fall off or deform.

[0028] Furthermore, in some embodiments, the top surface of the shielding pattern is flush with the surface of the transparent substrate, and the shielding pattern forming process includes: forming a shielding pattern film that fills the first groove and covers the surface of the transparent substrate; removing the shielding pattern film on the surface of the transparent substrate by a chemical mechanical polishing process to form a shielding pattern in the first groove. When the shielding pattern is formed in this way, since it is not necessary to etch the shielding pattern film by an etching process, the size of the shielding pattern formed will not be limited by the etching capability of the etching equipment (the etching of the shielding pattern film requires the use of a specific etching equipment), and a shielding pattern of a smaller size can be formed.

[0029] Furthermore, in some embodiments, after forming the first groove, it also includes: continuing to etch the transparent substrate along the bottom of the first groove to form an annular second groove in the transparent substrate, the annular second groove being connected to the bottom of the first groove, and the annular second groove being located below the bottom of the first groove; filling the first groove and the annular second groove with opaque material to form a shielding pattern in the first groove, and forming an annular deep groove structure connected to the bottom of the shielding pattern in the annular second groove, the annular deep groove structure being used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern after scattering and / or refraction at the edges of the shielding pattern. Due to the presence of the annular deep groove structure, the annular deep groove structure is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern after scattering and / or refraction at the edges of the shielding pattern, that is, the annular deep groove structure can constrain the exposure light in the light-transmitting area between adjacent shielding patterns, so that the exposure light will not reach the opaque area at the bottom of the shielding pattern due to the scattering and / or refraction of the edges of the shielding pattern, thereby further improving the position and size accuracy of the photolithographic pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology. In addition, the shielding pattern and the deep groove structure of the present application are an integrated structure, and both are deeply embedded in the transparent substrate, and there are multiple contact surfaces with the transparent substrate, so that the shielding pattern is tightly connected to the transparent substrate, and the shielding pattern is not easy to fall off or deform. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1-Figure 7 This is a structural schematic diagram of the photomask manufacturing process in some embodiments of the present application. DETAILED DESCRIPTION

[0031] The specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. When describing the embodiments of the present application in detail, for the sake of convenience, the schematic diagrams will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present application. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0032] Some embodiments of the present application firstly provide a method for manufacturing a photomask, and the photomask manufacturing process is described in detail below with reference to the accompanying drawings.

[0033] refer to Figure 1 , providing a transparent substrate 201.

[0034] The transparent substrate 201 is used as a carrier of the photomask. The material of the transparent substrate 201 is a light-transmitting material, and the light transmittance of the transparent substrate 201 is greater than 90%. In some embodiments, the material of the transparent substrate 201 can be quartz glass or soda glass. In some other embodiments, the material of the transparent substrate 201 can also be fused silica, calcium fluoride, silicon nitride, titanium oxide alloy, and sapphire.

[0035] In some embodiments, the transparent substrate 201 includes a middle area 21 and an edge area 22 surrounding the middle area 21. The middle area 21 may be square, circular or other suitable shapes, and the edge area 22 is annular and surrounds the middle area 21. The middle area 21 is used to form a shielding pattern (or light shielding pattern) 202, and the middle area 21 may also be used to form a phase shift layer, and the edge area 22 is subsequently used to form an annular frame.

[0036] refer to Figure 2 , etching the transparent substrate 201 to form a plurality of discrete first grooves 207 in the transparent substrate 201 .

[0037] The first groove 207 is used to form a shielding pattern later. The number of the first groove 207 is at least one.

[0038] The shape of the first groove 207 is the same as the shape of the shielding pattern to be formed. In some embodiments, the shape of the first groove 207 includes a square, a rectangle, a polygon (more than 4 sides) or other regular or irregular shapes.

[0039] In some embodiments, before forming the first groove 207, a first patterned mask layer (not shown in the figure) is formed on the surface of the transparent substrate 201, and the first patterned mask layer has a plurality of first openings exposing a portion of the surface of the transparent substrate 201, and the shape of the first openings corresponds to the formation of the first grooves formed subsequently; using the patterned first mask layer as a mask, the transparent substrate 201 is etched along the first openings to form a plurality of discrete first grooves 207 in the transparent substrate 201.

[0040] The transparent substrate 201 is etched using anisotropic dry etching processes, including anisotropic plasma etching processes, so that the sidewalls of the first groove 207 formed have a flat surface. When a shielding pattern is subsequently formed in the first groove 207, the interface between the surrounding sidewalls of the shielding pattern and the transparent substrate has a flat surface, thereby reducing the refraction and / or diffraction of light on the side of the shielding pattern, thereby improving the position and size accuracy of the photolithography pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology, improving the position and size accuracy of the photolithography pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology. In addition, the shielding pattern of the present application penetrates deep into the transparent substrate and has multiple contact surfaces with the transparent substrate, so that the shielding pattern is tightly connected to the transparent substrate and the shielding pattern is not easy to fall off or deform.

[0041] In the present application, a shielding pattern is subsequently formed in the first groove 207, that is, the shielding pattern formed in the present application is a shielding pattern that penetrates into the transparent substrate 201. The thickness of the shielding pattern can be relatively thick. When the exposure light passes through the transparent substrate and is incident on the edge of the shielding pattern, the scattering and / or refraction of light can be prevented or reduced, and the exposure light can be prevented or reduced from entering the opaque area at the bottom of the shielding pattern. In some embodiments, the depth of the first groove 207 is 50nm-1000nm.

[0042] In some embodiments, please refer to Figure 3 After forming the first groove 207, it also includes: continuing to etch the transparent substrate 201 along the bottom of the first groove 207 to form a ring-shaped second groove 208 in the transparent substrate 201, wherein the ring-shaped second groove 208 is connected to the bottom of the first groove 207 and the ring-shaped second groove 208 is located below the bottom of the first groove 207.

[0043] The annular second groove 208 is in an “annular” shape. The depth of the annular second groove 208 is greater than the depth of the first groove 207 , the width of the annular second groove 208 is much smaller than the width of the first groove, and the peripheral sidewall of the annular second groove 208 is flush with the sidewall of the first groove 207 in the vertical direction.

[0044] A ring-shaped deep groove structure is subsequently formed in the ring-shaped second groove 208. The ring-shaped deep groove structure is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges of the shielding pattern. That is, the ring-shaped deep groove structure can constrain the exposure light in the light-transmitting area between adjacent shielding patterns, so that the exposure light will not reach the opaque area at the bottom of the shielding pattern due to the scattering and / or refraction of the edges of the shielding pattern, thereby further improving the position and size accuracy of the photolithography pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology. In addition, the shielding pattern and the deep groove structure of the present application are an integrated structure, and both are deeply embedded in the transparent substrate, and there are multiple contact surfaces with the transparent substrate, so that the shielding pattern is tightly connected to the transparent substrate, and the shielding pattern is not easy to fall off or deform.

[0045] In some embodiments, the depth of the first groove 207 formed is 50nm-1000nm, the depth of the annular second groove 208 is 1.5um-2.5um, the width of the annular second groove 208 is smaller than the width of the first groove 207, and the width of the annular second groove 208 is 10nm-300nm. It should be noted that the depth of the first groove 207 is the distance from the bottom of the first groove 207 to the upper surface of the transparent substrate 201, and the depth of the second groove 208 is the distance from the bottom of the second groove 208 to the upper surface of the transparent substrate 201.

[0046] In this embodiment, the first groove 207 is formed before the annular second groove 208. In other embodiments, the first groove 207 can also be formed after the annular second groove 208, that is, the transparent substrate 201 is first etched to form the annular second groove 208 in the transparent substrate 201; then the transparent substrate 201 between the annular second grooves 208 is etched to remove a portion of the thickness to form the first groove 207, the bottom of the first groove 207 is connected to the annular second groove 208, and the annular second groove 208 is located below the bottom of the first groove 207.

[0047] In some embodiments, before forming the annular second groove 208, a second patterned mask layer (not shown in the figure) is formed on the surface of the transparent substrate 201, and the second patterned mask layer has an annular second opening exposing the surface around the bottom of the first groove 207 (when the annular second groove 208 is formed first, the annular second opening exposes part of the surface of the transparent substrate 201); using the patterned second mask layer as a mask, the transparent substrate 201 is etched along the second opening to form an annular second groove 208 in the transparent substrate 201.

[0048] refer to Figure 4 , Figure 4 exist Figure 2 Based on the above, in the first groove 207 (reference Figure 2 ) is filled with opaque material to form a shielding pattern 202.

[0049] The shielding pattern 202 formed in the present application is located in the first groove 207, that is, the shielding pattern 202 penetrates into the transparent substrate 201, and the thickness of the shielding pattern can be relatively thick. When the exposure light passes through the transparent substrate and is incident on the edge of the shielding pattern, it can prevent or reduce the scattering and / or refraction of light, and can prevent or reduce the exposure light from reaching the opaque area at the bottom of the shielding pattern, thereby improving the position and dimensional accuracy of the photolithography pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology. In addition, the shielding pattern of the present application penetrates into the transparent substrate, and there are multiple contact surfaces with the transparent substrate, so that the shielding pattern is tightly connected to the transparent substrate, and the shielding pattern is not easy to fall off or deform. In some embodiments, the thickness of the shielding pattern 202 in the transparent substrate 201 is 50nm-1000nm.

[0050] The top surface of the formed shielding pattern 202 is flush with the surface (upper surface) of the transparent substrate 201 or higher than the surface (upper surface) of the transparent substrate 201 .

[0051] In the present application, the top surface of the shielding pattern 202 is flush with the surface of the transparent substrate 201, and the process of forming the shielding pattern 202 includes: forming a shielding pattern film that fills the first groove 207 and covers the surface of the transparent substrate 201; removing the shielding pattern film on the surface of the transparent substrate by a chemical mechanical polishing process, and forming the shielding pattern 202 in the first groove. When the shielding pattern 202 is formed in this way, since it is not necessary to etch the shielding pattern film by an etching process, the size of the shielding pattern 202 formed will not be limited by the etching capability of the etching equipment (the etching of the shielding pattern film requires the use of a specific etching equipment), and a shielding pattern of a smaller size can be formed.

[0052] In other embodiments, when the top surface of the formed shielding pattern is higher than the surface of the transparent substrate 201, the process of forming the shielding pattern includes: forming a shielding pattern film that fills the first groove 207 and covers the surface of the transparent substrate 201; using a chemical mechanical polishing process to flatten the surface of the shielding pattern film; forming a patterned mask layer on the surface of the flattened shielding pattern film; using the patterned mask layer as a mask, etching and removing unnecessary shielding pattern films on the outside of the first groove, forming a shielding pattern in the first groove, and the surface of the shielding pattern protrudes from the surface of the transparent substrate 201.

[0053] In some embodiments, the material of the opaque material (or shielding graphic film) is one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, platinum, chromium oxide, iron oxide, niobium oxide, chromium nitride, molybdenum trioxide, molybdenum nitride, chromium oxide, titanium nitride, zirconium nitride, titanium oxide, tantalum nitride, tantalum oxide, silicon dioxide, niobium nitride, silicon nitride, silicon oxynitride, amorphous carbon, silicon oxycarbide, neutral aluminum oxide, and aluminum oxide.

[0054] In another embodiment, reference Figure 5 , Figure 5 exist Figure 3 Based on the above, in the first groove 207 (reference Figure 3 ) and the annular second groove 208 (reference Figure 3 ) is filled with opaque material, a shielding pattern 202 is formed in the first groove, and an annular deep groove structure 209 connected to the bottom of the shielding pattern 202 is formed in the annular second groove, and the annular deep groove structure 209 is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern 202 after being scattered and / or refracted at the edges of the shielding pattern 202.

[0055] In the present application, due to the presence of the annular deep groove structure 209, the annular deep groove structure 209 is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern 202 after being scattered and / or refracted at the edges of the shielding pattern 202, that is, the annular deep groove structure 209 can constrain the exposure light in the light-transmitting area between adjacent shielding patterns, so that the exposure light will not reach the opaque area at the bottom of the shielding pattern 202 due to the scattering and / or refraction of the edges of the shielding pattern, thereby further improving the position and size accuracy of the photolithographic pattern formed in the photoresist layer after exposure (using the photomask of the present application for exposure) and maintaining a good sidewall morphology. In addition, the shielding pattern and the deep groove structure of the present application are an integrated structure, and both are deeply embedded in the transparent substrate, and there are multiple contact surfaces with the transparent substrate, so that the shielding pattern is tightly connected to the transparent substrate, and the shielding pattern is not easy to fall off or deform.

[0056] In some embodiments, the depth of the bottom of the formed shielding pattern 202 is 50nm-1000nm, the depth of the bottom of the annular deep trench structure 209 is 1.5um-2.5um, the width of the annular deep trench structure 209 is smaller than the width of the shielding pattern 202, and the width of the annular deep trench structure 209 is 10nm-300nm.

[0057] In the present application, the top surface of the shielding pattern 202 is flush with the surface of the transparent substrate 201, and the process of forming the shielding pattern 202 includes: forming a shielding pattern film that fills the first groove 207, the annular second groove 208, and covers the surface of the transparent substrate 201; removing the shielding pattern film on the surface of the transparent substrate 201 by a chemical mechanical polishing process, forming the shielding pattern 202 in the first groove, and forming an annular deep groove structure 209 connected to the bottom of the shielding pattern 202 in the annular second groove. When the shielding pattern 202 is formed in this way, since the shielding pattern film does not need to be etched by an etching process, the size of the shielding pattern 202 formed will not be limited by the etching ability of the etching equipment (the etching of the shielding pattern film requires the use of a specific etching equipment), and a shielding pattern of a smaller size can be formed.

[0058] In other embodiments, when the top surface of the formed shielding pattern is higher than the surface of the transparent substrate 201, the process of forming the shielding pattern includes: forming a shielding pattern film that fills the first groove 207, the annular second groove 208 and covers the surface of the transparent substrate 201; using a chemical mechanical polishing process to flatten the surface of the shielding pattern film; forming a patterned mask layer on the surface of the flattened shielding pattern film; using the patterned mask layer as a mask, etching and removing unnecessary shielding pattern films on the outer side of the first groove, forming a shielding pattern in the first groove, and forming an annular deep groove structure connected to the bottom of the shielding pattern in the annular second groove, and the surface of the shielding pattern protrudes from the surface of the transparent substrate 201.

[0059] In some embodiments, the material of the opaque material (or shielding graphic film) is one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, platinum, chromium oxide, iron oxide, niobium oxide, chromium nitride, molybdenum trioxide, molybdenum nitride, chromium oxide, titanium nitride, zirconium nitride, titanium oxide, tantalum nitride, tantalum oxide, silicon dioxide, niobium nitride, silicon nitride, silicon oxynitride, amorphous carbon, silicon oxycarbide, neutral aluminum oxide, and aluminum oxide.

[0060] In the aforementioned steps of the present application, the shielding pattern 202 and the annular deep groove structure 209 can be formed in a synchronous process, saving process steps. In other embodiments, the shielding pattern can be first formed in the transparent substrate 201, and then the annular deep groove structure 209 can be formed in the transparent substrate around the shielding pattern 202.

[0061] In some embodiments, after forming the shielding pattern 202, a phase shift layer may be formed on the surface of the middle region 21 of the transparent substrate 201 and the surface of the shielding pattern 202, and the phase shift layer is used to change the phase of the exposure light incident into the substrate to improve the resolution during exposure. The material of the phase shift layer is MoSi or MoSiON.

[0062] In some embodiments, reference Figure 6 or Figure 7 , further comprising: forming an annular frame 204 surrounding the shielding pattern 202 on the edge area surface of the transparent substrate 201; and forming a protective film 206 on the top surface of the annular frame 204 to close the space inside the annular frame 204.

[0063] The annular frame 204 is used to support the protective film formed subsequently. The annular frame 204 and the protective film formed subsequently can isolate the shielding pattern 202 on the photomask 201 and the surface of the middle area of ​​the photomask 201 from the external environment to prevent contamination of the external environment.

[0064] The annular frame 204 is in a hollow annular shape, and the material of the annular frame 204 is a material with a certain mechanical strength. In some embodiments, the material of the annular frame 204 is aluminum. In some other embodiments, the material of the annular frame 204 can be aluminum alloy, ceramic, carbon steel or other suitable metal material or non-metal material.

[0065] In some embodiments, the annular frame 204 is adhered to the edge region of the transparent substrate through an adhesive layer 203 .

[0066] The material of the adhesion layer 203 is an organic adhesive. In some embodiments, the organic adhesive is a rubber adhesive, a polyurethane adhesive, an acrylic adhesive, a SEBS (styrene ethylene butylene styrene) adhesive, a SEPS (styrene ethylene propylene styrene) adhesive or a silicone adhesive.

[0067] The material of the protection film 206 is a light-transmitting material.

[0068] In some embodiments of the present application, a photomask is further provided, as shown in FIG6 , comprising:

[0069] Transparent substrate 201;

[0070] A plurality of discrete first grooves are formed in the transparent substrate 201;

[0071] The shielding pattern 202 completely fills the first groove.

[0072] In some embodiments, the top surface of the shielding pattern 202 is flush with or higher than the surface of the transparent substrate 201 .

[0073] In some embodiments, reference Figure 7 , further comprising: an annular second groove in the transparent substrate below the bottom of the first groove, the annular second groove being connected to the first groove; a shielding pattern 202 located in the first groove; an annular deep groove structure 209 located in the annular second groove, the annular deep groove structure 209 being connected to the bottom of the shielding pattern 202 on all sides, the annular deep groove structure 209 being used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern 202 after being scattered and / or refracted at the edges of the shielding pattern 202.

[0074] In some embodiments, the material of the shielding pattern 202 and the annular deep trench structure 209 is one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, platinum, chromium oxide, iron oxide, niobium oxide, chromium nitride, molybdenum trioxide, molybdenum nitride, chromium oxide, titanium nitride, zirconium nitride, titanium oxide, tantalum nitride, tantalum oxide, silicon dioxide, niobium nitride, silicon nitride, silicon oxynitride, amorphous carbon, silicon oxycarbide, neutral aluminum oxide, and aluminum oxide.

[0075] In some embodiments, the depth of the first groove is 50nm-1000nm, and the depth of the annular second groove is 1.5um-2.5um.

[0076] In some embodiments, it further includes: an annular frame 204 surrounding the shielding pattern 202 and located on the edge area surface of the transparent substrate 201 ; and a protective film 206 located on the top surface of the annular frame 204 and closing the space inside the annular frame 204 .

[0077] It should be noted that the limitations or descriptions of the same or similar parts in some embodiments of the photomask of the present application and in some embodiments of the aforementioned photomask forming method are not repeated here. Please refer to the limitations or descriptions of the corresponding parts in some embodiments of the aforementioned photomask forming method for details.

[0078] Although the present application has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present application. Any technical personnel in this field can use the methods and technical contents disclosed above to make possible changes and modifications to the technical solution of the present application without departing from the spirit and scope of the present application. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are within the protection scope of the technical solution of the present application.

Claims

1. A method for making a photomask, characterized in that: include: providing a transparent substrate; Etching the transparent substrate to form a plurality of discrete first grooves in the transparent substrate; Continue etching the transparent substrate along the periphery of the bottom of the first groove to form an annular second groove in the transparent substrate, wherein the annular second groove is connected to the periphery of the bottom of the first groove and is located below the periphery of the bottom of the first groove; The first groove and the annular second groove are filled with opaque material, a shielding pattern is formed in the first groove, and an annular deep groove structure connected to the bottom of the shielding pattern is formed in the annular second groove, the annular deep groove structure is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern after scattering and / or refraction at the edges of the shielding pattern.

2. The method for manufacturing a photomask according to claim 1, wherein: The top surface of the shielding pattern is flush with or higher than the surface of the transparent substrate.

3. The method for manufacturing a photomask according to claim 2, wherein: When the top surface of the shielding pattern is flush with the surface of the transparent substrate, the shielding pattern formation process includes: forming a shielding pattern film that fills the first groove and covers the surface of the transparent substrate; using a chemical mechanical polishing process to remove the shielding pattern film on the surface of the transparent substrate to form a shielding pattern in the first groove.

4. The method for manufacturing a photomask according to claim 1, wherein: The first groove is formed before the annular second groove or after the annular second groove.

5. The method for manufacturing a photomask according to claim 4, wherein: Before forming the first groove, forming a first patterned mask layer on the surface of the transparent substrate, wherein the first patterned mask layer has a plurality of first openings exposing a portion of the surface of the transparent substrate; The transparent substrate is etched along the first opening using the patterned first mask layer as a mask to form a plurality of discrete first grooves in the transparent substrate.

6. The method for manufacturing a photomask according to claim 5, wherein: Before forming the annular second groove, forming a second patterned mask layer on the surface of the transparent substrate, the second patterned mask layer having an annular second opening exposing the surrounding surface of the bottom of the first groove; The transparent substrate is etched along the second opening using the patterned second mask layer as a mask to form a second annular groove in the transparent substrate.

7. The method for manufacturing a photomask according to claim 1, wherein: The material of the opaque material is one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, platinum, chromium oxide, iron oxide, niobium oxide, chromium nitride, molybdenum trioxide, molybdenum nitride, chromium oxide, titanium nitride, zirconium nitride, titanium oxide, tantalum nitride, tantalum oxide, silicon dioxide, niobium nitride, silicon nitride, silicon oxynitride, amorphous carbon, silicon oxycarbide, neutral aluminum oxide, and aluminum oxide.

8. The method for manufacturing a photomask according to claim 1, wherein: The depth of the first groove is 50nm-1000nm, and the depth of the annular second groove is 1.5um-2.5um.

9. The method for manufacturing a photomask according to claim 1, wherein: Also includes: Forming an annular frame surrounding the shielding pattern on the surface of the edge area of ​​the transparent substrate; A protective film is formed on the top surface of the annular frame to seal the inner space of the annular frame.

10. A photomask, characterized in that: include: Transparent substrate; A plurality of discrete first grooves are formed in the transparent substrate; an annular second groove in the transparent substrate located below the bottom of the first groove, the annular second groove being in communication with the bottom of the first groove; a shielding pattern located in the first groove; An annular deep groove structure is located in the annular second groove, and the annular deep groove structure is connected to the bottom of the shielding pattern on all sides. The annular deep groove structure is used to prevent the exposure light from moving to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges of the shielding pattern.

11. The photomask according to claim 10, wherein: The top surface of the shielding pattern is flush with or higher than the surface of the transparent substrate.

12. The photomask according to claim 10, wherein: The material of the shielding pattern and the deep trench structure is one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, platinum, chromium oxide, iron oxide, niobium oxide, chromium nitride, molybdenum trioxide, molybdenum nitride, chromium oxide, titanium nitride, zirconium nitride, titanium oxide, tantalum nitride, tantalum oxide, silicon dioxide, niobium nitride, silicon nitride, silicon oxynitride, amorphous carbon, silicon oxycarbide, neutral aluminum oxide, and aluminum oxide.

13. The photomask according to claim 10, wherein: The depth of the first groove is 50nm-1000nm, and the depth of the annular second groove is 1.5um-2.5um.

14. The photomask according to claim 10, wherein: Also includes: An annular frame surrounding the shielding pattern and located on the surface of the edge region of the transparent substrate; A protective film is located on the top surface of the annular frame and closes the inner space of the annular frame.

Images