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 annular grooves in the transparent substrate; filling the annular grooves with opaque materials to form an annular deep groove structure; and forming a shielding pattern on the transparent substrate surface in the middle of the annular deep groove structure and on the surface of the annular deep groove structure. By forming a deep groove structure in the transparent substrate at the bottom of the shielding pattern, the deep groove structure is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges around the shielding pattern, that is, the deep groove structure can constrain the exposure light within the light-transmitting area between adjacent shielding patterns, so that the exposure light will not reach or diffuse into the opaque area at the bottom of the shielding pattern due to the scattering and / or refraction of the edges of the shielding pattern.

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 or diffuse 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 annular grooves in the transparent substrate;

[0008] Filling the annular groove with opaque material to form an annular deep groove structure;

[0009] A shielding pattern is formed on the surface of the transparent substrate in the middle of the annular deep groove structure and on the surface of the annular deep groove structure.

[0010] In some embodiments, the shielding pattern is formed after the deep trench structure, or the shielding pattern is formed simultaneously with the annular deep trench structure.

[0011] In some embodiments, when the shielding pattern is formed after the deep groove structure, the formation process of the deep groove structure and the shielding pattern includes: forming a patterned first mask layer on the surface of the transparent substrate, wherein the patterned first mask layer has a plurality of discrete annular first openings exposing a portion of the surface of the transparent substrate; using the patterned first mask layer as a mask, etching the transparent substrate along the annular first openings to form a plurality of discrete annular grooves in the transparent substrate; removing the patterned first mask layer; forming an opaque material film on the surface of the annular groove and the transparent substrate; and removing the opaque material on the surface of the transparent substrate by a chemical mechanical polishing process. A material film is formed to form an annular deep groove structure in the annular groove; a shielding pattern film is formed on the surface of the transparent substrate and on the surface of the annular deep groove structure; a patterned second mask layer is formed on the surface of the shielding pattern film, the patterned second mask layer covers the surface of the shielding pattern film on the transparent substrate surface in the middle of the annular deep groove structure and on the surface of the annular deep groove structure, and exposes the surface of the shielding pattern film in other areas; using the patterned second mask layer as a mask, etching the shielding pattern film to form a shielding pattern on the transparent substrate surface in the middle of the annular deep groove structure and on the surface of the annular deep groove structure; and removing the patterned second mask layer.

[0012] In some embodiments, the shielding pattern and the annular deep trench structure may be made of the same material or different materials.

[0013] In some embodiments, when the shielding pattern is formed synchronously with the annular deep groove structure, the formation process of the deep groove structure and the shielding pattern includes: forming a patterned first mask layer on the surface of the transparent substrate, wherein the patterned first mask layer has a plurality of discrete annular first openings exposing a portion of the surface of the transparent substrate; using the patterned first mask layer as a mask, etching the transparent substrate along the annular first openings to form a plurality of discrete annular grooves in the transparent substrate; removing the patterned first mask layer; forming an opaque material film on the surface of the annular groove and the transparent substrate; and using a chemical mechanical polishing process to grind the transparent substrate into a film. The invention relates to a method for planarizing the surface of the light-impermeable material film by a process of flattening the surface of the light-impermeable material film; forming a patterned second mask layer on the surface of the light-impermeable material film after the planarization, wherein the patterned second mask layer covers the surface of the transparent substrate in the middle of the annular groove and the surface of the light-impermeable material film on the annular groove, and exposes the surface of the light-impermeable material film in other areas; using the patterned second mask layer as a mask, etching the light-impermeable material film to form an annular deep groove structure in the annular groove, and forming a shielding pattern on the transparent substrate surface in the middle of the annular deep groove structure and the surface of the annular deep groove structure; and removing the patterned second mask layer.

[0014] In some embodiments, the shielding pattern and the annular deep trench structure are made of the same material.

[0015] In some embodiments, the material of the shielding pattern and the annular deep groove 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.

[0016] In some embodiments, the annular groove has a depth of 500nm-2.5um and a width of 10nm-300nm.

[0017] In some embodiments, a side surface of the shielding pattern is flush with a side surface of the annular deep trench structure in a vertical direction.

[0018] In some embodiments, the deep groove structure is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges of the shielding pattern.

[0019] 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.

[0020] Some embodiments of the present application further provide a photomask, including:

[0021] Transparent substrate;

[0022] a plurality of discrete annular grooves in the transparent substrate;

[0023] an annular deep groove structure that completely fills the annular groove;

[0024] A shielding pattern is located on the surface of the transparent substrate in the middle of the annular deep groove structure and on the surface of the annular deep groove structure.

[0025] In some embodiments, the shielding pattern and the annular deep trench structure may be made of the same material or different materials.

[0026] In some embodiments, the material of the shielding pattern or the annular deep groove 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.

[0027] In some embodiments, the annular groove has a depth of 500nm-2.5um and a width of 10nm-300nm.

[0028] In some embodiments, a side surface of the shielding pattern is flush with a side surface of the annular deep trench structure in a vertical direction.

[0029] In some embodiments, the deep groove structure is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges of the shielding pattern.

[0030] 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.

[0031] In the method for forming a photomask in some of the aforementioned embodiments of the present application, after providing a transparent substrate, etching the transparent substrate to form a plurality of discrete annular grooves in the transparent substrate; filling the annular grooves with opaque materials to form an annular deep groove structure; and forming a shielding pattern on the transparent substrate surface in the middle of the annular deep groove structure and on the surface of the annular deep groove structure. By forming a deep groove structure in the transparent substrate at the bottom of the shielding pattern, the deep groove structure is used to prevent the exposure light from moving or diffusing 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 deep groove structure can constrain the exposure light within the light-transmitting area between adjacent shielding patterns, so that the exposure light will not reach or diffuse into the opaque area at the bottom of the shielding pattern due to scattering and / or refraction at the edges of the shielding pattern, thereby improving the position and size accuracy of the photolithography pattern formed in the photoresist layer (using the photomask of the present application for exposure) after exposure and maintaining a good sidewall morphology.

[0032] Further, in some embodiments, when the shielding pattern is formed synchronously with the annular deep groove structure, the formation process of the deep groove structure and the shielding pattern includes: first forming a plurality of discrete annular grooves in the transparent substrate; forming an opaque material film on the surfaces of the annular grooves and the transparent substrate; using a chemical mechanical polishing process to flatten the surface of the opaque material film so that the opaque material film has a flat surface; forming a patterned second mask layer on the surface of the flattened opaque material film, the patterned second mask layer covers the surface of the transparent substrate in the middle of the annular groove and the surface of the opaque material film on the annular groove, exposing the surface of the opaque material film in other areas; using the patterned second mask layer as a mask, etching the opaque material film, forming an annular deep groove structure in the annular groove, and forming a shielding pattern on the transparent substrate surface in the middle of the annular deep groove structure and the surface of the annular deep groove structure; removing the patterned second mask layer. The shielding pattern and the annular deep groove structure are formed synchronously, which not only simplifies the process steps, but also because the formed shielding pattern and the annular deep groove structure are an integrated structure, the shielding pattern and the annular deep groove structure are more firmly connected, making it difficult for the shielding pattern to detach from the surface of the transparent substrate and deform. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1-Figure 5 This is a structural schematic diagram of the photomask manufacturing process in some embodiments of the present application. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] refer to Figure 1 , providing a transparent substrate 201.

[0037] 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.

[0038] 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.

[0039] refer to Figure 2 , etching the transparent substrate 201 to form a plurality of discrete annular grooves 207 in the transparent substrate 201 .

[0040] The annular groove 207 is used to form a deep groove structure later. The number of the annular groove 207 is at least one.

[0041] The annular groove 207 is in the shape of an annulus, and the outer wall shape of the annulus is the same as the side wall shape of the shielding pattern formed subsequently. In some embodiments, the annular shape includes a square annular shape, a rectangular annular shape, a polygonal annular shape (greater than 4 sides) or other regular or irregular graphic annular shapes.

[0042] In some embodiments, the depth of the annular groove 207 is 500 nm-2.5 um, the width of the annular groove 207 is smaller than the width of the shielding pattern formed subsequently, and the width of the annular groove 207 is 10 nm-300 nm.

[0043] In some embodiments, before forming the annular groove 207, a patterned first mask layer (not shown in the figure) is formed on the surface of the transparent substrate 201, and the patterned first mask layer has a plurality of discrete annular first openings exposing a portion of the surface of the transparent substrate 201; using the patterned first mask layer as a mask, the transparent substrate 201 is etched along the annular first openings to form a plurality of discrete annular grooves in the transparent substrate 201; and the patterned first mask layer is removed.

[0044] The transparent substrate 201 is etched using an anisotropic dry etching process, including an anisotropic plasma etching process, so that the side wall of the formed annular groove 207 has a flat surface. When a deep groove structure is subsequently formed in the annular groove 207, the interface between the side walls of the deep groove structure and the transparent substrate has a flat surface, thereby reducing the refraction and / or diffraction of light on the surface of the deep groove structure and reducing the loss of exposure energy.

[0045] refer to Figure 3 and Figure 4 In the annular groove 207 (reference Figure 2 ) is filled with opaque material to form an annular deep groove structure 209 (reference Figure 4 ); forming a shielding pattern 202 (reference Figure 4 ).

[0046] The deep groove structure 209 is used to prevent the exposure light from moving or diffusing 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 deep groove structure 209 can constrain the exposure light to the translucent area between adjacent shielding patterns 202, so that the exposure light will not reach or diffuse into the opaque area at the bottom of the shielding pattern 202 due to the scattering and / or refraction at the edges of the shielding pattern 202, thereby improving the position and size accuracy of the photolithography pattern formed in the photoresist layer after exposure (exposure is performed using the photomask of the present application) and maintaining a good sidewall morphology. Moreover, in some embodiments, since the shielding pattern 202 and the deep groove structure 209 are an integrated structure, and the deep groove structure 209 penetrates deep into the transparent substrate 201, there are multiple contact surfaces between the deep groove structure 209 and the transparent substrate 201, and thus the deep groove structure 209 is tightly connected to the transparent substrate 201, thereby making the shielding pattern 202 more tightly connected to the transparent substrate 201, and the shielding pattern 202 is not easy to fall off or deform.

[0047] In this embodiment, the shielding pattern and the annular deep trench structure are formed simultaneously to save process steps.

[0048] In some embodiments, when the shielding pattern 202 and the annular deep groove structure 209 are formed simultaneously, the process of forming the deep groove structure and the shielding pattern includes: firstly forming a plurality of discrete annular grooves 207 (refer to Figure 2 ); forming an opaque material film 208 on the surface of the annular groove and the transparent substrate (reference Figure 3); using a chemical mechanical polishing process to flatten the surface of the opaque material film 208 so that the opaque material film 208 has a flat surface; forming a graphic second mask layer (not shown in the figure) on the surface of the flattened opaque material film 208, the graphic second mask layer covers the surface of the transparent substrate in the middle of the annular groove and the surface of the opaque material film 208 on the annular groove, exposing the surface of the opaque material film 208 in other areas; using the graphic second mask layer as a mask, etching the opaque material film 208, forming an annular deep groove structure 209 in the annular groove 207, and forming a shielding pattern 202 on the surface of the transparent substrate 201 in the middle of the annular deep groove structure 209 and on the surface of the annular deep groove structure 209; removing the graphic second mask layer. The shielding pattern 202 and the annular deep groove structure 209 are formed synchronously, which not only simplifies the process steps, but also because the shielding pattern 202 and the annular deep groove structure 209 are formed as an integrated structure, the shielding pattern 202 and the annular deep groove structure 209 are more firmly connected, so that the shielding pattern 202 is not easy to detach from the surface of the transparent substrate 201 and deform.

[0049] In this embodiment, the shielding pattern 202 is made of the same material as the annular deep trench structure 209. The shielding pattern 202 and the annular deep trench structure 209 are made of one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or are made of 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.

[0050] In one embodiment, the side surface of the shielding pattern 202 is flush with the side surface of the annular deep trench structure 209 in the vertical direction.

[0051] In some embodiments, the depth of the bottom of the annular deep groove structure 209 is 500nm-2.5um, the width of the annular deep groove structure 209 is smaller than the width of the formed shielding pattern 202, and the width of the annular deep groove structure 209 is 10nm-300nm, so that the deep groove structure 209 can better confine the exposure light within the light-transmitting area between adjacent shielding patterns 202, and can better prevent the exposure light from reaching or diffusing into the opaque area at the bottom of the shielding pattern 202 due to scattering and / or refraction at the edge of the shielding pattern 202.

[0052] In some embodiments, the shielding pattern 202 is formed after the deep trench structure 209, and the formation process of the deep trench structure 209 and the shielding pattern 202 includes: forming a patterned first mask layer (not shown in the figure) on the surface of the transparent substrate 201, and the patterned first mask layer has a plurality of discrete annular first openings that expose a portion of the surface of the transparent substrate 201; using the patterned first mask layer as a mask, etching the transparent substrate 201 along the annular first openings to form a plurality of discrete annular grooves 207 in the transparent substrate 201 (refer to Figure 2 ); removing the patterned first mask layer; forming an opaque material film on the surface of the annular groove 207 and the transparent substrate 201; removing the opaque material film on the surface of the transparent substrate 201 by a chemical mechanical polishing process, and forming an annular deep groove structure 209 in the annular groove 207; forming a shielding graphic film on the surface of the transparent substrate 201 and the surface of the annular deep groove structure 209; forming a patterned second mask layer on the surface of the shielding graphic film, the patterned second mask layer covers the surface of the shielding graphic film on the surface of the transparent substrate 201 in the middle of the annular deep groove structure 209 and the surface of the annular deep groove structure 209, exposing the surface of the shielding graphic film in other areas; using the patterned second mask layer as a mask, etching the shielding graphic film, forming a shielding graphic 202 on the transparent substrate surface 201 in the middle of the annular deep groove structure 209 and the surface of the annular deep groove structure 209; removing the patterned second mask layer.

[0053] The shielding pattern 202 may be made of the same or different materials as the annular deep trench structure 209. The shielding pattern 202 (or the annular deep trench structure 209) may be made of one or more of chromium, nickel, aluminum, ruthenium, molybdenum, titanium, tantalum, copper, tungsten, silver, and platinum, or may be made of 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 some embodiments, after forming the shielding patterns 202, a phase shift layer is formed on the surface of the transparent substrate 201 between the shielding patterns 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.

[0055] In some embodiments, reference Figure 5, 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.

[0056] 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.

[0057] 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.

[0058] In some embodiments, the annular frame 204 is adhered to the edge region of the transparent substrate through an adhesive layer 203 .

[0059] 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.

[0060] The material of the protection film 206 is a light-transmitting material.

[0061] Some embodiments of the present invention further provide a photomask, referring to Figure 5 ,include:

[0062] Transparent substrate 201;

[0063] A plurality of discrete annular grooves located in the transparent substrate 201;

[0064] An annular deep groove structure 209 that completely fills the annular groove;

[0065] The shielding pattern 202 is located on the surface of the transparent substrate 201 in the middle of the annular deep groove structure 209 and on the surface of the annular deep groove structure 209 .

[0066] In some embodiments, the shielding pattern 202 and the annular deep trench structure 209 may be made of the same material or different materials.

[0067] In some embodiments, the material of the shielding pattern 202 or 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.

[0068] In some embodiments, the annular groove has a depth of 500nm-2.5um and a width of 10nm-300nm.

[0069] In some embodiments, the side surface of the shielding pattern 202 is flush with the side surface of the annular deep trench structure 209 in the vertical direction.

[0070] In some embodiments, the deep groove structure 209 is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges of the shielding pattern.

[0071] 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 .

[0072] 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.

[0073] 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 annular grooves in the transparent substrate; The annular groove is filled with opaque material to form an annular deep groove structure, wherein the deep groove structure is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted around the edges of the shielding pattern; A shielding pattern is formed on the surface of the transparent substrate in the middle of the annular deep groove structure and on the surface of the annular deep groove structure.

2. The method for manufacturing a photomask according to claim 1, wherein: The shielding pattern is formed after the deep trench structure, or the shielding pattern is formed synchronously with the annular deep trench structure.

3. The method for manufacturing a photomask according to claim 2, wherein: When the shielding pattern is formed after the deep groove structure, the formation process of the deep groove structure and the shielding pattern includes: forming a patterned first mask layer on the surface of the transparent substrate, wherein the patterned first mask layer has a plurality of discrete annular first openings exposing a portion of the surface of the transparent substrate; using the patterned first mask layer as a mask, etching the transparent substrate along the annular first openings to form a plurality of discrete annular grooves in the transparent substrate; removing the patterned first mask layer; forming an opaque material film on the surface of the annular groove and the transparent substrate; removing the opaque material film on the surface of the transparent substrate by a chemical mechanical polishing process, An annular deep groove structure is formed in the annular groove; a shielding graphic film is formed on the surface of the transparent substrate and on the surface of the annular deep groove structure; a patterned second mask layer is formed on the surface of the shielding graphic film, the patterned second mask layer covers the surface of the shielding graphic film on the transparent substrate surface in the middle of the annular deep groove structure and on the surface of the annular deep groove structure, exposing the surface of the shielding graphic film in other areas; using the patterned second mask layer as a mask, the shielding graphic film is etched to form a shielding pattern on the transparent substrate surface in the middle of the annular deep groove structure and on the surface of the annular deep groove structure; and the patterned second mask layer is removed.

4. The method for manufacturing a photomask according to claim 3, wherein: The shielding pattern and the annular deep trench structure may be made of the same or different materials.

5. The method for manufacturing a photomask according to claim 2, wherein: When the shielding pattern is formed synchronously with the annular deep groove structure, the formation process of the deep groove structure and the shielding pattern includes: forming a patterned first mask layer on the surface of the transparent substrate, wherein the patterned first mask layer has a plurality of discrete annular first openings exposing a portion of the surface of the transparent substrate; using the patterned first mask layer as a mask, etching the transparent substrate along the annular first openings to form a plurality of discrete annular grooves in the transparent substrate; removing the patterned first mask layer; forming an opaque material film on the surface of the annular groove and the transparent substrate; and flattening the transparent substrate by a chemical mechanical polishing process. The surface of the opaque material film; forming a patterned second mask layer on the surface of the flattened opaque material film, the patterned second mask layer covers the surface of the transparent substrate in the middle of the annular groove and the surface of the opaque material film on the annular groove, exposing the surface of the opaque material film in other areas; using the patterned second mask layer as a mask, etching the opaque material film to form an annular deep groove structure in the annular groove, and forming a shielding pattern on the transparent substrate surface in the middle of the annular deep groove structure and the surface of the annular deep groove structure; removing the patterned second mask layer.

6. The method for manufacturing a photomask according to claim 5, wherein: The shielding pattern is made of the same material as the annular deep trench structure.

7. The method for manufacturing a photomask according to claim 6, wherein: The material of the shielding pattern and the annular deep groove 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.

8. The method for manufacturing a photomask according to claim 1, wherein: The annular groove has a depth of 500nm-2.5um and a width of 10nm-300nm.

9. The method for manufacturing a photomask according to claim 1, wherein: The side surface of the shielding pattern is flush with the side surface of the annular deep groove structure in the vertical direction.

10. The method for manufacturing a photomask according to claim 1, wherein: The deep groove structure is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges around the shielding pattern.

11. 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.

12. A photomask, characterized in that: include: Transparent substrate; a plurality of discrete annular grooves in the transparent substrate; An annular deep groove structure that fills the annular groove, the deep groove structure is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted around the edges of the shielding pattern; A shielding pattern is located on the surface of the transparent substrate in the middle of the annular deep groove structure and on the surface of the annular deep groove structure.

13. The photomask according to claim 12, wherein: The shielding pattern and the annular deep trench structure may be made of the same or different materials.

14. The photomask according to claim 13, wherein: The material of the shielding pattern or the annular deep groove 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.

15. The photomask according to claim 12, wherein: The annular groove has a depth of 500nm-2.5um and a width of 10nm-300nm.

16. The photomask according to claim 12, wherein: The side surface of the shielding pattern is flush with the side surface of the annular deep groove structure in the vertical direction.

17. The photomask according to claim 12, wherein: The deep groove structure is used to prevent the exposure light from moving or diffusing to the opaque area at the bottom of the shielding pattern after being scattered and / or refracted at the edges around the shielding pattern.

18. The photomask according to claim 12, 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.

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