Photoetching mask with nanoscale graphical size and preparation method thereof
The photolithography mask plate with nano-scale patterned structure was prepared by nanoimprinting technology, and a photonic crystal enhancement layer was added thereon, which solved the high cost and low efficiency problems of preparing nano-scale linewidth mask plates in the prior art, and improved the efficiency of the lithography process and the service life of the equipment.
Patent Information
- Application Number
- CN202411839286.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2020-11-30
- Publication Date
- 2025-03-07
AI Technical Summary
When preparing nanoscale linewidth mask plates, the existing semiconductor mask plates have high equipment requirements, high cost, low production efficiency, and limited ultraviolet light propagation in traditional lithography processes, resulting in long exposure time and short equipment service life.
A photolithographic mask plate with nano-scale patterned size was prepared by nanoimprinting. By setting a nano-scale patterned structure on the mask layer and adding a photonic crystal emissive layer to the exposure surface, the transmissibility of ultraviolet light was improved.
A chip structure with low cost preparation of nano-scale linewidth is realized, which reduces exposure time in the lithography process, improves production capacity and equipment service life, reduces the reflection of ultraviolet light, and improves the uniformity of the optical path.
Smart Images
Figure CN119575748A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of semiconductor micro-nano processing, and in particular relates to a photolithography mask with nanometer-level graphic dimensions and a preparation method thereof. Background Art
[0002] According to the authoritative data of the "2020-2026 China Mask Industry Operation Status and Development Prospects Analysis Report" released by Zhiyan, the global semiconductor photolithography mask market size reached US$4.1 billion in 2019, of which China's mask demand accounted for 56% of the world. In the global market, American Phoenix and Japanese Toppan and DNP Printing accounted for 82% of the global market share. Mask products are heavily dependent on foreign manufacturers and have a low localization rate. Although the development of China's semiconductor industry started late, with its huge market capacity and production group, China has become the world's largest semiconductor consumer. The photolithography mask is a key link in the entire semiconductor industry. As the country increases its investment in the semiconductor industry, according to the forecast data of authoritative institutions such as CSIA, CCID Think Tank, and SEMI, it can be seen that the semiconductor industry will maintain a growth of 20%-30% in the next few years. With the vigorous development of the semiconductor industry, the demand for semiconductor masks has also exploded.
[0003] Traditional semiconductor masks are divided into two types: master and daughter. The master is prepared by laser direct writing, which has low production efficiency. The daughter is copied on the basis of the master by photolithography. The preparation process is cumbersome and the preparation equipment is expensive. The equipment required to prepare nanometer-level line width masks must be more advanced, with higher resolution requirements, and the cost is relatively high, and the preparation efficiency is low. This series of problems has been plaguing the further development of the entire industry.
[0004] The Chinese patent with the announcement number CN 105225279 discloses a mask plate and its preparation method and patterning method, wherein the mask plate includes: a mask substrate; a plurality of nano-protrusions formed on the mask substrate, and the plurality of nano-protrusions have spacing between them; and a shielding layer covering the surface of the plurality of nano-protrusions. The nano-protrusions have the effect of anti-reflection and anti-transmission and are arranged on the mask substrate, but the mask layer is not patterned, and a chip structure with a nano-level line width cannot be prepared. And the effect of the nano-protrusions on the anti-transmission of ultraviolet light is limited. Summary of the invention
[0005] In view of the above-mentioned technical problems, the purpose of the present invention is to provide a photolithography mask with nanometer-scale graphic size and a preparation method thereof, which is prepared by nanoimprinting, has low production cost, and the minimum feature size (minimum CD size) line width of the mask pattern can reach the nanometer level, which can be used to prepare chip structures with nanometer-scale line width. Secondly, a photonic crystal anti-reflection layer is made on the exposure surface, which can improve the anti-reflection of ultraviolet light, thereby reducing the exposure time in the photolithography process, which not only improves the production capacity, but also prolongs the service life of the ultraviolet lamp components, while reducing the reflection of ultraviolet light, which has a certain help to the uniformity of the optical path of the incident ultraviolet light. .
[0006] The technical solution of the present invention is:
[0007] A photolithography mask with nanometer-scale patterned size comprises a transparent substrate with a first surface and a second surface, wherein the first surface of the transparent substrate is provided with a mask layer having a nanometer-scale patterned structure, and the second surface of the transparent substrate is provided with a photonic crystal anti-reflection layer.
[0008] In a preferred technical solution, the mask layer is coated on a transparent substrate by sputtering or electron beam evaporation process, the material of the mask layer is a mixture of one or more of metallic chromium material, silicon material, non-transparent aluminum oxide material, and iron oxide material, and the thickness of the mask layer is 100-200nm.
[0009] In a preferred technical solution, a passivation layer is arranged on the mask layer, and the material of the passivation layer is a mixture of one or more of transparent aluminum oxide material, silicon nitride material, and silicon oxide material.
[0010] In a preferred technical solution, the thickness of the passivation layer is an odd multiple of 1 / 4 wavelength of the incident ultraviolet light.
[0011] In a preferred technical solution, the nanoscale patterned structure of the mask layer and the photonic crystal anti-reflection layer are obtained by etching after imprinting with a nanoimprint template.
[0012] In a preferred technical solution, the nanostructure of the photonic crystal anti-reflection layer is an array-arranged microlens structure, the curvature of the microlens is 0.5 to 3 rad, and the height of the microlens is 150 to 400 nm.
[0013] The present invention also discloses a method for preparing a photolithography mask with nanometer-scale patterning size, comprising the following steps:
[0014] S01: coating a mask layer on a first surface of a transparent substrate by sputtering or electron beam evaporation process;
[0015] S02: setting a nanoscale patterned structure on the mask layer;
[0016] S03: Disposing a photonic crystal anti-reflection layer on the second surface of the transparent substrate.
[0017] In a preferred technical solution, the method of setting a nanoscale patterned structure on the mask layer in step S02 includes:
[0018] S21: Apply UV photosensitive adhesive on the surface of the mask layer;
[0019] S22: Imprinting a nanoimprint template with a patterned structure on a UV photosensitive adhesive, curing the nanoimprint template by UV light irradiation, and demolding the nanoimprint template;
[0020] S23: etching a corresponding patterned structure in an area without resist blocking by an ICP etching process, and finally removing the resist to form a mask layer with a nanoscale patterned structure.
[0021] In the preferred technical solution, the method for manufacturing the photonic crystal anti-reflection layer in step S03 includes:
[0022] S31: Applying UV photosensitive adhesive on the second surface of the transparent substrate;
[0023] S32: Imprinting a nanoimprint template with a photonic crystal structure on a UV photosensitive adhesive, curing the nanoimprint template by UV light irradiation, and demolding the nanoimprint template;
[0024] S33: etching a corresponding photonic crystal structure in an area without resist blocking by an ICP etching process, and finally removing the resist to form a photonic crystal transmittance-enhancing layer.
[0025] In a preferred technical solution, the nanostructure of the photonic crystal anti-reflection layer is an array-arranged microlens structure, the curvature of the microlens is 0.5 to 3 rad, and the height of the microlens is 150 to 400 nm.
[0026] Compared with the prior art, the advantages of the present invention are:
[0027] 1. The nanoimprint method is used for preparation, which has low production cost. The minimum feature size (minimum CD size) line width of the mask pattern can reach the nanometer level, which can be used to prepare chip structures with nanometer line width. Secondly, a photonic crystal anti-reflection layer is made on the exposure surface, which can improve the anti-reflection of ultraviolet light, thereby reducing the exposure time in the photolithography process, not only improving production capacity, but also extending the service life of ultraviolet lamp components, while reducing the reflection of ultraviolet light, which is helpful for the uniformity of the optical path of the incident ultraviolet light. This method is simple in process and suitable for large-scale batch production. It can be widely used in the field of semiconductor nano-scale chip structure photolithography processing and other nano-scale line width optical mask fields.
[0028] 2. In addition, a high-density and high-hardness passivation layer is used on the contact surface or close surface of the photoresist to improve the scratch resistance of the photoresist, thereby greatly increasing the service life of the photoresist and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:
[0030] Figure 1 It is a schematic structural diagram of a photolithography mask with nanometer-scale patterning size according to the present invention;
[0031] Figure 2 It is a schematic diagram of the structure of the photonic crystal anti-reflection layer of the present invention;
[0032] Figure 3 A schematic diagram of a mask layer for preparing a nanoscale patterned structure by nanoimprinting of the present invention;
[0033] Figure 4 This is a schematic diagram of preparing a photonic crystal anti-reflection layer by nanoimprinting of the present invention. DETAILED DESCRIPTION
[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.
[0035] Example:
[0036] like Figure 1 As shown, a photolithography mask with nanoscale patterned dimensions is used. The photolithography mask adopts a nanoimprinting method to prepare a patterned mask layer and a photonic crystal anti-reflection layer. The minimum feature size (minimum CD size) line width of the mask patterning can reach the nanoscale. The photolithography mask comprises a transparent substrate 4 having a first surface and a second surface. The first surface of the transparent substrate 4 (the contact surface or the proximity surface of the photoresist) is provided with a mask layer 3, and the mask layer is provided with a nanoscale patterned structure 5. The second surface of the transparent substrate 4 is provided with a photonic crystal anti-reflection layer 9.
[0037] The transparent substrate 4 is made of one of transparent quartz material, transparent soda glass material and transparent sapphire single crystal material. The thickness of the transparent substrate is in the range of 50-2000um.
[0038] The nanoscale patterned structure 5 of the mask layer 3 and the photonic crystal anti-reflection layer 9 are obtained by etching after imprinting with a nanoimprint template.
[0039] The thickness of the mask layer 3 is in the range of 100-200 nm, and the nanoscale patterned structure 5 of the mask layer 3 can be set to different patterned mask structures according to different mask requirements.
[0040] In a preferred embodiment, the patterned mask layer can also be protected by a passivation layer. The passivation layer is selected from one of transparent aluminum oxide materials, silicon nitride materials, and silicon oxide materials with relatively dense materials and relatively high hardness. The passivation layer has an anti-scratch effect and can improve the scratch resistance of the mask photoresist contact surface or close surface. The thickness of the passivation layer is an odd multiple of 1 / 4 wavelength λ of the incident ultraviolet light. This thickness is more conducive to avoiding reflection of ultraviolet light. The passivation layer can be manufactured by sputtering or electron beam evaporation process.
[0041] like Figure 2 As shown, the nanostructure of the photonic crystal anti-reflection layer is a microlens 10 structure arranged in an array with a diameter d of 200 to 800 nm, the arrangement period setting range can be 400 to 1000 nm, the arc range of the microlens 10 can be set between 0.5 and 3 rad, and the height h of the microlens 10 is between 150 and 400 nm.
[0042] A method for preparing a photolithography mask with nano-scale patterned dimensions includes two major steps: first, preparing a nano-patterned structure mask layer by nanoimprinting; and second, preparing a photonic crystal anti-reflection layer by nanoimprinting.
[0043] The specific steps include:
[0044] Figure 3 This is a schematic diagram of preparing a nano-patterned structure mask layer by nanoimprinting in the present invention. The specific steps are as follows:
[0045] (1) A transparent material is selected as the transparent substrate 4 of the mask. The transparent substrate 4 is one of transparent quartz material, transparent soda glass material, and transparent sapphire single crystal material. The thickness of the transparent substrate 4 is in the range of 50-2000 um.
[0046] In a preferred embodiment, the transparent substrate 4 is made of transparent sapphire single crystal material with a thickness of 500 um.
[0047] (2) A coating mask layer 3 is formed on the upper surface of the transparent substrate 4 (i.e., the photoresist contact surface or the surface close to the photoresist) by sputtering or electron beam evaporation process. The material of the mask layer 3 is one of metal chromium material, silicon material, non-transparent aluminum oxide material, and iron oxide material. The thickness of the mask layer 3 is in the range of 100-200 nm.
[0048] In a preferred embodiment, the mask layer 3 is made of a mixture of silicon material and non-transparent aluminum oxide material, and has a thickness of 150 um.
[0049] (3) The mask layer 3 needs to be prepared with different patterned mask structures according to different mask requirements. First, UV photosensitive glue 2 is coated on the surface of the mask layer 3. Then, a nanoimprint template 1 with a patterned structure is imprinted 21 on the UV photosensitive glue 2. The UV photosensitive glue 2 is cured by UV light irradiation 20. The nanoimprint template 1 is removed from the mold. Then, an ICP etching (inductively coupled plasma etching) process is used to etch the corresponding patterned structure in the area not blocked by the UV photosensitive glue 2. Finally, the glue is removed to form a nano-patterned mask structure layer 5.
[0050] (4) The nano-patterned mask structure layer 5 is protected by a passivation layer 6. The passivation layer 6 is made of a transparent aluminum oxide material, a silicon nitride material, or a silicon oxide material that is relatively dense and has a relatively high hardness. The passivation layer 6 has an anti-scratch effect and can improve the scratch resistance of the mask photoresist contact surface or the close surface. The thickness of the passivation layer 6 is an odd multiple of 1 / 4 wavelength λ of the incident ultraviolet light. This thickness is more conducive to avoiding reflection of ultraviolet light. The passivation layer 6 can be made by sputtering or electron beam evaporation process.
[0051] In a preferred embodiment, the passivation layer 6 is made of transparent aluminum oxide material.
[0052] Figure 4 This is a schematic diagram of preparing a photonic crystal anti-reflection layer by nanoimprinting in the present invention, and the specific steps are as follows:
[0053] (1) First, a UV photosensitive adhesive 8 is applied to the other side of the transparent substrate 4, hereinafter referred to as the lower surface (i.e., the UV light exposure surface);
[0054] (2) Imprinting a nanoimprint template 7 with a photonic crystal structure onto a UV photosensitive adhesive 8, and curing the UV photosensitive adhesive 8 by UV light irradiation;
[0055] (3) demoulding and removing the nanoimprint template 7;
[0056] (4) Then, the ICP etching process is used to etch the corresponding photonic crystal patterned structure in the area not blocked by the UV photosensitive adhesive 8;
[0057] (5) Finally, the photonic crystal anti-reflection layer 9 is formed by removing the resist. Finally, the desired photolithography mask with nano-scale patterning size is obtained.
[0058] The photolithography mask prepared by the method of the present invention has low production cost, and the line width of the minimum feature size (minimum CD size) of the mask patterning can reach the nanometer level. It has good light transmission effect on the ultraviolet exposure lamp of the photolithography machine, high exposure efficiency, reduces ultraviolet light reflection and makes the light path uniform, and can be used to prepare chip structures with nanometer line width. The method is simple in process, suitable for large-scale batch production, and can be widely used in the field of semiconductor nanometer chip structure photolithography process processing and other nanometer line width optical mask fields.
[0059] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.
Claims
1. A method for preparing a photolithography mask having nanoscale patterning dimensions, characterized in that: The following steps are involved: S01: coating a mask layer on a first surface of a transparent substrate by sputtering or electron beam evaporation process; S02: setting a nanoscale patterned structure on the mask layer; S03: Disposing a photonic crystal anti-reflection layer on the second surface of the transparent substrate; The method of setting a nanoscale patterned structure on the mask layer in step S02 includes: S21: Apply UV photosensitive adhesive on the surface of the mask layer; S22: Imprinting a nanoimprint template with a patterned structure on a UV photosensitive adhesive, curing the nanoimprint template by UV light irradiation, and demolding the nanoimprint template; S23: etching a corresponding patterned structure in an area without resist blocking by an ICP etching process, and finally removing the resist to form a mask layer with a nanoscale patterned structure.
2. The method for preparing a photolithography mask having nanoscale patterning dimensions according to claim 1, characterized in that: The method for making the photonic crystal anti-reflection layer in step S03 comprises: S31: Applying UV photosensitive adhesive on the second surface of the transparent substrate; S32: Imprinting a nanoimprint template with a photonic crystal structure on a UV photosensitive adhesive, curing the nanoimprint template by UV light irradiation, and demolding the nanoimprint template; S33: etching a corresponding photonic crystal structure in an area without resist blocking by an ICP etching process, and finally removing the resist to form a photonic crystal transmittance-enhancing layer.
3. The method for preparing a photolithography mask having nanoscale patterning dimensions according to claim 2, characterized in that: The nanostructure of the photonic crystal anti-reflection layer is a microlens structure arranged in an array, the curvature of the microlens is 0.5-3 rad, and the height of the microlens is 150-400 nm.
4. A photolithography mask having nanometer-scale patterning dimensions, characterized in that: The method is prepared by any one of claims 1 to 3.
5. The photolithography mask with nanoscale patterning dimensions according to claim 4, characterized in that: The invention comprises a transparent substrate having a first surface and a second surface. The first surface of the transparent substrate is provided with a mask layer, the mask layer is provided with a nano-scale patterned structure, and the second surface of the transparent substrate is provided with a photonic crystal anti-reflection layer.
6. The photolithography mask with nanometer-scale patterning dimensions according to claim 5, characterized in that: The mask layer is coated on the transparent substrate by sputtering or electron beam evaporation process. The material of the mask layer is a mixture of one or more of metallic chromium material, silicon material, non-transparent aluminum oxide material, and iron oxide material. The thickness of the mask layer is 100-200nm.
7. The photolithography mask with nanometer-scale patterning dimensions according to claim 6, characterized in that: A passivation layer is arranged on the mask layer, and the material of the passivation layer is a mixture of one or more of transparent aluminum oxide material, silicon nitride material, and silicon oxide material.
8. The photolithography mask with nanoscale patterning dimensions according to claim 7, characterized in that: The thickness of the passivation layer is an odd multiple of 1 / 4 wavelength of the incident ultraviolet light.