Photoetching method and photomask
By setting a transparent release coating on the surface of the metal layer of the photomask, the problem of photoresist adhesion on the photomask is solved, the smooth separation of the photoresist is achieved, and the photolithography effect is improved.
Patent Information
- Application Number
- CN202410090503.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-22
- Publication Date
- 2025-07-22
AI Technical Summary
During the contact exposure process, the photoresist is prone to adhere to the photoconduit, resulting in photoresist residue and affecting the photolithography effect.
A transparent release coating is provided on the surface of the metal layer of the photomask to reduce the adhesion intensity between the photomask and the photoresist and prevent the photoresist from adhering to the photomask.
By setting a release coating on the surface of the metal layer of the photomask, the adhesion intensity between the photomask is reduced, the photomask is avoided, the photomask is retained, and the photomask is improved.
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Figure CN120353091A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular, to a lithography method and a photomask. Background Art
[0002] Contact Exposure is widely used in the field of semiconductor manufacturing and can obtain better lithography topography.
[0003] Figure 1 is a schematic diagram of Contact Exposure. As Figure 1 shown, in Contact Exposure, the photomask 10 inevitably contacts the photoresist 12 on the surface of the wafer 11. When the photoresist 12 is a thick film negative photoresist or the viscosity of the photoresist 12 is relatively large, the photoresist 12 will adhere to the photomask 10. Therefore, during the process of separating the photomask 10 from the wafer 11 after the exposure, part of the photoresist 12 may remain on the photomask 10, and even the entire wafer 11 may adhere to the photomask 10 through the photoresist 12.
[0004] It should be noted that the above introduction of the technical background is only for the convenience of clearly and completely explaining the technical solution of the present application and facilitating the understanding of those skilled in the art. It cannot be considered that the above technical solutions are well-known to those skilled in the art just because these solutions are described in the background art part of the present application. Summary of the Invention
[0005] The inventors of the present application have found that in Contact Exposure, how to avoid the adhesion of the photoresist to the photomask is an urgent problem to be solved.
[0006] To solve the above problems or at least similar problems, an embodiment of the present application provides a lithography method and a photomask. A release coating is provided on the surface of the metal layer of the photomask. Thus, during the exposure process, even if the metal layer of the photomask contacts the photoresist, the release coating can reduce the adhesion strength between the metal layer of the photomask and the photoresist, thereby avoiding the adhesion of the photoresist to the photomask.
[0007] According to one aspect of the embodiments of the present application, a lithography method is provided. The method includes:
[0008] providing a photoresist on the surface of a substrate; and
[0009] exposing the photoresist using a photomask, wherein the photomask has a transparent body and a metal layer provided on one surface of the body, and a release coating is provided on the surface of the metal layer. When performing the exposure, the surface of the metal layer provided with the release coating faces the photoresist.
[0010] In some embodiments, the method further includes:
[0011] Providing the release coating on the surface of the metal layer.
[0012] In some embodiments, the release coating is a transparent and colorless coating.
[0013] In some embodiments, the release coating includes at least one of polyvinyl alcohol, silicone oil, silicone grease, liquid or emulsified paraffin.
[0014] In some embodiments, the photoresist is a negative photoresist.
[0015] In some embodiments, the material of the metal layer of the photomask includes chromium.
[0016] In some embodiments, the method further includes:
[0017] Developing the exposed photoresist.
[0018] According to another aspect of the embodiments of the present application, there is provided a photomask having:
[0019] A transparent body; and
[0020] A metal layer located on one surface of the body, the metal layer having a predetermined pattern, wherein a release coating is provided on the surface of the metal layer.
[0021] The beneficial effect of the present application is that: a release coating is provided on the surface of the metal layer of the photomask. Thus, during the exposure process, even if the metal layer of the photomask contacts the photoresist, the release coating can reduce the adhesion strength between the metal layer of the photomask and the photoresist, thereby preventing the photoresist from adhering to the photomask.
[0022] Referring to the following description and the accompanying drawings, specific embodiments of the present application are disclosed in detail, indicating the ways in which the principles of the present application can be employed. It should be understood that the embodiments of the present application are not limited in scope thereby. Within the spirit and terms of the appended claims, the embodiments of the present application include many changes, modifications and equivalents.
[0023] Features described and / or illustrated for one embodiment can be used in the same or similar way in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.
[0024] It should be emphasized that the term "comprising / including" when used herein refers to the presence of features, whole things, steps or components, but does not exclude the presence or addition of one or more other features, whole things, steps or components. Description of the Drawings
[0025] The accompanying drawings included are used to provide a further understanding of the embodiments of the present application, which form a part of the specification, illustrate the implementation manners of the present application, and, together with the written description, explain the principles of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings:
[0026] Figure 1 is a schematic diagram of contact exposure;
[0027] Figure 2 is a schematic diagram of the lithography method of the present application;
[0028] Figure 3 is a schematic diagram of the photomask of the present application;
[0029] Figures 4 to 5 is a cross-sectional schematic diagram of the substrate corresponding to each step in the example of the lithography method. Detailed Implementation Manner
[0030] Referring to the accompanying drawings, through the following description, the foregoing and other features of the present application will become apparent. In the description and drawings, specific implementation manners of the present application are specifically disclosed, which show some implementation manners in which the principles of the present application can be adopted. It should be understood that the present application is not limited to the described implementation manners. On the contrary, the present application includes all modifications, variations, and equivalents falling within the scope of the appended claims.
[0031] In the description of the embodiments of the present application, for convenience of description, the direction parallel to the surface of the substrate is referred to as "lateral", the direction perpendicular to the surface of the substrate is referred to as "longitudinal", and the dimension in the "longitudinal" direction can be referred to as "height" or "thickness"; in the "longitudinal" direction, the direction from the surface of the substrate to the photoresist is referred to as the "upper" direction, and the opposite direction to the "upper" direction is the "lower" direction.
[0032] It should be noted that the above "upper" direction and "lower" direction are only for convenience of description and do not limit the orientation or attitude of the substrate of the present application during manufacturing or use.
[0033] Embodiment
[0034] Figure 2 is a schematic diagram of the lithography method of the present application.
[0035] As Figure 2 shown, the lithography method includes:
[0036] Operation 201, disposing a photoresist on the surface of the substrate; and
[0037] Operation 202: Expose the photoresist using a photomask. The photomask has a transparent body and a metal layer disposed on one surface of the body, and a release coating is provided on the surface of the metal layer.
[0038] According to an embodiment of the present application, a release coating is provided on the surface of the metal layer of the photomask. Thus, during the exposure process, even if the metal layer of the photomask contacts the photoresist, the release coating can reduce the adhesion strength between the metal layer of the photomask and the photoresist, thereby preventing the photoresist from adhering to the photomask.
[0039] In the present application, the substrate can be a substrate commonly used in semiconductor manufacturing processes. For example, the substrate can be a silicon wafer, a silicon-on-insulator (SOI) wafer, a silicon-germanium wafer, a glass substrate, a sapphire substrate, etc. In the embodiment of the present application, the case where the substrate is a silicon wafer is taken as an example for illustration. Electronic circuits or micro-mechanical structures, etc. can be formed on the surface or the back surface of the substrate.
[0040] In operation 201, the photoresist can be disposed on the surface of the substrate by spin coating or spraying, etc. The photoresist can be a photoresist with relatively high viscosity. For example, a negative photoresist.
[0041] Figure 3 is a schematic diagram of the photomask of the present application. As Figure 3 shown, the photomask 300 can have a transparent body 301 and a metal layer 302. The body 301 is, for example, a rectangular or square glass material. The metal layer 302 can be disposed on one surface of the body 301. The metal layer 302 can have a predetermined pattern. During exposure, the light emitted by the exposure machine tool is directed towards the photomask 300, and the light is blocked by the pattern of the metal layer 302, and the light passes through the portion not covered by the metal layer 302 and irradiates the photoresist, thereby exposing the photoresist.
[0042] In some examples, the material of the metal layer 302 of the photomask 300 can include chromium. In addition, the present application is not limited thereto, and the metal layer 302 can also include other materials.
[0043] In the present application, as Figure 3 shown, a release coating 303 can be provided on the surface of the metal layer 302 of the photomask 300. The function of the release coating 303 is to increase the surface fluidity of the molten mixture of high molecular materials such as photoresist, reduce the adhesion force of the high molecular materials to the metal layer 302, thereby preventing high molecular materials such as photoresist from adhering to the metal layer 302 of the photomask 300, and making the photoresist easier to separate from the photomask 300.
[0044] Thus, during the process of using the photomask 300 for exposure in operation 202, even if the photoresist contacts the metal layer 302, it will not adhere to the metal layer 302.
[0045] In the present application, the release coating 303 can be a transparent and colorless coating. Thus, during the exposure process, the release coating 303 will not obstruct the light used for exposure.
[0046] For example, the release coating 303 can include at least one of polyvinyl alcohol, silicone oil, silicone grease, liquid paraffin, or emulsified paraffin.
[0047] In the present application, as Figure 2 shown, the method can further include:
[0048] Operation 203: Set a release coating on the surface of the metal layer of the photomask.
[0049] For example, a release coating 303 is set on the surface of the metal layer 302 of the photomask 300 by means such as spraying or spin coating.
[0050] Operation 203 can be performed before operation 201 or operation 202.
[0051] In the present application, as Figure 2 shown, the method can further include:
[0052] Operation 204: Develop the exposed photoresist.
[0053] In operation 204, a developing machine can be used to develop the photoresist exposed in operation 202 with a developer.
[0054] Next, a lithography method of the present application will be described in conjunction with an example.
[0055] Figures 4 to 5 is a cross-sectional schematic diagram of the substrate corresponding to each step in the example of the lithography method. As Figures 4 to 5 shown, in this example, the lithography method includes:
[0056] 1. Set a transparent and colorless release coating on the chromium surface of the photomask. For example, as Figure 3 shown, a release coating 303 is set on the surface of the metal layer 302 of the photomask 300. The release coating 303 is a transparent and colorless coating, and the material of the release coating 303 includes, for example, at least one of polyvinyl alcohol, silicone oil, silicone grease, liquid paraffin, or emulsified paraffin. The material of the metal layer 302 can include chromium.
[0057] 2. As Figure 4 shown, use a spin coater to coat a photoresist 401 on the surface of the substrate 400. For example, the photoresist 401 is a negative photoresist, the thickness of the photoresist 401 is about 1 to 10 microns, etc., and the viscosity of the photoresist 401 is relatively high.
[0058] 3. AsFigure 5 As shown, contact exposure is performed on a contact exposure machine. Since there is a release coating 303 on the surface of the metal layer 302 of the photomask 300, when the photoresist 401 separates after contacting the metal layer 302 of the photomask 300, it is easy to release and demold, so that the photoresist 401 will not adhere to the metal layer 302 of the photomask 300.
[0059] 4. Develop the exposed photoresist 401 to form the final photolithography pattern of the photoresist 401.
[0060] According to the embodiments of the present application, a release coating is provided on the surface of the metal layer of the photomask. Thus, during the exposure process, even if the metal layer of the photomask contacts the photoresist, the release coating can reduce the adhesion strength between the metal layer of the photomask and the photoresist, thereby preventing the photoresist from adhering to the photomask.
[0061] The present application has been described above in conjunction with specific embodiments, but those skilled in the art should understand that these descriptions are exemplary and not a limitation on the protection scope of the present application. Those skilled in the art can make various variations and modifications to the present application according to the spirit and principle of the present application, and these variations and modifications are also within the scope of the present application.
Claims
1. A lithography method, characterized in that, The method includes: providing a photoresist on the surface of a substrate; and exposing the photoresist using a photomask, wherein the photomask has a transparent body and a metal layer provided on one surface of the body, and a release coating is provided on the surface of the metal layer, when performing the exposure, the surface of the metal layer provided with the release coating faces the photoresist.
2. The method according to claim 1, wherein The method further includes: providing the release coating on the surface of the metal layer.
3. The method according to claim 1, wherein, the release coating is a transparent and colorless coating.
4. The method according to claim 1, wherein, the release coating includes at least one of polyvinyl alcohol, silicone oil, silicone grease, liquid or emulsified paraffin.
5. The method according to claim 1, wherein, the photoresist is a negative photoresist.
6. The method according to claim 1, wherein, the material of the metal layer of the photomask includes chromium.
7. The method according to claim 1, wherein, the method further includes: developing the exposed photoresist.
8. A photomask, characterized in that, The photomask has: a transparent body; and a metal layer located on one surface of the body, the metal layer having a predetermined pattern, wherein a release coating is provided on the surface of the metal layer.
9. The photomask according to claim 8, wherein, the release coating is a transparent and colorless coating.
10. The photomask according to claim 8, wherein, the release coating includes at least one of polyvinyl alcohol, silicone oil, silicone grease, liquid or emulsified paraffin.