A process for preventing photoresist from bleaching and cracking

Abstract

The invention discloses a process for preventing photoresist from bleaching and cracking, and belongs to the field of semiconductor processing technology, comprising: S1, selecting a substrate of a required material as a wafer to be processed, and then processing an overlay mark on the wafer; S2, depositing a transition layer on the wafer; S3, sequentially pre-treating the wafer, spin-coating ZEP 520A photoresist, baking, then overlaying and exposing the wafer, making a pattern with a target pattern line width enlarged, developing the wafer, and finally baking a hard film; S4, etching the wafer transition layer; S5, removing the wafer; S6, sequentially pre-treating the wafer, spin-coating ZEP 520A photoresist, baking, then overlaying and exposing the wafer, making a target pattern, and developing the wafer; S7, depositing a target metal; S8, peeling the wafer; S9, removing the transition layer to obtain a target structure. The invention can prevent photoresist from bleaching and cracking.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor processing, and in particular relates to a process for preventing photoresist from bleaching and cracking. Background Art

[0002] As we all know, with the rapid development of the optoelectronic industry, the structural design of optoelectronic chips has become more diversified, and the types of wafer materials used are also increasing. On some wafers (such as lithium niobate materials, etc.), the adhesion of photoresist is poor and the stress is large, and the phenomenon of bleaching and cracking will occur after development. Summary of the invention

[0003] The invention provides a process for preventing photoresist from bleaching and cracking, which is used for preventing photoresist from bleaching and cracking.

[0004] The object of the present invention is to provide a process for preventing photoresist from bleaching and cracking, comprising:

[0005] S1, select a substrate of the required material as the wafer to be processed, and then process an overlay mark on the wafer;

[0006] S2, depositing a transition layer on the wafer;

[0007] S3, pre-treating the wafer, spin-coating ZEP 520A photoresist, baking, then overlaying and exposing the wafer to produce a pattern with a larger line width of the target pattern, developing the wafer, and finally hardening the film;

[0008] S4, etching the wafer transition layer;

[0009] S5, debonding the wafer;

[0010] S6, pre-treating the wafer, spin-coating ZEP 520A photoresist, baking, then overlaying and exposing the wafer, making a target pattern, and developing the wafer;

[0011] S7, depositing target metal;

[0012] S8, peeling off the wafer;

[0013] S9. Remove the transition layer to obtain the target structure.

[0014] Preferably, the wafer material is lithium niobate or lithium tantalate.

[0015] Preferably, S2 specifically comprises: using electron beam evaporation or sputtering or chemical vapor deposition equipment to deposit 50 nm thick silicon dioxide on the wafer.

[0016] Preferably, S3 is specifically as follows: pre-treating the wafer with O2 plasma, then spin-coating a 360nm thick ZEP 520A photoresist, and baking it in an oven at 180°C for 20 minutes, then using an electron beam lithography device to automatically overlay the wafer to produce a pattern with a target pattern line width enlarged, developing the wafer, and then baking it on a 120°C hot plate for 2 minutes to harden the film.

[0017] Preferably, S5 specifically includes: using a butanone solution to remove the adhesive from the wafer.

[0018] Preferably, S6 is specifically:

[0019] The wafer was pretreated with O2 plasma, then spin-coated with 360nm thick ZEP 520A photoresist and baked in an oven at 180°C for 20 minutes. The wafer was then automatically overlaid and exposed using electron beam lithography equipment to produce the target pattern and develop the wafer.

[0020] Preferably, S8 specifically includes: peeling the wafer using a butanone solution.

[0021] Preferably, S7 specifically includes: depositing 10 nm titanium and 50 nm gold.

[0022] Preferably, S9 specifically includes: selecting dry etching or wet etching according to actual conditions to remove the transition layer to obtain the target structure.

[0023] The advantages and positive effects of the present invention are:

[0024] The present invention has better effect than other methods for increasing photoresist adhesion and preventing photoresist drift (such as HMDS, etc.), and while preventing photoresist drift, the silicon oxide layer can reduce the photoresist stress caused by the different expansion coefficients of the wafer and the photoresist, thereby preventing photoresist cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Flowchart of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to further understand the content, features and effects of the present invention, the following embodiments are given as examples and described in detail with reference to the accompanying drawings:

[0027] like Figure 1 As shown, the technical solution of the present invention is:

[0028] A process for preventing photoresist from bleaching and cracking, firstly depositing a transition layer (such as silicon dioxide, silicon nitride, chromium, etc.) on a wafer (including lithium niobate and lithium tantalate, but not limited to these two), photolithography is performed after the line width of the target pattern is expanded, and then the exposed transition layer is removed by etching, and then the target pattern is overlaid by photolithography, and then a metal layer (the deposited metal includes gold, aluminum, platinum, but not limited to these) is deposited and peeled off, and finally wet etching or dry etching is used to remove the transition layer according to the wafer material and the transition layer material.

[0029] Specific steps: (The following takes the ZEP 520A photoresist stripping 50nm gold on lithium niobate wafer as an example, and is also applicable to the stripping of other metals by other photoresists on other wafers).

[0030] Step 1: Select a clean lithium niobate substrate as the wafer to be processed, and then use a conventional photolithography stripping process to process an overlay mark on the wafer;

[0031] Step 2: Deposit 50nm silicon dioxide on the wafer using electron beam evaporation equipment / sputtering equipment / chemical vapor deposition equipment;

[0032] Step 3: Pre-treat the wafer with O2 plasma, then spin-coat a 360nm thick ZEP 520A photoresist, and bake it in an oven at 180°C for 20 minutes. Then use an electron beam lithography device to automatically overlay the wafer to produce a pattern with the target pattern line width enlarged, develop the wafer, and bake it on a 120°C hot plate for 2 minutes to harden the film.

[0033] Step 4: Use etching equipment to etch 50nm of silicon dioxide on the wafer;

[0034] Step 5: Use butanone solution to remove the wafer:

[0035] Step 6: Pre-treat the wafer with O2 plasma, then spin-coat 360nm thick ZEP 520A photoresist, bake it in an oven at 180°C for 20 minutes, and then use electron beam lithography equipment to automatically overlay the wafer to produce the target pattern, and then develop the wafer;

[0036] Step 7: Use electron beam evaporation equipment to first deposit 10nm titanium (adhesion layer) and then deposit 50nm gold;

[0037] Step 8: Use butanone solution to peel off the wafer;

[0038] Step nine: Use a wet etching method to remove silicon dioxide (select dry etching or wet etching to remove silicon oxide according to actual conditions) to obtain the target structure.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are within the scope of the technical solution of the present invention.

Claims

1. A process for preventing photoresist from bleaching and cracking, characterized in that: At least: S1, select a substrate of the required material as the wafer to be processed, and then process an overlay mark on the wafer; S2, depositing 50 nm thick silicon dioxide on the wafer using electron beam evaporation or sputtering or chemical vapor deposition; S3, pre-treat the wafer with O2 plasma, then spin-coat a 360nm thick ZEP 520A photoresist, and bake it in an oven at 180°C for 20 minutes, then use an electron beam lithography device to automatically overlay the wafer to produce a pattern with the target pattern line width enlarged, develop the wafer, and then bake it on a 120°C hot plate for 2 minutes to harden the film; S4, etching silicon dioxide as a transition layer on the wafer; S5, debonding the wafer; S6, pre-treat the wafer with O2 plasma, then spin-coat a 360nm thick ZEP 520A photoresist, bake it in an oven at 180°C for 20min, and then use an electron beam lithography device to automatically overlay the wafer to produce the target pattern, and then develop the wafer; S7, depositing target metal; S8, peeling off the wafer; S9. Remove the transition layer to obtain the target structure.

2. The process for preventing photoresist from bleaching and cracking according to claim 1, characterized in that: The wafer material is lithium niobate or lithium tantalate.

3. The process for preventing photoresist from bleaching and cracking according to claim 1, characterized in that: S5 specifically includes: using a butanone solution to remove the adhesive from the wafer.

4. The process for preventing photoresist from bleaching and cracking according to claim 1, characterized in that: S8 specifically includes: peeling the wafer using a butanone solution.

5. The process for preventing photoresist from bleaching and cracking according to claim 1, characterized in that: S7 specifically includes: depositing 10nm titanium plus 50nm gold.

6. The process for preventing photoresist from bleaching and cracking according to claim 1, characterized in that: S9 specifically includes: selecting dry etching or wet etching according to actual conditions to remove the transition layer and obtain the target structure.

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