Small-angle preparation method for side wall of thin film
By growing a silicon dioxide film on a silicon wafer or glass substrate and using photolithography and etching techniques, combined with etching of a specific gas ratio, the problem of unstable thin-film circuit shape was solved, and the stability of the thin-film sidewalls and the satisfaction of product parameters were achieved.
Patent Information
- Application Number
- CN202511355517.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-22
- Publication Date
- 2026-01-16
AI Technical Summary
In the existing technology, the shape of the thin film circuit is unstable during the etching process of silicon dioxide thin film, resulting in inconsistent product parameters and performance.
A silicon dioxide film is grown on a silicon wafer or glass substrate using thin-film chemical vapor deposition (CVD) technology. A photoresist layer is formed by photolithography. The etching process is controlled by combining a magnetically enhanced reactive ion etching (MEI) machine with a specific gas ratio to form a stable thin film with a small sidewall angle.
This achieves stability of the thin film sidewall morphology, meets product parameter requirements, and facilitates subsequent magnetron sputtering deposition of metal thin films.
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Figure CN121358191A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of thin film side wall inclination, in particular to a preparation method of thin film side wall small angle. BACKGROUND
[0002] When a conventional silicon dioxide film is etched to make a line, the line naturally presents a trapezoidal inclined shape with the upper part narrow and the lower part wide due to the influence of various process steps in the preparation process, but the result is uneven and affects product parameters and product performance because it cannot be specifically controlled.
[0003] Therefore, in view of the above-mentioned technical problems, it is necessary to propose a new technical solution. SUMMARY
[0004] To at least solve one of the technical problems existing in the prior art, the present application provides a preparation method of thin film side wall small angle. The specific technical solution is as follows:
[0005] The present application provides a preparation method of thin film side wall small angle, and the specific steps are as follows:
[0006] S1: using thin film chemical vapor deposition process to grow 3-6um silicon dioxide film layer on the surface of silicon wafer or glass substrate, and then coating 2-10um thick photoresist on the silicon dioxide film layer by photoetching process to form photoresist layer;
[0007] S2: exposing and developing the photoresist layer, and during developing, the exposed area of the photoresist layer is removed by the developing solution to form 10-20um wide photoresist line;
[0008] S3: baking after developing, the baking temperature is 100-150℃, the baking time is 200-400S, and then cooling to room temperature;
[0009] S4: etching the silicon dioxide film layer after cooling, the etched area of the silicon dioxide film layer is the area of the silicon dioxide film layer exposed after removing the photoresist layer, and the silicon dioxide line with line width is obtained after etching;
[0010] S5: after etching, the photoresist layer covering the silicon dioxide film layer is removed by dry etching method, and then wet cleaning is carried out to obtain the exposed silicon dioxide line structure with inclined appearance.
[0011] As a preferred scheme of the preparation method of thin film side wall small angle, in step S4, the cavity pressure during etching is 200-500mTorr.
[0012] As a preferred scheme of the preparation method of thin film side wall small angle, the etching is carried out by using a magnetic enhanced reactive ion etching machine.
[0013] As a preferred scheme of the method for preparing the thin film side wall with a small angle, in step S4, the etching gas comprises CF4 and CHF3, and the gas flow ratio of CF4 to CHF3 is 2:1 to 3:2.
[0014] As a preferred scheme of the method for preparing the thin film side wall with a small angle, the etching gas further comprises O2, and the gas flow ratio of O2 to CF4 is 1:4 to 1:3.
[0015] As a preferred scheme of the method for preparing the thin film side wall with a small angle, in step S1, the thin film chemical vapor deposition process is performed under the conditions that the cavity pressure ranges from 1 to 4 Torr, and the working gas used comprises SiH4, N2 and N2O, and the flow ratio of SiH4 to N2 to N2O is 1:5:30.
[0016] As a preferred scheme of the method for preparing the thin film side wall with a small angle, in step S2, the developing is performed for 100 to 200 seconds using the TMAH developing solution.
[0017] As a preferred scheme of the method for preparing the thin film side wall with a small angle, after the baking, the transverse section of the photoresist layer has an arch-shaped appearance.
[0018] As a preferred scheme of the method for preparing the thin film side wall with a small angle, in step S4, after the etching, a certain line width of the silicon dioxide film layer is formed, the line width of the silicon dioxide film layer near the side of the silicon wafer is the bottom line width, the line width of the silicon dioxide film layer far from the side of the silicon wafer is the top line width, the ratio of the bottom line width to the top line width is 1:3 to 3:7, and the inclination angle of the side wall ranges from 20 to 50 degrees.
[0019] As a preferred scheme of the method for preparing the thin film side wall with a small angle, in step S4, after the etching, the line width of the silicon dioxide film layer is 10 to 20 microns.
[0020] Compared with the prior art, the technical scheme of the patent has at least the following beneficial effects:
[0021] The technical scheme of the patent forms a thin film with a relatively stable inclination angle, can meet the product parameter requirements, and is convenient for subsequent sputtering deposition of a magnetic metal film layer.
[0022] The etching is performed in a high pressure and low physical bombardment mode, and the purpose is to reduce the particle free path by high cavity pressure to reduce the physical bombardment. CF4 is used as the main etching gas, and CHF3 is used as the auxiliary gas to improve the C / F ratio and protect the sidewall. A certain amount of O2 is introduced to adjust the overall morphology of the silicon dioxide film, and the O2 flow is adjusted to affect the consumption of the photoresist to adjust and optimize the top line width and sidewall angle. The etching is performed by adjusting the pressure, gas type, flow ratio and other parameters to obtain a stable small-angle sidewall tilt morphology.
[0023] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS
[0024] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.
[0025] Figure 1 It is a schematic diagram of the thin film sidewall small-angle structure of the present application. DETAILED DESCRIPTION
[0026] The embodiments of the present application will be described in detail below, and the technical solutions of the embodiments of the present application will be described completely and clearly. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.
[0027] Please refer to Figure 1 As Figure 1 shown, the present application provides a preparation method of thin film sidewall small-angle, and the specific steps are as follows:
[0028] S1: using thin film chemical vapor deposition process, growing 3-6um silicon dioxide film on the surface of silicon wafer or glass substrate, and then coating 2-10um thickness of photoresist on the silicon dioxide film through photoetching process to form photoresist layer;
[0029] S2: exposing and developing the photoresist layer, and when developing, the exposed area of the photoresist layer is removed by the developing solution to form 10-20um wide photoresist line;
[0030] S3: After development, bake at 100-150℃ for 200-400 seconds, then cool to room temperature.
[0031] S4: After cooling, the silicon dioxide film is etched. The area of the silicon dioxide film that is etched is the area of the exposed silicon dioxide film after the photoresist layer is removed. After etching, silicon dioxide lines with linewidth are obtained.
[0032] S5: After etching, the photoresist layer covering the silicon dioxide film is removed by dry etching, and then wet cleaning is performed to obtain the exposed silicon dioxide line structure with tilted morphology 1.
[0033] The tilt angle of the thin film formed by this patented technology is relatively stable, which can meet the product parameter requirements and facilitate the subsequent magnetron sputtering deposition of magnetic metal film layers.
[0034] In this example, the photoresist used is an AZ series positive photoresist. The preferred photoresist layer thickness is 2–10 μm.
[0035] In a preferred embodiment, in step S1, the thin film chemical vapor deposition process conditions are: the chamber pressure range is 1 to 4 Torr, the working gases used include SiH4, N2 and N2O, and the flow rate ratio of SiH4, N2 and N2O is 1:5:30.
[0036] In the example, a silicon dioxide film is grown on the surface of a silicon wafer or glass substrate using a thin-film chemical vapor deposition process.
[0037] Preferably, in step S2, the developing process uses TMAH developing solution for 100-200 seconds.
[0038] In the example, baking is a single-step baking process.
[0039] Preferably, after baking, the transverse cross-section of the photoresist layer has an arched shape.
[0040] In a preferred embodiment, in step S4, the etching chamber pressure ranges from 200 to 500 mTorr. The etching process employs a high-pressure, low-physical-bombardment method, the purpose of which is to reduce the particle free path and thus mitigate physical bombardment through high chamber pressure. In this example, a magnetically enhanced reactive ion etching (MEI) machine is used for etching.
[0041] Preferably, in step S4, the etching gas includes CF4 and CHF3, and the gas flow ratio of CF4 to CHF3 is 2:1 to 3:2. CF4 serves as the main etching gas, assisting CHF3 gas to increase the C / F ratio, thereby protecting the sidewalls.
[0042] Further preferably, the etching gas also includes O2, with an O2 to CF4 gas flow rate ratio of 1:4 to 1:3. A certain amount of O2 is introduced to adjust the overall morphology of the silicon dioxide film. Fine-tuning the O2 flow rate affects the photoresist consumption, thereby optimizing the top linewidth, sidewall angle, and other parameters. The etching process achieves a stable, small-angle sidewall tilt morphology by adjusting parameters such as pressure, gas type, and flow rate ratio.
[0043] Preferably, in step S2, a silicon dioxide film layer with a certain linewidth is formed after etching. The linewidth of the silicon dioxide film layer with a certain linewidth is the bottom linewidth on the side closer to the silicon wafer, and the linewidth on the side farther from the silicon wafer is the top linewidth. The ratio of the bottom linewidth to the top linewidth is 1:3 to 3:7, and the tilt angle of the sidewall is in the range of 20 to 50°.
[0044] Example 1
[0045] S1: Thin film chemical vapor deposition process is adopted, the chamber pressure is 4 Torr, the working gas includes SiH4, N2 and N2O, the flow ratio of SiH4, N2 and N2O is 1:5:30, a 6um silicon dioxide film layer is grown on the surface of silicon wafer or glass substrate, and then AZ positive photoresist is coated on the silicon dioxide film layer by photolithography to form a 6um thick photoresist layer;
[0046] S2: Expose the photoresist layer and then develop it with TMAH developer for 200 seconds. The exposed area on the photoresist layer is removed by the developer, and after development, a photoresist line with a width of 15um-20um is formed.
[0047] S3: After development, bake at 110℃ for 400 seconds, then cool to room temperature.
[0048] S4: After cooling, the silicon dioxide film is etched. The etching chamber pressure is 400 mTorr. The etching gases include CF4, CHF3 and O2. The gas flow ratio of CF4 and CHF3 is 3:2, and the gas flow ratio of O2 and CF4 is 1:4. The area of the silicon dioxide film that is etched is the area of the exposed silicon dioxide film after the photoresist layer is removed. After etching, silicon dioxide lines with a linewidth of 15um-20um are obtained.
[0049] S5: After etching, the photoresist layer covering the silicon dioxide film is removed by dry etching, and then wet cleaning is performed to obtain the exposed silicon dioxide line structure 1 with an inclined morphology. The test results show that the bottom line width to the top line width ratio of the silicon dioxide line structure is about 3:7, and the tilt angle of the sidewall is about 30°.
[0050] It should be noted that, unless otherwise specified, the features in the above embodiments or embodiments described herein can be combined.
[0051] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.
[0052] Although embodiments of the invention have been shown and described above, it is to be understood that these embodiments are exemplary, and it will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
Claims
1. A method for producing a thin film side wall with a small angle, characterized by, The specific steps are as follows: S1: using a thin film chemical vapor deposition process, growing a 3-6um silicon dioxide film layer on the surface of a silicon wafer or a glass substrate, and then coating a 2-10um thick photoresist layer on the silicon dioxide film layer through a photolithography process to form a photoresist layer; S2: exposing and developing the photoresist layer, during the developing process, the exposed area of the photoresist layer is removed by the developing solution, forming a 10-20um wide photoresist line; S3: after developing, baking at a temperature of 100-150℃ for 200-400S, and then cooling to room temperature; S4: after cooling, etching the silicon dioxide film layer, the area of the silicon dioxide film layer that is etched is the area of the silicon dioxide film layer exposed after removing the photoresist layer, and a silicon dioxide line with a line width is obtained after etching; S5: after etching, the photoresist layer covering the silicon dioxide film layer is removed by dry etching, and then wet cleaning is performed to obtain a bare silicon dioxide line structure with an inclined morphology.
2. The production method according to claim 1, characterized by, In step S4, the chamber pressure during etching is 200-500mTorr; and / or The etching is performed using a magnetic enhanced reactive ion etching machine.
3. The production method according to claim 1 or 2, characterized by, In step S4, the etching gas includes CF4 and CHF3, and the gas flow ratio of CF4 to CHF3 is 2:1-3:
2.
4. The production method according to claim 3, characterized by, The etching gas also includes O2, and the gas flow ratio of O2 to CF4 is 1:4-1:
3.
5. The method of claim 1, wherein, In step S1, the conditions of the thin film chemical vapor deposition process are as follows: the chamber pressure is 1-4Torr, the working gas used includes SiH4, N2 and N2O, and the flow ratio of SiH4, N2 and N2O is 1:5:
30.
6. The method of claim 1, wherein, In step S2, the developing is performed using a TMAH developing solution for 100-200S.
7. The preparation method according to claim 1, characterized in that, After baking, the lateral cross-section of the photoresist layer has an arch-shaped morphology.
8. The method of claim 1, wherein, In step S4, after etching, a silicon dioxide film layer with a certain line width is formed, the line width of the silicon dioxide film layer near the silicon wafer side is the bottom line width, the line width of the silicon dioxide film layer away from the silicon wafer side is the top line width, the ratio of the bottom line width to the top line width is 1:3-3:7, and the inclination angle of the sidewall is in the range of 20-50°.
9. The production method according to claim 8, characterized by, The line width of the silicon dioxide film layer after etching is 10-20um.