Masking method for silicon carbide components
The method addresses the challenge of achieving high adhesion and selectivity in silicon carbide etching by forming an aluminum coating, mechanically removing excess aluminum, and forming an aluminum fluoride film to protect normal regions during etching.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- DRY CHEM CO LTD
- Filing Date
- 2026-05-25
- Publication Date
- 2026-07-23
AI Technical Summary
Existing masking methods for silicon carbide components during etching processes fail to achieve high adhesion and selectivity due to silicon carbide's stable nature, necessitating improved masking techniques for selective etching.
A method involving aluminum coating layer formation, mechanical removal of excess aluminum, and subsequent fluorination to form an aluminum fluoride film, which acts as a mask for selective etching.
The method achieves high adhesion and selectivity in etching processes by using aluminum as a mask, protecting normal regions while allowing etching in abnormal growth areas.
Smart Images
Figure 0007894199000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a masking method for silicon carbide members.
Background Art
[0002] It is known that the removal of an epitaxial layer in a silicon carbide member used for semiconductor manufacturing or the like is performed for the regeneration of defective wafers or the reuse of the substrate by removing unnecessary growth layers. At this time, masking in the formation of the epitaxial layer is required to grow crystals only in specific regions or to protect specific regions.
[0003] In particular, masking for CVD-SiC (chemical vapor deposition silicon carbide) is mainly required when finely processing silicon carbide having high hardness and high corrosion resistance by dry etching or the like.
[0004] Conventionally, a method for removing an epitaxial layer that has grown abnormally locally on the surface of a wafer subjected to a CVD film formation process is known (for example, see Patent Document 1 below). [[ID=2I]]
[0005] [[ID=z3]] In this method, a plastic film thinner than the height of the abnormally grown epitaxial layer is attached to the surface of the wafer, and a surface grinding process is performed to remove the abnormally grown epitaxial layer together with a part of the plastic film. [[ID=z5]]
Prior Art Documents
Patent Documents
[0006]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0007] However, because silicon carbide is a stable material, when used as a mask during etching, it was required to have high adhesion and a high selectivity ratio (ratio of ease of etching to SiC).
[0008] In view of the above, the present invention aims to provide a method for masking silicon carbide members that can achieve high adhesion and selectivity. [Means for solving the problem]
[0009] To achieve this objective, the present invention provides a method for masking a silicon carbide member, comprising: an aluminum coating layer formation step of forming an aluminum coating layer on the silicon carbide surface of the silicon carbide member; and an aluminum coating layer removal step of mechanically removing unnecessary areas of the aluminum coating layer and using the remaining aluminum coating layer as a mask.
[0010] Furthermore, in the aluminum coating layer formation step, it is preferable that the thickness of the aluminum coating layer be 3μ to 5μ.
[0011] Furthermore, in the present invention, it is preferable to include a fluorination step in which an aluminum fluoride film is formed on the surface of the aluminum coating layer formed as a mask by the aluminum coating layer removal step. [Effects of the Invention]
[0012] Through various tests, the inventors have found that aluminum is suitable for obtaining a coating layer with high adhesion to silicon carbide components. This invention is based on that finding.
[0013] According to the present invention, in the aluminum coating layer formation process, an aluminum coating layer is formed on the silicon carbide surface of the silicon carbide member (preferably all surfaces of the silicon carbide member, for example, by dipping) by, for example, plating. As a result, an aluminum coating layer is formed even in the portion where the epitaxial layer has grown abnormally (unnecessary region).
[0014] Next, in the aluminum coating layer removal process, the aluminum coating layer in the areas where the epitaxial layer has grown abnormally (unnecessary regions) is mechanically removed by blasting or the like.
[0015] This allows etching to occur when an etching gas, such as chlorine trifluoride, is applied to the areas where the epitaxial layer has grown abnormally. On the other hand, the areas where the aluminum coating layer remains are protected from the reaction by the etching gas, thus protecting the surfaces without abnormal growth, and thus allowing for selectivity.
[0016] As described above, by using the aluminum coating layer as a masking layer on the silicon carbide component, high adhesion and selectivity can be obtained. [Brief explanation of the drawing]
[0017] [Figure 1] An explanatory cross-sectional view showing a silicon carbide member that has undergone the aluminum coating layer formation process. [Figure 2] An explanatory cross-sectional view showing a silicon carbide component after the aluminum coating layer removal process. [Figure 3] An explanatory cross-sectional view showing a silicon carbide component that has undergone a fluorination process. [Modes for carrying out the invention]
[0018] Embodiments of the present invention will be described based on the drawings. The masking method of the present invention first involves a first step (aluminum coating layer formation step) in which an aluminum coating layer 2 is formed on the entire surface of a silicon carbide member 1, as shown in Figure 1. Next, a second step (aluminum coating layer removal step) is performed in which an unwanted area 3 of the aluminum coating layer 2 is removed, as shown in Figure 2. Furthermore, a third step (fluorination step) is performed in which an aluminum fluoride film 4 is formed on the surface of the aluminum coating layer 2, as shown in Figure 3.
[0019] Next, each of the above steps will be described. In the first step, as shown in FIG. 1, the aluminum coating layer 2 can be formed by applying aluminum plating to the entire surface of the silicon carbide member 1.
[0020] At this time, an aluminum coating layer 2 formed by plating is also formed on the outer surface of the portion where the epitaxial layer formed on the outer surface of the silicon carbide member 1 has grown abnormally. The portion where the epitaxial layer has grown abnormally is the unnecessary region 3 in the present embodiment.
[0021] In the second step, as shown in FIG. 2, the aluminum coating layer 2 in the unnecessary region 3 is removed. At this time, the aluminum coating layer 2 in the unnecessary region 3 is removed by grinding (i.e., mechanically) using, for example, shot blasting or a grinder. As a result, the aluminum coating layer 2 in the unnecessary region 3 (i.e., the portion where the epitaxial layer has grown abnormally) is removed, and the aluminum coating layer 2 in the other portions remains as a masked region.
[0022] In the first step, it is preferable that the thickness of the aluminum coating layer 2 formed by plating is 3 μm to 5 μm. If the thickness of the aluminum coating layer 2 is less than 3 μm, not only the durability against external forces is extremely reduced, but there is also a possibility that the subsequent fluorination will not be sufficiently performed. If the thickness of the aluminum coating layer 2 is greater than 5 μm, the boundary between the abnormal growth region and the normal region of the epitaxial layer will not be clear, and there is a possibility of a decrease in accuracy in the second step. Therefore, in the present embodiment, the thickness of the aluminum coating layer 2 is set within the range of 3 μm to 5 μm.
[0023] In the third step, as shown in FIG. 3, an aluminum fluoride film 4 is formed on the surface of the aluminum coating layer 2 of the portion remaining as the masking region by the second step. The aluminum fluoride film 4 is formed by fluorinating about 1 μm of the surface of the aluminum coating layer 2 by heat-treating an etching gas such as chlorine trifluoride at 300°C to 500°C.
[0024] In the third step, the aluminum fluoride film 4 becomes a non-conductive coating, allowing it to withstand etching gas treatment and enabling selective etching. [Explanation of symbols]
[0025] 1…Silicon carbide component 2…Aluminum coating layer 3…Unnecessary area 4…Aluminum fluoride film
Claims
1. An aluminum coating layer formation step, in which an aluminum coating layer is formed on the silicon carbide surface of a silicon carbide member, A method for masking a silicon carbide member, characterized by comprising an aluminum coating layer removal step of mechanically removing unnecessary areas of the aluminum coating layer and using the remaining aluminum coating layer as a mask.
2. The method for masking a silicon carbide member according to claim 1, characterized in that the thickness of the aluminum coating layer in the aluminum coating layer formation step is 3 μm to 5 μm.
3. The method for masking a silicon carbide member according to claim 1 or 2, further comprising a fluorination step of forming an aluminum fluoride film on the surface of the aluminum coating layer formed as a mask by the aluminum coating layer removal step.