Method for manufacturing a semiconductor device and a semiconductor device.
The method simplifies semiconductor manufacturing by patterning a second protective film to expose the first film during back surface processing, eliminating the need for protective tape and reducing costs and time.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2024-12-06
- Publication Date
- 2026-06-18
AI Technical Summary
Existing semiconductor manufacturing processes require the application and removal of protective films, which increase material costs and manufacturing time.
A method involving the use of a first and second protective film, where the second protective film is patterned to expose the first film, allowing back surface processing without additional protective tape, simplifying the manufacturing process.
Simplifies the manufacturing process by eliminating the need for protective tape application and removal, reducing material costs and time.
Smart Images
Figure 2026099130000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a method for manufacturing a semiconductor device and a semiconductor device.
Background Art
[0002] Patent Document 1 discloses a method for manufacturing a semiconductor device. In this manufacturing method, a surface structure of a semiconductor device is formed on the surface of a semiconductor wafer, and the surface of the semiconductor wafer is coated with a protective film except for a region where a wire is fixed during mounting in the surface structure. Next, the back surface of the semiconductor wafer covered with the protective film is ground. During back grinding, an adhesive tape is attached to the surface of the semiconductor wafer.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In Patent Document 1, in order to make the semiconductor substrate have a desired thickness, the back surface of the semiconductor substrate is ground. At this time, it is necessary to cover the surface of the semiconductor substrate with a protective film such as an adhesive tape so as not to be damaged during grinding. This protective film is peeled off after the processing of the back surface of the semiconductor substrate is completed. There has been a demand for simplifying the process of forming such a protective film and the process of removing the protective film to suppress material costs and manufacturing time.
[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a method for manufacturing a semiconductor device and a semiconductor device that can simplify the manufacturing process.
Means for Solving the Problems
[0006] A method for manufacturing a semiconductor device according to the present disclosure involves forming an electrode on the main surface of a semiconductor substrate having a main surface and a back surface opposite to the main surface, forming a first protective film on the electrode and the semiconductor substrate, forming a second protective film on the first protective film, patterning a portion of the second protective film formed directly above an exposed portion including a part of the electrode or a part of the semiconductor substrate to expose a portion of the first protective film formed directly above the exposed portion from the second protective film, processing the back surface of the semiconductor substrate after patterning the second protective film, and removing the patterned portion of the second protective film together with the portion of the first protective film formed directly above the exposed portion to expose the exposed portion from the first and second protective films.
[0007] The semiconductor device according to this disclosure comprises a semiconductor substrate having a main surface and a back surface opposite to the main surface, an electrode formed on the main surface of the semiconductor substrate, a first protective film formed on the electrode and the semiconductor substrate, and a second protective film formed on the first protective film, wherein an exposed portion is formed on a part of the electrode or a part of the semiconductor substrate that is exposed from the first protective film and the second protective film, and a cavity is formed between the end of the second protective film adjacent to the exposed portion and the exposed portion. [Effects of the Invention]
[0008] In the semiconductor device manufacturing method according to this disclosure, by patterning the portion of the second protective film formed directly above the exposed area, a portion of the first protective film formed directly above the exposed area becomes exposed from the second protective film. By processing the back surface in this state, the main surface of the semiconductor substrate can be protected by the second protective film while processing the back surface. Therefore, since there is no need to apply protective tape, the manufacturing process can be simplified. The semiconductor device relating to this disclosure can be manufactured by the simplified manufacturing process described above. [Brief explanation of the drawing]
[0009] [Figure 1]This is a diagram illustrating the manufacturing method of a semiconductor device according to Embodiment 1. [Figure 2] This is a diagram illustrating the manufacturing method of a semiconductor device according to Embodiment 1. [Figure 3] This is a diagram illustrating the manufacturing method of a semiconductor device according to Embodiment 1. [Figure 4] This is a cross-sectional view of the semiconductor device according to Embodiment 1. [Figure 5] This is a plan view of the semiconductor device according to Embodiment 1. [Figure 6] This is a flowchart illustrating the manufacturing method of a semiconductor device according to Embodiment 1. [Figure 7] This is an enlarged view of the semiconductor device according to Embodiment 1. [Figure 8] This is an enlarged view of the semiconductor device according to Embodiment 1. [Figure 9] This is a diagram illustrating the manufacturing method of a semiconductor device according to a comparative example. [Figure 10] This is a diagram illustrating the manufacturing method of a semiconductor device according to a comparative example. [Figure 11] This is an enlarged view of the semiconductor device according to the comparative example. [Figure 12] This is an enlarged view of the semiconductor device according to the comparative example. [Figure 13] This figure shows an example of the patterned portion of the second protective film according to Embodiment 2. [Figure 14] This figure shows an example of the patterned portion of the second protective film according to Embodiment 2. [Figure 15] This is a diagram illustrating the manufacturing method of a semiconductor device according to Embodiment 3. [Figure 16] This is a cross-sectional view of the semiconductor device according to Embodiment 3. [Figure 17] This is a diagram illustrating the manufacturing method of a semiconductor device according to Embodiment 4. [Figure 18] This is a diagram illustrating the manufacturing method of a semiconductor device according to Embodiment 4. [Figure 19] This is a cross-sectional view of the semiconductor device according to Embodiment 4. [Figure 20]It is a flowchart for explaining a method of manufacturing a semiconductor device according to Embodiment 4. [Figure 21] It is an enlarged view of the semiconductor device according to Embodiment 4. [Figure 22] It is an enlarged view of the semiconductor device according to Embodiment 4.
Embodiments for Carrying out the Invention
[0010] The method of manufacturing a semiconductor device and the semiconductor device according to each embodiment will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and the repeated description may be omitted.
[0011] Embodiment 1. FIGS. 1 - 3 are diagrams for explaining a method of manufacturing a semiconductor device 100 according to Embodiment 1. FIG. 4 is a cross-sectional view of the semiconductor device 100 according to Embodiment 1. FIG. 5 is a plan view of the semiconductor device 100 according to Embodiment 1. FIG. 6 is a flowchart for explaining a method of manufacturing the semiconductor device 100 according to Embodiment 1. The method of manufacturing the semiconductor device 100 of the present embodiment will be described using FIGS. 1 - 6.
[0012] First, as shown in FIG. 1, electrodes 12, 14, 15 are formed on the main surface of a semiconductor substrate 10 having a main surface and a back surface opposite to the main surface (Step 1). For example, electrode 12 is a gate electrode, electrode 14 is a source electrode, and electrode 15 is a drain electrode. Note that various semiconductor layers are previously formed on the semiconductor substrate 10. Next, a first protective film 20 is formed on electrodes 12, 14, 15 and the semiconductor substrate 10 (Step 2). The first protective film 20 is, for example, a silicon oxide film or a silicon nitride film.
[0013] Next, a second protective film 30 is formed on the first protective film 20 (step 3). The second protective film 30 is, for example, a polyimide film or a polybenzoxazole (PBO) film. Next, as shown in Figures 2 and 3, a portion of the second protective film 30 is patterned to form patterned portions 32 and 34 (step 4). Figures 2 and 3 are a cross-sectional view and a plan view, respectively, showing a portion of the second protective film 30 after patterning.
[0014] Here, the portion of the upper surface of the electrode 12 that is ultimately exposed from the first protective film 20 and the second protective film 30 is called the exposed portion 16. In other words, the exposed portion 16 is a part of the electrode 12. The exposed portion 16 is, for example, the part to which wiring is bonded during product assembly. Also, the portion of the main surface of the semiconductor substrate 10 that is ultimately exposed from the first protective film 20 and the second protective film 30 is called the exposed portion 18. The exposed portion 18 is formed at the chip termination of the semiconductor substrate 10. The exposed portion 18 is the part corresponding to the dicing line in the dicing process of cutting a semiconductor chip from a wafer. In this embodiment, an example in which both exposed portions 16 and 18 are formed is described, but it is sufficient if exposed portions are formed on at least a part of the electrodes 12, 14, and 15 or a part of the semiconductor substrate 10.
[0015] In step 4, the portion of the second protective film 30 formed directly above the exposed portions 16 and 18 is patterned, exposing a portion of the first protective film 20 formed directly above the exposed portions 16 and 18 from the second protective film 30. In other words, the patterned portions 32 and 34 are formed directly above the exposed portions 16 and 18, respectively. The patterned portions 32 and 34 are patterned with a structure and dimensions that ensure surface protection in step 5, described later, and that allow the second protective film 30 to be lifted off in step 6.
[0016] Next, after patterning the second protective film 30 (step 4), the back surface of the semiconductor substrate 10 is processed (step 5). The back surface of the semiconductor substrate 10 is processed without attaching protective tape to the second protective film 30. In other words, the back surface is processed while the main surface of the semiconductor substrate 10 is protected by the second protective film 30, which is a polyimide film or the like. The back surface processing is carried out by inverting the wafer. The back surface processing is, for example, grinding the semiconductor substrate 10. The back surface processing may also include forming a semiconductor layer on the back side, forming back surface electrodes, etc.
[0017] Next, after processing the back surface of the semiconductor substrate 10, the patterned portions 32 and 34 of the second protective film 30 are removed along with the portion of the first protective film 20 formed directly above the exposed portions 16 and 18 (step 6). Specifically, the first protective film 20 is wet-etched using the second protective film 30 as a mask. The etching solution is one that reacts with the first protective film 20 but not with the second protective film 30. For example, if the first protective film 20 is SiO2, hydrogen fluoride can be used as the etching solution. If the first protective film 20 is SiN, phosphoric acid (H3PO4) can be used as the etching solution. As a result, the portion of the first protective film 20 directly below the patterned portions 32 and 34 is removed. In addition, the portion of the first protective film 20 other than the portion directly below the patterned portions 32 and 34 is not etched because it is completely covered by the second protective film 30.
[0018] In this process, the patterned portions 32 and 34 of the second protective film 30 are also removed along with the first protective film 20 directly beneath it. In other words, the patterned portions 32 and 34 of the second protective film 30 are lifted off. As a result, as shown in Figures 4 and 5, the exposed portions 16 and 18 can be exposed from the first protective film 20 and the second protective film 30.
[0019] Figures 7 and 8 are enlarged views of the semiconductor device 100 according to Embodiment 1. Figure 7 is an enlarged view of the end of the exposed portion 16, and Figure 8 is an enlarged view of the end of the exposed portion 18. In step 6, the first protective film 20 is over-etched. As a result, a cavity 22 is formed between the end of the second protective film 30 adjacent to the exposed portion 16 and the exposed portion 16. The same applies to the exposed portion 18. In other words, the end of the first protective film 20 is recessed relative to the end of the second protective film 30. The height of the cavity 22 is approximately the same as the thickness of the first protective film 20. In this embodiment, the end faces of the first protective film 20 adjacent to the exposed portions 16 and 18 are exposed from the second protective film 30. The depth of the cavity 22 can be controlled by patterning the second protective film 30. Basically, the cavity 22 is created by over-etching, but it is also possible to create a structure without a cavity 22.
[0020] Figures 9 and 10 illustrate the manufacturing method of the semiconductor device 800 according to the comparative example. Figure 9 shows the state before back surface processing. The comparative example differs from this embodiment in that the exposed parts 16 and 18 are exposed from the first protective film 20 and the second protective film 30 before back surface processing. By covering the electrodes 14 and 15 around the electrode 12 with a protective film, the semiconductor device 800 can be protected and its voltage resistance maintained.
[0021] Next, the back surface of the semiconductor substrate 10 is ground to achieve the desired thickness. At this time, the surface of the semiconductor substrate 10 needs to be covered with a protective film to prevent damage during grinding. In this case, the second protective film 30 has openings formed for bonding, etc. Therefore, the second protective film 30 in the comparative example does not have the function of protecting the surface during back surface processing. Thus, as shown in Figure 10, a protective tape 840 is further applied. After the back surface processing, including grinding, is completed, the protective tape 840 is peeled off. Therefore, the process of forming the protective tape 840 and the process of removing the protective tape 840 are required, which may increase material costs and manufacturing time.
[0022] Figures 11 and 12 are enlarged views of the semiconductor device 800 according to the comparative example. Figure 11 is an enlarged view of the end of the exposed portion 16, and Figure 12 is an enlarged view of the end of the exposed portion 18. In the comparative example, the first protective film 20 directly above the exposed portions 16 and 18 is removed, then the second protective film 30 is formed, and then the second protective film directly above the exposed portions 16 and 18 is removed. In this case, the first protective film 20 is not exposed. Also, a cavity 22 due to over-etching as in this embodiment does not occur.
[0023] Next, the effects of this embodiment will be described. In this embodiment, the back surface is processed with the patterned portions 32 and 34 formed on the second protective film 30. At this time, the main surface of the semiconductor substrate 10 can be protected by the second protective film 30 while the back surface is processed. By giving the second protective film 30 the function of protecting the wafer surface, the conventional process of forming a protective tape and the process of removing the protective tape can be omitted. Therefore, the manufacturing process can be simplified, and material costs and manufacturing time can be reduced.
[0024] As a variation of this embodiment, the structure of the semiconductor substrate 10 itself, the number of electrodes, the material of the electrode protective film, etc., can be changed as appropriate. Furthermore, the semiconductor substrate 10 may be, for example, a silicon substrate, or it may be formed from a wide-bandgap semiconductor. Wide-bandgap semiconductors include, for example, silicon carbide, gallium nitride-based materials, or diamond.
[0025] The modifications described above can be appropriately applied to the semiconductor device manufacturing method and semiconductor device according to the following embodiments. Since the semiconductor device manufacturing method and semiconductor device according to the following embodiments have many similarities with Embodiment 1, the differences from Embodiment 1 will be the focus of this explanation.
[0026] Embodiment 2. Figures 13 and 14 show examples of patterned portions 32 of the second protective film 30 according to Embodiment 2. The patterned portions 32 need to be formed so that the surface of the semiconductor substrate 10 can be protected by the second protective film 30 during back surface processing of the semiconductor substrate 10. Furthermore, the patterned portions 32 need to be formed so that the patterned portions 32 are completely removed when lift-off occurs, that is, so that the chemical solution can reach the underlying first protective film 20. For this reason, the patterned portions 32 need to be formed so that a part of the portion of the second protective film 30 formed directly above the exposed portion 16 is open.
[0027] Specifically, from the viewpoint of surface protection of the semiconductor substrate 10, the coverage area of the first protective film 20 by the patterning portion 32 should be of a certain size. Also, from the viewpoint of lift-off, it is preferable that the coverage area of the first protective film 20 by the patterning portion 32 be small. It is preferable that, for example, 10% or more of the area of the first protective film 20 directly above the exposed portion 16 is covered by the second protective film 30. Preferably, about 50% of the area of the first protective film 20 directly above the exposed portion 16, specifically 40% to 60%, is covered by the second protective film 30.
[0028] From the above perspective, it is preferable to pattern the second protective film 30 in a mesh, grid, dot, island, or stripe pattern. In the example in Figure 13, the second protective film 30 is patterned in a dot or island pattern. The second protective film 30 can also be described as columnar. In the example in Figure 14, the second protective film 30 is patterned in a mesh or grid pattern. In the example in Figure 14, it can also be described as being formed in a way that linear second protective films 30 intersect. Thus, the patterned portion 32 is formed, for example, by a regular arrangement of the second protective film 30. Here, the patterned portion 32 has been described as an example, but a similar pattern can be applied to the patterned portion 34.
[0029] Embodiment 3. Figure 15 illustrates a method for manufacturing a semiconductor device according to Embodiment 3. Figure 15 shows a state in which a patterned portion 32 is formed on the second protective film 30. The first protective film 20 has different materials in the portion 20a formed directly above the exposed portions 16 and 18 and the other portion 20b. The other configurations are the same as those of Embodiment 1. Of the first protective film 20, the portion 20a formed directly above the exposed portions 16 and 18 is, for example, a silicon oxide film, and the other portion 20b is, for example, a silicon nitride film.
[0030] As a method for forming the first protective film 20, first, a SiN film is formed, and then the portion of the SiN film above the exposed parts 16 and 18 is removed. After that, an SiO2 film is formed on the exposed parts 16 and 18.
[0031] Figure 16 is a cross-sectional view of the semiconductor device 200 according to Embodiment 3. In step 6, etching removes the portion formed of SiO2, leaving the portion 20b formed of SiN. SiN has excellent electrode protection properties, and SiO2 is easy to remove. Therefore, in this embodiment, exposed portions 16 and 18 can be formed with high precision, and the electrodes can be reliably protected.
[0032] Embodiment 4. Figures 17 and 18 illustrate a method for manufacturing the semiconductor device 300 according to Embodiment 4. Figure 19 is a cross-sectional view of the semiconductor device 300 according to Embodiment 4. Figure 20 is a flowchart illustrating a method for manufacturing the semiconductor device 300 according to Embodiment 4. Steps 1 and 2 are the same as steps 1 and 2 of Embodiment 1. In this embodiment, as shown in Figure 17, an opening 24 is formed at a position adjacent to the portion of the first protective film 20 formed directly above the exposed portions 16 and 18 (step 2a). The opening 24 can also be said to be formed at the boundary between the exposed portions 16 and 18 and the region where the first protective film 20 remains. The opening 24 can be formed by etching.
[0033] Subsequently, the second protective film 30 is formed (step 3). As shown in Figure 18, when forming the second protective film 30, the opening 24 is filled with the second protective film 30. In other words, the second protective film 30 and the electrode 12 or semiconductor substrate 10 are in direct contact at the opening 24. Steps 4-6 are the same as steps 4-6 of Embodiment 1. Note that when removing the patterned portion of the second protective film 30 and the portion of the first protective film 20 formed directly above the exposed portions 16 and 18 in step 6, the portion of the second protective film 30 that filled the opening 24 remains.
[0034] Figures 21 and 22 are enlarged views of the semiconductor device according to Embodiment 4. Figure 21 is an enlarged view of the end of the exposed portion 16, and Figure 22 is an enlarged view of the end of the exposed portion 18. Similar to Embodiment 1, in step 6, the first protective film 20 is over-etched. As a result, a cavity 22 is formed between the end of the second protective film 30 adjacent to the exposed portion 16 and the exposed portion 16. The same applies to the exposed portion 18. In addition, the end faces of the first protective film 20 adjacent to the exposed portions 16 and 18 are covered by the second protective film 30. The portion of the second protective film 30 that covers the end faces of the first protective film 20 corresponds to the portion of the second protective film 30 in which the opening 24 is embedded.
[0035] In this embodiment, since the opening 24 is filled with the second protective film 30, over-etching of the first protective film 20 during lift-off can be suppressed. In other words, the portion of the second protective film 30 that fills the opening 24 can stop the etching of the first protective film 20. Therefore, the lifting of the second protective film 30 can be reduced. In addition, the shape of the edges of the second protective film 30 can be controlled, and exposure of the first protective film 20 can be prevented.
[0036] The various aspects of this disclosure are summarized below as an appendix. (Note 1) An electrode is formed on the main surface of a semiconductor substrate having a main surface and a back surface opposite to the main surface. A first protective film is formed on the electrode and the semiconductor substrate. A second protective film is formed on the first protective film. The portion of the second protective film formed directly above the exposed portion, including a part of the electrode or a part of the semiconductor substrate, is patterned to expose a portion of the first protective film formed directly above the exposed portion from the second protective film. After patterning the second protective film, the back surface of the semiconductor substrate is processed. A method for manufacturing a semiconductor device, characterized in that, after processing the back surface of the semiconductor substrate, the patterned portion of the second protective film is removed together with the portion of the first protective film formed directly above the exposed portion, thereby exposing the exposed portion from the first protective film and the second protective film. (Note 2) The method for manufacturing a semiconductor device according to Appendix 1, characterized in that the processing of the back surface is carried out without attaching protective tape to the second protective film. (Note 3) The method for manufacturing a semiconductor device according to Appendix 1 or 2, characterized in that the exposed portion includes a part of the electrode. (Note 4) A method for manufacturing a semiconductor device according to any one of appendices 1 to 3, characterized in that the exposed portion includes the chip termination portion of the semiconductor substrate. (Note 5) A method for manufacturing a semiconductor device according to any one of the appendices 1 to 4, characterized in that the second protective film is patterned in a mesh, grid, dot, island, or stripe pattern. (Note 6) The method for manufacturing a semiconductor device according to any one of Appendix 1 to 5, characterized in that the second protective film is a polyimide film or a polybenzoxazole film. (Note 7) A method for manufacturing a semiconductor device according to any one of appendices 1 to 6, characterized in that the first protective film is a silicon oxide film or a silicon nitride film. (Note 8) The method for manufacturing a semiconductor device according to any one of the appendices 1 to 7, characterized in that the first protective film has different materials in the portion formed directly above the exposed portion and in other portions. (Note 9) The method for manufacturing a semiconductor device according to Appendix 8, characterized in that the portion of the first protective film formed directly above the exposed portion is a silicon oxide film, and the other portion is a silicon nitride film. (Note 10) A method for manufacturing a semiconductor device according to any one of the appendices 1 to 9, characterized in that an opening is formed in the first protective film at a position adjacent to the portion formed directly above the exposed portion, and then the second protective film is formed. (Note 11) When forming the second protective film, the opening is filled with the second protective film. The method for manufacturing a semiconductor device according to Appendix 10, characterized in that when the patterned portion of the second protective film and the portion of the first protective film formed directly above the exposed portion are removed, the portion of the second protective film in which the opening is filled remains. (Note 12) A semiconductor substrate having a main surface and a back surface opposite to the main surface, An electrode formed on the main surface of the semiconductor substrate, The electrode and the first protective film formed on the semiconductor substrate, A second protective film formed on the first protective film, Equipped with, An exposed portion is formed on a part of the electrode or a part of the semiconductor substrate that is exposed from the first protective film and the second protective film. A semiconductor device characterized in that a cavity is formed between the end of the second protective film adjacent to the exposed portion and the exposed portion. (Note 13) The semiconductor device according to Appendix 12, characterized in that the end face of the first protective film adjacent to the exposed portion is exposed from the second protective film. (Note 14) The semiconductor device according to Appendix 12, characterized in that the end face of the first protective film adjacent to the exposed portion is covered by the second protective film. (Note 15) The semiconductor device according to any one of appendices 12 to 14, characterized in that the semiconductor substrate is formed of a wide-bandgap semiconductor. (Note 16) The semiconductor device according to Appendix 15, characterized in that the wide-bandgap semiconductor is silicon carbide, gallium nitride-based material, or diamond. [Explanation of symbols]
[0037] 10 Semiconductor substrate, 12, 14, 15 Electrodes, 16, 18 Exposed parts, 20 First protective film, 22 Cavity, 24 Opening, 30 Second protective film, 32, 34 Patterning parts, 100, 200, 300, 800 Semiconductor device, 840 Protective tape
Claims
1. An electrode is formed on the main surface of a semiconductor substrate having a main surface and a back surface opposite to the main surface. A first protective film is formed on the electrode and the semiconductor substrate. A second protective film is formed on the first protective film. The portion of the second protective film formed directly above the exposed portion, including a part of the electrode or a part of the semiconductor substrate, is patterned to expose a portion of the first protective film formed directly above the exposed portion from the second protective film. After patterning the second protective film, the back surface of the semiconductor substrate is processed. A method for manufacturing a semiconductor device, characterized in that, after processing the back surface of the semiconductor substrate, the patterned portion of the second protective film is removed together with the portion of the first protective film formed directly above the exposed portion, thereby exposing the exposed portion from the first protective film and the second protective film.
2. The method for manufacturing a semiconductor device according to claim 1, characterized in that the processing of the back surface is carried out without attaching protective tape to the second protective film.
3. The method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that the exposed portion includes a part of the electrode.
4. The method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that the exposed portion includes the chip termination portion of the semiconductor substrate.
5. The method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that the second protective film is patterned in a mesh, grid, dot, island, or stripe pattern.
6. The method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that the second protective film is a polyimide film or a polybenzoxazole film.
7. The method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that the first protective film is a silicon oxide film or a silicon nitride film.
8. The method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that the first protective film has different materials in the portion formed directly above the exposed portion and in other portions.
9. The method for manufacturing a semiconductor device according to claim 8, characterized in that the portion of the first protective film formed directly above the exposed portion is a silicon oxide film, and the other portion is a silicon nitride film.
10. A method for manufacturing a semiconductor device according to claim 1 or 2, characterized in that an opening is formed in the first protective film at a position adjacent to the portion formed directly above the exposed portion, and then the second protective film is formed.
11. When forming the second protective film, the opening is filled with the second protective film. The method for manufacturing a semiconductor device according to claim 10, characterized in that when the patterned portion of the second protective film and the portion of the first protective film formed directly above the exposed portion are removed, the portion of the second protective film in which the opening is filled remains.
12. A semiconductor substrate having a main surface and a back surface opposite to the main surface, An electrode formed on the main surface of the semiconductor substrate, The electrode and the first protective film formed on the semiconductor substrate, A second protective film formed on the first protective film, Equipped with, An exposed portion is formed on a part of the electrode or a part of the semiconductor substrate that is exposed from the first protective film and the second protective film. A semiconductor device characterized in that a cavity is formed between the end of the second protective film adjacent to the exposed portion and the exposed portion.
13. The semiconductor device according to claim 12, characterized in that the end face of the first protective film adjacent to the exposed portion is exposed from the second protective film.
14. The semiconductor device according to claim 12, characterized in that the end face of the first protective film adjacent to the exposed portion is covered by the second protective film.
15. The semiconductor device according to any one of claims 12 to 14, characterized in that the semiconductor substrate is formed of a wide-bandgap semiconductor.
16. The semiconductor device according to claim 15, characterized in that the wide bandgap semiconductor is silicon carbide, gallium nitride-based material, or diamond.