Semiconductor device and semiconductor module

Abstract

A semiconductor device (10) includes a semiconductor substrate (1) in which a cell portion (11) and a termination portion (12) are defined, an electrode (3) provided on an upper surface of the cell portion (11) of the semiconductor substrate (1), a withstand voltage holding structure (6) provided in the termination portion (12) of the semiconductor substrate (1) and holding a withstand voltage, an insulating protective layer (2) covering an upper surface of the withstand voltage holding structure (6), a waterproof layer (4) covering at least the insulating protective layer (2), and an organic protective layer (5) covering a portion of the waterproof layer (4). The outer peripheral end portion of the electrode (3) sits on the inner peripheral end portion of the insulating protective layer (2). The inner peripheral end portion of the organic protective layer (5) sits on the outer peripheral end portion of the electrode (3).An outer peripheral end of the organic protective layer (5) is located on the inner peripheral side with respect to the outer peripheral end of the insulating protective layer (2).

Description

Background of the inventionField of the invention

[0001] The present disclosure relates to a semiconductor device and a semiconductor module. Description of the state of the art

[0002] For example, Japanese Patent Application Laid-Open No. 2023-27528 discloses a silicon carbide semiconductor device having a structure in which a polyimide protective layer (corresponding to an organic protective layer) is provided on a termination region (corresponding to a termination part) of a semiconductor substrate by interposing a protective oxide layer (corresponding to an insulating protective layer) and a silicon nitride layer (corresponding to a waterproof layer), and an outer peripheral end part of the silicon nitride layer is exposed from the polyimide protective layer.

[0003] When a temperature-humidity bias (THB) test is performed on the semiconductor device described in Japanese Patent Application Laid-Open No. 2023-27528, a crack may occur in the silicon nitride layer due to a step formed in an outer peripheral end portion of the protective oxide layer. Moisture that has entered the semiconductor device penetrates the polyimide protective layer and remains in the crack of the silicon nitride layer, making this portion a starting point for a leakage path to the polyimide protective layer.In this case, since the polyimide protective layer is in contact with the semiconductor device on a high-voltage side, which is an outer peripheral side with respect to the termination region, there is a problem that the polyimide protective layer is subjected to dielectric breakdown when a rated voltage exceeding a test application condition is applied during an insulation test after the completion of the test.

[0004] It is an object of the present disclosure to provide a technique for improving reliability of a semiconductor device by preventing an outer peripheral end of an organic protective layer from becoming a starting point of a leakage path due to retained moisture.

[0005] A semiconductor device according to the present disclosure includes a semiconductor substrate, an electrode, a withstand voltage holding structure, an insulating protective layer, a waterproof layer, and an organic protective layer. A cell portion through which a main current flows and a termination portion surrounding an outer peripheral side of the cell portion are defined in the semiconductor substrate. The electrode is provided on an upper surface of the cell portion of the semiconductor substrate. The withstand voltage holding structure is provided in the termination portion of the semiconductor substrate and withstands a withstand voltage. The insulating protective layer covers an upper surface of the withstand voltage holding structure. The waterproof layer covers at least the insulating protective layer. The organic protective layer covers a part of the waterproof layer.An outer peripheral end portion of the electrode sits on an inner peripheral end portion of the insulating protective layer. An inner peripheral end portion of the organic protective layer sits on the outer peripheral end portion of the electrode. An outer peripheral end of the organic protective layer is located on an inner peripheral side relative to an outer peripheral end of the insulating protective layer.

[0006] Since the outer peripheral end of the organic protective layer is separated from the semiconductor substrate, it is possible to prevent the outer peripheral end of the organic protective layer from becoming a starting point of a leakage path due to retained moisture. As a result, the occurrence of dielectric breakdown of the organic protective layer is prevented, thus improving the reliability of the semiconductor device.

[0007] These and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying figures. Short description of the characters Fig. 1 is a cross-sectional view of a semiconductor module according to a preferred embodiment; Fig. 2 is a cross-sectional view of a main part of a semiconductor device according to the preferred embodiment; Fig. 3 is a cross-sectional view of a main part of a semiconductor device according to the prior art; Fig. 4 is a cross-sectional view illustrating a state before a reliability test of the semiconductor device according to the prior art; Fig. 5 is a cross-sectional view illustrating a state during the reliability test of the semiconductor device according to the prior art; and Fig. 6 is a cross-sectional view illustrating a state during a characteristic check after the reliability test of the semiconductor device according to the prior art. Description of the preferred embodiments<Bevorzugte Ausführungsform>

[0008] A preferred embodiment is described below with reference to the figures. Fig. 1 is a cross-sectional view of a semiconductor module 100 according to a preferred embodiment.

[0009] As in Fig. 1, the semiconductor module 100 includes a container 21, an insulating substrate 22, two semiconductor devices 10, a wire 25, external electrodes 26a and 26b, and a sealing material 27.

[0010] The container 21 includes a metal base plate 31 and a housing 32. The housing 32 has a rectangular shape in plan view and is fixed to a peripheral edge portion of the metal base plate 31. The peripheral edge portion of the metal base plate 31 is fixed to a lower end portion of an inner peripheral portion of the housing 32.

[0011] The insulating substrate 22 includes an insulating layer 22b, a metal pattern 22a provided on a lower surface of the insulating layer 22b, and a circuit pattern 22c provided on an upper surface of the insulating layer 22b, and is connected to the metal base plate 31 in the container 21 by means of a connecting material 24.

[0012] The semiconductor devices 10 are mounted on the insulating substrate 22 by interposing the bonding material 24 therebetween. The bonding material 24 is a sintered bonding material containing silver or copper. Although Fig. 1 illustrates two semiconductor devices 10, the number of semiconductor devices 10 may be one or two or more. Furthermore, the number of external electrodes 26a and 26b is not limited to two.

[0013] One end of the external electrode 26a is connected to the case 32, and the other end of the external electrode 26a is connected to a semiconductor device 10 by interposing the bonding material 24 therebetween. One end of the external electrode 26b is connected to the case 32, and the other end of the external electrode 26b is connected to the circuit pattern 22c of the insulating substrate 22 by interposing a bonding material (not illustrated) therebetween. The bonding material for connecting the external electrode 26b and the circuit pattern 22c is also a sintered bonding material containing silver or copper.

[0014] The wire 25 connects the external electrode 26b and the circuit pattern 22c of the insulating substrate 22, and connects the semiconductor devices 10 to each other. Furthermore, the wire 25 connects the other semiconductor device 10 and the external electrode 26b.

[0015] The sealing material 27 fills the housing 32 of the container 21 to seal the insulating substrate 22 and the semiconductor devices 10. That is, the sealing material 27 covers the semiconductor devices 10. The sealing material 27 is a curable gel.

[0016] Next, the semiconductor device 10 will be described. Fig. 2 is a cross-sectional view of a main part of the semiconductor device 10 according to the preferred embodiment.

[0017] As in Fig. 2, the semiconductor device 10 includes a semiconductor substrate 1, an electrode 3, a withstand voltage holding structure 6, an insulating protective layer 2, a waterproof layer 4, and an organic protective layer 5.

[0018] The semiconductor substrate 1 is mainly formed of silicon carbide. That is, the semiconductor device 10 is a compound semiconductor device, more specifically, a silicon carbide semiconductor device. A cell portion 11 and a termination portion 12 are defined in the semiconductor substrate 1. The cell portion 11 is an active region through which a current flows. The cell portion 11 is provided with a cell (not illustrated) for current supply. The cell is formed, for example, by implanting arbitrary dopants into the semiconductor substrate 1 and diffusing the dopants. For example, a semiconductor element such as a metal-oxide-semiconductor field-effect transistor (MOSFET) or a junction barrier Schottky diode (JBS) is formed in the cell.

[0019] The electrode 3, which covers the cell part 11, is provided on an upper surface of the cell part 11. For example, an aluminum electrode or the like is provided by interposing a barrier metal. A metal such as copper can be used as the main material of the electrode 3 instead of aluminum.

[0020] The termination part 12 is provided adjacent to an outer peripheral side of the cell part 11 so as to surround the outer peripheral side of the cell part 11. The withstand voltage holding structure 6, which holds a withstand voltage, and an excess region 13 are provided in the termination part 12. The withstand voltage holding structure 6 is located on an inner peripheral side of the termination part 12. The withstand voltage holding structure 6 is formed, for example, by implanting and diffusing arbitrary dopants into the semiconductor substrate 1, and is, for example, a guard ring structure. The guard ring structure includes a plurality of ring-shaped impurity layers and is formed in the flat semiconductor substrate 1. The excess region 13 is provided adjacent to an outer peripheral side of the withstand voltage holding structure 6 so as to cover the outer peripheral side of the withstand voltage holding structure 6.

[0021] The withstand voltage holding structure 6 and the excess region 13 in the termination part 12 are provided in an upper part of the semiconductor substrate 1. The insulating protective layer 2 is provided on upper surfaces of the withstand voltage holding structure 6 and the excess region 13 so as to cover the upper surfaces of the withstand voltage holding structure 6 and the excess region 13. The insulating protective layer 2 is, for example, a protective layer formed of silicon dioxide, and has high insulation by being provided on the upper surface of the flat semiconductor substrate 1. The insulating protective layer 2 has a thickness of approximately 1 μm or more and has a function of isolating the termination part 12 from the outside.

[0022] Compared with a silicon semiconductor device having a semiconductor substrate formed predominantly of silicon, the semiconductor device 10, which is a silicon carbide semiconductor device, can achieve downsizing of the withstand voltage holding structure 6 and thereby achieve cost reduction, and the withstand voltage holding structure 6 can be more effectively downsized by covering the withstand voltage holding structure 6 with the insulating protective layer 2. To prevent damage to the insulating layer 2 and deterioration of insulation properties, it is desirable that the insulating protective layer 2 be provided so that it does not reach an outer peripheral end of the semiconductor substrate 1, which is prone to chipping. In a part where the insulating protective layer 2 is in contact with the cell part 11, the electrode 3 is preferably seated on the insulating protective layer 2.The waterproof layer 4 is further provided with the insulating protective layer 2.

[0023] The waterproof layer 4 is formed, for example, from a layer made of silicon nitride. The waterproof layer 4 preferably extends to a position on the outer peripheral side with respect to the insulating protective layer 2 and does not reach a singulation region located at the outer peripheral end of the semiconductor substrate 1, so that it covers an outer peripheral end portion of the electrode 3, which is located near the termination part 12 and the insulating protective layer 2.

[0024] Since the waterproof layer 4 is only located on a step formed by the insulating protective layer 2, the waterproof layer 4 can be uniformly formed and have high waterproofing performance. The waterproof layer 4 has a layer density higher than that of the insulating protective layer 2, and it prevents moisture that has entered the semiconductor device 10 from spreading beneath the waterproof layer 4. Although a layer formed of silicon oxide may transport moisture, leading to corrosion of the termination part 12 such as the withstand voltage support structure 6, a layer formed of silicon nitride can appropriately prevent moisture penetration. To protect the waterproof layer 4, the organic protective layer 5, which covers part of the waterproof layer 4, is provided on the waterproof layer 4.

[0025] The organic protective layer 5 is, for example, a protective layer formed of polyimide. An inner peripheral end portion of the organic protective layer 5 is fitted on an outer peripheral end portion of the electrode 3 by interposing the waterproof layer 4. An outer peripheral end of the organic protective layer 5 is located on the inner peripheral side with respect to the outer peripheral end of the insulating protective layer 2. The inner peripheral end portion of the organic protective layer 5 overlaps the outer peripheral end portion of the electrode 3 to prevent a foreign matter from coming into contact with the electrode 3 and deteriorating insulation.

[0026] In the semiconductor device 10, which is a silicon semiconductor device, a width of the termination part 12 is shorter than that of a silicon semiconductor device, and creeping discharge is likely to occur when a shipping inspection or the like is performed in a state where the semiconductor device is exposed. Therefore, the outer peripheral part of the electrode 3 may be covered with the organic protective layer 5 to achieve a creeping distance. The creeping discharge occurs, for example, between a low-voltage side on which the electrode 3 is exposed and a high-voltage side on which the semiconductor substrate 1 is exposed, and a required creeping distance varies depending on conditions of the shipping inspection or the like of the semiconductor device 10. Therefore, a length by which the outer peripheral part of the electrode 3 is covered is also freely determined.

[0027] However, when the organic protective layer 5 is subjected to a durability test in which a voltage is continuously applied under a humid environment, moisture may propagate in the organic protective layer 5, creating a leakage path. Therefore, it is desirable that the organic protective layer 5 avoid contact with a portion where the semiconductor substrate 1 is exposed on the outer peripheral side of the semiconductor device 10.

[0028] As described above, the inner peripheral end portion of the organic protective layer 5 sits on the electrode 3 and is in contact with the electrode 3 by interposing the waterproof layer 4 therebetween. Although the waterproof layer 4 also has an insulating property, it is difficult to prevent the occurrence of a crack due to a step or the like located at a portion sitting on the electrode 3. At a corner portion of the electrode 3, a portion may occur where the organic protective layer 5 and the electrode 3 are in electrical contact with each other. For example, stress is likely to concentrate at an upper corner portion of the electrode 3, and at a lower end portion of the electrode 3, it is difficult to uniformly form the waterproof layer 4 due to an overlap problem when depositing the waterproof layer 4 at a boundary of the insulating protective layer 2.

[0029] In particular, when an external force is applied during handling of the semiconductor device 10 or during an assembly process or the like, the waterproof layer 4, which is a thin layer on the electrode 3, may develop a tiny crack and it is difficult to maintain insulation.

[0030] Since there exists a portion where the organic protective layer 5 is electrically in contact with the electrode 3 in the inner peripheral end portion of the organic protective layer 5, as described above, in a case where the organic protective layer 5 is in contact with a portion where the semiconductor substrate 1 is exposed on the outer peripheral side of the semiconductor device 10, the insulation of the organic protective layer 5 may be deteriorated due to a leakage path generated by moisture in the organic protective layer 5. As a result, there is a possibility that dielectric breakdown of the organic protective layer 5 may occur during the application of a high voltage after the humidity withstand voltage test.

[0031] Here, the contact includes a state in which the organic protective layer 5 and the semiconductor substrate 1 are in electrical contact with each other by interposing a gap therebetween, which is generated by a minute crack or a covering of a place where the waterproof layer 4 sits on a step of the insulating protective layer 2 or the like.

[0032] By avoiding contact between the organic protective layer 5 and the semiconductor substrate 1 on the high-voltage side, it is therefore possible to prevent the organic protective layer 5 from becoming a starting point of a leakage path. To avoid contact between the organic protective layer 5 and the semiconductor substrate 1 on the high-voltage side, the outer peripheral end of the organic protective layer 5 is preferably located on the inner peripheral side with respect to the outer peripheral side of the insulating protective layer 2.

[0033] Furthermore, on the high-voltage side, which is the outer peripheral side with respect to the termination part 12, a part of the insulating protective layer 2 covered with the organic protective layer 5 preferably avoids sitting on a groove, a step, or the like. Note that the groove or step is one formed by patterning or the like, and it is particularly desirable to avoid a groove or step having a height difference greater than a thickness of the insulating protective layer 2.

[0034] Although the cell portion 11 may have a step around a gate structure or the like on the inner peripheral side with respect to the termination portion 12, the step does not pose a problem because a voltage is not applied to this portion during application of a withstand voltage. Since the organic protective layer 5 is provided for the purpose of protecting the withstand voltage holding structure 6 from external influences, it is desirable that the organic protective layer 5 extend to the outer peripheral side with respect to the withstand voltage holding structure 6.

[0035] Further, since the waterproof layer 4 is provided for the purpose of preventing moisture from entering the withstand voltage withstanding structure 6, it is desirable that the waterproof layer 4 extends to the outer peripheral side with respect to the withstand voltage withstand structure 6. Moreover, the waterproof layer 4 is required to prevent moisture from entering below the insulating protective layer 2 at the outer peripheral end of the organic protective layer 5 in order to prevent the outer peripheral end of the organic protective layer 5 from becoming a starting point of a leakage path. Therefore, it is desirable that the waterproof layer 4 extends to the outer peripheral side with respect to the organic protective layer 5. Furthermore, it is desirable that the waterproof layer 4 extends to the outer peripheral side with respect to the insulating protective layer 2.The outer peripheral end of the insulating protective layer 2 has a step, and the waterproof layer 4 may develop a crack at the step. However, since the outer peripheral end of the organic protective layer 5 is separated from the semiconductor substrate 1, it is possible to prevent the outer peripheral end of the organic protective layer 5 from becoming a starting point of a leakage path due to retained moisture.

[0036] Next, an implementation of a reliability test and a characteristic check will be described with respect to the semiconductor module 100 on which the semiconductor device 10 is mounted, in comparison with a case where a semiconductor device 10A according to the prior art is mounted. Fig. 3 is a cross-sectional view of a main part of the semiconductor device 10A according to the prior art. Fig. 4 is a cross-sectional view illustrating a state before a reliability test of the semiconductor device 10A according to the prior art. Fig. 5 is a cross-sectional view illustrating a state during the reliability test of the semiconductor device 10A according to the prior art. Fig. 6 is a cross-sectional view illustrating a state during a characteristic check after the reliability test of the semiconductor device 10A according to the related art.

[0037] After an electrical characteristic check has been carried out on the semiconductor device 10, the semiconductor device 10 is mounted on the semiconductor module 100 as shown in Fig. 1. The semiconductor device 10 and the circuit pattern 22c, and the semiconductor device 10 and the external electrode 26a are connected by a solder bond using a solder material or by a sinter bond using a sinter bonding material containing silver or copper. As in the present exemplary embodiment, the semiconductor device 10 is a silicon carbide semiconductor device, and when the semiconductor module 100 is used at a high temperature, it is desirable that the bonding material 24 be one having high heat resistance, such as a sinter bonding material.

[0038] When the semiconductor device 10 is bonded by sinter bonding, pressure is applied. If a foreign matter gets caught between the semiconductor device 10 and the external electrode 26a when pressure is applied between the semiconductor device 10 and the external electrode 26a during sinter bonding, the electrode 3 of the semiconductor device 10 is short-circuited, thereby reducing the yield of the semiconductor module 100. However, since the outer peripheral part of the electrode 3 is covered with the organic protective layer 5, the occurrence of defective products can be reduced.

[0039] After the bonding between the semiconductor device 10 and the circuit pattern 22c, wire bonding, and the bonding between the external electrodes 26a and 26b are completed, the sealing material 27 is supplied. The sealing material 27 is, for example, a curable gel. By using the curable gel, insulation can be ensured even in a case where the semiconductor device 10 is relatively large, thus achieving both manufacturability and reliability of the semiconductor device 10. However, since the gel allows easy ingress of moisture, moisture resistance must be improved, particularly in the outer peripheral part of the semiconductor device 10.

[0040] Here, the semiconductor device 10A according to the prior art is described. As in Fig. 2, in the semiconductor device 10, the outer peripheral end of the organic protective layer 5 is located on the inner peripheral side with respect to the outer peripheral end of the insulating protective layer 2, whereas, as shown in Fig. As illustrated in FIG. 3, in the semiconductor device 10A, the outer peripheral end of the organic protective layer 5 is located on the outer peripheral side with respect to the outer peripheral end of the insulating protective layer 2. More specifically, the inner peripheral end of the organic protective layer 5 is in contact with the electrode 3 by interposing the waterproof layer 4, and the outer peripheral end of the organic protective layer 5 is in contact with the semiconductor substrate 1 by interposing the waterproof layer 4. The semiconductor device 10 and the semiconductor device 10A have the same structure except for this.

[0041] Various reliability tests are performed on the semiconductor module 100 to assess the risk of failure in the market. A typical test for evaluating moisture resistance is the High Voltage, High Humidity, High Temperature Reverse Bias (H3TRB) test. For example, the H3TRB test involves applying a voltage of 80% of the rated withstand voltage for 1,000 hours in an environment of 85% relative humidity. After the test, a voltage of 100% of the rated withstand voltage is applied to check for property fluctuations or the presence or absence of damage and deterioration.

[0042] In the semiconductor module on which the semiconductor device 10A is mounted, cracks 4a and 4b were generated in a part of the waterproof layer 4 sitting on the electrode 3 and a part of the waterproof layer 4 sitting on the insulating protective layer 2 before the reliability test, as shown in Fig. 4. It should be noted that the Fig. 4 to 6 illustrate only the semiconductor device 10A of the semiconductor substrate.

[0043] Next, as in Fig. 5 illustrates, after the reliability test, a leakage path 15, which was generated by moisture, is formed through the cracks 4a and 4b by applying a voltage of 85% of the rated withstand voltage. Next, as shown in Fig.As illustrated in Figure 6, dielectric breakdowns 16a and 16b due to the leakage path 15 occurred in some test pieces during the performance verification after the reliability test, that is, at the time of applying a voltage of 100% of the rated withstand voltage after the reliability test. This means that a dielectric breakdown failure of the organic protective layer 5 occurred.

[0044] Specifically, since the waterproof layer 4 is provided on the insulating protective layer 2, the dielectric breakdown mode of the organic protective layer 5 becomes apparent. This result suggests that the waterproof layer 4 failed to isolate the organic protective layer 5 and the semiconductor substrate 1 from each other and to isolate the organic protective layer 5 and the electrode 3 from each other. It is assumed that since the waterproof layer 4 was provided, moisture that entered from the sealing material 27 remained on the waterproof layer 4 without moving to a lower side of the insulating protective layer 2, thus creating a state in which the leakage path 15 is likely to occur in the organic protective layer 5.

[0045] On the other hand, in the semiconductor module 100 on which the semiconductor device 10 according to the preferred embodiment is mounted, it was confirmed that the dielectric breakdown of the organic protective layer 5 starting from a leakage path does not occur after the reliability test by employing the structure in which the outer peripheral end of the organic protective layer 5 is kept on the insulating protective layer 2.

[0046] As described above, the semiconductor device 10 according to the preferred embodiment includes the semiconductor substrate 1 in which the cell portion 11 through which a main current flows and the termination portion 12 surrounding the outer peripheral side of the cell portion 11 are defined, the electrode 3 provided on the upper surface of the cell portion 11 of the semiconductor substrate 1, the withstand voltage holding structure 6 provided in the termination portion 12 of the semiconductor substrate 1 and holding a withstand voltage, the insulating protective layer 2 covering the upper surface of the withstand voltage holding structure 6, the waterproof layer 4 covering at least the insulating protective layer 2, and the organic protective layer 5 covering a part of the waterproof layer 4. The outer peripheral end portion of the electrode 3 sits on the inner peripheral end portion of the insulating protective layer 2.The inner peripheral end portion of the organic protective layer 5 sits on the outer peripheral end portion of the electrode 3. An outer peripheral end of the organic protective layer 5 is located on the inner peripheral side with respect to the outer peripheral end of the insulating protective layer 2.

[0047] Therefore, the outer peripheral end portion of the organic protective layer 5 is separated from the semiconductor substrate 1, and it is therefore possible to prevent the outer peripheral end of the organic protective layer 5 from becoming a starting point of the leakage path 15 due to retained moisture. As a result, the occurrence of dielectric breakdown of the organic protective layer 5 is suppressed, so that the reliability of the semiconductor device 10 can be improved.

[0048] In addition, since the waterproof layer 4 covers the outer peripheral end part of the electrode 3 which is located near the termination part, and the inner peripheral end part of the organic protective layer 5 is fitted on the outer peripheral end part of the electrode 3 with the waterproof layer 4 interposed therebetween, the organic protective layer 5 protects the outer peripheral end part of the electrode 3, so that it is possible to prevent a foreign matter from coming into contact with the electrode 3 and causing a short circuit of the electrode 3.

[0049] Since the outer peripheral end of the organic protective layer 5 is located on the outer peripheral side with respect to the outer peripheral end of the withstand voltage holding structure 6, and the outer peripheral end of the waterproof layer 4 is located on the outer peripheral side with respect to the outer peripheral end of the organic protective layer 5, it is possible to prevent moisture from entering the lower side of the insulating protective layer 2.

[0050] Furthermore, since the outer peripheral end of the waterproof layer 4 is located on the outer peripheral side with respect to the outer peripheral end of the insulating protective layer 2, it is possible to prevent moisture from entering the lower side of the insulating protective layer 2.

[0051] The semiconductor module 100 includes the semiconductor device 10 and the sealing material 27 covering the semiconductor device 10. The sealing material 27 is a curable gel. Therefore, insulation can be easily ensured even in a case where the semiconductor device 10 is relatively large, so that both manufacturability and reliability of the semiconductor device 10 can be achieved.

[0052] The semiconductor module 100 further includes the external electrode 26a, which is connected to the semiconductor device 10 by interposing the sealing material 24 therebetween, and the connecting material 24 is a sintered connecting material. When the semiconductor device 10 is connected by sintering, pressure is applied. If a foreign matter gets caught between the semiconductor device 10 and the external electrode 26a when pressure is applied between the semiconductor device 10 and the external electrode 26a during sintering, the electrode 3 of the semiconductor device 10 is short-circuited, thereby reducing the yield of the semiconductor module 100. However, since the outer peripheral part of the electrode 3 is covered with the organic protective layer 5, the occurrence of defective products can be reduced.

[0053] The semiconductor device 10 is a compound semiconductor device. More specifically, the semiconductor device 10 is a silicon carbide semiconductor device. In the compound semiconductor device, the width of the termination part 12 can be shortened, but shortening the width of the termination part 12 increases an electric field applied to the organic protective layer 5, creates the leakage path 15 in the organic protective layer 5, and increases a possibility that the organic protective layer 5 will be damaged in a downstream rated withstand voltage test. As described above, in the preferred embodiment, the occurrence of dielectric breakdown of the organic protective layer 5 is suppressed, and therefore, a reduction in the cost of the semiconductor device 10 can be achieved by shortening the width of the termination part 12, and the reliability of the semiconductor device 10 can be increased.

[0054] It should be noted that the preferred embodiment may be modified or omitted as appropriate.

[0055] Various aspects of the present disclosure are described collectively below as an appendix. (Appendix 1)

[0056] Semiconductor device comprising: a semiconductor substrate in which a cell part through which a main current flows and a termination part surrounding an outer peripheral side of the cell part are defined; an electrode provided on an upper surface of the cell part of the semiconductor substrate; a withstand voltage holding structure provided in the termination part of the semiconductor substrate and holding a withstand voltage; an insulating protective layer covering an upper surface of the withstand voltage holding structure; a waterproof layer covering at least the insulating protective layer; and an organic protective layer covering part of the waterproof layer, whereby an outer peripheral end portion of the electrode sits on an inner peripheral end portion of the insulating protective layer, an inner peripheral end portion of the organic protective layer is located on the outer peripheral end portion of the electrode, and an outer peripheral end of the organic protective layer is located on an inner peripheral side with respect to an outer peripheral end of the insulating protective layer. (Appendix 2)

[0057] Semiconductor device according to Appendix 1, wherein the waterproof layer covers the outer peripheral end part of the electrode, which is located near the termination part, and the inner peripheral end portion of the organic protective layer is fitted on the outer peripheral end portion of the electrode with the waterproof layer interposed therebetween. (Appendix 3)

[0058] Semiconductor device according to Appendix 1 or 2, wherein the outer peripheral end of the organic protective layer is located on an outer peripheral side with respect to an outer peripheral end of the withstand voltage holding structure, and an outer peripheral end of the waterproof layer is located on an outer peripheral side with respect to the outer peripheral end of the organic protective layer. (Appendix 4)

[0059] A semiconductor device according to any one of appendices 1 to 3, wherein the outer peripheral end of the waterproof layer is located on an outer peripheral side with respect to the outer peripheral end of the insulating protective layer. (Appendix 5)

[0060] Semiconductor module comprising: the semiconductor device according to any one of Appendices 1 to 4; and a sealing material covering the semiconductor device, wherein the sealing material is a curable gel. (Appendix 6)

[0061] A semiconductor module according to Appendix 5, further comprising an external electrode connected to the semiconductor device by interposing a connecting material therebetween, wherein the joining material is a sintered joining material. (Appendix 7)

[0062] A semiconductor module according to Appendix 5 or 6, wherein the semiconductor device is a compound semiconductor device. (Appendix 8)

[0063] A semiconductor module according to Appendix 7, wherein the semiconductor device is a silicon carbide semiconductor device.

[0064] While the disclosure has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore understood that numerous modifications and variations may be devised. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-27528 [0002, 0003]

Claims

[1] Semiconductor device (10) comprising: • a semiconductor substrate (1) in which a cell part (11) through which a main current flows and a termination part (12) surrounding an outer peripheral side of the cell part (11) are defined; • an electrode (3) provided on an upper surface of the cell part (11) of the semiconductor substrate (1); • a withstand voltage holding structure (6) which is provided in the termination part (12) of the semiconductor substrate (1) and holds a withstand voltage; • an insulating protective layer (2) covering an upper surface of the withstand voltage holding structure (6); • a waterproof layer (4) covering at least the insulating protective layer (2); and • an organic protective layer (5) covering part of the waterproof layer (4), wherein • an outer peripheral end of the electrode (3) is seated on an inner peripheral end part of the insulating protective layer (2), • an inner peripheral end portion of the organic protective layer (5) is seated on the outer peripheral end portion of the electrode (3), and • an outer peripheral end of the organic protective layer (5) is located on an inner peripheral side with respect to an outer peripheral end of the insulating protective layer (2). [2] A semiconductor device (10) according to claim 1, wherein • the waterproof layer (4) covers the outer peripheral end part of the electrode (3) which is located near the termination part (12), and • the inner peripheral end part of the organic protective layer (5) is fitted on the outer peripheral end part of the electrode (3) with the waterproof layer (4) interposed therebetween. [3] A semiconductor device (10) according to claim 1 or 2, wherein • the outer peripheral end of the organic protective layer (5) is located on an outer peripheral side with respect to an outer peripheral end of the withstand voltage holding structure (6), and • an outer peripheral end of the waterproof layer (4) is located on an outer peripheral side with respect to the outer peripheral end of the organic protective layer (5). [4] The semiconductor device (10) according to any one of claims 1 to 3, wherein the outer peripheral end of the waterproof layer (4) is located on an outer peripheral side with respect to the outer peripheral end of the insulating protective layer (2). [5] Semiconductor module (100) comprising: • the semiconductor device (10) according to one of claims 1 to 4; and • a sealing material (27) covering the semiconductor device (10), wherein • the sealing material (27) is a curable gel. [6] The semiconductor module (100) according to claim 5, further comprising an external electrode (26a, 26b) connected to the semiconductor device (10) by interposing a bonding material (24) therebetween, wherein the bonding material (24) is a sintered bonding material. [7] The semiconductor module (100) according to claim 5 or 6, wherein the semiconductor device (10) is a compound semiconductor device. [8] The semiconductor module (100) according to claim 7, wherein the semiconductor device (10) is a silicon carbide semiconductor device.

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