Semiconductor device

Abstract

Semiconductor device, exhibiting: - a heat sink (23); - a semiconductor chip (3) which is attached to the heat sink (23) by means of a mounting material (5); - a lead wire (22) which is connected to the semiconductor chip (3) via a wire (6); and - a casting resin (7) which is formed on the heat sink (23) such that it covers part of the lead (22), the wire (6) and the semiconductor chip (3), and has a glass transition temperature of 195°C or higher, where: - a roughened plating with a surface roughness of RMS = 150 nm or higher is formed on a surface overlapping the casting resin (7) on the heat sink (23) and on a surface overlapping the casting resin (7) on the supply line (22), - the fastening material (5) is solder or sintered silver, - a water absorption rate of the casting resin (7) is 0.24% or less and - a surface roughness of the roughened plating RMS = 250 nm or less.

Description

Area

[0001] The present invention relates to a semiconductor device. background

[0002] Conventionally, as disclosed in, for example, JP 2015-164165 A, a semiconductor device is known in which a semiconductor chip formed of a wide-bandgap semiconductor material such as GaN is sealed with a mold resin. A semiconductor chip capable of operating at a high temperature is provided by using a wide-bandgap semiconductor having a larger band gap than that of silicon. In order to realize a mold enclosure structure adaptable to high-temperature operation, it is necessary to select a mold resin capable of withstanding high-temperature operation. In this regard, a preferable value of the glass transition temperature Tg of the mold resin is described in paragraph

[0023] of the above-described PTL 1 as a numerical value of 195°C or higher.Moreover, in paragraph

[0014] of the above-described PTL 1, it is also described that a semiconductor chip is bonded to a heat sink by using a sintered silver bonding body in order to withstand high temperature operation of the semiconductor chip. Citation listPatent literature

[0003] [PTL 1] JP 2015- 164 165 A

[0004] The document US 2009 / 0 039 486 A1 relates to a circuit part and comprises a frame substrate formed by forming a pattern on a rolled copper plate or a rolled copper alloy plate, having a chip pad portion for a semiconductor chip to be mounted thereon and a lead portion for electrical connection to the semiconductor chip, having rough surfaces formed as roughened surfaces on upper and side wall surfaces of the chip pad portion and the lead portion, smooth surfaces being provided on the lower surfaces of the chip pad portion and the lead portion, and the chip pad portion and the lead portion being buried in a sealing resin, with the lower surface of the lead portion being exposed.

[0005] The document US 2007 / 0 200 258 A1 shows a semiconductor device with semiconductor components embedded in a plastic housing compound, wherein a buffer layer is arranged on the surfaces of the semiconductor components of the semiconductor device. The buffer layer comprises a thermoplastic material. SummaryTechnical problem

[0006] However, as a result of serious investigations by the present inventor, it was discovered that the structure described in the above-mentioned PTL 1 causes a problem that the resin peels off from a heat sink during a reflow test due to moisture absorption. If this problem of resin peeling is not resolved, it causes a problem that makes it impossible to perform reflow assembly on a semiconductor device, and thus, the advantage of a resin-encapsulated structure cannot be utilized.

[0007] The present invention has been made to solve the above-described problem, and has an object to provide a semiconductor device having a resin-sealed type package structure capable of operation at a high temperature and improved to suppress resin peeling in a reflow step.

[0008] The object underlying the invention is achieved in a semiconductor device according to the invention with the features of claim 1, alternatively in a semiconductor device according to the invention with the features of claim 2, and further alternatively in a semiconductor device according to the invention with the features of claim 5. Advantageous further developments are the subject of the respective dependent claims.

[0009] A semiconductor device according to the present invention comprises, among others: a heat sink; a semiconductor chip attached to the heat sink with a mounting material; a lead connected to the semiconductor chip by a wire; and a molding resin provided on the heat sink to cover part of the lead, wire, and semiconductor chip, and having a glass transition temperature of 195 °C or higher, wherein a roughened plating having a surface roughness of RMS = 150 nm or higher is formed on a surface overlapping the molding resin on the heat sink and a surface overlapping the molding resin on the lead, the fastening material is solder or sintered silver, and a water absorption rate of the mold resin is 0.24% or less.

[0010] According to a first aspect of the present invention, a surface roughness of the roughened plating is RMS = 250 nm or less.

[0011] According to an alternative aspect of the present invention, the semiconductor chip is formed of a wide band gap semiconductor, and an initial temperature of thermal decomposition of the mold resin is 300°C or more.

[0012] According to another alternative aspect of the present invention, grooves are formed at four corners of the surface of the heat sink and extend to surround the semiconductor chip. Advantageous effect of the invention

[0013] According to the structure of the present invention, the present inventor recently discovered that even when using a mold resin with a high glass transition temperature, resin peeling during reflow assembly can be suppressed. Therefore, it is possible to provide a resin-sealed type semiconductor device in which resin peeling during the reflow step is suppressed and high-temperature operation can be performed. Short description of the drawings Fig. 1 is a perspective view showing an external appearance of a semiconductor device according to an embodiment of the present invention; Fig. 2 is a perspective view showing an internal structure of the semiconductor device according to the embodiment of the present invention; Fig.3 is a cross-sectional view showing the semiconductor device according to the embodiment of the present invention; Fig. 4 is a partially enlarged view showing the semiconductor device according to the embodiment of the present invention; Fig. 5 is a diagram showing an internal structure of a modification of the semiconductor device according to the embodiment of the present invention; Fig. 6 is a plan view showing a heat sink included in the modification of the semiconductor device according to the embodiment of the present invention; Fig. 7 is a cross-sectional view showing the modification of the semiconductor device according to the embodiment of the present invention. Description of an embodiment

[0014] Fig.1 is a perspective view showing an external appearance of a semiconductor device 1 according to an embodiment of the present invention. As shown in Fig. 1, the semiconductor device 1 includes a mold resin 7 provided on a heat sink 23 and leads 22 protruding from the mold resin 7. Fig. Fig. 2 is a perspective view showing an internal structure of the semiconductor device 1 according to the embodiment of the present invention. As shown in Fig. 2, the semiconductor device 1 comprises the heat sink 23, a semiconductor chip 3 and a circuit board 4, which are fixed to the heat sink 23 with fixing materials 5, and a plurality of leads 22, which are connected to the semiconductor chip 3 and the circuit board 4 via wires 6. As shown in Fig. 1 and Fig.2, the mold resin 7 covers parts of the leads 22, the wires 6 and the semiconductor chip 3 and exposes the rest of the leads 22.

[0015] The semiconductor device 1 is a resin package and can be subjected to reflow assembly. As an example, the thermal stress during reflow assembly is 260°C at a peak temperature and 30 seconds or less. The semiconductor device 1 is improved so that delamination of the mold resin 7 from the heat sink 23 and the leads 22 does not occur even when such thermal stress is applied.

[0016] Fig. 3 is a cross-sectional view showing the semiconductor device 1 according to the embodiment of the present invention. Fig. Fig. 3 is a cross-sectional view obtained when the semiconductor device 1 is cut along a line AA' of the Fig. 1 and Fig.2 is cut. Fig. 4 is a partial enlarged view showing the semiconductor device 1 according to the embodiment of the present invention. Fig. 4 is an enlarged view of an X-section of Fig. 3.

[0017] A roughened plating 21 with a surface roughness RMS = 150 nm or higher is provided on the entire surface of the heat sink 23. The roughened plating 21 is also provided on the entire surfaces of the leads 22. Note that the roughened plating 21 may be provided at least on surfaces of the heat sink 23 and the leads 22 that overlap the molding resin 7. Accordingly, the roughened plating 21 may not be provided on portions of the heat sink 23 and the leads 22 that are exposed from the molding resin 7. The heat sink 23 and the leads 22 are formed of copper. Copper has a high thermal conductivity of 398 W / mK.With respect to materials of the heat sink 23 and the lead wires 22, various modifications are possible as described later, but from the viewpoint of achieving high heat dissipation performance, it is preferable that the heat sink 23 and the lead wires 22 be formed of materials having a thermal conductivity of 200 W / mK or higher.

[0018] The semiconductor device 1 is a high-output, high-frequency semiconductor device that operates at a frequency of 1 GHz or higher and outputs 1 W or more of power. The semiconductor chip 3 incorporated in the semiconductor device 1 is made of gallium nitride (GaN). The GaN semiconductor device can operate at a higher temperature than a silicon (Si) semiconductor device and a gallium arsenide (GaAs) semiconductor device, which are conventionally used for high-frequency semiconductor devices. Specifically, the junction temperature of the semiconductor chip 3 during operation of the semiconductor device 1 is 250°C or more. In the embodiment, as an example, the semiconductor device 1 is a semiconductor device for wireless communication. The semiconductor device 1 can be a base station for portable telephones, which is one of semiconductor devices for wireless communication.In a high-power output field among technical fields related to semiconductor devices for wireless communication, there is a demand for band broadening and miniaturization of semiconductor devices due to an increase in communication capacity, and GaN semiconductor devices have been predominantly used. The semiconductor device 1 can meet this band broadening and miniaturization. Moreover, compared with conventional GaN semiconductor devices for which a screw-type metal-based package structure and a ceramic package structure have been used, the semiconductor device 1 according to the embodiment has a resin package structure, so that the cost can be reduced.

[0019] The semiconductor chip 3 and the circuit board 4 are attached to the surface of the heat sink 23 by the attachment material 5. The attachment material 5 is solder or sintered silver. Compared to a resin with silver paste, solder and sintered silver are less likely to absorb moisture and have better thermal conductivity.

[0020] The mold resin 7 seals the semiconductor chip 3 and the circuit board 4 to protect the semiconductor chip 3 and the circuit board 4 from foreign matter and external forces, etc. The glass transition temperature of the mold resin 7 is 195°C or more. The water absorption rate of the mold resin 7 is 0.24% or less. More specifically, in the embodiment, it is assumed that the mold resin 7 has a glass transition temperature of 200°C, a thermal decomposition initiation temperature of 300°C, a water absorption rate of 0.24%, and a linear expansion coefficient of 9 to 19 ppm.

[0021] Since the semiconductor chip 3 is formed of GaN, there is a risk of failure if the temperature rises to around 300°C. However, this means that the semiconductor chip 3 operates in a high-temperature state near 300°C as long as it remains within a range that does not cause failures. The initial temperature of thermal decomposition of the mold resin 7 is set to 300°C or higher, so it is possible to ensure that the mold resin 7 is not thermally decomposed even near the upper limit of high-temperature operation of the semiconductor chip 3.

[0022] The inventor of the present application has found that the following first to third countermeasures are effective for suppressing resin peeling during reflow mounting in a semiconductor device using a mold resin having a high glass transition temperature.

[0023] The first countermeasure is to reduce the water absorption rate of the material itself of the mold resin 7. A thermosetting resin containing epoxy resin and an inorganic filler can be used as the material of the mold resin 7. The mold resin 7 is provided by thermally curing a thermosetting resin. One of the physical properties of the mold resin 7 is the glass transition temperature (Tg). The epoxy resin contained in the mold resin 7 is selected so that the mold resin 7 has a high glass transition temperature and a high thermal decomposition initiation temperature, thus withstanding the high-temperature operation of the semiconductor device 1. However, in general, the water absorption rate of conventional mold resin materials also tends to increase when the glass transition temperature is high due to the molecular structure of the epoxy resin.One reason for mold resin delamination is that moisture within the enclosure evaporates during reflow assembly. Selecting only resin with a high glass transition temperature causes the water absorption rate to increase, leading to resin delamination due to thermal stress during reflow assembly.

[0024] Incidentally, according to a recently developed technology, mold resin materials that have a high glass transition temperature but keep their water absorption rates low are gradually being provided by controlling the molecular structure of epoxy resin. Therefore, the inventor of the present application focused on such technical trends and conducted an experiment using mold resin materials with high glass transition temperatures and reduced water absorption rates. Based on the experimental results shown in Tables 1 to 3 described later, it was found that when the water absorption rate is suppressed to 0.24% or less, it is possible to suppress resin peeling during reflow assembly by combining the second countermeasure and the third countermeasure described later.Note that according to the experimental results, when the water absorption rate exceeds 0.24%, there is a risk of partial peeling occurring during reflow assembly, and when the water absorption rate is 0.30% or more, complete peeling occurring.

[0025] The second countermeasure is that materials that easily absorb water are not incorporated into the mold resin 7. The semiconductor chip 3 and the circuit board 4 are die-bonded to the heat sink 23 with the mounting material 5 inside the mold resin 7. In the semiconductor device 1, this mounting material 5 is solder or sintered silver. When a material for die bonding such as silver paste resin is used, the mold resin 7 is peeled off during reflow mounting of the semiconductor device 1 due to moisture absorbed by the epoxy resin contained in the silver paste resin. In this regard, since the semiconductor chip 3 and the like in the semiconductor device 1 according to the embodiment are mounted by solder or sintered silver, moisture in the mold resin 7 can be suppressed.

[0026] The third measure is to sufficiently increase the bonding strength between the mold resin and the heat sink. In the semiconductor device 1, the bonding strength between the mold resin 7 and both the heat sink 23 and the leads 22 is increased by an anchor effect due to the provision of the roughened plating 21. Through an experiment by the present inventor, it was determined that the surface roughness of the roughened plating 21 needs to be 150 nm or more in RMS (root mean square) value. The surface roughness in the embodiment is an RMS value measured with an atomic force microscope (AFM). The RMS value is a square root of the mean of the square values ​​of deviations from a mean value.

[0027] Through the experiments of the inventor of the present application, it was clarified that the peeling of resin between the mold resin 7 and each of the heat sink 23 and the like during reflow mounting can be suppressed by combining all of the first to third countermeasures.

[0028] Note that, as a more preferable occasional countermeasure regarding the selection of the material of the mold resin 7, an improvement may be made to reduce the difference in the coefficient of linear expansion between the mold resin 7 and both the heat sink 23 and the lead wires 22. Since the coefficient of linear expansion of copper is about 17 ppm, the material components of the mold resin 7 can be adjusted so that the coefficient of linear expansion in an α1 region of the mold resin 7 at the glass transition temperature or lower is in a range of 9 to 19 ppm. As a result, stress occurring in the mold resin 7 can be reduced, and resin peeling can be suppressed.

[0029] The experimental results obtained by the present inventor are described with reference to the following Tables 1 to 3. Tables 1 to 3 show the results of moisture absorption reflow tests on samples with different surface roughness, bonding materials, and water absorption rate of the molding resin. The test condition is set to Jedec Lv. 3.

[0030] Table 1 shows the result of the test conducted on the first mold resin with a glass transition temperature Tg = 208 and a coefficient of linear expansion = 12 ppm. As shown in Table 1, when the water absorption rate of the first mold resin was 0.3%, peeling occurred upon moisture absorption after the reflow test, regardless of the combination of the surface roughness of the roughened plating and the bonding material. [Table 1] Surface roughness (RMS) Bonding material Water absorption rate of the mold resin Detachment or non-detachment after reflow test with moisture absorption 50 nm Resin with silver paste 0,3% Detachment (complete detachment) Lot Sintered silver 100 nm Resin with silver paste Lot Sintered silver 150 nm Resin with silver paste Lot Sintered silver 200 nm Resin with silver paste Lot Sintered silver 250 nm Resin with silver paste Lot Sintered silver

[0031] Table 2 shows a test result performed on the second mold resin with a glass transition temperature Tg = 195 and a coefficient of linear expansion = 10 ppm. As shown in Table 2, when the water absorption rate of the second mold resin was 0.27%, peeling occurred after the reflow test upon moisture absorption. However, partial peeling occurred in a sample in which the surface roughness was in the range of 150 nm to 250 nm and solder or sintered silver was used as the bonding material. [Table 2] Surface roughness (RMS) Bonding material Water absorption rate of the mold resin Detachment or non-detachment after reflow test with moisture absorption 50nm Resin with silver paste 0,27% Detachment (complete detachment) Lot Sintered silver 100nm Resin with silver paste Lot Sintered silver 150nm Resin with silver paste Detachment (complete detachment) Lot Detachment (partial detachment) Sintered silver 200nm Resin with silver paste Detachment (complete detachment) Lot Detachment (partial detachment) Sintered silver 250nm Resin with silver paste Detachment (complete detachment) Lot Detachment (partial detachment) Sintered silver

[0032] Table 3 shows a test result performed on the third mold resin with a glass transition temperature Tg = 195 and a coefficient of linear expansion = 12 ppm. As shown in Table 3, when the water absorption rate of the third mold resin was 0.24%, no delamination occurred in a sample in which the surface roughness was in a range of 150 nm to 250 nm and solder or sintered silver was used as the bonding material. [Table 3] Surface roughness (RMS) Bonding material Water absorption rate of the mold resin Detachment or non-detachment after reflow test with moisture absorption 50nm Resin with silver paste 0,24% Detachment (complete detachment) Lot Sintered silver 100nm Resin with silver paste Lot Sintered silver 150nm Resin with silver paste Complete replacement Lot No replacement Sintered silver No replacement 200nm Resin with silver paste Complete replacement Lot No replacement Sintered silver No replacement 250nm Resin with silver paste Complete replacement Lot No replacement Sintered silver No replacement

[0033] The semiconductor device 1 according to the embodiment can be modified as described below.

[0034] It is preferable that the surface roughness of the roughened plating 21 be in a range of RMS = 150 to 250 nm. If RMS = 150 nm or less, the adhesion strength is insufficient, and resin peeling occurs during reflow assembly. If RMS = 250 nm or more, it is also difficult to remove a plating solution residue by washing due to an influence of roughening. If staining and discoloration occur on the plating surface due to an influence of the plating solution residue, anti-adhesion and wire peeling, respectively, occur. According to these arguments, it is desirable that the surface roughness be in a range of RMS = 150 nm to 250 nm when measured with an atomic force microscope (AFM). This makes it possible to prevent washing and removing the residue of a plating solution from the heat sink 23 and the leads 22 from becoming difficult.However, if only an effect of suppressing resin detachment is considered, the surface roughness may be greater than 250 nm.

[0035] The initial temperature of thermal decomposition of the mold resin 7 may be lower than 300°C. The initial temperature of thermal decomposition of the mold resin 7 may be a low temperature lower than 300°C, provided that it is certain from the specification of the semiconductor device 1 that the operating temperature of the semiconductor chip 3 does not reach a high temperature around 300°C.

[0036] The semiconductor chip 3, which is a high-frequency semiconductor device, may specifically be, for example, a high-power amplifier, HEMT, MOSFET, or the like. Furthermore, the semiconductor device 1 is not limited to one that outputs electric power at a frequency of 1 GHz or higher and 1 W or more. The semiconductor device 1 may be a high-frequency semiconductor device with a frequency of less than 1 GHz or may have an output power of less than 1 W.

[0037] The material of the semiconductor chip 3 is not limited to gallium nitride (GaN). A wide-bandgap semiconductor material such as silicon carbide (SiC) or diamond may be used. Moreover, according to the semiconductor device 1, there is an effect of suppressing peeling of the mold resin 7 during reflow assembly while using the mold resin 7 with a high glass transition temperature, and this effect can be obtained regardless of the semiconductor material of the semiconductor chip 3. Therefore, it is not necessary to use a wide-bandgap semiconductor material, and the material of the semiconductor chip 3 may be silicon (Si) or gallium arsenide (GaAs).

[0038] The materials of the heat sink 23 and the lead wires 22 are not limited to copper. A copper alloy and aluminum can also be used as the materials of the heat sink 23 and the lead wires 22. An alloy of copper and molybdenum can be used as the copper alloy used as the materials of the heat sink 23 and the lead wires 22. The composition of the copper alloy can be Cu / PCM / Cu. "Cu / PCM(Cu-Mo) / Cu" is a clad material with a three-layer structure in which Cu is adhered to both surfaces of Cu-Mo as the core material. The copper alloy used as the materials of the heat sink 23 and the lead wires 22 can be an alloy of copper and tungsten. Note that the materials of the heat sink 23 and the lead wires 22 can be the same or different.

[0039] It is preferable that the heat sink 23 and the leads 22 be made of a material with a thermal conductivity of 200 W / mK or higher. This makes it possible to exhibit good heat dissipation when the semiconductor chip 3 operates at a high temperature. The thermal conductivity of copper is approximately 400 W / mK. The thermal conductivity of the copper-molybdenum alloy (copper 30%, molybdenum 70%) is 200 W / mK, and the thermal conductivity can be made higher than 200 W / mK by increasing the percentage of copper to more than 30% and the percentage of molybdenum to less than 70%. The thermal conductivity of copper-tungsten alloy (copper 20%, tungsten 80%) is 200 W / mK, and the thermal conductivity of copper-tungsten alloy (copper 11%, tungsten 89%) is 200 W / mK or more. The thermal conductivity of aluminum is 200 W / mK or more. If the required heat dissipation performance is not serious oris essential, it can be made of a material with a thermal conductivity of 200 W / mK or less.

[0040] It is preferable that the linear expansion coefficient of the mold resin 7 be 9 to 19 ppm. This point will be described, and first, the linear expansion coefficient of copper is about 17 ppm. The difference in linear expansion coefficient between the heat sink 23 formed of copper and the mold resin 7 according to the embodiment is suppressed to 8 ppm or less. Moreover, the linear expansion coefficient of a copper-molybdenum alloy to be used for the heat sink is in a range of 7 to 11.5 ppm. The difference in linear expansion coefficient between the heat sink 23 modified with the copper-molybdenum alloy and the mold resin 7 is suppressed to 12 ppm or less. The linear expansion coefficient of a copper-tungsten alloy to be used for the heat sink is in a range of 6 to 8.3 ppm.The difference in the coefficient of linear expansion between the copper-tungsten alloy-modified heat sink 23 and the mold resin 7 is suppressed to 13 ppm or less. The coefficient of linear expansion of aluminum is approximately 24 ppm. The difference in the coefficient of linear expansion between the aluminum-modified heat sink 23 and the mold resin 7 is suppressed to 15 ppm or less. As a result, it is possible to suppress peeling of the mold resin 7 even though the heat sink 23 is provided with high heat dissipation performance.

[0041] Fig. Fig. 5 is a diagram showing an internal structure of a modification of the semiconductor device 1 according to the embodiment of the present invention. Although the mold resin 7 in Fig. 5 is not shown, in this modification, the mold resin 7 covers as in the case of Fig. 1 also the heat sink 23 and the like. Fig. 6 is a plan view showing a heat sink 23 included in the modification of the semiconductor device 1 according to the embodiment of the present invention. Fig. 7 is a cross-sectional view showing the modification of the semiconductor device 1 according to the embodiment of the present invention. Fig. Fig. 7 shows a cross section of the semiconductor device 1 taken along a line BB' of Fig. 5, and the mold resin 7 is in Fig. 7 is also shown. In the Fig. In the modification shown in Figures 5 to 7, grooves 24 are provided at the four corners of the surface of the heat sink 23 so as to surround the semiconductor chip 3. Each of the grooves 24 in the four corners may be a plurality of grooves or a single groove. It is preferable that the depth of the groove 24 be 50 μm or more, and it is preferable that the length of the groove 24 be 1 mm or more. As shown in Fig.As shown in FIG. 7, the cross-sectional shape of the groove 24 may be a V-shape, a U-shape, an inverted trapezoidal shape, or the like. According to the present modification, even if resin peeling occurs between the mold resin 7 and the heat sink 23 or the like due to reflow or the like, a developing direction of the mold peeling can be changed by the grooves 24. As a result, it is possible to prevent peeling of the mold resin 7 from developing to a region where the semiconductor chip 3 and the circuit board 4 are mounted. List of reference symbols 1 semiconductor device 3 semiconductor chip 4 circuit board 5 Fastening material 6 wire 7 Casting resin 22 supply line 23 heat sinks 24 grooves

Claims

[1] Semiconductor device, comprising: - a heat sink (23); - a semiconductor chip (3) which is fastened to the heat sink (23) with a fastening material (5); - a supply line (22) connected to the semiconductor chip (3) via a wire (6); and - a mold resin (7) formed on the heat sink (23) to cover part of the lead (22), the wire (6) and the semiconductor chip (3), and having a glass transition temperature of 195°C or higher, where: - a roughened plating with a surface roughness of RMS = 150 nm or higher is formed on a surface overlapping the molding resin (7) on the heat sink (23) and a surface overlapping the molding resin (7) on the lead (22), - the fastening material (5) is solder or sintered silver, - a water absorption rate of the mold resin (7) is 0.24% or less, and - a surface roughness of the roughened plating RMS = 250 nm or less. [2] Semiconductor device, comprising: - a heat sink (23); - a semiconductor chip (3) which is fastened to the heat sink (23) with a fastening material (5); - a supply line (22) connected to the semiconductor chip (3) via a wire (6); and - a mold resin (7) formed on the heat sink (23) to cover part of the lead (22), the wire (6) and the semiconductor chip (3), and having a glass transition temperature of 195°C or higher, where: - a roughened plating with a surface roughness of RMS = 150 nm or higher is formed on a surface overlapping the molding resin (7) on the heat sink (23) and a surface overlapping the molding resin (7) on the lead (22), - the fastening material (5) is solder or sintered silver, - a water absorption rate of the mold resin (7) is 0.24% or less and - wherein the semiconductor chip (3) is formed from a wide band gap semiconductor and - an initial temperature of thermal decomposition of the mold resin (7) is 300°C or more. [3] A semiconductor device according to any one of the preceding claims, wherein: - materials of the heat sink (23) and the supply line (22) are copper, a copper-molybdenum alloy, a copper-tungsten alloy or aluminum and - a coefficient of linear expansion of the mold resin (7) is in a range of 9 to 19 ppm. [4] A semiconductor device according to any one of the preceding claims, wherein the heat sink (23) is formed of a material having a thermal conductivity of 200 W / m·K or higher. [5] Semiconductor device, comprising: - a heat sink (23); - a semiconductor chip (3) which is fastened to the heat sink (23) with a fastening material (5); - a supply line (22) connected to the semiconductor chip (3) via a wire (6); and - a mold resin (7) formed on the heat sink (23) to cover part of the lead (22), the wire (6) and the semiconductor chip (3), and having a glass transition temperature of 195°C or higher, where: - a roughened plating with a surface roughness of RMS = 150 nm or higher is formed on a surface overlapping the molding resin (7) on the heat sink (23) and a surface overlapping the molding resin (7) on the lead (22), - the fastening material (5) is solder or sintered silver, - a water absorption rate of the mold resin (7) is 0.24% or less and - grooves (24) extending to surround the semiconductor chip (3) are formed at four corners of the surface of the heat sink (23).

Images