Semiconductor component and manufacturing process for semiconductor components

Abstract

Semiconductor device comprising a semiconductor element (1) having a Ni-V electrode (7) and a conductor (31, 32), wherein the semiconductor element (1) and the conductor (31, 32) are bonded by means of a lead-free Sn-based solder (9), characterized in that an Sn-V compound layer (12) and a (Ni,Cu)3Sn4 compound layer (13) or a Ni3Sn4 compound layer (11) adjacent to the Sn-V compound (12) are formed adjacent to an interface between the semiconductor element (1) and the lead-free Sn-based solder (9).

Description

Technical field

[0001] The present invention relates to a semiconductor device and a manufacturing process for a semiconductor device. background

[0002] The use of lead in electronic control units (ECUs) in motor vehicles is regulated by the Restriction of Hazardous Substances Directive (RoHS Directive) and the End-of-Life Vehicles Directive (ELV Directive). To comply with these regulations, the use of lead-free solder for bonding processes related to these devices has been encouraged. For example, lead-free solder with the composition Sn-3Ag-0.5Cu, i.e., lead-free solder consisting primarily of Sn (tin), Ag (silver), and Cu (copper), is now widely used.

[0003] A nickel (Ni) electrode, bonded with solder, is used as an electrode for a semiconductor element in an electronic control device, and this nickel (Ni) electrode is often formed by sputtering. Among the various types of sputtering, magnetron sputtering, which enables faster and highly efficient film formation, has become the preferred standard in recent years. A problem arises when forming a Ni electrode using this magnetron sputtering process: pure Ni, with its strong magnetism, is difficult to control. For this reason, Ni-V, a material created by adding V (vanadium) to Ni, is used as the electrode film material. Therefore, a lead-free solder joint is required for an inverter, one that offers high reliability when bonded to a Ni-V electrode.

[0004] As background to the present invention, the following patent literature 1 describes a method in which a Cu film is formed on a Ni-V electrode and bonded by lead-free Sn-based solder, in which, by reacting Cu completely with Sn to bring about a (Cu, Ni)6Sn5 compound on the Ni-V electrode, the reaction between the Ni-V electrode and the lead-free Sn-based solder is suppressed in order to reduce time-dependent changes of a bonding interface relative to temperature changes under an operating environment. List of citations from patent literature

[0005] PTL 1: JP 4656275 B2 Summary of the invention: Technical problem

[0006] According to the method described in patent literature 1, the strength of the interface of a bonding section remains low because no Sn-V bonding layer is formed, which can impair the reliability of the semiconductor device. Furthermore, if a large shear stress develops on a bonding section, a creep cavity forms near the interface of the bonding section, which can further impair the reliability of the device. An object of the present invention, developed in consideration of the problems mentioned above, is to provide a semiconductor device and a manufacturing method for a semiconductor device that improve bonding reliability. Solution to the problem

[0007] A semiconductor device according to the present invention is a semiconductor device comprising a semiconductor element having a Ni-V electrode and a conductor, wherein the semiconductor element and the conductor are bonded by means of a lead-free, tin-based solder. In the semiconductor device, an Sn-V compound layer and a (Ni,Cu)3Sn4 compound layer or a Ni3Sn4 compound layer adjacent to the Sn-V connection are formed adjacent to an interface between the semiconductor element and the lead-free, tin-based solder.

[0008] A manufacturing process for a semiconductor device according to the present invention is a manufacturing process for a semiconductor device in which a semiconductor device with a Ni-V electrode is bonded to a conductor by means of lead-free tin-based solder. The manufacturing process comprises: causing the lead-free tin-based solder and the Ni-V electrode to react with each other to form an Sn-V layer and a (Ni,Cu)3Sn4 compound layer or a Ni3Sn4 compound layer at a location adjacent to an interface between the semiconductor device and the lead-free tin-based solder; and, after the formation of the Sn-V layer, leaving an unreacted layer of the Ni-V electrode intact, wherein the unreacted layer has not reacted with the lead-free tin-based solder. Advantageous effects of the invention

[0009] According to the present invention, a semiconductor device and a manufacturing process for a semiconductor device can be provided which improve bonding reliability. Brief description of the drawings [ Fig. 1] Fig. Figure 1 is a schematic representation of the dissociation of an intermetallic compound at a reaction section interface between a semiconductor element and a lead-free tin-based solder. [ Fig. 2] Fig. Figure 2 is a schematic representation of creepage cavities at the reaction section interface between the semiconductor element and the lead-free tin-based solder. [ Fig. 3] Fig. Figure 3 is a schematic representation of the mechanism of the formation of an intermetallic compound layer of the precipitation type according to a conventional technique. [ Fig. 4] Fig. Figure 4 is a schematic diagram of a mechanism for the formation of an intermetallic compound by reaction between a Ni electrode and the lead-free Sn-based solder. [ Fig. 5] Fig. Figure 5 is a schematic representation of the reaction transitions between a Ni-V electrode and the lead-free Sn-based solder. [ Fig. 6] Fig. Figure 6 is a diagram showing a relationship between a (Ni,Cu)-Sn compound and a creep cavity formation rate at a reaction section interface. [ Fig. 7] Fig. Figure 7 is a diagram showing a relationship between a temperature holding time to maintain the temperature of the bonding section at 150°C and the thickness of the Ni-V electrode, which disappears. [ Fig. 8] Fig. Figure 8 is a schematic view of a semiconductor device according to an embodiment of the present invention. [ Fig. 9] Fig. 9 shows a modification of the one in Fig. 8 semiconductor device shown. [ Fig. 10] Fig. Figure 10 is a table with examples according to an embodiment of the present invention, wherein the examples are subjected to testing under individual test conditions. [ Fig. 11] Fig. Figure 11 is a table with comparative examples according to one embodiment of the present invention, wherein the comparative examples are subjected to a test under individual test conditions.

[0010] Embodiments of the present invention are described below with reference to the drawings. The following description and the drawings provide examples for the explanation of the present invention, and, to clarify their explanation, they are omitted or simplified where necessary. The present invention can be implemented in various forms that differ from the embodiments described here. Unless otherwise stated, all components are applicable in both singular and plural form.

[0011] The positions, sizes, shapes, areas, and the like of components shown in the drawings serve to better understand the invention and therefore do not necessarily represent the actual positions, sizes, shapes, areas, and the like. The present invention is therefore not necessarily limited by the positions, sizes, shapes, areas, and the like shown in the drawings. (Comparison with the prior art - embodiment of the present invention)

[0012] Fig. Figure 1 is a schematic view of the dissociation of an intermetallic compound at a reaction section interface between a semiconductor element with a Ni electrode and Sn-3Ag-0.5Cu solder (lead-free solder based on Sn). Fig. Figure 2 is a schematic representation of creepage cavities at a bonding section between the semiconductor element and the lead-free tin-based solder.

[0013] For a semiconductor element 1 and the Sn-3Ag-0.5Cu solder 5 to react properly, it is necessary to allow the solder 5 to react with a Ni-based electrode formed on the semiconductor element 1 by sputtering. However, if the semiconductor element 1 and the Sn-3Ag-0.5Cu solder 5 react with each other, the reaction between the solder 5 and the Ni-based electrode can proceed excessively. In this case, a (Ni,Cu)3Sn4 compound 4, which is formed as a result of the reaction between the Ni-based electrode formed on the semiconductor element 1 and the solder 5, detaches from a reaction section interface (a layer consisting of an Al-based electrode 2 and a Ti-based electrode 3), as shown in Fig. 1 shown.

[0014] When a semiconductor device with a Ni-V electrode chip is used in an operating environment at 150 °C, the risk of detachment of an interface section increases with such an interface structure, leading to difficulties in maintaining the bonding state of the device and potentially affecting the reliability of the device.

[0015] As in Fig. As shown in Figure 2, the Ni-V electrode 7 reacts more rapidly with the lead-free, tin-based solder 9 when bonding is performed using a Ni-V electrode 7 than when bonding is performed using a Ni-based electrode 6. Therefore, there is concern that the risk of bond delamination is further increased. Furthermore, under an operating environment of 150°C, when a large shear stress is applied to a bonding section between the Ni-based electrode 6 and the semiconductor element 1, creepage cavities 21 develop near a junction 4 at a bonding section interface. The development of these cavities 21 is favored under an operating environment of 150°C or higher, which can impair the reliability of the device.

[0016] The cavities 21, which form near an interface between the solder 5 and the intermetallic compound 4, show a tendency to form more readily when the intermetallic compound 4 is thin, because a greater shear stress acts upon it. This leads to the understanding that such development of the cavities 21 and bond delamination in the component depend on the shape of the intermetallic compound 4.

[0017] Fig. Figure 3 is a schematic representation of a mechanism for the formation of an intermetallic compound layer of the precipitation type according to a conventional technique.

[0018] According to conventional techniques, a Cu film 8 is formed next to a Ni-V electrode 7 ( Fig. 3(a)), and when the Cu film 8 reacts with the lead-free Sn-based solder 9, a Cu6Sn5-based compound 10 is formed ( Fig. 3(b)). This compound 10 is deposited on the Ni-V electrode 7, thus forming a layer of the intermetallic compound 10 at a reaction section interface ( Fig. 3(c)). Since the metal compound layer 10 of Fig. 3 exhibits a lower bonding strength than the metal compound layer 11 of the Fig. 4, which will be described later, the metal compound layer 10 of the component offers lower bonding strength and can therefore impair the reliability of the component.

[0019] Fig. Figure 4 is a schematic diagram of a mechanism for the formation of an intermetallic compound by reaction between a Ni-V electrode and the lead-free, tin-based solder. Fig. 4 The mechanism is described using the lead-free, tin-based solder that does not contain Cu.

[0020] As in Fig. As shown in Figure 4, the reaction between the Ni-V electrode 7 and the lead-free Sn-based solder 9 forms a layer of a Ni3Sn4-based compound 11 ( Fig. 4(b)) and a layer of an Sn-V compound 12 ( Fig. 4(c)), the reaction layers are. Fig. 4 differs from Fig. 3 by forming a layer of an intermetallic compound in Fig. 4 is a layer of an intermetallic compound that has grown during the formation of the Ni3Sn4-based compound 11 and the layer of an Sn-V compound 12. This manufacturing process is used in the present invention.

[0021] Fig. Figure 5 is a schematic representation of the reaction transitions between a Ni-V electrode and the lead-free Sn-based solder.

[0022] As in the reaction transitions of Fig. 5(a) to Fig. As shown in Figure 5(d), the semiconductor element 1 with the Ni-V electrode 7 is reacted with the electrodes 2 and 3 arranged between the semiconductor element 1 and the Ni-V electrode 7 and the lead-free tin-based solder 9. This forms the Sn-V compound layer 12 at a reaction section interface and a layer of a (Ni,Cu)3Sn4 compound 13, which is also adjacent to the Sn-V compound 12, thus achieving sufficient bond strength of the device. Consequently, the reliability of the device can be ensured in the operating environment at 150°C. If the lead-free tin-based solder does not contain Cu, the layer of (Ni,Cu)3Sn4 compound 13 is a layer of a Ni3Sn4-based compound.

[0023] However, if, as in Fig. As shown in Figure 5(e), if the reaction between the semiconductor element 1 and the lead-free Sn-based solder 9 progresses excessively, the layer of the (Ni,Cu)3Sn4 compound 13 detaches from the Sn-V compound 12 at the reaction section interface. In such a case, there is a possibility that the Sn-V compound 12 and the lead-free Sn-based solder 9 separate at an interface under the operating conditions at 150°C, or that a thermally induced crack propagates directly through the interface. In this condition, the lifetime of the device is shortened, which impairs the reliability of the device. To prevent this, the present invention provides a feature for maintaining a Fig. 5(d) depicted state.

[0024] As in Fig. As shown in Figure 5(c), maintaining the bond with the adjacent Ti layer 3 is facilitated by leaving a section of the Ni-V layer 7, which has not reacted with the lead-free Sn-based solder 9, unchanged. This provides the device with higher bonding reliability under operating conditions of 150°C.

[0025] The layer of (Ni,Cu)3Sn4 compound 13, which is adjacent to the entire layer of Sn-V compound 12, offers higher reliability than the layer that is adjacent to a section of Sn-V compound 12.

[0026] Fig. Figure 6 is a diagram showing a relationship between a (Ni,Cu)-Sn compound and a creep cavity formation rate at a reaction section interface.

[0027] How the cavities 21 develop near the interface of the reaction section depends on the thickness of the layer of (Ni,Cu)3Sn4 compound 13 formed on the interface of the reaction section. Fig. Figure 6 shows the results of a creep test carried out at 150°C, with a weight of 600 g attached to a sample bonded to a Ni-coated Cu plate using the Sn-3Ag-0.5Cu solder 5 in an area of ​​5 mm × 5 mm × 1 mm.

[0028] As can be seen from the test results of Fig. As shown in Figure 6, it was found that a large number of cavities 21 are formed when the average thickness of the Ni3Sn4 compound layer formed on a bonding section interface is less than 2 µm, and that the formation of cavities 21 is suppressed when the average thickness is 2 µm or more. This leads to the conclusion that determining the thickness of the (Ni,Cu)3Sn4 compound layer 13 to 2 µm or more ensures the reliability of the device under the operating environment at 150°C.

[0029] Fig. Figure 7 is a diagram showing the relationship between the temperature holding time to maintain the temperature of a bonding section under the operating environment at 150°C and the thickness of the Ni-V electrode, which disappears.

[0030] The diagram in Fig. Figure 7 shows the thickness of the Ni-V electrode, which disappears when a sample bonded to a Ni-coated copper conductor using the Ni-V electrode semiconductor element and Sn-3Ag-0.5Cu solder is subjected to a 150°C high-temperature endurance test for 1000 hours. The horizontal axis of the diagram represents time raised to the power of 0.5, and 1000 hours is a reference value equivalent to a 10-year automobile warranty.

[0031] The test results show that the 300 nm thick Ni-V electrode disappears when the sample is held in the operating environment at 150°C for 1000 hours. This indicates that for higher reliability, it is desirable to choose a structure in which at least the unreacted 300 nm thick Ni-V electrode remains intact at the time of reaction. To keep the unreacted 300 nm thick Ni-V electrode intact, it is preferable to use a semiconductor device with a pre-reaction Ni-V electrode with a thickness of 700 nm or more.

[0032] Fig. Figure 8 is a schematic view of a semiconductor device according to an embodiment of the present invention. Fig. 9 shows a modification of the one in Fig. 8 of the semiconductor device shown. A table in Fig. 10 is a table of examples according to one embodiment of the present invention, wherein the examples are subjected to testing under individual test conditions, and a table in Fig. Figure 11 is a table of comparative examples according to one embodiment of the present invention, wherein the comparative examples are subjected to a test under individual test conditions.

[0033] The first to fourth examples of Fig. 10, to which the present invention is applied, are referred to Fig. 8 described. It should be noted that the present invention relates to the first to fourth examples of the table of Fig. 10 was applied, whereby the composition of the lead-free, tin-based solder 9 was varied for each of the first to fourth examples under the condition that no separation of the layer from the (Ni,Cu)3Sn4 compound 13 from the interface occurs, that the Sn-V compound layer is present, and that the unreacted Ni-V layer is present. If the lead-free, tin-based solder 9 does not contain Cu, the (Ni,Cu)3Sn4 compound is a Ni3Sn4-based compound.

[0034] The lead-free, tin-based solder 9 is applied to a solder deposition position on the collector-side copper conductor frames 31 and 32 with a roughened nickel coating (enlarged view A). The semiconductor element 1, with the 800 nm thick Ni-V electrode 7 on both sides, is mounted onto the lead-free, tin-based solder 9, and the semiconductor element 1 and the conductor frames 31 and 32 are bonded together. The lead-free, tin-based solder 9 is then applied to an electrode on the top side of the bonded semiconductor element 1.

[0035] This process creates a structure comprising a layer of the (Ni,Cu)3Sn4 compound 13 with an average thickness of 2 µm or more, adjacent to the reaction-formed Sn-V layer 12, while the unreacted Ni-V layer 7, with an average thickness of 300 nm or more, remains intact at a bonding section of the semiconductor element 1. Subsequently, resin sealing 33 is carried out by a transfer molding process to fabricate a semiconductor device.

[0036] The semiconductor device produced in this way was subjected to 50,000 cycles of a performance cycle test under the conditions of a 150°C high-temperature endurance test for 1000 hours, Tjmax150°C and ΔTj 100°C ( Fig. 10) During testing, a reduction in the bonding area of ​​the component after the test of within 10% is marked as “◯”, while a reduction in the bonding area of ​​the component of more than 10% is marked as “x”. This deterioration of the bond is confirmed by examining an ultrasound image and cross-sections.

[0037] Consequently, in the first four examples, no signs of degradation, such as delamination or creep void formation, were observed at any reaction section after the reliability test. Therefore, it was confirmed that the semiconductor device exhibits sufficient bonding reliability.

[0038] The fifth to eighth examples of Fig. 10, to which the present invention is applied, are now referred to Fig. 9 described. In the same way as in the case of the first to fourth examples, the present invention was applied to the fifth to eighth examples of the table of Fig. 10 was applied, whereby the composition of the lead-free, tin-based solder 9 was varied for each of the fifth to eighth examples under the condition that separation of the (Ni,Cu)3Sn4 compound layer 13 from the interface did not occur, that the Sn-V compound layer was present, and that the unreacted Ni-V layer was not present. If the lead-free, tin-based solder 9 did not contain Cu, the (Ni,Cu)3Sn4 compound was a Ni3Sn4-based compound.

[0039] A layer of lead-free, tin-based solder 44 is placed on a heat-dissipating base 45, a ceramic substrate 43 is stacked on the lead-free, tin-based solder 44, a layer of lead-free, tin-based solder 9 is placed on the substrate 43, and the semiconductor element 1 is placed on the lead-free, tin-based solder 9 and heated for bonding. After bonding the semiconductor element 1, an aluminum wire 42 and a terminal 41 are bonded, followed by the attachment of a housing 47 and the sealing of the semiconductor element 1 with gel 46 to fabricate a semiconductor device.

[0040] The semiconductor device produced in this way was subjected to 50,000 cycles of a performance cycle test under the conditions of a 150°C high-temperature endurance test for 1000 hours, Tjmax 150°C and ΔTj 100°C. In the test, a decrease in the bonding area of ​​the device after the test within 10% is rated as “◯”, while a decrease in the bonding area of ​​the device by more than 10% is rated as “×” ( Fig. 10). This deterioration of the bonding is confirmed by examining an ultrasound image and cross-sections.

[0041] Consequently, in samples five through eight, no signs of degradation, such as delamination, were observed at any reaction section after the reliability test. Although a few creep voids were found, the sufficient reliability of the bond was confirmed.

[0042] Next, in the first and second comparative examples, Fig. 11. The lead-free, tin-based solder 9 with the same composition of Sn-3Ag-0.5Cu was provided with a semiconductor device under the condition that separation of the (Ni,Cu)3Sn4 compound layer 13 from the interface occurs, that the Sn-V compound layer is present, and that the unreacted Ni-V layer is not present, and under the condition that contradicts the above condition, and then the semiconductor device was subjected to a reliability test. In the first comparative example of Fig. In the second comparative example of [item number], delamination occurred at a bonding section of the component during both the high-temperature endurance test and the performance cycle test, resulting in the corresponding evaluation scores of “×”. Fig. 11. The high-temperature endurance test yields a rating result of “◯”, but the performance cycle test, in which separation occurred at the reaction section interface, yields a rating result of “×”. This leads to the understanding that in the embodiment of Fig. 8 the reliability of the component is impaired if both the Sn-V junction 12 and the unreacted Ni-V layer 7 do not remain intact.

[0043] In the third and fourth comparative examples of the table in Fig. In 11, a semiconductor device was produced using the same method as in the fifth to eighth examples of Fig. Ten were manufactured and the reliability test was carried out. In the third comparative example of Fig. In test 11, delamination occurred at a bonding section of the component during both the high-temperature holding test and the performance cycle test, resulting in the corresponding evaluation scores of “×”. In the fourth comparative example of Fig. 11. The high-temperature endurance test yields a rating result of “◯”, but the performance cycle test, in which separation occurred at the reaction section interface, yields a rating result of “×”. This leads to the understanding that in the embodiment of Fig. 9 the reliability of the component is impaired if both the Sn-V junction 12 and the unreacted Ni-V layer 7 do not remain intact.

[0044] As described above, the test results in the Fig. 10 and Fig.11, that in a state in which the semiconductor element and a conductor are bonded by the lead-free Sn-based solder, leaving both the Sn-V connection 12 and the unreacted Ni-V layer 7 in place ensures the reliability of the device in both cases of maintaining the connection under the high-temperature operating environment at 150°C and continuous current cycles.

[0045] The present invention describes an example in which the layer of the (Ni,Cu)3Sn4 compound 13 is formed using the lead-free, tin-based solder containing Cu. If lead-free, tin-based solder without Cu is used, a layer of a Ni3Sn4-based compound is formed, providing the same effects.

[0046] The embodiment of the present invention described above offers the following effects. (1) The semiconductor device comprises the semiconductor element 1 with the Ni-V electrode 7 and the conductors 31 and 32, wherein the semiconductor element 1 and the conductors 31 and 32 are bonded by means of the lead-free tin-based solder 9. In the semiconductor device, the tin-V compound layer 13 and the (Ni,Cu)3Sn4 compound layer 4 or the Ni3Sn4 compound layer adjacent to the tin-V compound 13 are formed adjacent to the interface between the semiconductor element 1 and the lead-free tin-based solder 9. The semiconductor device structured in this way can be provided as a semiconductor device with improved bonding reliability. (2) In the semiconductor device, the Sn-V bonding layer 13 is a layer formed as a result of the reaction of a section of the Ni-V electrode 7 with the lead-free Sn-based solder 9. This improves the bonding reliability of the device. (3) In the semiconductor device, the (Ni,Cu)3Sn4 compound layer 4 or the Ni3Sn4 compound layer is arranged next to the interface along the entire section of the Sn-V compound layer 13. This enables an improvement in the bonding strength of the device. (4) The average thickness of the (Ni,Cu)3Sn4 compound layer 4 or the Ni3Sn4 compound layer of the semiconductor device is 2 µm or more. The semiconductor device structured in this way can be provided as a semiconductor device with improved bonding reliability. (5) An unreacted layer of the Ni-V electrode 7 of the semiconductor device, wherein the unreacted layer has not reacted with the lead-free Sn-based solder 9, has an average thickness of 300 nm or more. For this reason, a semiconductor device with improved bonding reliability, equivalent to a 10-year automotive warranty, can be provided. (6) When, in the semiconductor device, the semiconductor element 1 with the Ni-V electrode 7 is bonded to the conductors 31 and 32 by the lead-free Sn-based solder 9, the lead-free Sn-based solder 9 and the Ni-V electrode 7 are caused to react with each other to form the Sn-V layer 12 and the (Ni,Cu)3Sn4 compound layer 4 or the Ni3Sn4 compound layer at a location adjacent to the interface between the semiconductor element 1 and the lead-free Sn-based solder 9, and after the formation of the Sn-V layer 12, an unreacted layer of the Ni-V electrode 7 that has not reacted with the lead-free Sn-based solder 9 remains intact. This provides the semiconductor device of the present invention.

[0047] It should be noted that the present invention is not limited to the embodiment described above, and various modifications and other configurations may be combined, provided that such combination does not deviate from the core of the present invention. Furthermore, the present invention is not limited to an embodiment comprising all the configuration elements described above, but also includes an embodiment from which some configuration elements have been omitted. Reference symbol list 1 semiconductor element 2 Al-based electrodes 3 Ti-based electrode, Ti layer 4 (Ni,Cu)3Sn4 compound 5 Sn-3Ag-0.5Cu solder 6 Ni-based electrode 7 Ni-V electrode 8 Cu-Film 9 lead-free solder based on tin 10 Cu6Sn5-based compounds 11 Ni3Sn4-based compound 12 Sn-V connection 13 (Ni,Cu)3Sn4 compound 21 Creep cavity 31 emitter-side line 32 collector-side line 33 Harz 41 connection 42 aluminum wire 43 Ceramic substrate 44 lead-free solder based on tin 45 heat-dissipating base 46 Gel 47 cases QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] JP 4656275 B2

[0005]

Claims

[1] Semiconductor device comprising a semiconductor element having a Ni-V electrode and a conductor, wherein the semiconductor element and the conductor are bonded by means of a lead-free Sn-based solder, wherein an Sn-V compound layer and a (Ni,Cu)3Sn4 compound layer or a Ni3Sn4 compound layer adjacent to the Sn-V connection are formed adjacent to an interface between the semiconductor element and the lead-free Sn-based solder. [2] Semiconductor device according to claim 1, wherein the Sn-V compound layer is a layer formed as a result of the reaction of a section of the Ni-V electrode with the lead-free Sn-based solder. [3] Semiconductor device according to claim 1 or claim 2, wherein the (Ni,Cu)3Sn4 compound layer or the Ni3Sn4 compound layer is arranged next to the interface along the entire section of the Sn-V compound layer. [4] Semiconductor device according to claim 1 or claim 2, wherein the average thickness of the (Ni,Cu)3Sn4 compound layer or of the Ni3Sn4 compound layer 2 is by or more. [5] Semiconductor device according to claim 2, wherein an unreacted layer of the Ni-V electrode that has not reacted with the lead-free Sn-based solder has an average thickness of 300 nm or more. [6] Manufacturing process for a semiconductor device in which a semiconductor element with a Ni-V electrode is bonded to a conductor by means of lead-free Sn-based solder, the manufacturing process comprising: Causing the lead-free tin-based solder and the Ni-V electrode to react with each other to form an Sn-V layer and a (Ni,Cu)3Sn4 compound layer or a Ni3Sn4 compound layer at a location adjacent to an interface between the semiconductor element and the lead-free tin-based solder; and After the formation of the Sn-V layer, an unreacted layer of the Ni-V electrode remains intact, the unreacted layer not having reacted with the lead-free Sn-based solder.