JP5779666B2 - Automotive power modules, automobiles - Google Patents

Description

    The present invention relates to a solder material for a semiconductor device, a semiconductor device using the same, and a method for manufacturing the same, and more specifically, used for an on-vehicle AC generator (alternator) that converts an AC output of an AC generator into a DC output. The present invention relates to a semiconductor device.

    A semiconductor device used in an automotive alternator has a structure that reduces thermal stress based on a difference in thermal expansion coefficient between a semiconductor element and an electrode so as to withstand severe temperature cycles, as disclosed in, for example, Patent Document 1. doing. Moreover, since it is installed in the vicinity of the engine, a heat resistant temperature of 200 ° C. is required for the semiconductor device. Therefore, for connection of semiconductor elements, for example, a high Pb solder whose solidus line is around 300 ° C. (for example, a Pb—Sn alloy having a solid line of 300 ° C. and a liquidus line of 314 ° C. containing 95 wt% Pb and 5 wt% Sn) ) Is used for connection.

    However, from the viewpoint of environmental protection, a semiconductor device using a connection material from which Pb having a large environmental load is removed has been demanded. Pb-free solder materials that do not contain Pb and have a melting point close to high Pb solder include Au-20Sn (eutectic, 280 ° C), Au-12Ge (eutectic, 356 ° C), Au-3.15Si (eutectic, 363 ° C) ) Etc., but it is very expensive. Further, in the case of Au-20Sn having a relatively small Au content, since it is a hard solder, there is a disadvantage that a sufficient stress cannot be buffered by a large area connection and the semiconductor element is easily damaged.

    Other Pb-free solder materials include Sn-based medium-temperature solders such as Sn-3Ag-0.5Cu with a melting point of 200 ° C or higher, which are widely used for mounting components on substrates, and good connection reliability at 150 ° C or lower Have However, when it is kept for a long time in an environment of use at 200 ° C. or higher, the interface reaction proceeds at the connection interface, and there is a problem that the connection reliability decreases due to the formation of voids and the growth of the intermetallic compound layer.

    As a technique for suppressing the interfacial reaction of Sn-based solder with respect to this problem, for example, as disclosed in Patent Document 2, Sn-based solder composed of Cu: 0.1-2% by weight, Ni: 0.002-1% by weight, and the remaining Sn is used. It has been reported that it is possible to suppress Cu corrosion of connected materials by adding Cu, and at the same time, it is possible to suppress the growth of intermetallic compounds such as Cu6Sn5 and Cu3Sn at the connection interface by adding Ni. Yes. Further, in Patent Document 3, in forming solder bumps, two types of metal layers that react with Sn-based solder to form an intermetallic compound are provided on the surface of the material to be connected, and Sn-based solder balls are connected thereto. Thus, it has been reported that the interfacial reaction can be suppressed by forming a thin intermetallic compound layer composed of two or three kinds of elements including Sn at the connection interface.

Japanese Patent Application Laid-Open No. 07-212235 Japanese Patent No. 3152945 JP 2002-280417 A

    However, the conventional technology has the following problems, and the interface reaction is not sufficiently suppressed, and the connection reliability is low. In particular, it has been found that it is difficult to suppress the interfacial reaction in a conventional semiconductor device for an on-vehicle AC generator (alternator) used at high temperatures.

    In other words, in the case of the above-mentioned Patent Document 2, the suppression of the interfacial reaction can be expected somewhat by the addition of Ni, but since the Cu6Sn5 and Cu3Sn compounds are always in contact with Cu and Sn-based solder, the interfacial reaction occurs at a high temperature of 200 ° C. or higher. Proceed. As a result, the Cu—Sn compound continues to grow and voids and the like are generated at the interface, resulting in a decrease in connection reliability.

    On the other hand, in the case of the above-mentioned Patent Document 3, since the intermetallic compound formed at the closest solder is a barrier layer between the Sn-based solder and the metal layer, it is considered that the interface reaction suppressing effect is great. It is necessary to provide two layers of a first metal layer and a second metal layer in advance on the material, which increases the plating process, and is expensive due to selective local plating, and an electrode cannot be provided. In the case of the structure, there is a problem that it is difficult to form a metal layer. In addition, since the metal layer formed on the outermost surface of the connection surface needs to be reacted with Sn-based solder at the time of connection to form a barrier layer, if the metal layer formed on the outermost surface is thick, the unreacted outermost surface at the time of connection There is a possibility that the metal layer remains and the effect of the barrier layer cannot be sufficiently obtained, and that the adjustment of the process such as extending the connection time is required to completely react the outermost metal layer. is there. On the other hand, when the outermost metal layer is thin, the barrier layer for suppressing the interfacial reaction becomes thin, and the interfacial reaction may not be sufficiently suppressed at a high temperature of 200 ° C. or higher. Further, as shown in FIG. 2, when the unreacted portion of the layer (for example, Cu layer) 15 formed on the outermost surface layer of the connection surface remains and is exposed in the reaction with the Sn-based solder, oxidation from the exposed portion is performed. Corrosion occurs and becomes a problem. On the other hand, as shown in FIG. 3, in order to avoid the remaining of the outermost surface layer of the connection surface, if the uppermost surface layer of the connection surface is locally provided by local plating or the like, this time the Sn-based solder is in the lower layer. There is a risk that the metal layer (for example, the Ni layer) 11 may be wet and spread. In this case, an intermetallic compound (for example, Ni—Sn compound) 16 is formed between them, and an interfacial reaction proceeds at this portion, which may cause a void accompanying a volume change.

    An object of the present invention is to provide a connection material for a semiconductor element that can maintain connection reliability even if it is used at a high temperature of 200 ° C. or higher for a long time at a low environmental impact and at a low cost, and a semiconductor device using the connection material Another object is to provide an on-vehicle AC generator.

  In order to achieve the above object, in the present invention, a power module for an automobile comprising a semiconductor element, a first connected member, and a first connecting member for connecting the first connected member, A Ni-based layer is formed on the first surface on the semiconductor element side of the first connecting member, and the first connecting member is a Sn-based material mainly composed of a Cu6-Sn5 compound and Cu6-Sn5. It is composed of Sn-Cu binary solder containing solder phase, Sn solder phase is Sn-Cu solder with 3 to 7 wt% Cu, and Ni layer is connected to the first connecting member A power module for automobiles is provided in which a region to be covered is covered with a Cu6-Sn5 compound, and a Ni-based layer formed on the first surface is connected to the first surface with a Cu6-Sn5 compound. To do.
  Further, in the present invention, an automobile having a power module including a semiconductor element, a first connected member, and a first connecting member for connecting the first connected member, A Ni-based layer is formed on the first surface of the one connecting member on the semiconductor element side, and the first connecting member is composed of a Cu6-Sn5 compound and an Sn-based solder mainly composed of other than Cu6-Sn5. It is composed of Sn-Cu binary solder containing phase, Sn-based solder phase is Sn-Cu based solder with 3 to 7 wt% Cu, and Ni-based layer is connected to the first connecting member An automobile is characterized in that a region to be covered is covered with a Cu6-Sn5 compound, and the Ni-based layer formed on the first surface and the first surface are connected with the Cu6-Sn5 compound.
  Moreover, in this invention, it is a motor vehicle which has an alternating current generator provided with the semiconductor element, the 1st to-be-connected member, and the 1st connecting member which connects a 1st to-be-connected member, Comprising: In addition, a Ni-based layer is formed on the first surface on the semiconductor element side of the first connecting member, and the first connecting member is composed of a Cu6-Sn5 compound and Sn containing Cu6-Sn5 as a main component. Sn-Cu binary solder containing a solder-based solder phase, the Sn-based solder phase is Sn-Cu solder with 3 to 7 wt% Cu, and the Ni-based layer is the first connecting member Provided is an automobile characterized in that a region to be connected is covered with a Cu6-Sn5 compound, and a Ni-based layer formed on a first surface and the first surface are connected with a Cu6-Sn5 compound.

    According to the present invention, it is possible to provide a semiconductor device having a small environmental load and heat resistance of 200 ° C. or higher.

It is sectional drawing which shows typically the connection condition of this invention. It is sectional drawing which shows typically the connection condition which is possible in patent document 3. FIG. It is sectional drawing which shows typically the connection condition which is possible in patent document 3. FIG. It is sectional drawing which shows the connection mechanism of this invention typically. It is the figure which showed the Young's modulus and yield stress of various materials which can be used as a thermal expansion coefficient difference relaxation material. It is sectional drawing which shows the connection mechanism of this invention typically. It is sectional drawing which shows the connection mechanism of this invention typically. It is a figure which shows one Embodiment of the semiconductor device of this invention. It is a figure which shows one Embodiment of the semiconductor device of this invention. It is sectional drawing which shows typically the void formation condition of a joining interface. It is sectional drawing which shows typically the void formation condition of a joining interface. It is sectional drawing which shows typically the joining interface after a high temperature leaving test. It is sectional drawing which shows typically the joining interface after a high temperature leaving test. It is a Cu-Sn binary system phase diagram. It is a figure which shows one Embodiment of the semiconductor device of this invention. It is a figure which shows one Embodiment of the semiconductor device of this invention. It is a figure which shows one Embodiment of the semiconductor device of this invention.

    First, the connection material and connection mechanism of the present invention will be described with reference to FIG.

    An example of the connection material of the present invention is an Sn-based solder foil 17 containing a phase 10 of a Cu—Sn compound (for example, Cu 6 Sn 5) from room temperature to 200 ° C. By using the solder foil 17 to connect the material 12 to which the Ni-based plating 11 is applied, the Cu6Sn5 phase 10 floating as a phase in the solder foil 17 precipitates or moves on the Ni-based plating 11. A compound layer 10 mainly composed of a Cu—Sn compound is formed. As a result, even when exposed to a high temperature of 200 ° C. or higher for a long time, the compound layer 10 mainly composed of a Cu—Sn compound becomes a barrier layer for the Ni-based plating 11 and the Sn-based solder, and the compound layer grows by a connection interface reaction. And the formation of the void accompanying it can be suppressed.

    In the connection mechanism of the present invention, it is only necessary to provide at least one layer of Ni plating such as Ni, Ni-P, Ni-B, etc. on the material to be connected, so that connection with a small number of steps is possible. In the connection mechanism of the present invention, the thickness of the formed barrier layer depends on the amount of the Cu-Sn compound phase contained in the solder foil. Therefore, the barrier thickness can be adjusted by increasing or decreasing the amount of Cu-Sn compound. It becomes. Furthermore, as shown in FIG. 1, the Cu—Sn compound 10 in the solder actively precipitates or moves on the Ni-based plating 11 at the connection interface where the solder is wet, and a Cu—Sn compound barrier layer is formed. Therefore, the above-described problems in FIGS. 2 and 3 do not occur in the connection portion after connection.

    Here, as in the connection material of the present invention, a state in which a Cu—Sn compound is included as a phase, a condition that becomes a state of a Sn-based solder containing Cu6Sn5 from room temperature to 200 ° C., is a Sn—Cu binary phase diagram. It demonstrates using FIG. 14 shown.

    In a composition with less Cu content than Sn-0.9Cu, when the solder melts and solidifies, Sn contained more than the eutectic composition first precipitates as the primary crystal, and finally Sn and Cu6Sn5 solidify as the eutectic structure. To do. At this time, since Cu6Sn5 is dispersed and precipitated at the grain boundaries and the like inside the connection, it does not precipitate in the form of a barrier layer on the Ni-based plating. Therefore, heat resistance cannot be obtained. On the other hand, in a composition having a higher Cu content than Sn-0.9Cu, when the solder melts and solidifies, the Cu6Sn5 phase is first precipitated. At this time, since Cu6Sn5 is preferentially deposited on the Ni-based plating, a Cu-Sn compound barrier layer is formed. Finally, Sn and Cu6Sn5 solidify as a eutectic structure. The barrier layer of the Cu—Sn compound is formed by the mechanism as described above.

    That is, as the connection material of the present invention, a composition having a higher Cu6Sn5 phase content than the eutectic composition may be selected. If it is Sn-Cu binary system, Cu should be 0.9wt% or more, but when other elements are included, the eutectic composition differs depending on the alloy system. A connection material having a composition containing a large amount of Cu6Sn5 phase may be selected. In this case, in the case of Sn-3Ag-0.5Cu or Sn-0.7Cu that is usually used, since there are few Cu6Sn5 phases compared to the eutectic composition, no barrier layer is formed on the Ni-based plating.

    As described above, the connection material of the present invention and the connection mechanism thereof have been described. However, the connection material is supplied in any shape such as paste or wire as shown in FIGS. Even after the connection, a barrier layer of Cu—Sn compound is formed on the Ni-based plating after connection. It is possible to select a supply method according to the connection environment as appropriate.

    In order to obtain good wetting, Sn-based solder containing a Cu6Sn5 phase from room temperature to 200 ° C. should preferably be selected so that the liquidus temperature is equal to or lower than the connection temperature.

    Next, one embodiment of a semiconductor device using the connection material of the present invention and a manufacturing method thereof will be described with reference to FIGS. 8 and 9 showing a semiconductor device for an on-vehicle AC generator.

    The semiconductor device shown in FIG. 8 performs Ni-based plating on a semiconductor element 1 and a connection portion connected to the first surface of the semiconductor element 1 via a connection member 2 formed using the connection material of the present invention. Thermal expansion coefficient difference buffer in which Ni-plating is applied to the connecting portion connected via the connecting member 4 connected to the lead electrode body 7 and the second surface of the semiconductor element 1 using the connecting material of the present invention. A support electrode body 3 in which Ni-plating is applied to a connection portion connected via a connection member 6 connected to the material 5 and the other surface of the thermal expansion coefficient difference buffer material 5 using the connection material of the present invention; Have

    By using the connection material of the present invention for connection, an interface reaction can be suppressed even when used at high temperatures, and a semiconductor device having connection reliability can be provided. In addition, although not using the connection material of this invention in all the connection parts, the use of a part of other materials is also possible, but it is preferable to use the connection material of this invention in all the connection parts from a viewpoint of connection reliability. At this time, any connection material having a composition having a higher Cu6Sn5 phase content than the eutectic composition may be used, and different materials may be used for each connection portion.

    Here, as the thermal expansion coefficient difference buffer material 5, any of Al, Mg, Ag, Zn, Cu, and Ni can be used. These are metals with low yield stress and are susceptible to inertial deformation. Therefore, by applying these metals to the connection portion, it is possible to buffer the stress generated by the difference in thermal expansion coefficient of the connected material at the connection portion during cooling after connection and during the temperature cycle. At this time, as shown in FIG. 5, the yield stress is preferably 75 MPa or less. When the yield stress is 100 MPa or more, the stress cannot be sufficiently buffered and the semiconductor element may be cracked. The thickness is preferably 30 to 500 μm. When the thickness is 30 μm or less, the stress cannot be sufficiently buffered, and cracks may occur in the semiconductor element and the intermetallic compound. When the thickness is 500 μm or more, Al, Mg, Ag, and Zn have a higher coefficient of thermal expansion than Cu electrodes, so that the effect of the coefficient of thermal expansion is increased, leading to a decrease in reliability.

    Moreover, as the thermal expansion coefficient difference buffer material 5, any one of Cu / Invar alloy / Cu composite material, Cu / Cu2O composite material Cu-Mo alloy, Ti, Mo, and W can be used. By this thermal expansion coefficient difference buffer material 5, it is possible to buffer the stress generated in the connection during the temperature cycle and the cooling after the connection resulting from the difference in the thermal expansion coefficient between the semiconductor element and the Cu electrode. At this time, if the thickness is too thin, the stress cannot be sufficiently buffered, and cracks may occur in the semiconductor element and the intermetallic compound. Therefore, the thickness is preferably 30 μm or more.

    Since Sn-based solder has higher thermal conductivity than high-lead solder, it is possible to reduce the resistance and heat dissipation of the semiconductor device, and the thermal expansion coefficient buffer material 5 may be omitted as shown in FIG. Although it is possible, it is preferable to insert it in order to obtain sufficient connection reliability even if Sn type solder harder than high lead solder is used.

    As described above, Ni, Ni—P, Ni—B or the like may be used as the Ni-based plating provided on each connected material, but Au plating or Ag plating may be further applied on the plating. Thereby, wettability can be improved. In that case, a Cu—Sn compound barrier layer can be formed on the underlying Ni-based plating by diffusing all the plating layers such as Au and Ag into the solder at the time of connection.

    Next, a method for manufacturing a semiconductor device will be described. In the order of the members and connecting members as shown in FIG. 8, that is, on the support electrode body 3, the Sn-based solder foil 6 containing the Cu6Sn5 phase from room temperature to 200 ° C. has a thermal expansion coefficient of 11 × 10 −6 / ° C. Ni-plated CIC (Cu / Inver / Cu) clad material thermal expansion coefficient buffer material 5 with a diameter of 6.8 mm, Sn-type solder foil 4 containing Cu6Sn5 phase from room temperature to 200 ° C., diameter 6 mm thick 0.2 mm Ni plated semiconductor element 1, Sn-based solder foil 2 containing Cu6Sn5 phase from room temperature to 200 ° C., Cu plate electrode 7 with a Cu plate 4.5 mm in diameter and 0.2 mm thick Place in a matching jig and connect in a heat treatment furnace in a reducing atmosphere in which 50% hydrogen is mixed with nitrogen at a temperature of 380 ° C. for 1 minute, and then inject silicone rubber 8 around the joint and cure. Thus, a semiconductor device is manufactured. In addition, if a connection process is performed at 220-450 degreeC and a reducing atmosphere, favorable connection can be performed without using a flux.

Table 1 shows the results of actual measurement of the connection strength between the semiconductor element and each member after the temperature cycle test and the high temperature storage test of this semiconductor device.

    A case where the strength is 80% or more of the initial connection strength is indicated by ○, and a case where the strength is less than 80% is indicated by ×. In all of Examples 1 to 6, it was confirmed that a strength of 80% or more of the initial connection strength was maintained after a temperature cycle test of 500 cycles of −40 ° C. (30 min.) / 200 ° C. (30 min.). In addition, it was confirmed that the strength of 80% or more of the initial connection strength was maintained in all of Examples 1-6 after the high temperature standing test at 210 ° C. for 1000 hours. Further, for these, it was also confirmed that the thermal resistance fluctuation was within 10% before and after the test. FIG. 12 shows, as an example, a cross section of the connection interface when a sample connected using Sn-5Cu solder is left at a high temperature of 210 ° C. for 1000 hours. Due to the barrier layer of Cu-Sn compound, the Ni layer does not disappear even after being left at high temperature, and void formation due to volume change is not observed.

    In the above description, the process of connecting the entire structure simultaneously with Sn-based solder containing Cu6Sn5 phase from room temperature to 200 ° C. has been described. On the thermal expansion coefficient difference buffer material 5, the semiconductor element 1 and the lead electrode body with a Cu plate are provided. 3 is connected with Sn-based solder containing Cu6Sn5 phase from room temperature to 200 ° C, and then connected to support electrode 3 with Sn-based solder containing Cu6Sn5 phase from room temperature to 200 ° C. The connection may be divided into several parts.

    In the order of the members and connecting members as shown in FIG. 9, that is, on the support electrode body 3, the connecting member 4 of Sn-based solder foil containing Cu6Sn5 phase from room temperature to 200 ° C., having a diameter of 6 mm and a thickness of 0.2 mm Stacked Ni-plated semiconductor element 1, connecting member 2 of Sn-based solder foil containing Cu6Sn5 phase from room temperature to 200 ° C., and Cu lead electrode body 7 with a diameter of 4.5 mm and a thickness of 0.2 mm within the alignment jig Then, in a heat treatment furnace, connection is made at a temperature of 450 ° C. for 5 minutes in a reducing atmosphere in which 50% of hydrogen is mixed with nitrogen. Is made.

    Table 1 shows the results of actual measurement of the connection strength between the semiconductor element and each member after the temperature cycle test and the high temperature storage test of this semiconductor device. A case where the strength is 80% or more of the initial connection strength is indicated by ○, and a case where the strength is less than 80% is indicated by ×. In all of Examples 7 to 12, after a temperature cycle test of −40 ° C. (30 min.) / 200 ° C. (30 min.) 500 cycles, it was confirmed that the strength of 80% or more of the initial connection strength was maintained. Further, it was confirmed that the strength of 80% or more of the initial connection strength was maintained in all of Examples 7-12 even after the high temperature standing test at 210 ° C. for 1000 hours. Further, for these, it was also confirmed that the thermal resistance fluctuation was within 10% before and after the test.

    Next, as a comparative example, the results of measuring a connection material having a composition in which the Cu6Sn5 phase content does not increase from the eutectic composition will be described below.

    The connection structure is the same as that of Example 1-6. As shown in Table 1, the results are indicated by ○ when the strength is 80% or more of the initial connection strength and by × when the strength is less than 80%. In Comparative Examples 1 and 2, after a temperature cycle test of -40 ° C. (30 min.) / 200 ° C. (30 min.) 500 cycles, it was confirmed that the strength of 80% or more of the initial connection strength was maintained. However, after the high-temperature standing test at 210 ° C. for 1000 hours, both Comparative Examples 1 and 2 had a strength of less than 80% of the initial connection strength. When the connection cross section was observed, voids 14 as shown in FIGS. 10 and 11 were formed at the connection interface. It is considered that the interfacial reaction progressed by leaving at high temperature, and the connection strength decreased due to void formation caused by the volume change accompanying the growth of the compound layer. FIG. 13 shows, as an example, a cross section of the connection interface when a sample connected with Sn-3Ag-0.5Cu solder is left at 210 ° C. for 1000 hours. Since the Cu—Sn compound barrier layer is not formed, Sn and Ni react to completely disappear the Ni layer, and even the underlying Cu reacts with Sn to form a thick Cu—Sn compound layer. As a result, a large volume change occurs, voids are formed, and a good connection state cannot be maintained.

    In Comparative Examples 3 and 4, the initial connection strength of both Comparative Examples 1 and 2 was observed after a temperature cycle test of 500 cycles of −40 ° C. (30 min.) / 200 ° C. (30 min.) And after a high temperature storage test of 210 ° C. for 1000 hours. The strength was less than 80%. When the connection cross section was observed, voids 14 as shown in FIGS. 10 and 11 were formed at the connection interface. It is considered that the interfacial reaction progressed by leaving at high temperature, and the connection strength decreased due to void formation caused by the volume change accompanying the growth of the compound layer.

    In addition, the comparative example 5 is a comparative example by a high lead free solder, and all have a favorable result.

    Next, another embodiment of a semiconductor device using the connection material of the present invention will be described with reference to FIGS.

    FIG. 15 shows an example of component mounting on a printed circuit board. The printed circuit board 102, the surface mounted component 101 connected to the printed circuit board 102 using the connection material of the present invention, and mounted thereon, and the printed circuit board 102 and the book The chip component 103 is connected and mounted using the connection material of the invention, and the insertion mounting component 104 is connected and mounted using the connection material of the present invention with the printed board 102. Although not shown, Ni-based plating is applied to each surface to be connected. By mounting using the connection mechanism of the present invention, the interface reaction can be suppressed even at high temperatures, and a semiconductor device with high connection reliability can be provided.

    In FIG. 15, all of the surface mounting component 101, the chip component 103, and the insertion mounting component 104 are mounted, but any one or two of them may be mounted. Also, other solder materials such as Sn-3Ag-0.5Cu may be used in some connections.

Next, another embodiment of a semiconductor device using the connection material of the present invention will be described with reference to FIGS.

    The semiconductor device shown in FIG. 16 is electrically connected by the semiconductor element 1, the frame 105 connected to the semiconductor element 1 using the connection material of the present invention, electrodes (not shown) provided on the semiconductor element 1, and wires 108. And an external lead 107 connected to, and a mold resin provided so as to cover the semiconductor element 1. Although not shown, Ni-based plating is applied to each surface to be connected. By using the connection mechanism of the present invention, an interface reaction can be suppressed even at high temperatures, and a semiconductor device with high connection reliability can be provided.

    Another semiconductor device mode is described with reference to FIGS.

    The semiconductor device shown in FIG. 17 has a structure typified by an RF module or the like, and includes a module substrate 109, a surface mount component 101 connected to the module substrate using the connection material of the present invention, and a module substrate of the present invention. It has a semiconductor element 1 connected using a connection material, a chip component connected to the module substrate using the connection material of the present invention, and a solder ball 110 provided on the back surface of the module substrate 1. Although not shown, Ni-based plating is applied to each surface to be connected. By using the connection mechanism of the present invention, an interface reaction can be suppressed even at high temperatures, and a semiconductor device with high connection reliability can be provided.

    In FIG. 15, all of the surface mounting component 101, the chip component 103, and the insertion mounting component 104 are mounted, but any one or two of them may be mounted. Also, other solder materials such as Sn-3Ag-0.5Cu may be used in some connections.

    Although several embodiments of the semiconductor device have been described above, the present invention is not limited to these embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. For example, it may be used for die bonding of a power transistor, a power IC, an IGBT substrate, a front end module such as an RF module, an automobile power module, or the like. In addition, if the connection material of the present invention used for connection is Sn-based solder having a composition containing more Cu6Sn5 phase than the eutectic composition, leveling treatment to the printed circuit board, dip to the component, regardless of its supply form Any method such as printing, foil, and wire may be used.

DESCRIPTION OF SYMBOLS 1 Semiconductor element, 2, 4, 6 Connecting member, 3 Support electrode body, 5 Thermal expansion coefficient difference relaxation material, 7 Lead electrode, 8 Silicone rubber, 10 Cu-Sn compound, 11 Ni plating, 12 Connected material, 13 Metal Intermetallic compound, 14 Void, 15 Cu layer, 16 Ni-Sn compound, 17 Solder foil, 18 Solder paste, 19 Solder wire, 101 Surface mount component, 102 Printed circuit board, 103 Chip component, 104 Insertion mount component, 105 Frame, 106 Mold resin, 107 leads, 108 wires, 109 module board, 110 solder balls.

Claims (15)

A power module for an automobile comprising a semiconductor element, a first connected member, and a first connecting member for connecting the first connected member,
A Ni-based layer is formed on the first surface on the semiconductor element side of the first connection member,
The first connecting member is composed of a Sn-Cu binary solder containing a Cu6-Sn5 compound and a Sn-based solder phase mainly composed of other than Cu6-Sn5,
The Sn-based solder phase is Sn-Cu based solder with 3 to 7 wt% Cu,
In the Ni-based layer, a region connected to the first connection member is covered with the Cu6-Sn5 compound,
An automotive power module, wherein the Ni-based layer formed on the first surface and the first surface are connected by the Cu6-Sn5 compound. The automobile power module according to claim 1,
A second connecting member and a second connected member;
The second connected member is made of Sn-Cu binary solder similar to the first connecting member,
A Ni-based layer is formed on the second surface of the second connecting member on the semiconductor element side,
In the Ni-based layer, a region connected to the second connection member is covered with the Cu6-Sn5 compound,
An automotive power module, wherein the Ni-based layer formed on the second surface and the first surface are connected by the Cu6-Sn5 compound. The automobile power module according to claim 2 ,
The power module for automobiles, wherein the Ni-based layer is formed by plating a Ni-based layer formed on the surface of the first surface or the second surface. The automobile power module according to claim 1, wherein
The power module for automobiles, wherein the Ni-based layer is Ni, Ni-P, or Ni-B. The power module for automobiles according to claim 2 or 3 ,
The automotive power module, wherein the entire area of the first surface or the second surface is covered with a laminate of the Ni-based layer and the Cu6-Sn5 compound. The power module for automobiles according to claim 2, 3 or 5 ,
The semiconductor device, wherein the entire area of the first surface or the second surface is covered with the Ni layer. The power module for automobiles according to claim 2, 3, 5 or 6 ,
The semiconductor device, wherein the Cu6-Sn5 compound is a barrier layer that protects the Ni-based layer and the first connected member or the second connected member from the Sn-based solder phase. The automobile power module according to any one of claims 2, 3, 5 to 7 ,
The power module for automobiles, wherein the first connected member or the second connected member is made of Cu. A power module for automobiles according to any one of claims 2, 3, 5 to 8 ,
The power module for automobiles, wherein the first connected member or the second connected member is an electrode. An automobile having a power module comprising a semiconductor element, a first connected member, and a first connecting member for connecting the first connected member,
The power module is
A Ni-based layer is formed on the first surface on the semiconductor element side of the first connection member,
The first connecting member is composed of a Sn-Cu binary solder containing a Cu6-Sn5 compound and a Sn-based solder phase mainly composed of other than Cu6-Sn5,
The Sn-based solder phase is Sn-Cu based solder with 3 to 7 wt% Cu,
In the Ni-based layer, a region connected to the first connection member is covered with the Cu6-Sn5 compound,
The Ni-based layer formed on the first surface and the first surface are connected by the Cu6-Sn5 compound. The automobile according to claim 10,
The power module further includes:
A second connecting member and a second connected member;
The second connected member is made of Sn-Cu binary solder similar to the first connecting member,
A Ni-based layer is formed on the second surface of the second connecting member on the semiconductor element side,
In the Ni-based layer, a region connected to the second connection member is covered with the Cu6-Sn5 compound,
An automobile characterized in that the Ni-based layer formed on the second surface and the first surface are connected by the Cu6-Sn5 compound. The vehicle of claim 11, wherein,
The automobile is characterized in that the Ni-based layer is formed by plating a Ni-based layer formed on the surface of the first surface or the second surface. An automobile having an alternator comprising a semiconductor element, a first connected member, and a first connecting member for connecting the first connected member,
The alternator is
A Ni-based layer is formed on the first surface on the semiconductor element side of the first connection member,
The first connecting member is composed of a Sn-Cu binary solder containing a Cu6-Sn5 compound and a Sn-based solder phase mainly composed of other than Cu6-Sn5,
The Sn-based solder phase is Sn-Cu based solder with 3 to 7 wt% Cu,
In the Ni-based layer, a region connected to the first connection member is covered with the Cu6-Sn5 compound,
The Ni-based layer formed on the first surface and the first surface are connected by the Cu6-Sn5 compound. The vehicle of claim 1 3, wherein,
The AC generator further includes:
A second connecting member and a second connected member;
The second connected member is made of Sn-Cu binary solder similar to the first connecting member,
A Ni-based layer is formed on the second surface of the second connecting member on the semiconductor element side,
In the Ni-based layer, a region connected to the second connection member is covered with the Cu6-Sn5 compound,
An automobile characterized in that the Ni-based layer formed on the second surface and the first surface are connected by the Cu6-Sn5 compound. The vehicle of claim 14, wherein,
The automobile is characterized in that the Ni-based layer is formed by plating a Ni-based layer formed on the surface of the first surface or the second surface.

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