Semiconductor equipment

Abstract

To provide a semiconductor device in which the deformation when current is on or off in a semiconductor module can be suppressed and pump-out of a compound can be reduced.SOLUTION: A semiconductor device includes: a semiconductor module 1 including an insulating circuit board, a semiconductor chip provided on one main surface side of the insulating circuit board, and external connection terminals 6a to 6c provided on the one main surface side of the insulating circuit board; an external printed board 20 provided facing one main surface of the semiconductor module 1 and having penetration holes 20a and 20b to which the external connection terminals 6a to 6c are inserted; elastic members 71 and 72 provided between the one main surface of the semiconductor module 1 and the external printed board 20 and applying pressing forces F1 and F2 on the one main surface of the semiconductor module 1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0005]

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

Background Art

[0002] As a conventional semiconductor device, there is known a semiconductor module in which a power semiconductor chip (hereinafter simply referred to as "semiconductor chip") constituting a power semiconductor device such as a switching element for power conversion is mounted on an insulating circuit board. When the semiconductor module 101 has a configuration in which both ends are screwed, fixing spring plates are attached to both ends of a case that houses the semiconductor chip and the insulating circuit board inside. By fastening the fixing spring plates to the cooler with screws and washers, the semiconductor module is fixed to the cooler via a compound.

[0003] Patent Document 1 discloses a semiconductor module including a ceramic circuit board, a circuit pattern, and a sealing material, and having external connection terminals as press-fit terminals. Patent Document 2 discloses a configuration in which a spring restraining bracket is arranged below a control circuit board, and a leaf spring is arranged between the lower part of the spring restraining bracket and the upper part of the semiconductor module to press the semiconductor module from above.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In conventional semiconductor devices, when an electric current is applied to a semiconductor module, the heat generated by the current flowing through the semiconductor chip and other components causes them to expand. Because both ends of the case are fixed, the center of the case deforms upward. As the case deforms, the compound is also pulled upward in the center. Subsequently, when the current to the semiconductor module is cut off, the heat generation ceases, causing the components to contract, and the case deformation returns to its original state. As this phenomenon is repeated, the compound is gradually pushed out and flows out. This phenomenon is called pump-out. As a result, the compound is depleted, heat dissipation deteriorates, and the temperature of the semiconductor chip rises, which is a problem.

[0006] In view of the above issues, the present invention aims to provide a semiconductor device that can suppress deformation of the semiconductor module when the current is switched on and off, and can reduce compound pump-out. [Means for solving the problem]

[0007] One aspect of the present invention is a semiconductor device comprising: (a) an insulating circuit board, a semiconductor chip provided on one main surface side of the insulating circuit board, and an external connection terminal provided on one main surface side of the insulating circuit board; (b) an external printed circuit board provided opposite one main surface of the semiconductor module and having a through hole into which the external connection terminal is inserted; and (c) an elastic member provided between one main surface of the semiconductor module and the external printed circuit board and applying a pressing force to one main surface of the semiconductor module. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a semiconductor device that can suppress deformation of the semiconductor module when the current is switched on and off, and can reduce compound pump-out. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view of a semiconductor device according to an embodiment. [Figure 2] This is a side view of a semiconductor module according to the embodiment. [Figure 3] This is a plan view of a semiconductor module and an elastic member according to an embodiment. [Figure 4] This is an equivalent circuit diagram of a semiconductor module according to the embodiment. [Figure 5] This is a schematic cross-sectional view illustrating a method for assembling a semiconductor device according to an embodiment. [Figure 6] This is a schematic cross-sectional view of a semiconductor device relating to a comparative example. [Figure 7] This is a plan view of a semiconductor module relating to a comparative example. [Figure 8] This is a schematic cross-sectional view of a semiconductor module during deformation, relating to a comparative example. [Modes for carrying out the invention]

[0010] Embodiments will be described below with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals, and redundant explanations are omitted. However, the drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of the thickness of each layer, etc., may differ from the actual ones. Furthermore, there may be parts where the dimensional relationships and ratios differ between drawings. In addition, the embodiments shown below are illustrative examples of devices and methods for realizing the technical concept of the present invention, and the technical concept of the present invention is not limited to the materials, shapes, structures, arrangements, etc. of the components described below.

[0011] In the following explanation, the "first main electrode" of a semiconductor chip refers to either the source electrode or the drain electrode in the case of a field-effect transistor (FET) or electrostatic induction transistor (SIT). In the case of an insulated-gate bipolar transistor (IGBT), it refers to either the emitter electrode or the collector electrode. In the case of an electrostatic induction thyristor (SI thyristor), gate turn-off thyristor (GTO), or diode, it refers to either the anode electrode or the cathode electrode. Furthermore, the "second main electrode" of a semiconductor device refers to either the source electrode or the drain electrode that is not the first main electrode in the case of an FET or SIT. In the case of an IGBT, it refers to either the emitter electrode or the collector electrode that is not the first main electrode. In the case of an SI thyristor, GTO, or diode, it refers to either the anode electrode or the cathode electrode that is not the first main electrode. In other words, if the "first main electrode" is the source electrode, the "second main electrode" is the drain electrode. If the "first main electrode" is the emitter electrode, the "second main electrode" is the collector electrode. If the "first main electrode" is the anode electrode, then the "second main electrode" refers to the cathode electrode.

[0012] Furthermore, the definitions of directions such as "up," "down," "up and down," "left," "right," and "left and right" in the following explanation are merely for the convenience of explanation and do not limit the technical concept of the present invention. For example, it is obvious that if an object is rotated 90° and observed, "up and down" will be converted to "left and right" and read accordingly, and if it is rotated 180° and observed, "up and down" will be reversed and read accordingly.

[0013] <Configuration of semiconductor device> FIG. 1 shows a schematic cross-sectional view of a semiconductor device according to an embodiment. In FIG. 1, illustration of components appearing in the cross-section of a semiconductor module (power semiconductor module) 1 of the semiconductor device according to the embodiment is omitted, and a side surface of a case 8 on the front side of the semiconductor module 1 is illustrated. In the cross-sectional view shown in FIG. 1, the left-right direction in FIG. 1 is defined as the X-axis, and the right direction in FIG. 1 is defined as the positive direction of the X-axis. Further, a direction orthogonal to the X-axis, which is the back-and-forth direction in FIG. 1, is defined as the Y-axis, and the back side in FIG. 1 is defined as the positive direction of the Y-axis. Further, a direction orthogonal to the X-axis and the Y-axis, which is the up-down direction in FIG. 1, is defined as the Z-axis, and the up direction in FIG. 1 is defined as the positive direction of the Z-axis. The same shall apply to FIGS. 2 and subsequent figures.

[0014] As shown in FIG. 1, the semiconductor device according to the embodiment includes a semiconductor module 1, an external printed circuit board 20 provided to face one main surface (upper surface) side of the semiconductor module 1, elastic members 71 and 72 provided between one main surface of the semiconductor module 1 and the external printed circuit board 20, and a cooler (heat sink) 32 provided via a compound (bonding material) 31 on the main surface (lower surface) side opposite to one main surface of the semiconductor module 1.

[0015] The semiconductor module 1 is a semiconductor module called a “2-in-1” having functions equivalent to two power semiconductor elements. FIG. 2 is a side view of the semiconductor module 1. In FIG. 2, it is shown through a sealing member 7, and illustration of a portion of the case 8 covering the front side of the sealing member 7 is omitted.

[0016] As shown in FIG. 2, the semiconductor module 1 includes an insulating circuit board 10 and semiconductor chips 2a and 2b provided on one main surface (upper surface) side of the insulating circuit board 10. An internal printed circuit board 4 is provided on the other main surface (upper surface) side opposite to one main surface (lower surface) side of the semiconductor chips 2a and 2b facing the insulating circuit board 10.

[0017] The insulating circuit board 10 has, for example, a rectangular planar shape. The insulating circuit board 10 includes an insulating substrate 11, upper conductor layers 12a and 12b provided on one main surface (upper surface) side of the insulating substrate 11, and a lower conductor layer 13 provided on the other main surface (lower surface) side of the insulating substrate 11. The insulating circuit board 10 may be, for example, a direct copper bonding (DCB) substrate, an active brazing (AMB) substrate, or the like. The insulating substrate 11 is composed of, for example, a ceramic substrate made of aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), boron nitride (BN), or the like, or a resin insulating substrate using a polymer material or the like. The upper conductor layers 12a and 12b and the lower conductor layer 13 are composed of, for example, conductor foils made of copper (Cu), aluminum (Al), or the like. A predetermined circuit pattern is formed on the upper conductor layers 12a and 12b.

[0018] The semiconductor chips 2a and 2b may be made of, for example, a silicon (Si) material, or may be made of a wide-bandgap semiconductor material such as silicon carbide (SiC), gallium nitride (GaN), or gallium oxide (Ga2O3). Although the types of the semiconductor chips 2a and 2b differ depending on the application, for example, power semiconductor devices such as a metal oxide semiconductor field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), an electrostatic induction (SI) thyristor, and a gate turn-off (GTO) thyristor, and rectifying elements such as a freewheeling diode (FWD) can be adopted. Here, a case where the semiconductor chips 2a and 2b are SiC MOSFETs, the semiconductor chip 2a is the upper arm side semiconductor chip, and the semiconductor chip 2b is the lower arm side semiconductor chip will be described.

[0019] In FIG. 2, a case where the semiconductor module 1 has one semiconductor chip 2a and 2b each as the upper arm side and the lower arm side semiconductor chips is illustrated, but the number of semiconductor chips is not particularly limited and can be appropriately selected according to the rated current and the like. For example, the semiconductor module 1 may have two or more semiconductor chips each as the upper arm side and the lower arm side semiconductor chips.

[0020] The semiconductor chips 2a and 2b each have a first main electrode (drain electrode) on their lower side and a control electrode (gate electrode) and a second main electrode (source electrode) on their upper side. The drain electrode of semiconductor chip 2a is bonded to the upper conductor layer 12a of the insulating circuit board 10 via a bonding material such as solder or sintered material (not shown), or directly using direct bonding technology. The drain electrode of semiconductor chip 2b is bonded to the upper conductor layer 12b of the insulating circuit board 10 via a bonding material such as solder or sintered material, or directly using direct bonding technology.

[0021] The semiconductor chips 2a and 2b are electrically connected to the internal printed circuit board 4 via a plurality of bumps (post electrodes) 3a and 3b. The source electrode of semiconductor chip 2a is joined to a portion of the plurality of bumps 3a via a bonding material (not shown) such as solder or sintered material. The gate electrode of semiconductor chip 2a is joined to another portion of the plurality of bumps 3a via a bonding material (not shown) such as solder or sintered material. The source electrode of semiconductor chip 2b is joined to a portion of the plurality of bumps 3b via a bonding material (not shown) such as solder or sintered material. The gate electrode of semiconductor chip 2b is joined to another portion of the plurality of bumps 3b via a bonding material (not shown) such as solder or sintered material.

[0022] The bumps 3a and 3b may be, for example, rod-shaped, pin-shaped, or columnar, and specifically may be polygonal prisms such as cylinders, elliptical prisms, triangular prisms, or quadrangular prisms. For the material of the bumps 3a and 3b, metal materials such as copper (Cu) can be used. The bumps 3a and 3b may be bonded to the lower wiring layer 43 of the internal printed circuit board 4, or they may penetrate the internal printed circuit board 4 and be bonded to the upper wiring layer 42. The bumps 3a and 3b may be stud bumps made of gold (Au), solder, metal sintered bodies such as nano-silver (Ag) paste, pillar electrodes or ball-shaped electrodes made of various metal materials.

[0023] The internal printed circuit board 4 comprises an insulating layer 41, an upper wiring layer 42 provided on one main surface (upper surface) of the insulating layer 41, and a lower wiring layer 43 provided on the other main surface (lower surface) of the insulating layer 41. For example, the insulating layer 41 is made of a resin substrate made of polyimide resin or a combination of glass fiber and polyimide resin. The upper wiring layer 42 and the lower wiring layer 43 are made of conductive foil made of, for example, copper (Cu) or aluminum (Al). A predetermined circuit pattern is formed on the upper wiring layer 42 and the lower wiring layer 43. For example, the upper wiring layer 42 and the lower wiring layer 43 may have the same circuit pattern formed on them. The upper wiring layer 42 and the lower wiring layer 43 may be electrically connected to each other through through holes that penetrate the insulating layer 41.

[0024] The lower end of the drain-side connection terminal 6a, which is an external connection terminal for the main wiring on the positive electrode side, is joined to the upper conductor layer 12a of the insulating circuit board 10 via a bonding material (not shown), such as solder or sintered material. The drain-side connection terminal 6a extends upward toward the insulating circuit board 10. The drain-side connection terminal 6a is made of a metallic material such as copper (Cu). The drain-side connection terminal 6a supplies current to the drain electrode of the semiconductor chip 2a via the upper conductor layer 12a of the insulating circuit board 10.

[0025] The lower end of the source-side connection terminal 6b, which is an external connection terminal for the negative electrode main wiring, is joined to the upper wiring layer 42 of the internal printed circuit board 4 via solder or a bonding material such as sintered material (not shown). The source-side connection terminal 6b extends upward toward the top of the internal printed circuit board 4. The source-side connection terminal 6b is made of a metallic material such as copper (Cu). The source-side connection terminal 6b carries the current from the source electrode of the semiconductor chip 2b through the bump 3b and the internal printed circuit board 4 to the external printed circuit board 20 shown in Figure 1.

[0026] The lower end of the output terminal 6c, which is an external connection terminal for the main wiring on the output side, is joined to the upper conductor layer 12b of the insulating circuit board 10 via a bonding material (not shown) such as solder or sintered material. The output terminal 6c extends upward toward the insulating circuit board 10 and penetrates the internal printed circuit board 4. The output terminal 6c is electrically connected to the upper wiring layer 42 and the lower wiring layer 43 of the internal printed circuit board 4. The output terminal 6c is made of a metallic material such as copper (Cu). When the semiconductor chip 2a is ON, the output terminal 6c allows current from the source electrode of the semiconductor chip 2a to flow through the bump 3a and the internal printed circuit board 4 to the external printed circuit board 20 shown in Figure 1. When the semiconductor chip 2b is ON, the output terminal 6c supplies current from the external printed circuit board 20 shown in Figure 1 to the drain electrode of the semiconductor chip 2b via the upper conductor layer 12b of the insulating circuit board 10.

[0027] Although not shown in Figure 2, the internal printed circuit board 4 is electrically connected to multiple gate control terminals, which are external connection terminals for control wiring. Each gate control terminal applies a control signal to control the on / off state of the semiconductor chips 2a and 2b to the gate electrodes of the semiconductor chips 2a and 2b, respectively, via the internal printed circuit board 4 and bumps 3a and 3b.

[0028] The insulating circuit board 10, semiconductor chips 2a and 2b, bump 3a, and internal printed circuit board 4 are sealed by a sealing member 7. For the sealing member 7, a resin material such as a thermosetting resin with high heat resistance and rigidity can be used; specifically, epoxy resin, maleimide resin, cyanate resin, etc., can be used. The lower conductor layer 13 of the insulating circuit board 10 is exposed on the lower side of the sealing member 7.

[0029] The upper parts of the drain-side connection terminal 6a, source-side connection terminal 6b, and output terminal 6c protrude from the upper surface of the sealing member 7. The drain-side connection terminal 6a, source-side connection terminal 6b, and output terminal 6c are press-fit terminals. The drain-side connection terminal 6a has a main body portion 61 and a protruding portion (thickened portion) 62 that is thicker than the main body portion 61. The source-side connection terminal 6b has a main body portion 63 and a protruding portion 64 that is thicker than the main body portion 63. The output terminal 6c has a main body portion 65 and a protruding portion 66 that is thicker than the main body portion 65. Multiple gate control terminals, which are not shown in Figure 2, are also made of press-fit terminals.

[0030] A case 8 is provided to house the semiconductor chips 2a and 2b, the internal printed circuit board 4, and the sealing member 7 inside. The case 8 is made of a thermoplastic resin such as polyphenylene sulfide (PSS), polybutylene terephthalate (PBT), polybutylene succinate (PBS), polyamide, or acrylonitrile butadiene styrene (ABS). The case 8 is provided so as to surround the sides of the sealing member 7.

[0031] The external shapes of the sealing member 7 and the case 8 constitute the external shape of the semiconductor module 1 and have a substantially rectangular parallelepiped shape. The upper surfaces of the sealing member 7 and the case 8 correspond to the upper surface of the semiconductor module 1, and the lower surfaces of the sealing member 7 and the case 8 correspond to the lower surface of the semiconductor module 1. The case 8 may have not only side walls that cover the sides of the sealing member 7, but also a lid that covers the upper surface of the sealing member 7. In this case, the upper surface of the case 8 corresponds to the upper surface of the semiconductor module 1. An opening is provided in the lid of the case 8, and the drain-side connection terminal 6a, the source-side connection terminal 6b, and the output terminal 6c pass through the opening in the lid.

[0032] As shown in Figure 1, the lower surface of the semiconductor module 1 is bonded to the cooler 32 via a compound 31. The compound 31 is composed of, for example, a thermal interface material (TIM). Suitable TIMs include thermally conductive materials such as thermally conductive grease, elastomer sheets, room-temperature curing (RTV) rubber, gel, phase change material, solder, and silver solder. The cooler 32 is composed of a metallic material such as aluminum (Al).

[0033] An external printed circuit board 20 is provided opposite the upper surface of the semiconductor module 1. The external printed circuit board 20 has, for example, a rectangular planar shape. The external printed circuit board 20 comprises an insulating layer 21, an upper wiring layer 22 disposed on the upper surface of the insulating layer 21, and a lower wiring layer 23 disposed on the lower surface of the insulating layer 21. For example, the insulating layer 21 is made of a resin substrate made of polyimide resin or a combination of glass fiber and polyimide resin. The upper wiring layer 22 and the lower wiring layer 23 are made of conductive foil made of, for example, copper (Cu) or aluminum (Al). A predetermined circuit pattern is formed on the upper wiring layer 22 and the lower wiring layer 23.

[0034] The external printed circuit board 20 is provided with a plurality of through-holes 20a, 20b that penetrate through the external printed circuit board 20. The protruding portion 62 of the drain-side connection terminal 6a is press-fitted into the through-hole 20a of the external printed circuit board 20 and joined (press-fitted), and is electrically connected to at least one of the upper wiring layer 22 and the lower wiring layer 23. The protruding portion 64 of the source-side connection terminal 6b is press-fitted into the through-hole 20b of the external printed circuit board 20 and is electrically connected to at least one of the upper wiring layer 22 and the lower wiring layer 23. The protruding portion 66 of the output terminal 6c, which is located further back than the drain-side connection terminal 6a and the source-side connection terminal 6b, is press-fitted into the through-hole (not shown) of the external printed circuit board 20 and is electrically connected to at least one of the upper wiring layer 22 and the lower wiring layer 23.

[0035] Elastic members 71 and 72 are provided between the upper surface of the semiconductor module 1 and the external printed circuit board 20. The outer circumferential surfaces of the elastic members 71 and 72 are in contact with the upper surface of the semiconductor module 1 and one of the main surfaces (lower surface) of the external printed circuit board 20. The elastic members 71 and 72 are provided spaced apart from the drain-side connection terminal 6a, the source-side connection terminal 6b, and the output terminal 6c. The elastic members 71 and 72 may be in contact with at least one of the drain-side connection terminal 6a, the source-side connection terminal 6b, and the output terminal 6c. Elastic member 71 is provided between the drain-side connection terminal 6a and the output terminal 6c. Elastic member 72 is provided between the output terminal 6c and the source-side connection terminal 6b.

[0036] Figure 1 illustrates the case where the elastic members 71 and 72 are cylindrical, but they may also be cylindrical or other tubular shapes, columnar shapes such as cylindrical or prismatic shapes, point-like (dot-like) shapes, or hollow ball-like shapes. The elastic members 71 and 72 are made of materials that have elastic and insulating properties. As materials for the elastic members 71 and 72, elastomers such as silicone rubber, fluororubber, or urethane rubber can be used.

[0037] In Figure 1, the elastic members 71 and 72 are elastically deformed, sandwiched between the semiconductor module 1 and the external printed circuit board 20. The cross-sectional shape of the elastic members 71 and 72 is an ellipse, which is a circle that has been flattened by elastic deformation. As schematically shown by the arrows in Figure 1, the elastic members 71 and 72 apply pressing forces F1 and F2 due to elastic force to the upper surface of the sealing member 7, which is the upper surface of the semiconductor module 1. As a result, the semiconductor module 1 is pressed against the cooler 32 via the compound 31, and heat is dissipated. The elastic members 71 and 72 may be fixed in position by the pressing forces F1 and F2, or they may be bonded to the upper surface of the semiconductor module 1 and the lower surface of the external printed circuit board 20 with an adhesive or the like.

[0038] Figure 3 shows a plan view of the semiconductor module 1 and elastic members 71 and 72 shown in Figure 1. In Figure 3, the outlines of the planar patterns of the semiconductor chips 2a and 2b embedded in the semiconductor module 1 are schematically shown by dashed lines. The outlines of the planar patterns of the internal printed circuit board 4 embedded in the semiconductor module 1 are schematically shown by dashed lines. Figure 3 also illustrates the gate control terminals 9a to 9f that are electrically connected to the gate electrodes of the semiconductor chips 2a and 2b via the internal printed circuit board 4. The drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f are press-fit terminals, but are schematically shown as circles in Figure 3. Some of the gate control terminals 9a to 9f may constitute auxiliary source terminals for detecting the source-side current of the semiconductor chips 2a and 2b.

[0039] As shown in Figure 3, the semiconductor module 1 has a roughly rectangular planar shape. The X-axis in Figure 3, which is the left-right direction, is the longitudinal direction of the semiconductor module 1, and the Y-axis in Figure 3, which is the up-down direction, is the short-side direction of the semiconductor module 1.

[0040] The output terminal 6c is located approximately in the center of the semiconductor module 1. The drain-side connection terminal 6a and the source-side connection terminal 6b are located side by side in the longitudinal direction of the semiconductor module 1 at positions different from the output terminal 6c. The gate control terminals 9a to 9f are located in a row in the longitudinal direction of the semiconductor module 1, opposite the drain-side connection terminal 6a and the source-side connection terminal 6b relative to the output terminal 6c. The arrangement positions of the drain-side connection terminal 6a, the source-side connection terminal 6b, the output terminal 6c, and the gate control terminals 9a to 9f are not particularly limited.

[0041] The elastic members 71 and 72 are provided approximately in the center of the semiconductor module 1 in the longitudinal direction. The elastic members 71 and 72 are provided so as to extend parallel to the short direction of the semiconductor module 1, with the output terminal 6c in between. The number of elastic members 71 and 72 is not limited; only one of the elastic members 71 or 72 may be provided, or three or more elastic members may be provided. The elastic members 71 and 72 may be provided so as to extend parallel to the longitudinal direction of the semiconductor module 1, with the output terminal 6c in between. The elastic members may be ring-shaped and provided so as to surround the output terminal 6c.

[0042] As shown in Figure 1, the external printed circuit board 20 is fixed to the cooler 32 at both ends in the longitudinal direction of the semiconductor module 1 by fixing parts (24a, 25a, 26a) and (24b, 25b, 26b). The fixing parts (24a, 25a, 26a) and (24b, 25b, 26b) may be arranged at the four corners of the rectangular planar shape of the external printed circuit board 20.

[0043] The fixing parts (24a, 25a, 26a) include a screw 24a, a washer 25a, and a spacer 26a. The screw 24a is fastened to the cooler 32 via the washer 25a and spacer 26a. The fixing parts (24b, 25b, 26b) include a screw 24b, a washer 25b, and a spacer 26b. The screw 24b is fastened to the cooler 32 via the washer 25b and spacer 26b.

[0044] Next, the operation of the semiconductor module 1 of the semiconductor device according to the embodiment when the current is turned on will be described. Control signals that control the on / off switching of the semiconductor chips 2a and 2b shown in Figure 2 are applied to the gate electrodes of the semiconductor chips 2a and 2b via the gate control terminals 9a to 9f shown in Figure 3, through the internal printed circuit board 4 and bumps 3a and 3b, causing the semiconductor chips 2a and 2b to switch alternately.

[0045] The arrows I1 to I6 in Figure 2 schematically show the current path of semiconductor module 1. Current entering from the drain-side connection terminal 6a (arrow I1) flows through the upper conductor layer 12a of the insulating circuit board 10, from the semiconductor chip 2a on the upper arm side to the bump 3a (arrow I2), through the internal printed circuit board 4, and flows from the output terminal 6c to the external printed circuit board 20 (arrow I3). Next, current entering the output terminal 6c from the external printed circuit board 20 (arrow I4) flows through the upper conductor layer 12b of the insulating circuit board 10, from the semiconductor chip 2b on the lower arm side to the bump 3b (arrow I5), through the internal printed circuit board 4, and flows from the source-side connection terminal 6b to the external printed circuit board 20 (arrow I6).

[0046] Next, Figure 4 shows an example of the equivalent circuit of the semiconductor module 1 of the semiconductor device according to the embodiment. As shown in Figure 4, the semiconductor module 1 constitutes part of a three-phase bridge circuit. The second main electrode (drain electrode) of the upper arm transistor T1 is connected to the drain-side connection terminal P, and the first main electrode (source electrode) of the lower arm transistor T2 is connected to the source-side connection terminal N. The source electrode of transistor T1 and the drain electrode of transistor T2 are connected to the output terminal U and the auxiliary source terminal S1. The auxiliary source terminal S2 is connected to the source electrode of transistor T2. Gate control terminals G1 and G2 are connected to the gate electrodes of transistors T1 and T2. Body diodes D1 and D2, which act as freewheeling diodes (FWDs), are built into transistors T1 and T2 in antiparallel connection.

[0047] The drain-side connection terminal P, source-side connection terminal N, and output terminal U shown in Figure 4 correspond to the drain-side connection terminal 6a, source-side connection terminal 6b, and output terminal 6c shown in Figure 1. Transistors T1 and T2 shown in Figure 4 correspond to semiconductor chips 2a and 2b shown in Figure 1, respectively. Gate control terminals G1 and G2 and auxiliary source terminals S1 and S2 shown in Figure 4 correspond to gate control terminals 9a to 9f shown in Figure 3.

[0048] <Manufacturing method for semiconductor devices> Next, an example of a semiconductor device manufacturing method (assembly method) according to the embodiment will be described. An insulating circuit board 10 shown in Figure 2 is prepared, and semiconductor chips 2a and 2b are mounted on the upper surface of the upper conductor layers 12a and 12b of the insulating circuit board 10 via a bonding material. Next, bumps 3a and 3b are mounted on the upper surface of the semiconductor chips 2a and 2b via a bonding material, and an internal printed circuit board 4 is mounted on the bumps 3a and 3b via a bonding material.

[0049] Next, the lower ends of the drain-side connection terminal 6a and output terminal 6c are mounted on the upper surfaces of the upper conductor layers 12a and 12b of the insulating circuit board 10 via a bonding material, and the lower end of the source-side connection terminal 6b is mounted on the upper surface of the upper wiring layer 42 of the internal printed circuit board 4 via a bonding material. The gate control terminals 9a to 9f shown in Figure 3 are also mounted on the upper surface of the upper wiring layer 42 of the internal printed circuit board 4 via a bonding material. Next, the insulating circuit board 10, semiconductor chips 2a and 2b, bumps 3a and 3b, internal printed circuit board 4, drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f are bonded to each other by heat treatment.

[0050] Next, the insulating circuit board 10, semiconductor chips 2a and 2b, bumps 3a and 3b, and internal printed circuit board 4 are placed inside the case 8. The sealing material 7 is filled inside the case 8, sealing the insulating circuit board 10, semiconductor chips 2a and 2b, bumps 3a and 3b, and internal printed circuit board 4 with the sealing material 7. The upper parts of the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f protrude from the upper surface of the sealing material 7. As a result, the semiconductor module 1 is completed.

[0051] Next, as shown in Figure 5, elastic members 71 and 72 are placed on the upper surface of the semiconductor module 1. An external printed circuit board 20 is prepared and placed above the semiconductor module 1, and aligned. Then, as shown in Figure 1, the external printed circuit board 20 is fastened and fixed to the cooler 32 by fixing parts (24a, 25a, 26a) and (24b, 25b, 26b), thereby press-fitting the drain-side connection terminal 6a and source-side connection terminal 6b into the through-holes 20a and 20b of the external printed circuit board 20, and press-fitting the output terminal 6c and gate control terminals 9a to 9f into the through-holes (not shown) of the external printed circuit board 20. At this time, the elastic members 71 and 72 are sandwiched between the semiconductor module 1 and the external printed circuit board 20 and undergo elastic deformation, generating pressing forces F1 and F2 on the elastic members 71 and 72. In this way, the semiconductor device according to the embodiment is completed.

[0052] Alternatively, instead of pre-placing the elastic members 71 and 72 on the upper surface of the semiconductor module 1 and elastically deforming them when fixing the external printed circuit board 20 to the cooler 32, the elastic members 71 and 72 may be inserted between the external printed circuit board 20 and the semiconductor module 1 after the external printed circuit board 20 has been fixed to the cooler 32, in an elastically deformed state.

[0053] <Comparative Example> Here, a semiconductor device relating to the comparative example will be described with reference to Figures 6 to 8. Figure 6 is a schematic cross-sectional view of the semiconductor device relating to the comparative example, and Figure 7 is a plan view of only the semiconductor module 101 of the semiconductor device relating to the comparative example. In Figure 6, the illustration of the components appearing in the cross-section of the semiconductor module 101 is omitted, and the side view of the case 108 on the front side of the semiconductor module 101 is shown. As shown in Figure 6, the semiconductor device relating to the comparative example differs from the semiconductor device according to the embodiment in that it does not have an elastic member between the external printed circuit board 20 and the semiconductor module 101.

[0054] Furthermore, the semiconductor device in the comparative example differs from the semiconductor device in the embodiment in that the semiconductor module 101 has a screw-fastened configuration at both ends, as shown in Figures 6 and 7. Fixing spring plates 102a and 102b are attached to both ends of the case 108 of the semiconductor module 101. The fixing spring plates 102a and 102b are fixed to the cooler 32 by screws 104a and 104b via washers 103a and 103b.

[0055] Furthermore, the semiconductor device relating to the comparative example differs from the semiconductor device according to the embodiment in that, as shown in Figures 6 and 7, the drain-side connection terminal 106a, source-side connection terminal 106b, output terminal 106c, and gate control terminals 107a to 107f are terminals of a fixed thickness rather than press-fit terminals. As shown in Figure 6, the drain-side connection terminal 106a and source-side connection terminal 106b are joined to the external printed circuit board 20 via solder 105a and 105b. Similarly, the output terminal 106c and gate control terminals 107a to 107f are joined to the external printed circuit board 20 via solder (not shown).

[0056] In the semiconductor device of the comparative example, the semiconductor module 101 is screw-fastened at both ends, making it prone to pump-out. Specifically, when current is applied to the semiconductor module 101, and the semiconductor chip and components contained within the semiconductor module 101 expand due to the heat generated by the current flowing through them, the central part of the case 108 deforms upward, as schematically shown by arrow 109 in Figure 8, because both ends of the case 108 are fixed. Along with the deformation of the case 108, the central part of the compound 31 is also pulled upward. Subsequently, when the current to the semiconductor module 101 is turned off and heat generation ceases, the components contract, and the deformation of the case 108 returns to its original state. As the above phenomenon is repeated, the compound 31 is gradually pushed out and flows out. As a result, the compound 31 is depleted, heat dissipation deteriorates, and the temperature of the semiconductor chip rises.

[0057] <Effects> In contrast, according to the semiconductor device of this embodiment, by fitting elastic members 71 and 72 between the external printed circuit board 20 and the semiconductor module 1, the pressing forces F1 and F2 of the central part of the semiconductor module 1 are directly transmitted, and the semiconductor module 1 is pressed with a strong force by the cooler 32 via the compound 31. As a result, deformation of the semiconductor module 1 that occurs when the current of the semiconductor module 1 is turned on and off can be suppressed, and pump-out can be reduced.

[0058] Furthermore, according to the semiconductor device of the embodiment, the semiconductor module 1 is pressed firmly against the cooler 32 via the compound 31 by the elastic members 71 and 72. Therefore, unlike the semiconductor device of the comparative example shown in Figures 6 and 7, it is not necessary to fix the semiconductor module 101 to the cooler 32 using fixing spring plates 102a and 102b, washers 103a and 103b, and screws 104a and 104b at both ends of the case 108 of the semiconductor module 101. Thus, compared to the semiconductor device of the comparative example, the space required for arranging the fixing spring plates 102a and 102b, washers 103a and 103b, and screws 104a and 104b can be reduced, and the semiconductor device of the embodiment can be miniaturized. In addition, since the semiconductor module 1 can be freely deformed laterally when the current of the semiconductor module 1 is turned on and off, upward deformation of the semiconductor module 1 can be suppressed.

[0059] Furthermore, according to the semiconductor device of the embodiment, the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f are configured as press-fit terminals. As a result, when the semiconductor module 1 is switched on and off, even if the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f move upward along with the upward deformation of the semiconductor module 1, the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f can slide up and down inside the through holes 20a, 20b, etc. of the external printed circuit board 20, thereby suppressing the vertical movement of the external printed circuit board 20 and maintaining the pressing forces F1, F2 by the elastic members 71, 72.

[0060] Furthermore, by configuring the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f as press-fit terminals, when assembling the semiconductor device according to the embodiment, after placing the elastic members 71 and 72 on the upper surface of the semiconductor module 1, and then pressing the elastic members 71 and 72 with the external printed circuit board 20 to cause elastic deformation, the external printed circuit board 20 can be moved vertically by adjusting the tightening by the fixing parts (24a, 25a, 26a) and (24b, 25b, 26b), thereby adjusting the amount of elastic deformation and the pressing force F1 and F2 of the elastic members 71 and 72.

[0061] (Other embodiments) As described above, the present invention has been described by embodiments, but the descriptions and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure.

[0062] For example, while the semiconductor module 1 of the semiconductor device according to the embodiment is shown as a "2-in-1" configuration having the functions of two power semiconductor elements, it is also applicable to a "1-in-1" configuration having the functions of one power semiconductor element. Furthermore, the semiconductor device according to the embodiment may have multiple semiconductor modules 1; for example, three semiconductor modules 1 may be arranged in a row to form a "6-in-1" configuration.

[0063] Furthermore, although the embodiment illustrates a case where the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f are press-fit terminals, the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f may not be press-fit terminals but rather terminals of a certain thickness. In this case, the drain-side connection terminal 6a, source-side connection terminal 6b, output terminal 6c, and gate control terminals 9a to 9f may be joined to the external printed circuit board 20 via a bonding material such as solder.

[0064] Furthermore, the configurations disclosed in the embodiments can be combined as appropriate, within a non-contradictory scope. Thus, it goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined solely by the inventive features relating to the claims that are reasonable based on the above description. [Explanation of Symbols]

[0065] 1,101… Semiconductor module 2a, 2b… Semiconductor chips 3a, 3b... Post electrodes (bumps) 4…Internal printed circuit board 6a, 106a... External connection terminals (drain side connection terminals) 6b, 106b… External connection terminals (source side connection terminals) 6c, 106c… External connection terminals (output terminals) 7...Sealing member 8,108... cases 9a~9f, 107a~107f... External connection terminals (gate control terminals) 10…Insulated circuit board 11…Insulating substrate 12a, 12b… Upper conductor layer 13…Lower conductor layer 20…External printed circuit board 20a, 20b...Through hole 21…Insulating layer 22…Upper wiring layer 23...Lower wiring layer 24a, 24b... screws 25a, 25b... Washers 26a, 26b… Spacers 31... Compound 32...Cooler 41…Insulating layer 42…Upper wiring layer 43...Lower wiring layer 61, 62, 63... Main body 62, 64, 66... ​​protruding parts (thick parts) 71, 72… Elastic members 102a, 102b... Fixing spring plate 103a, 103b... Washers 104a, 104b... Screws 105a, 105b... solder 109... Arrow D1, D2... Body diodes F1,F2…pressing force G1, G2... Gate control terminals I1~I6…Arrows (current path) N...Source side connection terminal P...Drain side connection terminal S1, S2... Auxiliary source terminals T1, T2… Transistors U...Output terminal

Claims

1. A semiconductor module comprising an insulating circuit board, a semiconductor chip provided on one main surface side of the insulating circuit board, and an external connection terminal provided on the one main surface side of the insulating circuit board, An external printed circuit board is provided facing one main surface of the semiconductor module and has a through hole into which the external connection terminal is inserted, An elastic member provided between the one main surface of the semiconductor module and the external printed circuit board, which applies a pressing force to the one main surface of the semiconductor module, Equipped with, A semiconductor device characterized in that the elastic member is made of a cylindrical elastomer.

2. The semiconductor device according to claim 1, characterized in that the external connection terminal is a press-fit terminal.

3. The one main surface of the semiconductor module is rectangular. The elastic member is provided in the central part of the semiconductor module in the longitudinal direction. The semiconductor device according to claim 1 or 2.

4. The semiconductor device according to claim 3, characterized in that the elastic member extends parallel to the short direction of the semiconductor module.

5. The external connection terminal is provided in the central part in the longitudinal direction of the semiconductor module. The two elastic members are provided sandwiching the external connection terminal. The semiconductor device according to feature 4.

6. The semiconductor device according to any one of claims 1 to 5, further comprising a cooler provided via a compound on the other main surface side of the semiconductor module opposite to the one main surface.

7. The semiconductor device according to claim 6, further comprising a fixing part for fixing the external printed circuit board to the cooler.

8. The semiconductor device according to any one of claims 1 to 7, wherein the semiconductor module further comprises a sealing member for sealing the semiconductor chip.

9. The semiconductor device according to any one of claims 1 to 8, wherein the semiconductor module further comprises an internal printed circuit board provided facing the other main surface side of the semiconductor chip opposite to the one main surface facing the insulating circuit board, and electrically connected to the semiconductor chip.

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