JP2012238749A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device having a structure where conductor members serving as electrodes are easily exposed on main surfaces of a module.SOLUTION: In a semiconductor device, a semiconductor chip 1 is sealed with a sealing member 9 and a first conductor member 3 and a second conductor member 5 are respectively exposed on main surfaces. The first conductor member has a joining part 31, a free end part 32, and a deformation part 33 positioned between the joining part and the free end part. The deformation part is disposed so as to be bent at an obtuse angle or an acute angle with respect to the joining part and also be bent at an acute angle with respect to the free end part.

Description

  The present invention relates to a semiconductor device, and more particularly to a semiconductor device having a configuration in which both opposing surfaces of a semiconductor chip are electrically connected to a conductor member.

  As shown in Patent Document 1 and Patent Document 2, a conventional resin mold type semiconductor module (hereinafter referred to as a module) is a semiconductor from either one of two main surfaces of a resin sealing portion in which a semiconductor element is sealed. The heat generated in the element is dissipated to the outside, and the electrode terminal that is electrically connected to the semiconductor element and connected to the external device is exposed to the outside from the side surface of the resin sealing portion.

  In the case of a product in which a plurality of such modules are arranged close to each other and electrically connected to each other to form a desired circuit, the electrode terminals of adjacent modules need to be arranged so as not to contact each other. . In addition, when the semiconductor element is an element for high voltage, the electrode terminals of adjacent modules are not in contact with each other, but it is necessary to secure a spatial distance and an insulation distance necessary for insulation between adjacent electrode terminals. There was a hindrance to product miniaturization.

  In contrast, the modules disclosed in Patent Document 3 and Patent Document 4 have a configuration in which the conductor member electrically connected to the semiconductor element is exposed on the main surface of the resin sealing portion. In Patent Document 3 and Patent Document 4, the conductor member exposed on the main surface of the resin sealing portion is only used for heat dissipation. However, by utilizing this conductor member as an electrode terminal, it is possible to improve the problems in the modules disclosed in Patent Document 1 and Patent Document 2.

Japanese Patent No. 4403665 Japanese Patent Laid-Open No. 2002-033445 JP 2010-109000 A Japanese Patent No. 3601432

  As in the modules disclosed in Patent Document 3 and Patent Document 4, in order to expose the conductor member electrically connected to the semiconductor element to the main surface of the resin sealing portion, resin sealing is performed with a mold. When conducting the process, make sure that the side surface of the conductor member and the inner surface of the mold die are in close contact with each other so that there is no gap between the side surface of the conductor member that should be the exposed surface and the inner surface of the mold die. It is necessary to keep.

  However, in the structure in which the conductor member and the semiconductor element are laminated via the solder, it is very difficult to manufacture the module with the accuracy of matching the module dimension in the lamination direction with the mold clamping dimension of the mold. It can be easily guessed.

  Further, the conductor member and the solder are highly rigid metal members and are not in a shape that can be easily deformed including the semiconductor element. Therefore, it can be inferred that it is still difficult to absorb the mismatch between the dimension of the module and the clamping dimension in the stacking direction by deformation of any member.

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a semiconductor device having a structure in which a conductor member serving as an electrode can be easily exposed to the main surface of a module.

In order to achieve the above object, the present invention is configured as follows.
That is, a semiconductor device according to an aspect of the present invention includes a semiconductor chip, a first conductor member bonded to the element formation surface of the semiconductor chip, and a first surface bonded to the facing surface of the semiconductor chip facing the element formation surface. A two-conductor member, the semiconductor chip, and a sealing member that seals a part of the first conductor member and the second conductor member, the first conductor member and the second conductor member, In the semiconductor device having an exposed surface exposed to each main surface of the sealing member in a stacking direction in which the semiconductor chip, the first conductor member, and the second conductor member are stacked, the first conductor member is a plate. A member having a joint portion, a deformable portion, and a free end portion which are arranged to be bent with respect to each other, and the joint portion is located on one end side of the first conductor member and joined to the element formation surface And the free end is It is a part that is located on the other end side of the conductor member and forms the exposed surface, and the deformed part is located between the joined part and the free end part and bent at an obtuse or acute angle with respect to the joined part. It is arrange | positioned and it bends and arrange | positions at an acute angle with respect to a free end part, It is characterized by the above-mentioned.

  According to the semiconductor device of one aspect of the present invention, the joint portion, the deformable portion, and the free end portion that constitute the first conductor member are arranged to be bent with respect to each other, and are arranged between the joint portion and the free end portion. The deformed portion was bent and arranged at an obtuse or acute angle with respect to the joint portion, and was bent and arranged at an acute angle with respect to the free end portion. With this configuration, when the mold is clamped in the stacking direction, the deformed portion is displaced with respect to the fixed joint portion, and the free end portion moves toward the anti-semiconductor chip side. Try to move. Therefore, the free end can always maintain a close state to the mold. Therefore, since the exposed side surfaces of the first conductor member and the second conductor member are always in close contact with the mold, the first conductor member and the second conductor member are placed on the main surface of the sealing member in the semiconductor device. It can be easily exposed.

It is a schematic sectional drawing which shows the structure of the semiconductor device in Embodiment 1 of this invention. FIG. 3 is a process diagram illustrating a method for manufacturing the semiconductor device shown in FIG. 1. FIG. 7 is a schematic cross-sectional view showing a structure in a modified example of the semiconductor device shown in FIG. 1. FIG. 4 is a circuit diagram showing a circuit configuration example that can be formed by the semiconductor device shown in FIG. 3. FIG. 10 is a schematic cross-sectional view showing a structure in another modification of the semiconductor device shown in FIG. 1. It is a schematic sectional drawing which shows the structure of the semiconductor device in Embodiment 2 of this invention. It is a figure for demonstrating the effect by the 1st conductor member shown in FIG.

  A semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings. In each figure, the same or similar components are denoted by the same reference numerals.

Embodiment 1 FIG.
A semiconductor device 100 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view of the semiconductor device 100. The semiconductor device 100 includes a semiconductor chip 1, a first conductor member 3, a second conductor member 5, and a sealing member 9 as basic components.

  In this embodiment, the semiconductor chip 1 is a semiconductor chip mainly made of Si or SiC and having a thickness of about 0.1 to 0.2 mm. The element formation surface 1a on which the emitter electrode is formed, and the element formation surface 1a And a back surface 1b having a collector electrode formed on the opposing surface.

  The first conductor member 3 is a conductive member made of a strip-shaped plate material that serves as an electrode, and includes a joining portion 31, a deforming portion 33, and a free end portion 32 in the extending direction thereof. The portion 33 and the free end portion 32 are arranged so as to be bent with respect to each other in the angular relationship described below.

That is, the joint portion 31 is a portion located on one end side of the first conductor member 3 and extending in parallel or substantially parallel to the element formation surface 1a of the semiconductor chip 1, and is a joint member (first member) having electrical conductivity. The solder 4 as an example of the bonding member) is a portion bonded to the emitter electrode of the element forming surface 1a.
The free end portion 32 is a portion located on the other end side of the first conductor member 3 and is a free end with respect to the fixed joint portion 31. Further, the free end portion 32 forms an exposed surface 3a.

  The deformable portion 33 is located between the joint portion 31 and the free end portion 32, is bent with respect to the joint portion 31 at an obtuse angle θ <b> 1 in the present embodiment, and is acute with respect to the free end portion 32. It is bent at a certain angle θ2. The joint portion 31 and the free end portion 32 are disposed substantially in parallel via the deformable portion 33, and the first conductor member 3 has a U-shape deformed as illustrated.

  Further, the element forming surface 1a of the semiconductor chip 1 has a part such as a guard ring that causes a malfunction when the potential is the same as that of the emitter electrode. When this part comes into contact with the first conductor member 3, the first conductor member 3 is attached. The same potential as the emitter electrode. Therefore, the joint portion 31 of the first conductor member 3 is configured to be joined only to the emitter electrode of the semiconductor chip 1.

The second conductor member 5 is a block-like conductive member that serves as an electrode, and is electrically connected to the collector electrode on the back surface 1b of the semiconductor chip 1 via a solder 4 that is an example of a second bonding member. . In the second conductor member 5, the surface facing the surface connected to the collector electrode is the exposed surface 5a.
In the present embodiment, Cu or Cu alloy is used as the first conductor member 3 and the second conductor member 5.

  For example, an epoxy mold resin can be used for the sealing member 9. The sealing member 9 is injected into a mold described later, and the semiconductor chip 1, the first conductor member 3 excluding the exposed surface 3 a, and the exposed surface 5 a are excluded. Although not shown, the second conductor member 5 and the bonding wires and part of the control terminals are collectively sealed. In the sealing member 9 that seals the semiconductor chip 1 and the like, the exposed surface 3a of the first conductor member 3 and the exposed surface 5a of the second conductor member 5 are exposed on the two opposing main surfaces 9a and 9b, respectively. To do.

  In this way, the semiconductor device 100 of this embodiment is configured. In this semiconductor device 100, heat generated from the semiconductor chip 1 is mainly transmitted to the second conductor member 5 through the solder 4 having excellent thermal conductivity, and heat is radiated from the exposed surface 5a of the second conductor member 5. It can be done.

  In addition, a cooling member or the like may be brought into contact with the exposed surface 5a of the second conductor member 5 to further promote heat dissipation. Further, the first and second conductor members 3 and 5 are electrical paths to the semiconductor chip 1. That is, conduction with the collector electrode of the semiconductor chip 1 is achieved via the second conductor member 5, and conduction with the emitter electrode of the semiconductor chip 1 is achieved via the first conductor member 3.

Next, a method for manufacturing the semiconductor device 100 described above will be described with reference to FIG.
First, the joint portion 31 of the first conductor member 3 is arranged in parallel or substantially parallel to the element formation surface 1a of the semiconductor chip 1, and the joint portion 31 is sandwiched between the plate-like solder 4 and the emitter electrode of the element formation surface 1a. Deploy. Further, the second conductor member 5 is disposed with the plate-like solder 4 sandwiched between the collector electrodes on the back surface 1 b of the semiconductor chip 1. Thus, in a state where the semiconductor chip 1, the first conductor member 3, and the second conductor member 5 are stacked and arranged, the solder 4 is melted by collectively heating them in a reducing atmosphere, and then cooled. Thus, a semi-finished product in which the first conductor member 3 and the second conductor member 5 are joined to the semiconductor chip 1 is manufactured.

  Next, as shown in FIG. 2A, the above-mentioned semi-finished product is brought into contact with the exposed surface 5a of the second conductor member 5 on the inner surface of the lower mold 11b with the mold 11 opened. Arrange in a state. Next, when the mold 11 is closed along the mold opening / closing direction 12, the inner surface of the upper mold 11a is connected to the free end 32 of the first conductor member 3 as shown in FIG. It contacts the exposed surface 3a. At this time, the mold 11 is not completely closed and is slightly in the state of a gap.

  When the mold 11 is further closed, the upper mold 11a presses the exposed surface 3a of the free end 32. As a result, the deformed portion 33 of the first conductor member 3 is bent and deformed like a cantilever, and the upper end 33 a of the deformed portion 33 is displaced in a direction approaching the semiconductor chip 1. At this time, if the angle θ2 formed by the deformed portion 33 and the free end portion 32 does not change, the free end portion 32 should be displaced in the direction as indicated by the arrow A, for example, away from the semiconductor chip 1. However, in practice, since the upper mold 11a exists in the direction of arrow A, the free end 32 cannot be displaced. As a result, the exposed surface 3a in the free end portion 32 is pressed against the inner wall surface of the upper mold 11a over the entire surface.

  Therefore, as shown in FIG. 2C, when the mold 11 is completely closed, the repulsive force of the deformed portion 33 of the first conductor member 3 causes the exposed surface 3a of the first conductor member 3 and the first The exposed surface 5a of the two-conductor member 5 is pressed and brought into close contact with the inner wall surfaces of the upper mold 11a and the lower mold 11b.

  In such a state, by injecting the sealing member 9 into the mold die 11, the second conductor is provided between the exposed surface 3a of the first conductor member 3 and the inner wall surface of the upper mold die 11a. The sealing member 9 does not enter between the exposed surface 5a of the member 5 and the inner wall surface of the lower mold die 11b. Therefore, each member such as the semiconductor chip 1 is sealed by the sealing member 9 with the exposed surface 3a of the first conductor member 3 and the exposed surface 5a of the second conductor member 5 exposed, and the semiconductor device 100 is completed. .

  As described above, in the semiconductor device 100 according to the first embodiment, the first conductor member 3 is joined to the element forming surface 1a of the semiconductor chip 1 via the solder 4 and the outside of the sealing member 9. And relaying a free end 32 which is a free end with respect to the fixed joint 31 having the exposed surface 3a exposed to the surface, one end of the joint 31 and one end of the free end 32. And a deformable portion 33 that can be deformed by an external force. Further, when the upper end 33a of the deformable portion 33 is displaced in a direction approaching the semiconductor chip 1, the other end portion 32a of the free end portion 32 is displaced away from the semiconductor chip 1, for example, in a direction indicated by an arrow A. did. That is, the deformable portion 33 is configured to be bent at an obtuse angle θ1 in the present embodiment with respect to the joint portion 31 and bend at an acute angle θ2 with respect to the free end portion 32. .

  With such a configuration, with respect to the semi-finished product in which the semiconductor chip 1, the first conductor member 3, and the second conductor member 5 are joined with the solder 4, the mold opening / closing direction 12 of the mold 11, that is, the semi-finished product. The dimension variation in the stacking direction is absorbed, the semiconductor chip 1 is damaged and destroyed, and the exposed surface 3a of the first conductor member 3 and the exposed surface 5a of the second conductor member 5 are covered with the sealing member 9. This makes it possible to produce products with stable quality at low cost.

  In the first embodiment, the case where only one semiconductor chip 1 is provided has been described. However, a plurality of semiconductor chips 1 may be provided in the semiconductor device 100. In this case, the first conductor member 3 and the second conductor member 5 may be arranged for each semiconductor chip 1, and further, as shown in FIG. 3, the first conductor member 3 and the second conductor member 5 are A plurality or a plurality of types of semiconductor chips 1 may be joined together.

  With such a configuration, even when a plurality of semiconductor chips 1 are used, an increase in the number of components can be suppressed to a minimum. Further, when two types of semiconductor chips 1 are used and an IGBT is applied as the semiconductor chip 1 and an FWD is applied as the semiconductor chip 2, the IGBT and FWD that constitute a part of the inverter circuit 20 as shown in FIG. The circuit 21 can be easily configured.

  Moreover, the element structure differs between IGBT and FWD, and generally IGBT has lower breakdown resistance against external force. When the first conductor member 3 is deformed during resin sealing with the molding die 11 as described above, a deformation force acts on the semiconductor chip 1 adjacent to the deformed portion 33. Therefore, when the configuration shown in FIG. 3 is adopted, it is desirable to configure the semiconductor chip 1 close to the deforming portion 33 as FWD and the semiconductor chip 2 relatively far from the deforming portion 33 as IGBT.

  Further, when the first conductor member 3 and the second conductor member 5 and the sealing member 9 are separated, there is a problem that the reliability of the semiconductor device 100 cannot be maintained due to corrosion or the like due to moisture entering from the separation interface. There is also. Therefore, in order to improve the adhesion between the first conductor member 3 and the second conductor member 5 and the sealing member 9, the surfaces of the first conductor member 3 and the second conductor member 5 may be roughened.

  Further, as a method for connecting the external wiring to the exposed surface 3a of the free end portion 32, solder bonding or ultrasonic bonding can be employed. However, when ultrasonic bonding is performed, the bonding surface is preferably smooth. . Therefore, it is preferable that the surface of the first conductor member 3 is roughened as described above. However, when ultrasonic bonding is used as a wiring connection method to the first conductor member 3, at least the free end portion 32 is exposed. The surface 3a is preferably not roughened. With this configuration, it is possible to ensure both the reliability of the semiconductor device 100 and the stability of ultrasonic bonding.

  Further, when ultrasonic bonding is used as a wiring connection method to the first conductor member 3, since the ultrasonic vibration is applied to the free end portion 32, the free end portion 32 is provided even if the roughening is performed. There is also concern that peeling of the interface between the sealing member 9 and the sealing member 9 is promoted. Therefore, in order to prevent the occurrence of such an adverse effect, a protrusion 32b that protrudes toward the semiconductor chip 1 may be formed on the first conductor member 3 as shown in FIG. FIG. 5 illustrates a configuration in which the protrusion 32b is formed by bending the other end 32a of the first conductor member 3 toward the semiconductor chip 1 as an example of forming the protrusion 32b. By providing such a protrusion 32 b on the first conductor member 3, the interface peeling between the free end 32 and the sealing member 9 can be suppressed due to the anchor effect of the sealing member 9.

Embodiment 2. FIG.
In Embodiment 1, the 1st conductor member 3 demonstrated as a U-shaped deformation | transformation shape as shown in FIG. However, the first conductor member 3 is not limited to such a shape. For example, even if it is a Z-shaped first conductor member 3-2 as shown in FIG. Can be easily guessed.
That is, also in the semiconductor device 102 in the second embodiment, the first conductor member 3-2 is pressed by the upper mold 11a and deformed. In that case, the 1st conductor member 3-2 should just be comprised so that the free end part 32 may be pressed on the upper mold 11a.

  For example, when the first conductor member has a shape as shown in FIG. 6, that is, the deformed portion 33 is bent at an obtuse angle with respect to the joint portion 31 and is also bent at an obtuse angle with respect to the free end portion 32. In the configuration, when the deformation portion 33 is displaced by clamping the mold 11, the free end portion 32 is displaced in a direction away from the upper mold 11 a as indicated by a dotted line. Therefore, when the first conductor member has the shape shown in FIG. 6, it is obvious that the above-described effect cannot be obtained.

  Therefore, when the first conductor member 3-2 is pressed and deformed by the upper mold 11a, the first conductor member 3-2 has a deformed portion so that the free end 32 is pressed against the upper mold 11a. In the second embodiment, 33 is bent at an acute angle θ3 and is bent at an acute angle θ2 with respect to the free end 32, corresponding to the angle θ1. It was configured as follows.

  As described above, from the first and second embodiments, the deformed portion 33 of the first conductor member is bent and arranged at an obtuse or acute angle with respect to the joint portion 31 and is acute with respect to the free end portion 32. By being configured to be bent at an angle, the free end portion 32 can be pressed against the upper mold 11a when the first conductor member is pressed and deformed by the upper mold 11a.

  Various modifications to the semiconductor device 100 described in the first embodiment can also be applied to the semiconductor device 102 of the second embodiment.

DESCRIPTION OF SYMBOLS 1 Semiconductor chip, 1a Element formation surface, 1st conductor member, 3a Exposed surface,
5 Second conductor member, 5a Exposed surface, 9 Sealing member,
11a Upper mold die, 11b Lower mold die,
31 joint part, 32 free end part, 33 deformation part,
100, 102 Semiconductor device.

Claims (4)

A semiconductor chip;
A first conductor member bonded to the element forming surface of the semiconductor chip;
A second conductor member bonded to the facing surface of the semiconductor chip facing the element forming surface;
A sealing member that seals a part of the semiconductor chip and the first conductor member and the second conductor member;
The first conductor member and the second conductor member have exposed surfaces exposed to the respective principal surfaces of the sealing member in the stacking direction in which the semiconductor chip, the first conductor member, and the second conductor member are stacked. In semiconductor devices,
The first conductor member is a plate-like member, and has a joint portion, a deformation portion, and a free end portion that are arranged to be bent with respect to each other, and the joint portion is located on one end side of the first conductor member. The portion that is joined to the element forming surface, the free end is a portion that is located on the other end side of the first conductor member and forms the exposed surface, and the deformed portion is a portion between the joined portion and the free end. Located between, bent and arranged at an obtuse or acute angle with respect to the joint, and arranged at an acute angle with respect to the free end,
A semiconductor device.   The semiconductor device according to claim 1, wherein a plurality of the semiconductor chips are provided, and the first conductor member and the second conductor member are joined by connecting at least two semiconductor chips.   3. The semiconductor device according to claim 1, wherein surfaces of the first conductor member and the second conductor member in contact with the sealing member are roughened rough surfaces.   4. The semiconductor device according to claim 1, wherein the free end portion of the first conductor member has a protrusion that protrudes toward the semiconductor chip. 5.

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