Semiconductor module manufacturing method

Abstract

Provided is a method for manufacturing a semiconductor module that comprises: a plurality of semiconductor elements constituting an upper arm circuit and a lower arm circuit; a first conductor plate to which, among the plurality of semiconductor elements, the semiconductor element constituting the upper arm circuit is bonded; a second conductor plate to which, among the plurality of semiconductor elements, the semiconductor element constituting the lower arm circuit is bonded; and a sealing member for mold-sealing the plurality of semiconductor elements, the first conductor plate, and the second conductor plate. The method comprises: forming a plate-like member that has a first region forming the first conductor plate, a second region forming the second conductor plate, and a thin portion located between the first region and the second region and having a thickness smaller than the thickness of junction regions where the plurality of semiconductor elements are bonded; and forming the first conductor plate and the second conductor plate by cutting the thin portion to separate the first region and the second region.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a semiconductor module.

Background Art

[0002] Power modules that are required to take measures against biased current to chips tend to increase in size due to their layout, so there is a demand to manufacture compact power modules while implementing countermeasures against biased current. Regarding miniaturization of power modules, for example, the following Patent Document 1 discloses a technology that achieves miniaturization of a semiconductor device by press-punching a thick plate, crushing a portion different from the punched portion, and moving the crushed volume to the press-punched portion to form a product.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The thickness of the part where the chip is mounted on the lead frame needs to be increased for heat diffusion, but increasing the thickness of the lead frame also requires the press-punching width to be increased in manufacturing, which gives rise to the problem that the power module increases in size.

Means for Solving the Problems

[0005] A method for manufacturing a semiconductor module comprising: a plurality of semiconductor elements constituting an upper arm circuit and a lower arm circuit; a first conductor plate to which the semiconductor elements constituting the upper arm circuit are joined; a second conductor plate to which the semiconductor elements constituting the lower arm circuit are joined; and a sealing member for molding and sealing the plurality of semiconductor elements, the first conductor plate, and the second conductor plate, wherein a plate-shaped member is formed having a first region for forming the first conductor plate, a second region for forming the second conductor plate, and a thin-walled portion between the first and second regions having a thickness smaller than the thickness of the joining region to which the plurality of semiconductor elements are joined; and the first region and the second region are separated by cutting the thin-walled portion to form the first conductor plate and the second conductor plate. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a method for manufacturing a semiconductor module that achieves both heat dissipation of the chip and miniaturization. [Brief explanation of the drawing]

[0007] [Figure 1] Overall perspective view of the semiconductor module [Figure 2] Diagram illustrating the semiconductor module with the thermal conductive sheet removed (Figure 1). [Figure 3] Diagram of the circuit assembly after removing the sealing resin from the semiconductor module shown in Figure 2. [Figure 4] Figure 2 is a view from the R direction. [Figure 5] Figure 4 shows the circuit configuration after disassembling the semiconductor module, removing the sealing resin. [Figure 6] Cross-sectional view of a semiconductor module relating to one embodiment of the present invention. [Figure 7] A partially enlarged view of the cross-sectional view of Figure 6, relating to one embodiment of the present invention. [Figure 8] Explanatory diagram of the cut portion and thin-walled portion of a plate-shaped member according to one embodiment of the present invention. [Figure 9] A diagram illustrating the process of manufacturing a conductive component from a plate-shaped member according to one embodiment of the present invention. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (Manufacturing method) (Figure 1) The semiconductor module 100 is formed by molding and sealing it with a sealing resin 101, which is a sealing member. The semiconductor module 100 has the upper arm control terminal 102A, P main terminal 102B, N main terminal 103A, AC main terminal 104A, and lower arm control terminal 104B protruding from the sealing resin 101 to the outside. A thermal conductive sheet 105 is bonded to both sides of the semiconductor module 100. In this way, the semiconductor module 100 and the thermal conductive sheet 105 are integrated into one unit.

[0011] (Figure 2) The semiconductor module 100 is formed by temporarily bonding a portion of the fourth conductor plate 106 and a portion of the fifth conductor plate 107 to the thermal conductive sheet 105, and then forming a sealing resin 101. Since the sealing resin 101 is formed along the surface of the thermal conductive sheet 105, the sealing resin 101 and the exposed portion of the fourth conductor plate 106 and the exposed portion of the fifth conductor plate 107 that are not sealed by the sealing resin 101 are substantially the same surface.

[0012] (Figure 3) The circuit body 200 in a state before the aforementioned semiconductor module 100 is sealed with the sealing resin 101 includes a first conductor plate 102, a second conductor plate 104, a third conductor plate 103, a fourth conductor plate 106, a fifth conductor plate 107, and a semiconductor element 109. The semiconductor element 109 is, for example, a SiC chip or the like, and constitutes an upper arm circuit and a lower arm circuit.

[0013] The first conductor plate 102, the second conductor plate 104, and the third conductor plate 103 are arranged on the same plane on a flat surface. The first conductor plate 102 is opposed to the fourth conductor plate 106 with at least one semiconductor element 109 constituting the upper arm circuit interposed therebetween. The semiconductor element 109 interposed therebetween is electrically joined to the first conductor plate 102 and the fourth conductor plate 106 using solder or the like. In FIG. 3, two semiconductor elements 109 are arranged side by side on the first conductor plate 102.

[0014] The second conductor plate 104 is opposed to the fifth conductor plate 107 with at least one semiconductor element 109 (not shown) constituting the lower arm circuit interposed therebetween. The semiconductor element 109 interposed therebetween is electrically joined to the second conductor plate 104 and the fifth conductor plate 107 using solder or the like. Although not illustrated in FIG. 3, two semiconductor elements 109 are arranged side by side on the second conductor plate 104 in the same manner as on the first conductor plate 102.

[0015] The semiconductor elements 109 on the first conductor plate 102 and the second conductor plate 104 respectively are electrically joined to the upper arm control terminal 102A and the lower arm control terminal 104B using unillustrated aluminum wires or the like.

[0016] The temperature sensor 108 is arranged on the surface side for connecting the semiconductor elements 109 on at least one of the first conductor plate 102 and the second conductor plate 104. The output terminal of the temperature sensor 108 is connected to at least one of the upper arm control terminal 102A and the lower arm control terminal 104B. By doing so, the temperature sensor 108 detects the temperature of the semiconductor element 109 and outputs a temperature signal.

[0017] (FIG. 4) A part of the surface of the convex shape 102C and a part of the surface of the convex shape 104C, which will be described later, are temporarily bonded to the heat conductive sheet 105, respectively. Thereafter, the sealing resin 101 is formed to fabricate the semiconductor module 100. Since the sealing resin 101 is formed along the surface of the heat conductive sheet 105 after the temporary bonding of the exposed surface of the convex shape 102C, the exposed surface of the convex shape 104C, the convex shape 102C, the convex shape 104C and the heat conductive sheet 105, the sealing resin 101, the part of the surface of the convex shape 102C that is not sealed by the sealing resin 101, and the part of the surface of the convex shape 104C that is not sealed by the sealing resin 101 are substantially flush with each other.

[0018] (Figure 5) In the first conductor plate 102, a convex shape 102C is provided on the surface opposite to the surface to which the semiconductor element 109 is bonded. In the third conductor plate 103, a convex shape 103C protruding in the same direction as the protruding direction of the convex shape 102C is provided. In the second conductor plate 104, a convex shape 104C is provided on the surface opposite to the surface to which the semiconductor element 109 is bonded.

[0019] Between the convex shape 102C and the convex shape 104C, a thin portion 102D having a thickness smaller than the thickness of the convex shape 102C and a thin portion 104D having a thickness smaller than the thickness of the convex shape 104C are formed. Further, between the convex shape 103C and the convex shape 104C, a thin portion 103E having a thickness smaller than the thickness of the convex shape 103C and the thin portion 104D are formed.

[0020] The first conductor plate 102, the second conductor plate 104, and the third conductor plate 103 are arranged on the same plane. The fourth conductor plate 106 and the fifth conductor plate 107 are arranged on the same plane.

[0021] The fourth conductor plate 106 has a pedestal portion 106B electrically connected to at least one semiconductor element 109. The fifth conductor plate 107 has a pedestal portion 107B electrically connected to at least one semiconductor element 109.

[0022] (Figure 6) Figure 6(a) is a cross-sectional view illustrating the connection relationship between the first conductor plate 102, the second conductor plate 104, the fourth conductor plate 106, and the fifth conductor plate 107, and Figure 6(b) is a cross-sectional view illustrating the connection relationship between the second conductor plate 104, the third conductor plate 103, and the fifth conductor plate 107.

[0023] On the first conductor plate 102, a convex shape 102C is provided on the surface opposite to the surface to which the semiconductor element 109 is joined, and the convex shape 102C is exposed from the sealing resin 101. On the second conductor plate 104, a convex shape 104C is provided on the surface opposite to the surface to which the semiconductor element 109 is joined, and the convex shape 104C is exposed from the sealing resin 101. The convex shapes 102C and 104C exposed from the sealing resin 101 are made to be on the same plane and bonded to the thermal conductive sheet 105.

[0024] A base portion 106B is provided on the fourth conductor plate 106. The semiconductor element 109 is sandwiched between the first conductor plate 102 and the base portion 106B and electrically connected to each. A base portion 107B is provided on the fifth conductor plate 107. The semiconductor element 109 is sandwiched between the second conductor plate 104 and the base portion 107B and electrically connected to each.

[0025] On the fourth conductor plate 106, the surface opposite to the surface on which the base portion 106B is provided is exposed from the sealing resin 101. On the fifth conductor plate 107, the surface opposite to the surface on which the base portion 107B is provided is exposed from the sealing resin 101. The surfaces of the fourth conductor plate 106 and the fifth conductor plate 107 that are exposed from the sealing resin 101 are made to be on the same plane and bonded to the thermal conductive sheet 105.

[0026] A connection portion 107A is provided on the fifth conductor plate 107. The fifth conductor plate 107 is electrically connected to the third conductor plate 103 via the connection portion 107A using solder or the like.

[0027] (Figure 7) In the third conductor plate 103, a convex shape 103C is provided in the same direction as the convex shape 102C. Between the first conductor plate 102 and the second conductor plate 104, a thin-walled portion 102D having a thickness smaller than the thickness of the convex shape 102C and a thin-walled portion 104D having a thickness smaller than the thickness of the convex shape 104C are formed. Furthermore, between the third conductor plate 103 and the second conductor plate 104, a thin-walled portion 103E and a thin-walled portion 104D are formed, both having thicknesses smaller than the thickness of the convex shape 103C.

[0028] Each component of the semiconductor module 100 is connected and sealed with sealing resin 101, but a gap 110 is provided between the thin-walled portion 102D, the thin-walled portion 104D, and the thin-walled portion 103E. This gap 110 is a cut portion 111, which is the cutting point of the plate-like member when forming each conductive plate from the plate-like member, as will be described later.

[0029] (Figure 8) Each conductor plate is formed by manufacturing a plate-shaped member 1 for manufacturing a semiconductor module 100 using the manufacturing method shown in Figure 9, which will be described later. By cutting the thin-walled portion, it is separated into thin-walled portion 102D, thin-walled portion 104D, and thin-walled portion 103E, forming the first conductor plate 102, the second conductor plate 104, and the third conductor plate 103. The gap portion formed by this cutting is the cut portion 111.

[0030] Terminals 102A, 102B, 103A, 104A, and 104B are terminals that protrude from the sealing member mentioned above, but they are integrally molded from the plate-shaped member 1 at the same time as the conductor plate is formed. This improves the accuracy of the formation on the plane of the conductor plate, prevents variations in thickness and steps, and also prevents resin leakage because there is no gap between the mold and the conductor plate when filling with sealing resin.

[0031] As described above, multiple semiconductor elements 109 are arranged side by side on the side of the first conductor plate 102 opposite to the convex shape 102C and on the side of the second conductor plate 104 opposite to the convex shape 104C (see Figures 3 and 5), and the thin-walled portion is cut along the direction of arrangement of the multiple semiconductor elements. In this way, the cut portion 111 is parallel to the direction of drawing (or rolling, etc.) in the left-right direction in Figure 8 of the conductor plate being formed, and the cut portion 111 can always be formed within the range of the thin-walled portion of the plate-shaped member 1.

[0032] The cutting width of the cutting section 111 is made smaller than the thickness (length) of each of the convex shapes 102C, 103C, and 104C. Also, the cutting width of the cutting section 111 is made equal to or greater than the thickness (length) of each of the thin-walled sections 102D, 103E, and 104D.

[0033] Furthermore, by molding in the manner described above, the cutting width of the cut portion 111 in the third conductor plate 103, which is the negative terminal, can be narrowed to reduce its size and lower costs.

[0034] (manufacturing process) (Figure 9) Figure 9(a) illustrates the plate-shaped member 1 before punching, Figure 9(b) illustrates the plate-shaped member 1 during punching, and Figure 9(c) illustrates the plate-shaped member 1 after punching.

[0035] As shown in Figure 9(a), in its pre-processing state, the plate-shaped member 1 has a first region 1a that forms the first conductor plate 102, a second region 1b that forms the second conductor plate 104, and a thin-walled portion 2 between the first region 1a and the second region 1b that has a thickness smaller than the thickness of the bonding region where multiple semiconductor elements 109 are bonded. Although not shown, the plate-shaped member 1 also has a third region, which becomes the third conductor plate 103 after processing.

[0036] As shown in Figure 9(b), the thin-walled portion 2 is cut by punching a press die 3 into the thin-walled portion 2 from the side 1c where the semiconductor element 109 is joined, toward the opposite side. When cutting, the cutting width of the thin-walled portion 2 is set to a press punch width (cutting width) smaller than the thickness of the joining area of ​​the semiconductor element 109. In this way, the cutting (punching) of the thin-walled portion 2 becomes easier, and deformation after punching is less likely to occur, so it can be formed into the desired shape without additional steps. Furthermore, it is possible to prevent the semiconductor module 100 to be formed from becoming larger, reduce the amount of material used for formation, and lower costs.

[0037] Furthermore, as a method for making the thin-walled portion 2 thinner than the thickness of the first region 1a and the second region 1b, a method of pre-forming it to a smaller size using roll material may be used.

[0038] As shown in Figure 9(b), a portion of the thin-walled section 2 is punched out from the semiconductor element mounting surface 1c side by press punching, thereby punching out a fragment 5 equal to the press width. The burrs 4 formed on the thin-walled section 2 when punched out occur on the side opposite to the semiconductor element mounting surface 1c. In this way, the burrs 4 do not extend in the direction of the conductor plate (see Figure 7) facing the semiconductor element, thus preventing a reduction in the insulation distance and ensuring reliable insulation. Furthermore, the possibility of damaging the semiconductor element with the burrs 4 when the semiconductor element is mounted is reduced.

[0039] Since the side 1c on which the semiconductor element is mounted becomes a shear surface, the shape can be formed with high precision. During press punching, a portion of the thin-walled section 2 is left on both the first conductor plate 102 and the second conductor plate 104. In this way, the cut section 3a is always present within the range of the thin-walled section 2, and the thin-walled section 2 can be reliably punched out during the punching process, taking into account dimensional variations. This contributes to ease of press punching and high precision in molding, resulting in higher productivity compared to conventional methods. Furthermore, it contributes to the manufacture of a semiconductor module 100 that achieves both heat dissipation and miniaturization of the semiconductor element.

[0040] Furthermore, by employing this manufacturing method, when the semiconductor module 100 is formed by sealing with the sealing resin 101, the resin flows around the thin-walled portion 2, resulting in good adhesion between the conductor plate and the resin, ensuring secure sealing. In addition, the sealing resin 101 can support the conductor plate, contributing to stability.

[0041] According to the embodiments of the present invention described above, the following effects and advantages are achieved.

[0042] (1) A method for manufacturing a semiconductor module 100 comprising: a plurality of semiconductor elements 109 constituting an upper arm circuit and a lower arm circuit; a first conductor plate 102 to which the semiconductor elements 109 constituting the upper arm circuit are joined; a second conductor plate 104 to which the semiconductor elements 109 constituting the lower arm circuit are joined; and a sealing member 101 for molding and sealing the plurality of semiconductor elements 109, the first conductor plate 102 and the second conductor plate 104, wherein a plate-shaped member 1 is formed having a first region 1a for forming the first conductor plate 102, a second region 1b for forming the second conductor plate 104, and a thin-walled portion 2 between the first region 1a and the second region 1b having a thickness smaller than the thickness of the joining region to which the plurality of semiconductor elements 109 are joined; and the first region 1a and the second region 1b are separated by cutting the thin-walled portion 2 to form the first conductor plate 102 and the second conductor plate 104. In this way, it is possible to provide a method for manufacturing a semiconductor module 100 that achieves both heat dissipation of the chip and miniaturization.

[0043] (2) The cutting width of the thin-walled portion 2 is made smaller than the thickness of the bonding region. This contributes to the formation of a miniaturized semiconductor module 100.

[0044] (3) Terminals protruding from the sealing member 101 on the first conductor plate 102 and the second conductor plate 104 are integrally formed from the plate-shaped member 1. This improves the accuracy of the formation on the plane of the conductor plate.

[0045] (4) The plate-shaped member 1 has a third region that forms the third conductor plate 103. By cutting the thin portion, the third region is separated from the first region 1a and the second region 1b to form the third conductor plate 103. In this way, components of the semiconductor module 100 can be manufactured in a miniaturized form.

[0046] (5) The thin-walled portion 2 is cut from the surface 1c on the side to which the semiconductor element 109 is joined toward the opposite surface. This ensures reliable insulation.

[0047] (6) Multiple semiconductor elements 109 are arranged side by side on the first conductor plate 102 and the second conductor plate 104, respectively, and the thin-walled portion 2 is cut along the direction in which the multiple semiconductor elements 109 are arranged. In this way, the cut portion 111 can always be formed within the range of the thin-walled portion 2 of the plate-shaped member 1.

[0048] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted. [Explanation of Symbols]

[0049] 1. Plate-shaped member 1a 1st area 1b 2nd area 1c Semiconductor element mounting surface 2 Thin-walled section 3 Press die 3a cutting section 4 Bali 5 fragments 100 semiconductor modules 101 Sealing resin 102 First Conductor Plate 102A Upper arm control terminal 102B P main terminal 102C convex shape 102D Thin-walled section 103 Third Conductor Plate 103A N main terminal 103C convex shape 103E Thin wall part 104 Second Conductor Plate 104A AC main terminal 104B Lower arm control terminal 104C convex shape 104D Thin section 105 Thermal conductive sheet 106 Fourth Conductor Plate 106A Connection 106B Base 107 Fifth Conductor Plate 108 Temperature Sensor 109 Semiconductor devices 110 Gap 111 Cutting section

Claims

1. Multiple semiconductor elements constituting the upper arm circuit and the lower arm circuit, Among the plurality of semiconductor elements, a first conductor plate to which the semiconductor elements constituting the upper arm circuit are joined, Among the plurality of semiconductor elements, a second conductor plate to which the semiconductor elements constituting the lower arm circuit are joined, A method for manufacturing a semiconductor module comprising the plurality of semiconductor elements, the first conductor plate, and a sealing member for molding and sealing the second conductor plate, A plate-like member is formed having a first region for forming the first conductive plate, a second region for forming the second conductive plate, and a thin-walled portion between the first region and the second region having a thickness smaller than the thickness of the bonding region where the plurality of semiconductor elements are bonded. By cutting the thin-walled portion, the first region and the second region are separated to form the first conductor plate and the second conductor plate. A method for manufacturing semiconductor modules.

2. In the method for manufacturing a semiconductor module described in claim 1, The cutting width of the thin-walled portion is made smaller than the thickness of the joining region. A method for manufacturing semiconductor modules.

3. In the method for manufacturing a semiconductor module described in claim 1, The terminals protruding from the sealing member on the first conductor plate and the second conductor plate are integrally formed from the plate-shaped member. A method for manufacturing semiconductor modules.

4. In the method for manufacturing a semiconductor module described in claim 1, The plate-like member has a third region that forms a third conductive plate, By cutting the thin portion, the third region is separated from the first and second regions to form the third conductive plate. A method for manufacturing semiconductor modules.

5. In the method for manufacturing a semiconductor module described in claim 1, The thin portion is cut from the side to which the semiconductor element is joined toward the opposite side. A method for manufacturing semiconductor modules.

6. In the method for manufacturing a semiconductor module described in claim 1, The plurality of semiconductor elements are arranged side by side on the first conductor plate and the second conductor plate, respectively. The thin portion is cut along the arrangement direction of the plurality of semiconductor elements. A method for manufacturing semiconductor modules.

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