Semiconductor module and method for fabricating semiconductor module

Abstract

This semiconductor module comprises a lead frame, a semiconductor element joined by solder to a first surface of the lead frame, and a resin member encapsulating the lead frame and the semiconductor element. The semiconductor module includes an insulating orientation retaining member that is bonded to the lead frame, extends from the lead frame toward a lateral surface of the resin member, and has an exposed portion where a part of the insulating orientation retaining member is exposed to the outside from the lateral surface of the resin member. The orientation retaining member has an opening in a region where the solder is joined to the first surface. In the orientation retaining member, the periphery of the opening is bonded to the first surface.

Description

Semiconductor module and method for manufacturing semiconductor module

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

[0002] In the mounting process of a semiconductor module with a double-sided cooling structure, for example, Patent Document 1 listed below discloses a configuration in which an island and a semiconductor chip mounted on the island are held by tape attached to a lead frame.

[0003] Japanese Patent Application Laid-Open No. 2001-077280

[0004] In view of the technology described in Patent Document 1, an object of the present invention is to provide a semiconductor module and a method for manufacturing the semiconductor module that achieves improved insulation, cost reduction, and miniaturization.

[0005] A semiconductor module comprising a lead frame, a semiconductor element soldered to a first surface of the lead frame, and a resin member sealing the lead frame and the semiconductor element, the semiconductor module further comprising an insulating posture-maintaining member adhered to the lead frame, extending from the lead frame toward a side surface of the resin member, and having an exposed portion, a portion of which is exposed to the outside from the side surface of the resin member, the posture-maintaining member having an opening in an area where the solder is joined to the first surface, and the periphery of the opening in the posture-maintaining member being adhered to the first surface.

[0006] It is possible to provide a semiconductor module and a method for manufacturing the semiconductor module that achieves improved insulation, reduced costs, and miniaturization.

[0007] 1 is a schematic diagram of a lead frame mounted on a double-sided cooled power module during manufacturing. 2 is a schematic diagram of a problem that occurs in the power module when the lead frame of FIG. 1 is cut. 3 is a schematic diagram of a lead frame according to an embodiment of the present invention. 4 is a schematic diagram of a power module after the lead frame of FIG. 3 has been cut. 5 is a schematic diagram of a power module after the lead frame of FIG.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and some omissions and simplifications have been made as appropriate for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] In order to facilitate understanding of the invention, the position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0010] (Conventional Configuration) (FIG. 1) FIG. 1(a) is a plan view of a lead frame 100, and FIG. 1(b) is a cross-sectional view showing a state in which a semiconductor module 400 is mounted on the lead frame 100 of FIG. 1(a). In the manufacturing process of the semiconductor module 400, the lead frame 100 before a cutting process described below has leads 101 and suspension leads 102. The leads 101 are connected to the outer frame portion of the lead frame 100 by the suspension leads 102, and are held in a suspended position. The semiconductor module 400 is mounted on the leads 101.

[0011] The surface of the lead 101 on which the semiconductor element 105 is mounted is referred to as the first surface. One surface of the semiconductor element 105 is joined to the first surface side of the lead 101 in the lead frame 100 with solder 104. Similarly, the other surface of the semiconductor element 105 is joined to another lead 101 via solder 104. This results in a structure that allows the semiconductor element 105 to be cooled on both sides. The lead frame 100 on which the semiconductor element 105 is mounted has an area shown as a molding area 106 sealed with resin.

[0012] After resin sealing, the lead frame 100 and the position-retaining member 110 are cut at predetermined cutting positions, i.e., separation lines 500, around the semiconductor module 400. This allows the position-retaining member 110 to be separated from the lead frame 100 without requiring additional man-hours, thereby contributing to improved productivity.

[0013] (FIG. 2) Fig. 2(a) is a plan view of the semiconductor module 400 formed by cutting, and Fig. 2(b) is a cross-sectional view taken along the line A-A of Fig. 2(a). As described above, by cutting along the separation line 500, the resin sealing body sealed with the resin member 106a is separated from the lead frame 100, and this separated resin sealing body is used as the semiconductor module 400. Although not shown, the outer frame of the lead frame 100 that remains after cutting is unnecessary and is therefore removed.

[0014] 2A, in the conventional semiconductor module 400 formed after cutting, a broken remainder 102a, which is the waste paper of the suspension lead 102, is formed. This is because, after the cutting process described above, a portion corresponding to the thickness of the die / punch remains outside the resin encapsulant of the semiconductor module 400. Furthermore, as a result of the cutting process described above, external terminals 102b are formed in the semiconductor module 400, protruding outside the resin encapsulant from a side different from the broken remainder 102a.

[0015] When multiple semiconductor modules 400 are mounted in a power conversion device (not shown), the presence of the broken remnant 102a may cause adjacent semiconductor modules 400 to be closer to each other, potentially reducing the insulation of the semiconductor modules 400. Furthermore, adopting a layout that increases the distance between the semiconductor modules 400 in an attempt to ensure insulation results in an increase in the size of the device. Therefore, the present invention employs the following configuration.

[0016] (One embodiment and overall configuration) (Fig. 3) Fig. 3(a) shows a lead frame 100 of the present invention, and Fig. 3(b) is a cross-sectional view of Fig. 3(a). In this invention, an insulating posture-maintaining member 110 is provided that is adhered to the lead frame 100 instead of the aforementioned suspension leads 102. The posture-maintaining member 110 is a resin tape such as polyimide tape or polyamide-imide tape, which contributes to improving the wettability of the solder 104, adhesion to the resin member 106a and the leads 101, heat resistance, and strength.

[0017] The posture-maintaining member 110 has an opening 111 in an area where the solder 104 is bonded to the first surface of the lead frame 100. In the manufacturing process, the portion of the posture-maintaining member 110 surrounding the opening 111 is bonded to the first surface of the lead 101. The semiconductor element 105 is mounted on the lead 101 at a position corresponding to the position of the opening 111. This prevents the solder 104 from spreading over the bonding surface of the lead 101, eliminating the need to form a resin member or the like to prevent the solder 104 from spreading over the bonding surface of the lead 101 as in the past.

[0018] With the leads 101 carrying the semiconductor element 105 suspended by the attitude-maintaining member 110, the leads 101, the semiconductor element 105, and the attitude-maintaining member 110 are sealed with a resin material. After the resin sealing, the lead frame 100 and the attitude-maintaining member 110 are cut around the periphery of the semiconductor module 400 at the separation lines 500, which are predetermined cutting positions.

[0019] (FIG. 4) Fig. 4(a) shows the semiconductor module 400 after cutting the lead frame of Fig. 3, and Fig. 4(b) is a cross-sectional view taken along the line B-B of Fig. 4(b). The posture-maintaining member 110 is formed by extending from the lead frame 100 toward the side surface of the resin member 106a. Furthermore, an exposed portion 110a, which is a part of the posture-maintaining member 110, is exposed to the outside of the resin encapsulant from the side surface of the semiconductor module 400.

[0020] The semiconductor module 400 has external terminals 102b that protrude from the resin sealing body from a side other than the exposed portion 110a. In this way, the exposed portion 110a is provided on a surface of the semiconductor module 400 that is different from the surface from which the external terminals 102b protrude, thereby ensuring insulation.

[0021] The configuration of the present invention eliminates the need for a suspension lead 102 in the lead frame 100 during manufacturing. Furthermore, since the fractured remains 102a, which are metal fracture surfaces as shown in FIG. 2, are not exposed to the periphery, insulation is improved. Furthermore, when semiconductor modules 400 are mounted in a power converter, the semiconductor modules 400 can be arranged close to each other, contributing to the miniaturization of the power converter. Furthermore, since there is no need to increase the resin sealing area to ensure insulation, costs are reduced. Furthermore, costs are reduced because processing steps that define the wettable area of ​​the solder 104, such as laser marking or applying a paint that inhibits solder wetting, are no longer necessary. Furthermore, costs are reduced because there is no need to use a lead frame 100 with an irregular cross-section in which the cross-sectional sizes of the suspension lead 102 and the lead 101 are different, which was previously required to provide the suspension lead 102.

[0022] (First to Third Modifications) (FIG. 5) FIG. 5(a) shows the first modification, FIG. 5(b) shows the second modification, and FIG. 5(c) shows the third modification. As shown in the first modification, the posture maintaining member 110 is not only attached to the lead frame 100 in one direction, but posture maintaining members 110 may also be formed in a direction perpendicular to that direction and attached to the lead frame 100. This ensures the stability of the posture maintaining member 110 on the lead frame 100, and further stabilizes the posture of the leads 101.

[0023] Furthermore, as shown in a second modification, two posture maintaining members 110 may be attached in parallel to the lead frame 100 so as to sandwich the region where the semiconductor element 105 is bonded. This eliminates the need to form openings 111 in the posture maintaining members 110 during the manufacturing stage, contributing to cost reduction.

[0024] Furthermore, as shown in a third modified example, the posture-maintaining member 110 may have a plurality of openings 111 formed at the same pitch, which eliminates the need to form the openings 111 in accordance with the joining locations of the semiconductor elements 105, thereby contributing to cost reduction.

[0025] According to the embodiment of the present invention described above, the following advantageous effects are achieved.

[0026] (1) A semiconductor module 400 includes a lead frame 100, a semiconductor element 105 bonded to a first surface of the lead frame 100 with solder 104, and a resin member 106a that encapsulates the lead frame 100 and the semiconductor element 105, and includes an insulating posture-retaining member 110 that is bonded to the lead frame 100, extends from the lead frame 100 toward a side surface of the resin member 106a, and has an exposed portion 110a that is partially exposed to the outside from the side surface of the resin member 106a, the posture-retaining member 110 has an opening 111 in an area where the solder 104 is bonded to the first surface, and the periphery of the opening 111 in the posture-retaining member 110 is bonded to the first surface. This configuration allows for the realization of a semiconductor module 400 that achieves improved insulation, cost reduction, and miniaturization.

[0027] (2) The external terminals 102b protrude from the resin member 106a to the outside, and the exposed portion 110a is provided on a surface of the semiconductor module 400 that is different from the surface from which the external terminals 102b protrude. This improves insulation.

[0028] (3) The posture maintaining member 110 is made of polyimide or polyamide-imide, which contributes to improving the wettability of the solder 104, the adhesion to the resin member 106a and the leads 101, the heat resistance, and the strength.

[0029] (4) A method for manufacturing a semiconductor module 400 including a lead frame 100, a semiconductor element 105, and a resin member 106a that seals the lead frame 100 and the semiconductor element 105, in which an attitude-retaining member 110 having an opening 111 is attached to the lead frame 100, the semiconductor element 105 is mounted on the lead frame 100 so as to correspond to the position of the opening 111, and the lead frame 100, the semiconductor element 105, and the attitude-retaining member 110 are sealed with the resin member 106a while the lead frame 100 with the semiconductor element 105 mounted thereon is suspended by the attitude-retaining member 110. This method provides a method for manufacturing a semiconductor module 400 that achieves improved insulation, cost reduction, and miniaturization.

[0030] (5) In addition to the manufacturing method of (4), a method is also implemented in which the lead frame 100 and the position-retaining member 110 are cut at predetermined cutting positions around the semiconductor module 400 sealed with the resin member 106a, the lead frame 100 carrying the semiconductor element 105 and the position-retaining member 110 are separated, and the remaining portion of the lead frame 100 is removed. This contributes to reducing the number of steps and improving productivity.

[0031] The present invention is not limited to the above-described embodiments, and various modifications and combinations of other configurations are possible without departing from the spirit of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted.

[0032] REFERENCE SIGNS LIST 100 Lead frame 101 Lead 102 Suspension lead 102a Fracture remainder 102b External terminal 104 Solder 105 Semiconductor element 106 Molding area 106a Resin member 110 Position-maintaining member 110a Exposed portion 111 Opening 400 Semiconductor element module 500 Separation line

Claims

1. A semiconductor module comprising a lead frame, a semiconductor element soldered to a first surface of the lead frame, and a resin member encapsulating the lead frame and the semiconductor element, wherein the semiconductor module further comprises an insulating position-retaining member bonded to the lead frame, extending from the lead frame toward a side surface of the resin member and having an exposed portion partially exposed to the outside from the side surface of the resin member, the position-retaining member having an opening in an area where the solder is bonded to the first surface, and the periphery of the opening in the position-retaining member being bonded to the first surface.

2. The semiconductor module according to claim 1, further comprising external terminals protruding from the resin member, and the exposed portion is provided on a surface of the semiconductor module different from the surface from which the external terminals protrude.

3. The semiconductor module according to claim 1, wherein the position-maintaining member is made of polyimide or polyamide-imide.

4. A method for manufacturing a semiconductor module comprising a lead frame, a semiconductor element, and a resin member that seals the lead frame and the semiconductor element, comprising: attaching an attitude-retaining member having an opening to the lead frame; mounting the semiconductor element on the lead frame so that it corresponds to the position of the opening; and, with the lead frame with the semiconductor element mounted thereon suspended by the attitude-retaining member, sealing the lead frame, the semiconductor element, and the attitude-retaining member with the resin member.

5. A method for manufacturing a semiconductor module according to claim 4, further comprising the steps of: cutting the lead frame and the position-maintaining member at predetermined cutting positions around the semiconductor module sealed with the resin member; separating the lead frame carrying the semiconductor element and the position-maintaining member; and removing the remaining portion of the lead frame.

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