JP2010219093A - Electronic circuit device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more appropriately suppress separation of a sealing resin section for sealing a circuit board of an electronic circuit device and a flexible wiring board from the flexible wiring board. <P>SOLUTION: The electronic circuit device 20 including the circuit board 22 on which electronic components 21 have been packaged includes: the flexible wiring board 23 that is adhered to the circuit board 22 and electrically connects the circuit board 22 to external equipment 100; a sealing resin section 25a made of resin that is formed so that the circuit board 22 and one portion of the flexible wiring board 23 are sealed; and a separation suppression section 30 composed of an elastic material interposed between the flexible wiring board 23 and the sealing resin section 25a along an outer periphery of the sealing resin section 25a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic circuit device, and more particularly to an electronic circuit device including a circuit board on which electronic components are mounted.

  Conventionally, as an electronic circuit device of this type, a circuit board on which electronic components are mounted and bumps or conductive balls are bonded to a plurality of lands formed on the surface, and a resin film having flexibility and electrical insulation A flexible wiring board that is patterned so as to extend in a direction in which the wiring conductor is in contact with or separated from the circuit board and the land of the wiring conductor is bonded to a bump or a conductive ball of the circuit board; and an electronic component, a circuit board, There has been proposed one that includes a flexible wiring board via a bump or a conductive ball and a mold resin that seals an electrical connection portion between a circuit board (for example, see Patent Document 1). In addition, this type of electronic circuit device includes an electronic circuit constituted by electronic components, a flexible wiring board that is connected to the electronic circuit and constitutes a wiring circuit, and a copper that contacts and dissipates heat from the flexible wiring board. A base member made of an alloy material, and an electronic circuit, a flexible wiring board, and a sealing resin for sealing including the base member, and the linear expansion coefficient of the flexible wiring board and the linear expansion coefficient of the base member are apparently identical As described above, there has also been proposed a flexible wiring board disposed on a base member (see, for example, Patent Document 2).

JP 2006-140273 A JP 2004-095974 A

  When thermal shock is applied to an electronic circuit device having a structure in which an electronic circuit or a flexible wiring board is sealed with a resin as described above, the thermal expansion coefficient of the sealing resin, the circuit board, the flexible wiring board, etc. Then, there is a risk of peeling at the interface between the sealing resin and the flexible wiring board. In order to suppress the occurrence of such interfacial peeling, as described in Patent Document 2, it is preferable to make the thermal expansion coefficients of the constituent members of the electronic circuit device as close as possible. Therefore, measures should be taken separately to improve the adhesion between the sealing resin and the flexible wiring board.

  Therefore, the main object of the present invention is to better suppress the peeling between the sealing resin portion for sealing the circuit board of the electronic circuit device and the flexible wiring board and the flexible wiring board.

  The electronic circuit device of the present invention employs the following means in order to achieve the main object described above.

An electronic circuit device according to the present invention comprises:
An electronic circuit device including a circuit board on which electronic components are mounted,
A flexible wiring board that is bonded to the circuit board and enables electrical connection between the circuit board and an external device;
A sealing resin portion made of a resin molded to seal the circuit board and a part of the flexible wiring board;
A peeling suppressing portion that is provided between the flexible wiring board and the sealing resin portion and suppresses peeling between the flexible wiring board and the sealing resin portion;
Is provided.

  In this electronic circuit device, since the peeling suppressing portion is provided between the flexible wiring board and the sealing resin portion, peeling between the flexible wiring board and the sealing resin portion can be more favorably suppressed.

  Moreover, the said peeling suppression part may be comprised with the elastic material interposed between the said flexible wiring board and the said sealing resin part so that the outer periphery of the said sealing resin part may be followed. In this way, if the elastic material is interposed between the flexible wiring board and the sealing resin portion along the outer periphery of the sealing resin portion, the flexible wiring board and the elastic material are in close contact with each other and the elastic material As a result, the adhesiveness between the flexible wiring board and the sealing resin portion can be enhanced. In addition, even if stress is applied to the interface between the flexible wiring board and the sealing resin portion due to thermal shock or the like, the elastic material is elastically deformed to suppress the separation between the flexible wiring board and the sealing resin portion. Can do. Therefore, in this electronic circuit device, it is possible to suppress the peeling between the flexible wiring board and the sealing resin portion very well.

  Furthermore, the flexible wiring board may include a base film, a wiring conductor bonded to the base film via an adhesive layer, and a cover film covering the wiring conductor, You may form by exposing the said adhesive bond layer along the outer periphery of the said sealing resin part. Thereby, since an adhesive bond layer and a sealing resin part closely_contact | adhere, the adhesiveness of a flexible wiring board and a sealing resin part can be improved as a result. In addition, since the cover film and the wiring conductor are not present in the exposed portion of the adhesive layer, the contact area between the flexible wiring board and the sealing resin portion can be increased accordingly. Therefore, also in this electronic circuit device, it is possible to suppress the peeling between the flexible wiring board and the sealing resin portion very well.

  In addition, the peeling suppression portion is interposed between the flexible wiring board and the sealing resin portion so as to follow the outer periphery of the sealing resin portion, and the surface on the side in contact with the sealing resin portion is rough. You may comprise by the layer which was made into. Thereby, since the layer having the roughened surface and the sealing resin portion are in close contact with each other, the adhesion between the flexible wiring board and the sealing resin portion can be enhanced as a result. Moreover, the contact area of a flexible wiring board and a sealing resin part can be increased by the part which roughened the surface of the said layer. Therefore, also in this electronic circuit device, it is possible to suppress the peeling between the flexible wiring board and the sealing resin portion very well. The layer having the roughened surface may be a layer such as a copper foil that does not function as a wiring, or may be a layer made of a metal plate or the like.

  The electronic circuit device may further include at least a heat radiating member bonded to the flexible wiring board, and the sealing resin portion may include a part of the circuit board, the flexible wiring board, and the heat radiating member. You may shape | mold so that a part may be sealed.

It is a top view which shows the electronic circuit apparatus 20 which concerns on one Example of this invention. It is sectional drawing along the II-II line of FIG. 4 is a cross-sectional view illustrating a flexible wiring board 23. FIG. It is sectional drawing which illustrates the flexible wiring board 23B. It is sectional drawing which shows the electronic circuit apparatus 20B which concerns on a modification. It is explanatory drawing which shows the principal part of the electronic circuit apparatus 20B. It is sectional drawing which shows 20C of electronic circuit apparatuses which concern on a modification. It is sectional drawing which shows electronic circuit device 20D which concerns on a modification. It is explanatory drawing which shows the principal part of electronic circuit device 20D. It is sectional drawing which shows the electronic circuit apparatus 20E which concerns on a modification.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a plan view showing an electronic circuit device according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. The electronic circuit device 20 of the embodiment shown in these drawings is configured as an electronic control device that controls a vehicle automatic transmission (not shown), and is mounted, for example, on a unit base fixed to a lower portion of a transmission case. The electronic circuit device 20 according to the embodiment includes a circuit board 22 on which various electronic components 21 are mounted, and flexible wiring that is bonded to the circuit board 22 and enables electrical connection between the circuit board 22 and the external device 100. A board (FPC: Flexible Printed Circuit Board) 23, a heat radiation plate (heat sink) 24 bonded to the flexible wiring board 23, a circuit board 22, a part of the flexible wiring board 23, and a part of the heat radiation plate 24 are sealed. Sealing resin portions 25a and 25b made of a resin molded as described above.

  The circuit board 22 is made of a base material made of a material having excellent heat resistance and thermal conductivity, such as ceramic, and having a relatively small coefficient of thermal expansion, and a wiring pattern formed on one surface of the base material. Have. The surface of the circuit board 22 on which the wiring pattern is formed is a mounting surface for a plurality of electronic components 21 including an IC chip. On this mounting surface, bonding terminals (circuit side connection terminals) connected to the wiring pattern are provided. A plurality of 26 are arranged.

  The flexible wiring board 23 is a deformable wiring material having flexibility, and has a thickness of about 0.1 to 0.2 mm, for example. The flexible wiring board 23 included in the electronic circuit device 20 of the embodiment has a so-called single-sided structure as shown in FIG. 3, and a base film 230 formed of a resin such as polyimide resin, and the base film 230 on the base film 230. The wiring conductor 232 made of a copper foil or the like attached to the wiring layer 231 with the adhesive layer 231 and the wiring conductor 232 attached to the wiring conductor 232 or the base film 230 via the adhesive layer 233. And a cover film 234 for covering. As shown in FIG. 1, the flexible wiring board 23 has a plurality of bonding terminals (wiring board side connection terminals) 236 connected to the corresponding wiring conductors 232. Each bonding terminal 236 is exposed from the cover film 234 and is connected to the corresponding bonding terminal 26 of the circuit board 22 through the bonding wire 27. And the connector (illustration omitted) used for the connection with the external apparatus 100 is connected to the flexible wiring board 23 (wiring conductor 232). The external device 100 connected to the circuit board 22 via the flexible wiring board 23 includes various sensors such as a solenoid valve, an oil temperature sensor, and a hydraulic sensor included in a hydraulic circuit that operates a hydraulic clutch and a hydraulic brake of an automatic transmission. Other electronic control units etc. are included.

  In the embodiment, the heat radiating plate 24 is, for example, a rectangular plate made of a low expansion metal having excellent thermal conductivity such as ordinary steel (SPCC) or a clad material and a relatively small thermal expansion coefficient. As shown in FIG. 2, the heat radiating plate 24 is bonded to the flexible wiring board 23 from the side opposite to the circuit board 22 through a silicon-based heat radiating adhesive layer. In the embodiment, after the base film 230 of the flexible wiring board 23 and the heat radiating plate 24 are joined, the circuit board 22 is bonded to the cover film 234 of the flexible wiring board 23, whereby the circuit board 22, the flexible board The wiring board 23 and the heat dissipation plate 24 are integrated.

  The sealing resin portions 25a and 25b are formed by setting the integrated circuit board 22, the flexible wiring board 23, and the heat radiating plate 24 in the mold, and then heating and pressurizing a thermosetting resin such as an epoxy resin, for example. The molten resin is molded by transfer molding which injects and pressurizes the molten resin into the mold. As shown in FIG. 2, the upper sealing resin portion 25 a in the drawing seals the circuit board 22 and a part of the flexible wiring board 23, and the lower sealing resin portion 25 b in the drawing includes the heat dissipation plate 24. A part of is sealed. The shape (mass) and position of the upper sealing resin portion 25a in the figure and the lower sealing resin portion 25b in the figure are reduced by stress acting between the sealing resin portions 25a, 25b and other members. Determined to be. Note that an ATF (automatic transmission fluid) is introduced into the unit base of the automatic transmission on which the electronic circuit device 20 of the embodiment is disposed, and an exposed portion that is not sealed by the sealing resin portions 25a and 25b of the heat radiating plate 24. Further, heat generated in the circuit board 22 is released to the outside by heat exchange between the surfaces of the sealing resin portions 25a and 25b and the ATF.

  Here, when a thermal shock is applied to the electronic circuit device 20 having a structure in which the circuit board 22 and the flexible wiring board 23 are sealed with resin as described above, the sealing resin portions 25a and 25b and the flexible wiring board 23 Due to the difference in thermal expansion coefficient, there is a risk of peeling at the interface between the sealing resin portion 25a and the flexible wiring board 23. Based on this, in the electronic circuit device 20 of the embodiment, the peeling suppression that suppresses the peeling between the cover film 234 and the sealing resin portion 25a of the flexible wiring board 23 between the flexible wiring board 23 and the sealing resin portion 25a. A part 30 is provided. In the embodiment, before the integrated circuit board 22, the flexible wiring board 23 and the heat radiating plate 24 are set in the mold for transfer molding, for example, oil resistance is achieved by liquid injection molding (LIM). The peeling suppression part 30 is comprised by forming the thin layer which consists of elastic materials, such as a property silicone elastomer, on the cover film 234 of the flexible wiring board 23 along the outer periphery of the sealing resin part 25a (FIG. 1). Reference, except for a portion where an opening is formed in the flexible wiring board 23). Moreover, in the Example, the peeling suppression part 30 is formed so that it may protrude a little outside from the final outer periphery of the sealing resin part 25a. In addition, the peeling suppression part 30 is formed by forming a thin layer made of an elastic material such as a thermoplastic elastomer on the cover film 234 of the flexible wiring board 23 along the outer periphery of the sealing resin part 25a by injection molding. May be. Further, the peeling suppressing unit 30 is formed on the flexible wiring board 23 (cover film 234) before the integrated circuit board 22, flexible wiring board 23, and heat dissipation plate 24 are set in the mold for transfer molding. The peeling suppression unit 30 may be formed before the flexible wiring board 23 and the heat dissipation plate 24 are joined, before the flexible wiring board 23 and the circuit board 22 are joined, and between the flexible wiring board 23 and the circuit board 22. It may be formed at any stage after joining.

  Thus, if the peeling suppression part 30 which is a layer of an elastic material is interposed between the flexible wiring board 23 (cover film 234) and the sealing resin part 25a along the outer periphery of the sealing resin part 25a, As a result, the cover film 234 of the flexible wiring board 23 and the peeling suppressing portion 30 (elastic material) are in close contact with each other and the peeling suppressing portion 30 (elastic material) and the sealing resin portion 25a are in close contact with each other. The adhesion between the flexible wiring board 23 and the sealing resin portion 25a can be enhanced. Further, even if stress is applied to the interface between the flexible wiring board 23 (cover film 234) and the sealing resin portion 25a due to thermal shock or the like, the flexible wiring is caused by the elastic deformation of the peeling suppressing portion 30 made of an elastic material. Peeling between the plate 23 and the sealing resin portion 25a can be suppressed. Therefore, in the electronic circuit device 20 of the embodiment, it is possible to suppress the peeling between the flexible wiring board 23 and the sealing resin portion 25a very well. Further, as shown in FIG. 2, the peeling suppressing portion 30 is formed so as to slightly protrude from the cover film 234 of the flexible wiring board 23, so that transfer molding is performed to suppress disconnection of the wiring conductor 232. Even if the clamping pressure at that time is slightly reduced, it is possible to favorably suppress the molten resin from flowing out of the mold by the peeling suppressing unit 30.

  As described above, in the electronic circuit device 20 according to the embodiment, since the peeling suppression unit 30 is provided between the flexible wiring board 23 and the sealing resin part 25a, the flexible wiring board 23 and the sealing resin part 25a It becomes possible to suppress peeling more favorably. In addition, although the above-mentioned electronic circuit apparatus 20 was demonstrated as what is used for controlling the automatic transmission for vehicles, it is not restricted to this. That is, the electronic circuit device 20 may be configured as an electronic control unit that controls other in-vehicle devices such as an internal combustion engine and an electric motor, or may be configured as an electronic circuit device that controls devices other than the in-vehicle devices.

  In the electronic circuit device 20, it goes without saying that a flexible wiring board 23B having a so-called double-sided structure as shown in FIG. 4 may be employed instead of the flexible wiring board 23 having a single-sided structure. A flexible wiring board 23B shown in FIG. 4 has a base film 230 formed of a resin such as polyimide resin, and a wiring for a copper foil or the like attached to one surface of the base film 230 via an adhesive layer 231u. The conductor 232u, the wiring conductor 232l made of copper foil or the like attached to the other surface of the base film 230 via the adhesive layer 231l, and the adhesive layer 233u on the wiring conductor 232u or the base film 230 are provided. A cover film 234u that is attached to the wiring conductor 232u and a cover film 234l that is attached to the wiring conductor 232l and the base film 230 via the adhesive layer 233l and covers the wiring conductor 232l. Is included.

  FIG. 5 is an enlarged cross-sectional view of an electronic circuit device 20B according to a modification. In the electronic circuit device 20B shown in the figure, the peeling suppressing portion 30B exposes the adhesive layer 231 between the base film 230 of the flexible wiring board 23 and the wiring conductor 232 along the outer periphery of the sealing resin portion 25a. It is formed by. Such a peeling suppressing portion 30B is formed so that the cover film 234 does not exist in a region along the outer periphery of the sealing resin portion 25a in a region where the wiring conductor 232 does not exist when the flexible wiring board 23 is manufactured. It is formed by (so as not to be formed). In addition, as shown in FIG. 6, the region of the flexible wiring board 23 in which a large number of wiring conductors 232 exist is a portion that is along the outer periphery of the sealing resin portion 25 a and is adjacent to each other. What is necessary is just to make it the cover film 234 not exist in the site | part between 232. In the electronic circuit device 20B provided with such a peeling suppression part 30B, the adhesive layer 231 and the sealing resin part 25a are in close contact with each other. As a result, the adhesiveness between the flexible wiring board 23 and the sealing resin part 25a is improved. Can be increased. Further, since the wiring conductor 232 and the cover film 234 are not present in the peeling suppression portion 30B, that is, the exposed portion of the adhesive layer 231, the contact area between the flexible wiring board 23 and the sealing resin portion 25a is increased accordingly. Can be increased. Therefore, also in the electronic circuit device 20B, it is possible to suppress the peeling between the flexible wiring board 23 and the sealing resin portion 25a very well. In addition, like the electronic circuit device 20C shown in FIG. 7, the adhesive layer 231 between the base film 230 of the flexible wiring board 23 and the wiring conductor 232 is exposed along the outer periphery of the sealing resin portion 25a. Thus, the peeling suppressing portion 30C may be configured by forming a layer of an elastic material such as an oil-resistant silicone elastomer or a thermoplastic elastomer on the exposed adhesive layer 231.

  FIG. 8 is an enlarged cross-sectional view of an electronic circuit device 20D according to another modification. In the electronic circuit device 20D shown in the figure, the peeling suppressing portion 30D is interposed between the flexible wiring board 23 and the sealing resin portion 25a so as to be along the outer periphery of the sealing resin portion 25a and the sealing resin portion. The surface on the side in contact with 25a is constituted by a layer made of a roughened copper foil. In the manufacture of the flexible wiring board 23, the peeling suppressing unit 30 </ b> D attaches a copper foil 232 </ b> D that does not function as a wiring on the base film 230 and prevents the copper foil 232 </ b> D from being covered with the cover film 234. Above, it is comprised by roughening the surface of the said copper foil using an etching etc. Further, as shown in FIG. 9, the flexible wiring board 23 has a large number of wiring conductors 232, which are portions along the outer periphery of the sealing resin portion 25a and adjacent to each other. A copper foil 232D that does not function as a wiring is attached to a portion between 232, and the cover film 234 is not present on the copper foil 232D, and then the surface of the copper foil is roughened. . In the electronic circuit device 20D provided with such a peeling suppression part 30D, the peeling suppression part 30D, which is a layer made of a copper foil having a roughened surface, and the sealing resin part 25a are in close contact with each other. The adhesion between the flexible wiring board 23 and the sealing resin portion 25a can be enhanced. In this case, the contact area between the flexible wiring board 23 and the sealing resin portion 25a can be increased by the amount of roughening the surface of the layer made of copper foil. Therefore, also in the electronic circuit device 20D, it is possible to suppress the peeling between the flexible wiring board 23 and the sealing resin portion 25a very well. Instead of interposing a layer made of copper foil between the flexible wiring board 23 and the sealing resin portion 25a as in the electronic circuit device 20D in FIG. 8, as in the electronic circuit device 20E shown in FIG. A thin plate made of metal such as ordinary steel (SPCC) or clad material with surface roughening is interposed between the flexible wiring board 23 and the sealing resin portion 25a so as to follow the outer periphery of the sealing resin portion 25a. You may set up. Moreover, since the peeling suppression part 30E which consists of a thin metal plate will be arrange | positioned so that it may protrude a little from the cover film 234 of the flexible wiring board 23, as shown in FIG. 10, the disconnection etc. of the conductor 232 for wiring are suppressed. Even if the clamping pressure at the time of transfer molding is slightly reduced, it is possible to favorably suppress the molten resin from flowing out of the mold by the peeling suppressing portion 30E. Furthermore, if the peeling suppression part 30E is comprised with a metal plate, it will also become possible to utilize the peeling suppression part 30E as a heat radiating member.

  Here, the correspondence between the main elements of the embodiments and the modified examples and the main elements of the invention described in the column of means for solving the problems will be described. That is, in the embodiment and the modified example, the circuit board 22 on which the electronic component 21 is mounted corresponds to a “circuit board”, and can be electrically connected to the circuit board 22 by being bonded to the circuit board 22. The flexible wiring boards 23 and 23B are equivalent to a “flexible wiring board”, and a sealing resin portion 25a made of a resin molded so as to seal part of the circuit board 22 and the flexible wiring board 23 is “ Peeling suppression portions 30 and 30B that correspond to a “sealing resin portion” and are provided between the flexible wiring board 23 and the like and the sealing resin portion 25a and suppress peeling between the flexible wiring board 23 and the sealing resin portion 25a. , 30C, 30D, and 30E correspond to the “separation suppressing portion”, and the heat radiation plate 24 bonded to the flexible wiring board 23 and the like corresponds to the “heat radiation member”. However, the correspondence between the main elements of these embodiments and modifications and the main elements of the invention described in the column of means for solving the problem is described in the column of means for the embodiment to solve the problem. This is an example for specifically describing the best mode for carrying out the invention, and does not limit the elements of the invention described in the column of means for solving the problem. In other words, the examples are merely specific examples of the invention described in the column for means for solving the problem, and the interpretation of the invention described in the column for means for solving the problem is described in the description of the column. Should be done on the basis.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. Needless to say.

  The present invention can be used in the electronic circuit device manufacturing industry.

  20, 20B, 20C, 20D, 20E Electronic circuit device, 22 Circuit board, 23, 23B Flexible wiring board, 24 Heat radiation plate, 25a, 25b Sealing resin part, 26, 236 Bonding terminal, 27 Bonding wire, 30, 30B, 30C, 30D, 30E Peeling suppression part, 100 External device, 230 Base film, 231,231u, 231l, 233,233u, 233l Adhesive layer, 232,232u, 232l Wiring conductor, 232D Copper foil, 234,234u, 234l Cover film.

Claims (5)

An electronic circuit device including a circuit board on which electronic components are mounted,
A flexible wiring board that is bonded to the circuit board and enables electrical connection between the circuit board and an external device;
A sealing resin portion made of a resin molded to seal the circuit board and a part of the flexible wiring board;
A peeling suppressing portion that is provided between the flexible wiring board and the sealing resin portion and suppresses peeling between the flexible wiring board and the sealing resin portion;
An electronic circuit device comprising: The electronic circuit device according to claim 1,
The said peeling suppression part is an electronic circuit apparatus comprised with the elastic material interposed between the said flexible wiring board and the said sealing resin part so that the outer periphery of the said sealing resin part may be followed. The electronic circuit device according to claim 1,
The flexible wiring board includes a base film, a wiring conductor bonded to the base film via an adhesive layer, and a cover film that covers the wiring conductor, and the peeling suppressing portion includes the sealing resin. An electronic circuit device formed by exposing the adhesive layer along the outer periphery of the part. The electronic circuit device according to claim 1,
The peeling suppressing portion is interposed between the flexible wiring board and the sealing resin portion so as to follow the outer periphery of the sealing resin portion, and a surface on the side in contact with the sealing resin portion is roughened. Electronic circuit device comprising a plurality of layers. An electronic circuit device according to any one of claims 1 to 4,
A heat dissipating member bonded to at least the flexible wiring board;
The said sealing resin part is an electronic circuit device shape | molded so that the said circuit board, a part of said flexible wiring board, and a part of said heat radiating member may be sealed.

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