JP2015002323A - Electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which allows for easy confirmation of whether or not the bonding by means of a connection member has been made excellently, while attaining stress relaxation effect by means of a connection member, when bonding a connection terminal and a through hole by means of a connection member.SOLUTION: A connection terminal 65 is provided with a flange 65a, which is separated from a circuit board 10, and when bonding a through hole 13 and the connection terminal 65, a connection member 15 is arranged on the flange 65a. Since the flange 65a is provided, volume of the connection member 15 can be increased, and stress relaxation effect can be exhibited by a fillet of the connection member 15 spread, while wetting, on the surface of the flange 65a over a wide range. Furthermore, since the flange 65a is separated from the circuit board 10, the connection member 15 can be confirmed between the flange 65a and the circuit board 10.

Description

  The present invention relates to an electronic device in which an electronic component is mounted on one side of a substrate and the one side is sealed with a mold resin.

  Conventionally, in Patent Document 1, as a connection structure for a plurality of circuit boards on which an electric circuit is formed, a connection terminal erected on another circuit board is inserted into a through hole formed in the circuit board. A structure for electrical connection by soldering is disclosed. In this connection structure, the tip of the connection terminal has a stepped shape whose diameter is gradually reduced in the tip direction, and the connection terminal is brought into contact with a circuit board in which a through hole is formed in the largest diameter portion. Positioning in the terminal insertion direction is performed.

JP 2007-109832 A

  However, in the connection structure shown in Patent Document 1, since the portion of the connection terminal having the largest diameter is in contact with the substrate, the connection member such as soldering is located closer to the distal end side of the connection terminal than the through hole. Only placed. For this reason, since the sufficient stress relaxation effect by the connection member cannot be exhibited, the local distortion (deformation) of the connection member due to the thermal expansion / contraction of the circuit board cannot be suppressed, resulting in damage to the connection member. Problems with poor connections can occur. Further, since the connection member is hidden in the through hole, it has not been possible to accurately check whether or not the connection by the connection member is performed satisfactorily.

  In view of the above points, in the present invention, when the connection terminal and the through hole are joined by the connection member, whether or not the stress relaxation effect by the connection member is obtained and the joining by the connection member is satisfactorily performed. An object of the present invention is to provide an electronic device having a connection structure that makes it easy to confirm the above.

  In order to achieve the above object, the invention according to any one of claims 1 to 6 has one surface (11) and another surface (12) which is the opposite surface of the one surface, and the wiring pattern is formed and the wiring pattern is formed. The through-hole (13) connected to the board (10), the electronic component (20, 30) mounted on one side of the board, and inserted into the through-hole from the tip, And a rod-shaped connection terminal (65) electrically connected via a connection member (15) made of solder, and the connection terminal is a tip inserted into the through hole of the connection terminal At least one dimension in the direction perpendicular to the insertion direction to the through hole is made larger than the portion inserted into the through hole and positioned at a predetermined distance from the substrate on the rear end side of the position. Bowl (65a) has a connecting member, the flange portion, is characterized that it is wet spread state in the one direction.

  As described above, the connection terminal is provided with the hook-shaped portion, the hook-shaped portion is separated from the substrate, and the connection member is arranged on the hook-shaped portion in joining the through hole and the connection terminal. For this reason, it is possible to increase the volume of the connecting member disposed on the hook-shaped portion as compared with the case where the hook-shaped portion is not provided. The stress relief effect is exhibited by the fillet. Thereby, local distortion (deformation) of the connecting member due to thermal expansion / contraction of the substrate can be suppressed, and the problem of poor connection due to damage to the connecting member can be suppressed. In addition, since the hook-shaped portion is separated from the substrate and the connecting member can be confirmed between the hook-shaped portion and the substrate, it is possible to check whether or not the connection by the connecting member is performed properly. It becomes possible.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows an example of a corresponding relationship with the specific means as described in embodiment mentioned later.

1 is a cross-sectional view of an electronic device according to a first embodiment of the present invention. It is II-II perspective sectional drawing of FIG. 6 is a top surface layout diagram in the vicinity of a connection terminal 65. FIG. It is a top surface layout figure of the vicinity of the connecting terminal 65 with which the electronic device concerning 2nd Embodiment of this invention is equipped. It is a top surface layout figure of the vicinity of the connecting terminal 65 with which the electronic device concerning 3rd Embodiment of this invention is equipped. It is sectional drawing of the electronic device concerning 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other will be described with the same reference numerals.

(First embodiment)
With reference to FIGS. 1-3, the whole structure of electronic device S1 concerning 1st Embodiment of this invention is demonstrated. The electronic device S1 is mounted on a vehicle such as an automobile, and is applied as a device for driving each device for the vehicle.

  As shown in FIGS. 1 and 2, the electronic device S <b> 1 is configured to include a substrate 10, electronic components 20 and 30, a mold resin 40, a heat sink 50, a case 60, a lid 70, and a heat dissipation gel 80.

  As shown in FIG. 1, the substrate 10 is a plate-like member having one surface 11 on which the electronic components 20 and 30 are mounted and covered with the mold resin 40 and the other surface 12 which is the opposite surface. is there. In the present embodiment, the substrate 10 is a plate-like member having a rectangular top surface as shown in FIG. Specifically, the substrate 10 is a wiring substrate based on a resin such as an epoxy resin, and is formed by sealing both surfaces of a glass cloth knitted with glass fibers with a thermosetting resin, for example. Consists of prepreg. As the prepreg resin, an epoxy resin or the like is used, and a filler having excellent electrical insulation and heat dissipation properties such as alumina or silica may be contained as necessary.

  A wiring pattern (not shown) constituted by an inner layer wiring or a surface layer wiring is formed on the substrate 10, and the wiring pattern is extended to the outside of the mold resin 40, so that the electronic components 20, 30 can be connected to the substrate 10 through the wiring pattern. The electrical connection can be achieved. In addition, on both sides of the substrate 10 in the longitudinal direction (left-right direction in FIG. 1), through holes 13 provided with metal plating or the like connected to the wiring pattern are provided. A plurality of through holes 13 are arranged side by side along two opposite sides of the substrate 10, specifically, along both short sides of the substrate 10. Through this through hole 13, the wiring pattern can be electrically connected to the outside of the substrate.

  The substrate 10 thus configured is supported by the case 60 at the four corners. In the case of the present embodiment, fixing holes 14 serving as through holes are formed at the four corners of the substrate 10, and after mechanical connection portions 64 protruding from the bottom surface 61 of the case 60 are fitted therein, the mechanical holes 64 are mechanically inserted. The substrate 10 is supported on the case 60 by heat caulking the tip of the connecting portion 64.

  The electronic components 20 and 30 are electrically connected to the wiring pattern by being mounted on the substrate 10, and may be any surface mounting component or through-hole mounting component. In the case of the present embodiment, the semiconductor element 20 and the passive element 30 are exemplified as the electronic components 20 and 30. Examples of the semiconductor element 20 include a microcomputer, a control element, or a power element that generates a large amount of heat, such as an IGBT (Insulated Gate Bipolar Transistor) or a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). A bonding wire 21 and a die bonding material 22 such as solder are connected to a land connected to the wiring pattern of the substrate 10 or a land constituted by a part of the wiring pattern, and the passive element 30 includes a chip resistor and a chip capacitor. The passive element 30 is connected to a land provided on the substrate 10 by a die bonding material 31 such as solder, etc. With these configurations, the electronic components 20 and 30 are connected to the substrate 10. Electrically connected to the formed wiring pattern and connected to the wiring pattern It can be electrically connected to the outside through the luohole 13.

  The mold resin 40 is composed of a thermosetting resin such as an epoxy resin, and is formed by a transfer molding method using a mold or a compression molding method. In the case of the present embodiment, a so-called half mold structure is formed in which the one surface 11 side of the substrate 10 is sealed with the mold resin 40 and the other surface 12 side of the substrate 10 is exposed without being sealed with the mold resin 40. .

  Further, as shown in FIG. 2, the mold resin 40 has a rectangular top surface, and the two opposite sides of the substrate 10, specifically, both sides perpendicular to the longitudinal direction of the substrate 10 are exposed. It is formed only on the inner side than both sides. That is, both longitudinal ends of the substrate 10 protrude from the mold resin 40 and are exposed from the mold resin 40. A through hole 13 is disposed in a portion exposed from the mold resin 40, and an electrical connection between the wiring pattern formed on the substrate 10 and the outside is possible through the through hole 13. Further, both sides of the substrate 10 are exposed from the mold resin 40, so that the four corners of the substrate 10 are exposed. In the portion exposed from the mold resin 40, the substrate 10 is attached to the case 60 as described above. It is supported.

  The heat sink 50 is made of a metal material having a high heat transfer rate, such as aluminum or copper, and is in close contact with the other surface 12 side of the substrate 10 via a bonding member 51. As the joining member 51, for example, a conductive adhesive containing a metal filler, a conductive material such as a solder material, or an insulating material such as a heat radiating gel or a heat radiating sheet is used. The heat sink 50 plays a role of radiating heat when the heat generated by the electronic components 20 and 30 is transmitted from the other surface 12 side of the substrate 10 and is made of a metal material having high thermal conductivity, such as copper. Has been. In particular, when the semiconductor element 20 is composed of an IGBT or a MOSFET, since these are heating elements, they generate a lot of heat, but this heat is transmitted to the heat sink 50, so that the semiconductor elements 20 and the passive elements 30 High temperature is suppressed. In the case of the present embodiment, the heat sink 50 is thermally connected to the lid 70 via the heat radiating gel 80, and heat transferred from the back surface of the substrate 10 is further transmitted to the lid 70 through the heat radiating gel 80. Heat is radiated from 70 to the outside.

  The case 60 is a rectangular housing that accommodates the electronic components 20, 30 mounted on the one surface 11 side of the substrate 10 and sealed with the mold resin 40. In the case of the present embodiment, the case 60 is a member constituting the housing recess 63 in which the periphery of the bottom surface 61 is covered by the side wall surface 62, and the substrate 10 mounted with the electronic components 20 and 30 and sealed with the mold resin 40 is used. In the housing recess 63, the one surface 11 side faces the bottom surface 61 side.

  As described above, the mechanical connection portion 64 that supports the substrate 10 is formed on the bottom surface 61 of the case 60. The mechanical connection portion 64 is a stepped rod-like member that protrudes in the vertical direction from the bottom surface 61 and whose sectional dimensions are partially changed. Specifically, in the state before the substrate 10 is fixed, the mechanical connection portion 64 has a cross-sectional dimension on the bottom side larger than that of the fixing hole 14 formed in the substrate 10, and a cross-sectional dimension on the tip side is larger than the fixing hole 14. Is almost the same or slightly smaller. Because of such dimensions, the mechanical connection portion 64 holds the substrate 10 at the stepped portion between the front end side and the bottom surface side while the front end side is inserted into the fixing hole 14. Then, the front end side of the mechanical connection portion 64 is fitted into the fixing hole 14 and then heat caulked, so that a portion protruding from the substrate 10 has a cross-sectional dimension larger than that of the fixing hole 14 and a step difference from that portion. The substrate 10 is sandwiched between and supported.

  The protruding amount of the mechanical connection portion 64 is set to be lower than the height of the side wall surface 62 so that the substrate 10 enters the inside of the housing recess 63 rather than the tip of the side wall surface 62.

  In addition, a plurality of rod-like connection terminals 65 are erected on the bottom surface 61 of the case 60 in a direction perpendicular to the bottom surface 61. Each connection terminal 65 is arranged according to the arrangement of the through holes 13 formed in the substrate 10. For example, each connection terminal 65 is made of a copper alloy that is tin-plated or nickel-plated. Each of the plurality of connection terminals 65 is inserted into a through hole 13 formed in the substrate 10 and is electrically connected to the through hole 13 via a connection member 15 made of solder.

  Further, a hook-shaped portion 65 a is formed on the rear end (the bottom surface 61 of the case 60) side of each connection terminal 65 with respect to the front end position inserted into the through hole 13. The hook-shaped portion 65 a is a portion in which the dimension in at least one direction perpendicular to the insertion direction into the through hole 13 is larger than the portion inserted into the through hole 13. In the case of this embodiment, the cross-sectional area in the cross section perpendicular to the insertion direction into the through hole 13 is made larger than the portion inserted into the through hole 13. Specifically, as shown in FIG. 3, in the present embodiment, the bowl-shaped portion 65 a has a circular top surface, and its diameter is larger than the diameter of the through hole 13. The axis line passes through the center position of the bowl-shaped portion 65a.

  The hook-shaped portion 65 a is located on the bottom surface 61 side of the case 60 with respect to the contact portion with the substrate 10 in the mechanical connection portion 64, that is, the stepped portion whose cross-sectional dimension is changed, and is not in contact with the substrate 10. It is arranged at a predetermined distance from the substrate 10. The connecting member 15 is disposed above the hook-shaped portion 65a, and the connecting member 15 is formed so as to spread over a wide area of the surface of the hook-shaped portion 65a on the substrate 10 side. For this reason, the connecting member 15 is a fillet that is wider on the flange-like portion 65a than on the distal end side.

  The case 60 is basically composed of an insulator based on a resin such as PPS (polyphenylene sulfide) or PBT (polybutylene terephthalate), but a wiring pattern extending to the outside of the case 60 is used. I have. A plurality of connection terminals 65 are connected to the wiring pattern, and the wiring pattern of the substrate 10 on which the electronic components 20 and 30 are mounted is electrically connected to the outside through the connection terminals 65 and the wiring pattern. Yes.

  The lid 70 seals the inside of the case 60 by being connected to the opening end of the case 60, that is, the tip of the side wall surface 62. The lid 70 is fixed to the case 60 via an adhesive or the like, for example. In the case of this embodiment, the lid 70 is made of a metal material having a high heat transfer coefficient, such as aluminum or copper, and is made of a rectangular plate-like member.

  The heat dissipating gel 80 is disposed between the heat sink 50 and the lid 70, and is disposed so as to be in contact with both, thereby transferring heat from the heat sink 50 to the lid 70. For example, the heat radiating gel 80 is made of a silicone oil compound having a high thermal conductivity. Although it is possible to eliminate the heat-dissipating gel 80 and make the structure in which the heat sink 50 and the lid 70 are in direct contact with each other, it is difficult to adjust the height of the heat sink 50 and the heat sink 50 may be pressed when the lid 70 is fixed. For this reason, it is preferable to provide a heat-dissipating gel 80 that can be deformed.

  As described above, the electronic device S1 according to the present embodiment is configured. Such an electronic device S1 is manufactured by the following manufacturing method.

  First, the substrate 10 on which the wiring pattern and the through hole 13 are formed is prepared, and the case 60 provided with the connection terminal 65 having the hook-shaped portion 65a is prepared. And after mounting the electronic components 20 and 30 on the one surface 11 of the board | substrate 10, the board | substrate 10 with which the electronic components 20 and 30 were mounted is sealed with the mold resin 40 by the transfer molding method or the compression molding method. Then, after the heat sink 50 is bonded to the other surface 12 side of the substrate 10 via the bonding member 51, the substrate 10 is disposed in the housing recess 63 of the case 60 with the one surface 11 side facing the bottom surface 61 side. At this time, the plurality of connection terminals 65 are inserted into the through holes 13 so that the tips of the mechanical connection portions 64 are fitted into the fixing holes 14.

  Thereafter, the tip of the mechanical connection portion 64 is heat caulked, and the through hole 13 and the plurality of connection terminals 65 are connected by the connection member 15 by soldering. At this time, the soldered connecting member 15 is wet spread on the surface of the bowl-shaped portion 65a, or is cured in this state. Finally, after disposing the heat radiating gel 80 on the surface of the heat sink 50, the lid 70 is disposed thereon, and the space between the lid 70 and the side wall surface 62 of the case 60 is fixed with an adhesive or the like. The electronic device S1 is completed.

  In the electronic device configured as described above, the connecting terminal 65 includes the hook-shaped portion 65 a, the hook-shaped portion 65 a is separated from the substrate 10, and the bonding of the through-hole 13 and the connecting terminal 65 is performed on the hook-shaped portion 65 a. The connection member 15 is arranged on the top. For this reason, it becomes possible to increase the volume of the connection member 15 arranged on the hook-shaped part 65a, compared with the case where the hook-shaped part 65a is not provided, and the surface of the hook-shaped part 65a spreads over a wide area. The stress relaxation effect is exhibited by the fillet of the connecting member 15. As a result, local distortion (deformation) of the connection member 15 due to thermal expansion / contraction of the substrate 10 or the case 60 can be suppressed, and the problem of poor connection due to breakage of the connection member 15 can be suppressed. Become. Moreover, since the hook-shaped part 65a is spaced apart from the board | substrate 10, since the connection member 15 can be confirmed between the hook-shaped part 65a and the board | substrate 10, it is determined whether the connection by the connection member 15 is performed favorably. It is possible to accurately check the above.

(Second Embodiment)
A second embodiment of the present invention will be described. In the present embodiment, the shape of the hook-shaped portion 65a is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only different portions from the first embodiment will be described.

  As shown in FIG. 4, in the present embodiment, the upper surface shape of the bowl-shaped portion 65 a is a cross shape (a shape obtained by removing each corner of the rectangular shape). The widths of the lines constituting the cross shape (lines parallel to the left and right direction of the paper and lines parallel to the vertical direction of the paper) are both larger than the diameter of the through hole 13 and are viewed from the vertical direction of the substrate 10. In this layout, the through hole 13 is arranged inside the hook-shaped portion 65a. And it is set as the structure where the axis line of the connecting terminal 65 passes the center position of the bowl-shaped part 65a.

  Thus, even if the upper surface shape of the bowl-shaped portion 65a is a cross shape, the same effect as in the first embodiment can be obtained.

(Third embodiment)
A third embodiment of the present invention will be described. In the present embodiment, the shape of the hook-shaped portion 65a is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only the parts different from the first embodiment will be described.

  As shown in FIG. 5, in the present embodiment, the upper surface shape of the bowl-shaped portion 65a is rectangular, more specifically rectangular (single character type). Thus, even when the hook-shaped portion 65a is rectangular, the axis of the connection terminal 65 has a structure that passes through the center position of the hook-shaped portion 65a, and at least the long side dimension of the hook-shaped portion 65a is that of the through hole 13. It is larger than the diameter. In the case of this embodiment, the short side dimension of the bowl-shaped portion 65a is also the same as or larger than that of the through hole 13.

  Thus, even if the upper surface shape of the bowl-shaped portion 65a is rectangular, the same effect as in the first embodiment can be obtained.

(Fourth embodiment)
A fourth embodiment of the present invention will be described. In the present embodiment, the shape of the hook-shaped portion 65a is changed with respect to the first embodiment, and the other parts are the same as those in the first embodiment. Therefore, only the parts different from the first embodiment will be described.

  As shown in FIG. 6, in this embodiment, the hook-shaped portion 65a has a press-fit shape. In other words, the connection terminal 65 is partially crushed to form the hook-shaped portion 65 a, and the dimension of one direction in the cross section perpendicular to the insertion direction to the through hole 13 of the connection member 15 is inserted into the through hole 13. The area is larger than In the present embodiment, the hole 65b that penetrates the hook-shaped portion 65a in a direction perpendicular to the axis of the connection terminal 65 is formed, but the hole 65b may not be formed.

  As described above, even when the flange-shaped portion 65a has a press-fit shape, the dimension of the connecting member 15 in one direction in the cross section perpendicular to the insertion direction into the through hole 13 is larger than the portion inserted into the through hole 13. Can also be expanded. For this reason, the effect similar to 1st Embodiment can be acquired.

(Other embodiments)
The present invention is not limited to the embodiment described above, and can be appropriately changed within the scope described in the claims.

  For example, in each of the embodiments described above, an example of the electronic device S1 to which the electronic components 20 and 30 are mounted on the one surface 11 of the substrate 10 and then the electronic components 20 and 30 are sealed with the mold resin 40 is applied. Although shown, it does not have to be the structure described in the above embodiments. For example, the one surface 11 side of the substrate 10, that is, the mold resin 40 side is arranged to face the bottom surface 61 side of the case 60, but the other surface 12 side, that is, the side opposite to the mold resin 40 is directed to the bottom surface 61 side. You may arrange in.

  Further, the fixing method of the substrate 10 by the mechanical connection portion 64 is not limited to heat caulking, and may be press fit or screw fastening. Further, the connection between the connection terminal 65 and the through hole 13 is not limited to soldering, and may be a press fit or the like.

  In each of the above embodiments, the connection terminal 65 provided upright on the case 60 is connected to the through hole 13 formed in the substrate 10. However, the connection terminal 65 is provided upright on another board or the like. However, the present invention can also be applied to the case of connecting to the through hole 13.

DESCRIPTION OF SYMBOLS 10 Board | substrate 11 One side 12 Other side 13 Through hole 20, 30 Electronic component 60 Case 64 Mechanical connection part 65 Connection terminal 65a A bowl-shaped part S1 Electronic device

Claims (6)

A substrate (10) having one surface (11) and another surface (12) opposite to the one surface, on which a wiring pattern is formed and a through hole (13) connected to the wiring pattern is formed When,
Electronic components (20, 30) mounted on one side of the substrate;
A rod-shaped connection terminal (65) inserted into the through-hole from the tip and electrically connected to the through-hole via a connection member (15) made of solder;
The connection terminal is inserted into the through hole at least one dimension in a direction perpendicular to the insertion direction into the through hole on the rear end side of the front end position of the connection terminal inserted into the through hole. A flange-shaped portion (65a) that is larger than the portion to be formed and is disposed at a position spaced apart from the substrate by a predetermined distance,
The electronic device according to claim 1, wherein the connecting member is in a state of being wetted and spread in the one direction in the bowl-shaped portion. A case having a bottom surface (61), the mechanical connection portion (64) for mechanically supporting the substrate being provided on the bottom surface, and the connection terminal being erected from the bottom surface toward the substrate (60)
The substrate is formed with a fixing hole (14) into which the tip of the mechanical connection portion is inserted,
The mechanical connection portion has a portion inserted into the fixing hole and a cross-sectional dimension in a direction perpendicular to the insertion direction into the fixing hole rather than the portion on the bottom surface side of the case from the portion. And a step portion due to the
The electronic device according to claim 1, wherein the hook-shaped portion is located closer to a bottom surface side of the case than the stepped portion.   3. The electronic device according to claim 1, wherein the hook-shaped portion has a circular shape when viewed from a direction in which the connection terminal is inserted into the through hole.   3. The electronic device according to claim 1, wherein the hook-shaped portion has a cross shape when viewed from the insertion direction of the connection terminal into the through hole.   3. The electronic device according to claim 1, wherein the hook-shaped portion has a rectangular shape when viewed from a direction in which the connection terminal is inserted into the through-hole.   The electronic device according to claim 1, wherein the hook-shaped portion is configured by partially crushing the connection terminal.

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