JP2005117719A - Adhesive sheet for manufacturing circuit structure and manufacturing method of circuit structure using adhesive sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive sheet for bonding a control circuit board to a bus bar which are main components constituting a circuit structure, capable of suppressing the deflection of the circuit construction even after thermal setting. <P>SOLUTION: An adhesive sheet 36 bonds a plurality of bus bars 32 constituting a power circuit to a control circuit board 34 which controls energization/cutting off of the power circuit. A slit 36a having the shape of the gap between bus bars is formed at the position corresponding to somewhere between specific bus bars. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an insulating property for bonding the bus bar and the control circuit board of a circuit configuration body including a plurality of bus bars constituting the power circuit and a control circuit board for controlling energization interruption of the power circuit. The present invention relates to an adhesive sheet and a method of manufacturing a circuit structure using the adhesive sheet.

  2. Description of the Related Art Conventionally, as a means for distributing electric power from a common in-vehicle power source to each electronic unit, an electric connection box in which a power distribution circuit is configured by a plurality of bus bars and a switch element or the like is incorporated therein is generally known. In recent years, as a means for realizing the miniaturization, for example, Patent Document 1 has bonded a bus bar constituting a power circuit and a control circuit board for controlling driving of a semiconductor switching element provided in the power circuit. An invention of a circuit structure manufactured in this manner is disclosed.

In this document, as for the bonding method for directly bonding the bus bar of the circuit structure and the control circuit board, a method of applying an adhesive to the bonding surface of the bus bar or the bonding surface of the control circuit board, or the control circuit board An example of a method of applying and bonding an adhesive only to the edge portion of the adhesive surface is described.
JP 2003-164039 A

  As a method of applying the adhesive, printing with a roll or a press plate on which an adhesive application pattern is formed may be considered. However, the roll and the press plate are expensive, and the cost of the apparatus is reduced according to this bonding method. It will be expensive. Therefore, instead of applying the adhesive, there is a method of using an insulating adhesive sheet as a method of easily and inexpensively adhering.

  When a sheet made of a thermosetting resin is used as the insulating adhesive sheet, as shown in FIG. 7 (a), the bus bar 32, the adhesive sheet 36, and the control circuit board 34 are overlapped as a whole. The bus bar 32 and the control circuit board 34 can be bonded by heating up to a temperature and pressing the pressing sheet up and down to completely cure the adhesive sheet 36.

  However, in this adhesion method using a sheet made of a thermosetting resin, when the circuit component is pressed by the pressing device, the adhesive sheet is compressed by the bus bar 32 and the control circuit board 34, and the compressed thermosetting resin is compressed. The adhesive is raised downward between the bus bars. Furthermore, since the adhesive swelled due to the shrinkage of the adhesive accompanying the heat curing also contracts in the horizontal direction, a horizontal force that attracts the bus bars under the control circuit board in the previous period works, as shown in FIG. 7B. The control circuit board may be greatly warped. And when adhering the said circuit structure to a heat sink etc., the whole surface contact | adherence of a circuit structure and a heat sink becomes difficult because of this curvature.

  In view of such circumstances, the present invention provides an adhesive sheet and an adhesive sheet that can suppress warpage of the control circuit board after thermosetting of the adhesive sheet when the bus bar and the control circuit board are bonded using the adhesive sheet. It aims at providing the manufacturing method of the circuit structure using this.

  According to the first aspect of the present invention, the bus bar and the control circuit board of the circuit structure including the plurality of bus bars constituting the power circuit and the control circuit board for controlling the energization interruption of the power circuit are bonded to each other. In this case, a slit having a shape along the gap between the bus bars is formed at a position corresponding to between the specific bus bars in the bus bar.

  The invention according to claim 2 is the adhesive sheet according to claim 1, wherein a through-hole for allowing a switch element mounted on the bus bar to cut off the power supply to the power circuit is provided. .

  The invention according to claim 3 is the adhesive sheet according to claim 1 or 2, wherein the slit formed in the adhesive sheet extends in a direction perpendicular to the long side direction of the control circuit board. Is formed.

  According to a fourth aspect of the present invention, the bus bar and the control circuit board of a circuit structure including a plurality of bus bars constituting the power circuit and a control circuit board for controlling energization interruption of the power circuit are bonded to each other. The adhesive sheet is divided into a plurality of sheets, and a gap having a shape along a gap between specific bus bars among the bus bars is provided between adjacent sheets. It is an adhesive sheet in which the outer shape of each sheet is determined so that it can be formed.

  According to a fifth aspect of the present invention, there is provided a method of manufacturing a circuit structure including a plurality of bus bars constituting a power circuit and a control circuit board for controlling energization interruption of the power circuit. The adhesive sheet according to any one of? 3 is overlaid so that the position of the slit formed in the adhesive sheet and the position of the gap between specific bus bars coincide with each other, and the control is performed on the adhesive sheet side. It is a method for manufacturing a circuit component including a step of superposing circuit boards and a step of bonding by thermocompression while maintaining the superposed state.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing a circuit structure including a plurality of bus bars constituting a power circuit and a control circuit board for controlling energization interruption of the power circuit. And the step of superimposing the divided adhesive sheets so that the outer shape of each of the divided sheets is along the gap between the specific bus bars, and superimposing the control circuit board on the adhesive sheet side. And a step of adhering by thermocompression bonding while maintaining the state.

  According to the invention according to claim 1, by forming a slit at a position corresponding to between the bus bars in the adhesive sheet, the horizontal force works to attract the bus bars due to the shrinkage of the adhesive due to heat curing. As a result, the warpage of the control circuit board after the thermosetting of the adhesive sheet can be suppressed. This effect will be described with reference to the drawings. For example, as shown in FIG. 8A, a slit 36a is formed at a position corresponding to between the bus bars in the adhesive sheet 36, thereby transmitting the force connecting the bus bars. This reduces the action of the horizontal force that attracts the bus bars even when the adhesive contracts. Therefore, even after the adhesive sheet is thermally cured, the warp of the control circuit board can be suppressed as shown in FIG.

  According to the second aspect of the present invention, the space for inserting the switch element is secured by bonding the bus bar and the control circuit board using the adhesive sheet provided with the through hole at the position of the switch element provided in the power circuit. Therefore, the switch element can be easily mounted even after bonding.

  According to the invention according to claim 3, since the warp of the control circuit board is large in the long side direction of the control circuit board, the slits of the adhesive sheet are prevented from being warped by the long side of the control circuit board. By forming in a shape extending in a direction that forms a right angle, warping of the control circuit board after thermosetting of the adhesive sheet can be more effectively suppressed.

  According to the invention of claim 4, the adhesive sheet is divided into a plurality of sheets, and a gap having a shape along a gap between specific bus bars among the bus bars can be formed between adjacent sheets. As the outer shape of each sheet is determined so that the gap between the sheets has the same effect as the slit, the control circuit after thermosetting the adhesive sheet even if the adhesive sheet is divided in this way Warpage of the substrate can be suppressed.

  According to the invention which concerns on Claim 5, since the circuit structure body by which curvature was suppressed by this process using the adhesive sheet in any one of Claims 1-3 can be manufactured, in a subsequent process, a circuit structure body When adhering to a heat sink or the like, the entire surface of the circuit structure and the heat sink can be easily adhered.

  According to the invention according to claim 6, by using the adhesive sheet according to claim 4, each of the divided sheets is disposed so that the outer shape thereof is along the gap between the specific bus bars. Since the same effect as the slit can be obtained by the gap formed between the two, the warpage of the control circuit board after the thermosetting of the adhesive sheet can be suppressed also by this method.

  An example in which the circuit structure manufactured using the adhesive sheet of the present invention is used is shown in FIGS. The product shown in FIGS. 1 and 2 includes a heat radiating plate (heat radiating member) 10, a case body 20, and a circuit component 30, and a circuit body is obtained by mounting appropriate mounting parts on the circuit component 30. Is configured. The mounted components include circuit elements such as a board-mounted relay switch element 40, a power input connector 50, an external connection connector 60, and other semiconductor elements and resistor elements. A cover 70 that covers the circuit board 30 is mounted on the connectors 50 and 60.

  The circuit structure 30 includes a power circuit unit that constructs a power circuit (a power distribution circuit for distributing power from a vehicle-mounted power source to a plurality of loads in the illustrated example), and a control circuit unit that controls on / off of the circuit in the power circuit unit And have both. The power circuit section is formed by arranging a plurality of bus bars 32 on the same plane, and the control circuit section is constituted by a control circuit board 34 such as a thin printed circuit board. Each bus bar 32 is bonded to the lower surface of 34 in an insulating state via an adhesive sheet 36. As the adhesive sheet 36, a sheet made of a thermosetting resin such as highly insulating epoxy resin is preferable.

  FIG. 3 shows the circuit structure 30 extracted and shown on a plane. In FIG. 3, the adhesive sheet 36 is indicated by a solid line, the control circuit board 34 is indicated by a two-dot chain line, and the state where the bus bar 32 is visible and hidden from the opening of the adhesive sheet 36 is indicated by a solid line and a dotted line. Further, the adhesive sheet 36 is extracted and shown in FIG.

  In the adhesive sheet 36 of this embodiment, slits 36a are formed at three positions corresponding to each other between specific bus bars. The three places are a position corresponding between the bus bar 32a and the bus bar 32b, a position corresponding between the bus bar 32c and the bus bar 32d, and a position corresponding between the bus bar 32e and the bus bar 32f. Since it is difficult to understand the relationship between the slit 36a and the bus bar 32, FIG. 5 shows a circuit structure when an adhesive sheet without a slit is used, and FIG. 6 shows the adhesive sheet. As can be understood by comparing FIGS. 3 and 5 and FIGS. 4 and 6, the slits 36 a of the adhesive sheet are formed at corresponding positions between the bus bars.

  For example, paying attention to the bus bar 32a and the bus bar 32b, in the region where the slit 36a is formed, the adhesive that connects the bus bars is removed by the slit 36a, so that a horizontal force that attracts the bus bar 32a and the bus bar 32b is generated. There are no elements to be transmitted or elements to be transmitted. Thus, the warp of the control circuit board after thermosetting of the adhesive sheet is provided at a suitable position on the adhesive sheet where a horizontal force that attracts the bus bars that cause the warp of the control circuit board does not act. Can be suppressed.

  In addition, when the control circuit board is rectangular, the warp of the control circuit board is large in the direction along the long side direction. By forming in a shape extending in a direction perpendicular to the adhesive sheet, it is possible to more effectively suppress warping of the control circuit board after thermosetting the adhesive sheet.

  The slits 36a formed in the adhesive sheet 36 are not limited to the position and quantity as in the present embodiment. If the shape of the circuit structure to be manufactured or the number or pattern of bus bars is changed, the slit 36a of the control circuit board generated after the thermosetting of the adhesive sheet is performed. Since the mode of warping also changes, it is appropriately formed according to the situation. Further, the shape of the slit 36a is not limited to the linear shape as in the present embodiment, and may have a bent portion adapted to the shape of the bus bar, and the width of the slit is not necessarily the same as the gap between the bus bars. However, it may be narrower or thicker than the gap between the bus bars as long as it has the effect of suppressing the warpage of the circuit structure.

  Since the relay switch element 40 and the semiconductor switching element 42 (FIG. 3) are mounted on the bus bar 32 constituting the power circuit, the control circuit board 32 is provided with through holes into which these switch elements can be inserted, As shown in FIG. 4, the adhesive sheet 36 is also provided with a through hole 36b through which the switch element can pass. Furthermore, since the terminals 52 and 62 (FIG. 2) of the connectors 50 and 60 mounted on the circuit structure 30 penetrate the control circuit board 34 and the adhesive sheet 36 and are electrically connected to the bus bar 32, the control sheet 36 is provided with a through-hole 36c through which a terminal can pass. By providing these through holes, the switch element insertion space and the terminal passage space are secured even after the control circuit board 34 and the bus bar 32 are bonded, so that the switch elements, connectors, etc. can be easily mounted. can do.

  In the present embodiment, an example is shown in which the terminals 52 and 62 of the connectors 50 and 60 are mounted on the circuit structure 30 in a state of penetrating the control circuit board 34 and the adhesive sheet 36. Since it is also possible to use a connector with an extended end located at the edge of the circuit component 30, the terminal through hole 36c of the adhesive sheet 36 is not necessarily required.

  Next, an example of a method for producing a circuit structure using the adhesive sheet of the present invention will be described.

  In the adhesive sheet 36, slits 36a and various through holes 36b and 36c are formed by punching or the like.

  A control circuit board 34 is placed on the bus bar 32 with the adhesive sheet 36 interposed therebetween. At that time, the control signal terminal of the switch element mounted on the bus bar 32 is further arranged on the circuit of the control circuit board 34 so that the slits 36a of the adhesive sheet 36 coincide with each other between the specific bus bars. The bus bar 32, the adhesive sheet 36, and the control circuit board 34 are overlapped so as to match the positions to be connected.

  Such a superposition operation can be easily performed by using a bus bar constituting plate having a shape in which a plurality of bus bars 32 are joined together by a bridge portion at an appropriate location. Further, the bus bar constituting plate, the adhesive sheet 36 and the control circuit board 34 are formed with through holes having the same diameter, and the through holes are fitted to pins provided on a work plate or the like. If the adhesive sheet 36 and the control circuit board 34 are superposed, the positioning is performed by the pins, so that the superposition operation can be performed more easily.

  The bus bar 32 and the control circuit board 34 can be bonded by heating the whole to an appropriate temperature while maintaining the overlapping state, and pressing the sheet up and down with a press device to completely cure the adhesive sheet 36. it can.

  As shown in FIG. 8A, the adhesive sheet 36 of the present invention attracts the bus bars 32 due to the shrinkage of the adhesive due to the heat curing by forming the slits 36a at the corresponding positions between the bus bars 32. Since the action of the matching horizontal force is suppressed, the warpage of the control circuit board is suppressed even after the adhesive sheet is thermally cured as shown in FIG. The circuit structure 30 can be manufactured.

  Further, the slit 36a of the adhesive sheet 36 is extended in the length direction as it is, and the adhesive sheet 36 is divided into a plurality of sheets (in this embodiment, the slits 36a are formed at three locations, so four sheets). And, by arranging each divided sheet so that its outer shape is along the gap between the specific bus bars, the same effect as the slit can be obtained by the gap formed between the adhesive sheets, Thus, even if the adhesive sheet is divided, the warp of the control circuit board after thermosetting of the adhesive sheet can be suppressed.

  Then, the process until the product shown in FIG. 1 is completed using the circuit structure 30 will be described.

  Components such as a relay switch element 40, a semiconductor switching element 42, a power input connector 50, and an external connection connector 60 are mounted on the circuit structure 30 to construct a circuit body. The case body 20 is set around the circuit body, and the heat sink 10 is set under the circuit body with the adhesive sheet 18 interposed therebetween.

  The circuit body and the heat radiating plate 10 are bonded together by thermocompression bonding in the same manner as the method of manufacturing the circuit structure 30. In this case, the circuit structure 30 that forms the bottom surface of the circuit body can be easily brought into close contact with the heat sink 10 because warpage is suppressed in the manufacturing process.

  In order to perform waterproofing of the circuit portion, a gel made of silicone resin is injected into a region surrounded by the seal member 26 of the case body 20 to an appropriate height (for example, the height of the two-dot chain line 38 in FIG. 2). To cure. Thereby, the mounting part of each element in a circuit body is sealed in the said silicone resin, and will be in a waterproof state. Thereafter, the product is completed by attaching the cover 70 for protecting the substrate.

It is a disassembled perspective view of the product in which the circuit structure manufactured using the adhesive sheet which is one Example of this invention is used. It is a cross-sectional front view of the product. It is a top view of the circuit structure manufactured using the adhesive sheet which is one Example of this invention. It is a top view of the adhesive sheet which is one Example of this invention. It is a top view of the circuit structure manufactured using the adhesive sheet in which the slit is not formed. It is a top view of the adhesive sheet in which the slit is not formed. It is the schematic diagram of the circuit structure manufactured using the adhesive sheet in which the slit is not formed, (a) shows the state before adhesive sheet thermosetting, (b) shows the state after adhesive sheet thermosetting. It is shown. It is the schematic diagram of the circuit structure manufactured using the adhesive sheet of this invention, (a) showed the state before adhesive sheet thermosetting, (b) showed the state after adhesive sheet thermosetting It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Heat sink 30 Circuit structure body 32 Bus bar 34 Control circuit board 36 Adhesive sheet 36a Slit 36b, 36c Through-hole 40 Relay switch element 42 Semiconductor switching element

Claims (6)

  An insulating adhesive sheet for adhering the bus bar and the control circuit board of the circuit structure including a plurality of bus bars constituting the power circuit and a control circuit board for controlling energization interruption of the power circuit. And the slit of the shape along the clearance gap between the said bus-bars is formed in the position corresponding between between specific bus-bars among the said bus-bars, The adhesive sheet characterized by the above-mentioned.   2. The adhesive sheet according to claim 1, wherein a through hole is provided to allow a switch element mounted on the bus bar to cut off the power circuit to pass through.   3. The adhesive sheet according to claim 1, wherein the slit formed in the adhesive sheet is formed in a shape extending in a direction perpendicular to a long side direction of the control circuit board. Adhesive sheet.   An insulating adhesive sheet for adhering the bus bar and the control circuit board of the circuit structure including a plurality of bus bars constituting the power circuit and a control circuit board for controlling energization interruption of the power circuit. The adhesive sheet is divided into a plurality of sheets, and a gap having a shape along a gap between specific bus bars among the bus bars can be formed between adjacent sheets. An adhesive sheet characterized in that the outer shape of the sheet is defined.   In the method of manufacturing the circuit structure provided with the several bus-bar which comprises a power circuit, and the control circuit board which controls energization interruption of the power circuit, the said bus-bar and any one of Claims 1-3 Superimposing the adhesive sheet with the position of the slit formed in the adhesive sheet and the position of the gap between the specific bus bars, and superimposing the control circuit board on the adhesive sheet side; And a step of adhering by thermocompression bonding while maintaining the superposed state.   In a method of manufacturing a circuit configuration body including a plurality of bus bars constituting a power circuit and a control circuit board for controlling energization interruption of the power circuit, the bus bar and the adhesive sheet according to claim 4, Superimposing the divided sheets so that the outer shape of each sheet follows the gap between the specific bus bars and superimposing the control circuit board on the adhesive sheet side, and thermocompression bonding while maintaining the superimposed state And a step of bonding the circuit structure.

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