JP2011029313A - Thick conductor substrate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thick conductor substrate for allowing a high current to flow, which is formed by injection molding and configured to prevent damage by thermal expansion, and also to provide a manufacturing method thereof. <P>SOLUTION: In the thick conductor substrate 100, the ratio of a cross-sectional area of a conductor is enlarged thereby to allow a linear expansion coefficient to be equal to or less than a prescribed reference linear expansion coefficient in the cross section passing at least between the solder joint parts 141 of electronic components 140. That is, the area of copper with the linear expansion coefficient of about 17 [ppm/°C] is increased in the cross section passing at least the solder joint parts 141, so that an average linear expansion coefficient is reduced to be equal to or less than the reference linear expansion coefficient. The reference expansion coefficient is allowed to be 24 [ppm/°C] at a degree being the same as that of a conventional electronic substrate using glass epoxy, for example. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technical field of a thick conductor substrate having a large calorific value and a manufacturing method thereof.

  The DC-DC converter for automobiles is generally of a system composed of four parts: a switching MOS-FET, a voltage converting transformer, a rectifying diode, and a smoothing choke coil. A DC-DC converter for a hybrid vehicle is configured such that each component is individually cooled by a cooling component such as a water jacket because heat from each component increases due to high voltage and large current. That is, each is separately mounted on a cooling component, and each component is electrically connected by a bus bar or the like (for example, Patent Document 1).

  However, in the configuration as described above, screw fastening work and welding work etc. at the connection location increase, and not only the assembly man-hours increase, but also to avoid electrical problems due to variations in contact resistance at the connection location. Therefore, it is necessary to add a dedicated component on the circuit.

  As a countermeasure to such a problem, by forming the coil components constituting the voltage conversion transformer and the smoothing choke coil with the circuit pattern of the substrate on which the switching MOS-FET and the rectifying diode are mounted, The components can be integrated, thereby reducing the number of connection points. In addition, the heat generation components are concentrated by integrating the components, but by inserting the heat dissipation sleeve directly under the heat generation components, the heat on the upper surface of the board is released to the lower surface and further radiated from the lower surface of the substrate to the outside. It can be constituted as follows.

  By the way, when a switching MOS-FET, a rectifying diode, a voltage converting transformer, and a smoothing choke coil are formed and integrated on the same substrate, the conductive layer energization amount increases. The thickness needs to be approximately 0.4 mm or more. Conventionally, a substrate is manufactured by laminating a conductor layer having such a thickness with a glass epoxy insulator.

JP 2005-143215 A

  However, in the method of manufacturing a substrate by laminating a conventional conductor layer and glass epoxy, the resin cannot sufficiently spread between conductors separately formed on the same layer, and there is a gap between them. There is a risk that. When such voids are formed, the plating solution and etching solution used in the plating and etching processes remain in the voids, and the components change as the remaining liquid mixes with other liquids during the manufacturing process. Or the insulation performance of the substrate may be reduced.

  Further, when a gap is formed on the joint surface between the conductor layer and the insulating layer, there is a possibility that the etching solution or the like may permeate into that portion. In order to prevent this, a step of roughening the conductor layer by applying a neo-brown treatment or the like, a step of improving the adhesion of the conductor, and the like are necessary, which has been a factor in increasing costs.

  Therefore, the present invention has been made to solve such problems, and a thick conductor substrate formed of a conductor layer and an insulating layer of a thick conductor so as not to have a gap inside, and a method for manufacturing the same. The purpose is to provide.

  A first aspect of the thick conductor substrate of the present invention is a thick conductor substrate capable of surface mounting electronic components, wherein two or more conductor layers on which a circuit pattern is formed by processing a metal plate are interlayer-connected, An insulating layer is formed by injection molding a resin between two or more conductor layers.

  According to another aspect of the thick conductor substrate of the present invention, a cross-sectional average linear expansion coefficient obtained by weighted averaging of a cross-sectional area of the insulating layer and a cross-sectional area of the conductor layer at least in a region where the electronic component is surface-mounted is an overall average linear expansion. The thickness of the insulating layer or the conductor layer is determined so as to reduce deformation due to thermal expansion by making it smaller than the coefficient.

を満たすように決定されていることを特徴とする。 In another aspect of the thick conductor substrate of the present invention, when the cross-sectional area and the linear expansion coefficient of the insulating layer are Si and αi, respectively, and the cross-sectional area and the linear expansion coefficient of the conductor layer are Sc and αc, respectively, the insulating layer The ratio of the cross-sectional area Si of the layer and the cross-sectional area Sc of the conductor layer is expressed by the following formula with respect to a predetermined reference thermal expansion coefficient αm.

It is determined to satisfy.

  Another aspect of the thick conductor substrate of the present invention is characterized in that the conductor layer is covered with the insulating layer except for a region where the electronic component is surface-mounted.

  Another aspect of the thick conductor substrate of the present invention is characterized in that the outer periphery of the conductor layer is covered with the same resin as the insulating layer.

  Another aspect of the thick conductor substrate of the present invention is characterized in that a contact surface between the conductor layer and the insulating layer is fixed by an anchor formed of the same resin as the insulating layer.

  Another aspect of the thick conductor substrate of the present invention is characterized in that the anchor fixes between the uppermost layer surface and the lowermost layer surface of the conductor layer.

  According to another aspect of the thick conductor substrate of the present invention, a groove is formed in the outermost conductor layer, and an insulating layer formed between the insulating layer formed by injection molding the resin into the groove and the conductor layer. The anchor is formed so as to connect between the layers.

  Another aspect of the thick conductor substrate according to the present invention is characterized in that a surface of the conductor layer in contact with the insulating layer has a roughened structure.

  According to another aspect of the thick conductor substrate of the present invention, the conductor layer is divided into two or more conductor pieces on the same plane, and one of the two adjacent conductor pieces is engaged with the other. An end side of each conductor piece is formed.

  According to another aspect of the thick conductor substrate of the present invention, the conductor layer includes an elastic portion having an elastic structure that can be deformed in a direction perpendicular to the surface of the conductor layer, and a joint portion whose tip side is joined to another conductor layer. And a connecting portion for electrically connecting to the another conductor layer.

  Another aspect of the thick conductor substrate of the present invention is characterized in that the elastic portion is provided on the conductor layer side of the connection portion.

  According to another aspect of the thick conductor substrate of the present invention, the two conductor layers having the connecting portion provided with the elastic portion on the joint portion side connect the elastic portions to each other by the joint portion. It is possible to deform in a direction perpendicular to the surface of the conductor layer.

  Another aspect of the thick conductor substrate of the present invention is characterized in that a coil having a U-shaped cross section is formed in the conductor layer.

  Another aspect of the thick conductor substrate of the present invention is characterized in that the insulating layer is formed by injection molding a polyphenylene sulfide resin (PPS).

  According to a first aspect of the method for manufacturing a thick conductor substrate of the present invention, a conductor layer connecting step of electrically connecting two or more conductor layers on which a circuit pattern is formed by processing a metal plate in advance, A mold housing step for housing and fixing the conductor layer in a mold for forming an insulating layer so as to reduce deformation due to thermal expansion corresponding to the circuit pattern, and a predetermined injection molding for the mold And an injection molding process for injecting resin.

  According to the electronic substrate of the present invention, a thick conductor substrate formed of a conductive layer of a thick conductor and an insulating layer so as not to have voids therein by forming the insulating layer by injection molding, and a method for manufacturing the same Can be provided.

It is sectional drawing which shows schematic structure of the thick conductor board | substrate which concerns on the 1st Embodiment of this invention. It is the perspective view and sectional drawing which show schematic structure of the thick conductor board | substrate which concerns on the 2nd Embodiment of this invention. It is a top view which shows arrangement | positioning of several electronic components when the soldering junction part of one electronic component is arrange | positioned on a straight line. It is sectional drawing for demonstrating the cross-sectional area and linear expansion coefficient of the thick conductor board | substrate of 2nd Embodiment. It is explanatory drawing for demonstrating the dispersion | variation in the distance between conductor layers. It is a perspective view which shows the structure of a connection part. It is explanatory drawing explaining the manufacturing method of the thick conductor board | substrate of 2nd Embodiment. It is explanatory drawing explaining the metal mold | die which provided the hollow part. It is the perspective view and sectional drawing which show schematic structure of the thick conductor board | substrate which concerns on the 3rd Embodiment of this invention. It is a perspective view which shows the structure of another connection part. It is sectional drawing which shows the thick conductor board | substrate which provided the outer periphery insulating layer. It is sectional drawing which shows the thick conductor board | substrate which provided the anchor. It is sectional drawing and bottom view which show the thick conductor board | substrate which provided another anchor. It is sectional drawing of the thick conductor board | substrate which made the surface which touches the insulating layer of a conductor layer into the roughening structure. It is a top view of the thick conductor board | substrate made into the shape which mutually attracts the opposing edge of a conductor layer. It is sectional drawing of the coil formed in the U-shape.

  A thick conductor substrate and a manufacturing method thereof according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each structural part which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description. In the following, a case where there are two conductor layers will be described as an example.

  A thick conductor substrate according to a first embodiment of the present invention will be described with reference to FIG. A thick conductor substrate 50 according to the present embodiment shown in FIG. 1 includes two conductor layers 51 and 52 formed by punching or bending, and an insulating layer 53 formed by injection molding a resin therebetween. It is configured. In this manufacturing method, the interlayer connection portion 54 that connects the conductor layers 51 and 52 is connected in advance by welding or brazing, and then an injection molding resin is injected between the conductor layers to form the insulating layer 53. .

  As described above, by forming the insulating layer 53 by injection molding, it is possible to provide the thick conductor substrate 50 having no voids therein at a low cost. In the thick conductor substrate 50 of this embodiment, when two or more conductors are arranged in each of the conductor layers 51 and 52, the resin is injected between the conductors without a gap. In addition, the resin is injected into the contact surface with the conductor layer without any gap. As a result, it is possible to provide a thick conductor substrate that is low in cost and does not have a void in the interior thereof, has high reliability equivalent to that of a conventional substrate, and can flow a large current.

  Next, a thick conductor substrate according to a second embodiment of the present invention will be described. In a conventional electronic substrate using glass epoxy, the thickness of the conductor layer of the substrate is 35 μm to 70 μm per layer, whereas the thickness of the insulating layer is 200 μm to 1600 μm per layer, It was formed more than twice as thick. In this case, the volume ratio occupied by the insulating layer in the substrate is increased, and the linear expansion coefficient of the entire substrate including the conductor layer is dominated by the linear expansion coefficient of the insulating layer.

  Therefore, in order to ensure the reliability of the joints soldered to the conductor layer of electronic components mounted on the board and to prevent the conductor layer and the insulating layer from peeling off, the linear expansion coefficient of the insulating layer is required. Is preferably small. The surface direction linear expansion coefficient of the insulating layer using glass epoxy is generally a very small value of about 14 to 24 [ppm / ° C.]. The expansion coefficient was about 17 [ppm / ° C.] when copper was used, for example.

  On the other hand, in the thick conductor substrate and the manufacturing method thereof according to the present invention, the insulating layer is formed using a resin for injection molding having a linear expansion coefficient of 8 to 30 [ppm / ° C.]. Therefore, even when the linear expansion coefficient is reduced to about 8 ppm / ° C. in the resin flow direction at the time of injection molding, the linear expansion coefficient increases in the direction perpendicular to the flow direction and may be about 30 ppm / ° C. is there. Thus, when the substrate is formed by injection molding, the linear expansion coefficient of the insulating layer is difficult to predict compared to glass epoxy.

  For this reason, when, for example, life prediction is performed at the design stage, it is necessary to use the most conservative value of 30 ppm / ° C. as the linear expansion coefficient. As described above, when a large value is used for the coefficient of linear expansion of the insulating layer, the thermal expansion / heat of the insulating layer is mainly applied to the joint part of the electronic component soldered to the conductor layer and the joint surface between the conductor layer and the insulating layer. The result is that stress due to contraction is concentrated. This shortens the predicted life of the solder joint of the electronic component, but this result must be used for the design.

  Therefore, the thick conductor substrate according to the second embodiment of the present invention is configured such that the average coefficient of linear expansion is equal to or less than that of a conventional electronic substrate using glass epoxy. A thick conductor substrate according to the second embodiment will be described below with reference to FIG. 2A and 2B are diagrams showing a schematic configuration of the thick conductor substrate 100 of the present embodiment. FIG. 2A is a perspective view of the thick conductor substrate 100, and FIG. It is sectional drawing when cut | disconnecting. The thick conductor substrate 100 includes conductor layers 111 and 112 made of copper, and an insulating layer 130 disposed between the conductor layers 111 and 112. The insulating layer 130 is formed of an injection molding resin such as polyphenylene sulfide resin (PPS). A plurality of electronic components 140 are surface-mounted on the upper surface of the conductor layer 111.

  In the thick conductor substrate 100 of the present embodiment, the conductor is cut so that the average linear expansion coefficient is not more than a predetermined reference linear expansion coefficient in at least a cross section passing through the solder joint portion 141 of the electronic component 140 shown in FIG. The area ratio is increased. That is, at least in the cross section passing between the solder joints 141, by increasing the area of copper having a linear expansion coefficient of about 17 [ppm / ° C.], the average linear expansion coefficient is reduced below the reference linear expansion coefficient. Yes. The reference linear expansion coefficient can be set to 24 [ppm / ° C.], which is the same as that of an electronic substrate using a conventional glass epoxy, for example.

  In FIG. 2, the solder joint portions 141 of the two electronic components 140 are arranged on a straight line. However, the present invention is not limited to this. For example, as shown in FIG. Even in the case where only the conductor is disposed, it is preferable to reduce the average linear expansion coefficient to be equal to or lower than the reference linear expansion coefficient by increasing the cross-sectional area ratio of the conductor in at least the cross section passing through the solder joint portion 141 as described above.

ここで、αｃ、αｉはそれぞれ導体層１１１、１１２の線膨張係数、絶縁層１３０の線膨張係数であり、αｍは基準線膨張係数を表す。αｍ＝２４［ｐｐｍ／℃］とするのがよい。 As described above, in order to reduce the average linear expansion coefficient in the cross section passing through the solder joint portion 141 below the reference linear expansion coefficient, in this embodiment, the area ratio of the conductor layers 111 and 112 and the insulating layer 130 in the cross sectional area is set. It is determined as follows. When the cross-sectional area and the linear expansion coefficient of the conductor layers 111 and 112 and the insulating layer 130 are expressed by the parameters shown in FIG. 4, the conductor layer is set so that the average linear expansion coefficient αav in the cross section passing through the solder joint 141 satisfies the following equation. The total sectional area Sc of 111 and 112 and the sectional area Si of the insulating layer 130 are determined.

Here, αc and αi are the linear expansion coefficient of the conductor layers 111 and 112 and the linear expansion coefficient of the insulating layer 130, respectively, and αm represents the reference linear expansion coefficient. It is preferable that αm = 24 [ppm / ° C.].

  In the thick conductor substrate 100 of this embodiment formed by injection molding by determining the total cross-sectional area Sc of the conductor layers 111 and 112 and the cross-sectional area Si of the insulating layer 130 so as to satisfy the above formula (1), The reliability equivalent to or higher than that of a conventional electronic substrate using glass epoxy can be ensured.

As an example, the total cross-sectional area Sc of the conductor layers 111 and 112 is 39.2 mm ² , the cross-sectional area Si of the insulating layer 130 is 20.8 mm ^2, and the linear expansion coefficient αc of the conductor layers 111 and 112 is 16.8 [ppm / And the linear expansion coefficient αi of the insulating layer 130 = 30 [ppm / ° C.], the average linear expansion coefficient on the left side of the equation (1) is 21.4 [ppm / ° C.]. This is smaller than the average linear expansion coefficient of 24 [ppm / ° C.] of the electronic substrate using the conventional glass epoxy, and secures reliability higher than that of the conventional solder joint portion 141 of the electronic component 140.

  In the method of manufacturing the thick conductor substrate 100 of the present embodiment by injection molding, the step of electrically connecting the plurality of conductor layers 111 and 112 needs to be performed before the step of injection molding. . This is to prevent the injected resin from entering the connecting portion connecting the conductor layers 111 and 112. However, if there is variation in the distance between the conductor layers, a problem as shown in FIG. 5 may occur during injection molding.

  FIG. 5 is an explanatory diagram for explaining the variation in the distance between the conductor layers. FIG. 5A shows the case where the distance between the conductor layers 11 and 12 matches the designed distance L0. Shows the case where the distance between the conductor layers 11 and 12 is a distance L1 longer than the design distance L0, and (c) shows the case where the distance between the conductor layers 11 and 12 is a distance L2 shorter than the design distance L0. Is shown.

  As shown in FIG. 5B, when the distance between the conductor layers 11 and 12 is a distance L1 longer than the design distance L0, the conductor layers 11 and 12 are connected by the connecting portion 13 to form the mold 20. When housed inside, there arises a problem that the upper mold 21 and the lower mold 22 cannot be sealed. 5C, when the distance between the conductor layers 11 and 12 is a distance L2 shorter than the design distance L0, there is a gap between the conductor layers 11 and 12 and the mold 20. There is a problem that the injected resin enters the gap and hinders mounting of electronic components.

  Therefore, in the thick conductor substrate 100 of the present embodiment, the connection portion 113 that electrically connects the conductor layers 111 and 112 has a structure having an elastic portion 113a as shown in FIG. That is, the connection portion 113 is fixed to the conductor layer 112 via the elastic portion 113a that can be bent in a direction perpendicular to the surface of the conductor layer 112. In addition, a junction 113 b is provided at the end of the connection portion 113 opposite to the elastic portion 113 a and connected to the conductor layer 111. As shown in FIG. 6B, the elastic portion 113 a is preferably bent to the conductor layer 111 side from the surface of the conductor layer 112. And it is preferable that the distance of the connection part 113 from the conductor layer 112 to the junction point 113b is made slightly longer than the design distance L0.

  By connecting the conductor layers 111 and 112 using the connection portion 113 having the above-described structure, the above problem in the injection molding process can be solved. That is, the joining point 113 b of the connecting portion 113 is welded or brazed to the conductor layer 111 to electrically connect the conductor layers 111 and 112, and this is stored in the mold 20. At this time, since the connecting portion 113 is formed to be slightly longer than the design distance L0, the conductive layer 111 is brought into close contact with the upper die 21 and pressed toward the lower die 22 so that the elastic portion 113a becomes the bottom side of the lower die 22 Bend. Thereby, there is no possibility that a gap is formed between the conductor layers 111 and 112 and the mold 20.

  A method for manufacturing the thick conductor substrate 100 of the present embodiment will be described with reference to FIG. First, in FIG. 7A, the conductor layers 111 and 112 are electrically connected by welding or brazing the joint point 113 b of the connection portion 113 to the conductor layer 111. In FIG. 7B, the connected conductor layers 111 and 112 are accommodated in the lower mold 22 of the mold 20 and fixed with the fixing pins 23. In FIG.7 (c), the upper mold | type 21 is sealed to the lower mold | type 22 without a gap. At this time, the elastic portions 113 a of the connecting portion 113 are bent toward the bottom of the lower mold 22, so that the conductor layers 111 and 112 are in close contact with the bottom of the upper mold 21 and the lower mold 22. Further, in FIG. 7D, a predetermined resin is injected into the mold 20 to form the insulating layer 130.

  In the above process, when the upper mold 21 and the lower mold 22 are sealed because the connecting section 113 is too long, the elastic section 113a may be pressed against the bottom of the lower mold 22. It is preferable to form a recess 22a as shown in FIG. Thereby, even if the elastic part 113a may bend toward the lower mold 22 by any chance, the connection part 113 is not likely to be pressed from the bottom of the lower mold 22 by the elastic part 113a entering the recessed part 22a.

  The connecting portion 113 shown in FIG. 6 is connected to the conductor layer 112 side via the elastic portion 113a, but is not limited to this, and may be provided on the conductor layer 111 side. A connection part may be provided in both 112, and the edge part of each connection part may be connected.

  The thick conductor substrate 100 of the present embodiment is surface-mounted by increasing the total cross-sectional area of the conductor layers 111 and 112 so that the average coefficient of linear expansion is equal to or less than that of a conventional electronic substrate using glass epoxy. Further, the reliability equal to or higher than that of the conventional electronic substrate can be ensured for the solder joint portion 141 of the electronic component 140.

  A thick conductor substrate according to a third embodiment of the present invention will be described below with reference to FIG. FIG. 9 is a diagram illustrating a schematic configuration of the thick conductor substrate 200 according to the third embodiment. FIG. 9A is a perspective view of the thick conductor substrate 200, and FIG. FIG. In the present embodiment, the conductor layers 211 and 212 are formed using pure aluminum. The linear expansion coefficient of pure aluminum is about 24 [ppm / ° C.], which is substantially equal to the standard linear expansion coefficient of 24 [ppm / ° C.]. Therefore, in the cross-sectional area shown in FIG. 9B, even if the cross-sectional areas of the conductor layers 211 and 212 are increased, the average linear expansion coefficient of the thick conductor substrate 200 cannot be made smaller than the reference linear expansion coefficient.

  Therefore, in order to prevent damage to the substrate due to thermal expansion, in the thick conductor substrate 200 of the present embodiment, the upper surface of the conductor layer 211 and the lower surface of the conductor layer 212 except for the surface mounting portion 233 on which the electronic component 140 and the like are mounted. Are covered with an upper insulating layer 231 and a lower insulating layer 232, respectively. Thus, by covering the three-layer structure of the conductor layers 211 and 212 and the insulating layer 230 with the upper insulating layer 231 and the lower insulating layer 232, it is possible to maintain the adhesion between the respective layers and prevent the peeling. Yes. The electronic component 140 is mounted on the surface mounting portion 233, and the solder joint portion 141 of the electronic component 140 is soldered to the conductor layer 211 exposed from the joint hole 234 of the upper insulating layer 231.

  In the present embodiment, connection portions 213 and 214 shown in FIG. 10 are used as connection portions for electrically connecting the conductor layers 211 and 212. The connection parts 213 and 214 are erected on the conductor layers 211 and 212, respectively, and elastic parts 213a and 214a are formed at the ends of the connection parts 213 and 214, respectively. Further, joint points 213b and 214b are provided in the elastic portions 213a and 214a, respectively, and the conductor layers 211 and 212 are electrically connected by welding or brazing the joint points 213b and 214b. In this embodiment, the connection portion 113 shown in FIG. 6 may be used, or the connection portions 213 and 214 shown in FIG. 10 may be used for the thick conductor substrate 100 of the first embodiment.

  In the third embodiment, the upper and lower surfaces of the conductor layers 211 and 212 except for the surface mounting portion 233 are covered with the upper insulating layer 231 and the lower insulating layer 232. However, the present invention is not limited to this. For example, FIG. As described above, the outer peripheral insulating layer 251 may be formed on the outer peripheries of the conductor layers 211 and 212 to prevent peeling between the conductor layers 211 and 212 and the insulating layer 230. Alternatively, by providing an anchor 252 formed of an injection molding resin having a shape as shown in FIG. 12, it is possible to prevent peeling between the conductor layers 211 and 212 and the insulating layer 230 as in the above embodiment. Can do.

  Furthermore, instead of the anchor 252 as shown in FIG. 12, another anchor 253 as shown in FIG. 13 may be provided. Since the anchor 252 shown in FIG. 12 protrudes from the surface of the conductor layers 211 and 212, the surface of the substrate may be uneven, which may hinder the mounting of electronic components. Therefore, as shown in the cross-sectional view of FIG. 13A, a groove is provided in each of the conductor layers 211 and 212, and the insulating layer 254 is formed by injecting an injection molding resin into each groove. As shown in the bottom view of FIG. 13B, an anchor 253 for connecting the insulating layer 254 to the insulating layer 255 formed between the conductor layers 211 and 212 is provided at the end of the substrate. Thereby, peeling between the conductor layers 211 and 212 and the insulating layer 255 can be prevented.

  In order to prevent peeling between the conductor layers 211 and 212 and the insulating layer 230, the surfaces of the conductor layers 211 and 212 that are in contact with the insulating layer 230 may have a roughened structure 221 as shown in FIG. By forming the roughened structure 221, it is possible to prevent the contact surfaces of the conductor layers 211 and 212 and the insulating layer 230 from being displaced, and thereby, between the conductor layers 211 and 212 and the insulating layer 230. The possibility that peeling will occur can be further reduced.

  In the second and third embodiments, the conductor layers 111, 112 or 211, 212 are not limited to those formed as an integral conductor layer, but may be divided into a plurality of conductor pieces. In that case, for example, as shown in FIG. 15, when the conductor piece 211a on which the electronic component 140 is mounted and the conductor piece 211b to which the solder joint 141 of the electronic component 140 is connected move relatively due to thermal expansion or the like. The solder joint 141 may be pulled and damaged by the electronic component 140.

  Therefore, in order to prevent the conductor pieces 211a and 211b from moving relative to each other, the end sides of the conductor pieces 211a and 211b are arranged such that one (211a) is the other (211b) as shown in FIG. It is good to make it the shape which latches. Injection molding resin 240 is injected between the respective ends of the conductor pieces 211a and 211b, which insulates between the conductor pieces 211a and 211b, while the conductor pieces 211a and 211b are relatively opposite to each other. To prevent movement.

  In any of the embodiments described above, a voltage converting transformer and a smoothing choke coil can be integrally formed on a thick conductor substrate. Since a high frequency current of several tens kHz to several hundreds kHz flows in the coil portion of such a transformer or choke coil, the high frequency current concentrates on the edge of the coil due to the skin effect. Therefore, there is a problem that a larger amount of heat is generated at the coil edge than when a direct current is passed. Therefore, in any embodiment of the present invention, when a coil is formed, it is preferable that the edge of the coil be bent at a right angle so that the cross-sectional shape thereof becomes a U-shape.

  In the thick conductor substrate 200 of the third embodiment shown in FIG. 9, a coil 260 is provided, and the cross section has a U shape as shown in FIG. By making the edge part into such a U shape, the area of the edge part of the coil can be increased. As a result, it is possible to efficiently dissipate heat from the edge portion.

  In addition, the description in this Embodiment shows an example of the thick conductor board | substrate which concerns on this invention, and its manufacturing method, It is not limited to this. The detailed configuration and detailed operation of the thick conductor substrate and the like in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

50, 100, 200 Thick conductor substrate 11, 12, 51, 52, 111, 112, 211, 212 Conductor layer 13, 54, 113, 213, 214 Connection part 20 Mold 21 Upper mold 22 Lower mold 22a Depression 23 Fixing Pin 113a, 213a, 214a Elastic part 113b, 213b, 214b Junction point 53, 130, 230, 254, 255 Insulating layer 140 Electronic component 141 Solder joint part 211a, 211b Conductive piece 221 Roughening structure 231 Upper insulating layer 232 Lower insulating layer 233 Surface mounting portion 234 Joint hole 240 Injection molding resin 251 Peripheral insulating layer 252 253 Anchor 260 Coil 261 Edge

Claims (16)

A thick conductor substrate on which electronic components can be surface-mounted,
A thick conductor substrate, wherein a metal plate is processed to connect two or more conductor layers on which a circuit pattern is formed, and an insulating layer is formed by injection molding a resin between the two or more conductor layers. At least in the region where the electronic component is surface-mounted, the cross-sectional area of the insulating layer and the cross-sectional area of the conductor layer are weighted and averaged so that the cross-sectional average linear expansion coefficient is smaller than the overall average linear expansion coefficient. The thick conductor substrate according to claim 1, wherein the thickness of the insulating layer or the conductor layer is determined so as to reduce the thickness. When the cross-sectional area and linear expansion coefficient of the insulating layer are Si and αi, respectively, and the cross-sectional area and linear expansion coefficient of the conductor layer are Sc and αc, respectively, the cross-sectional area Si of the insulating layer and the cross-sectional area of the conductive layer are The ratio of Sc to the predetermined reference thermal expansion coefficient αm is as follows:

The thick conductor substrate according to claim 1, wherein the thick conductor substrate is determined so as to satisfy the following. The thick conductor substrate according to any one of claims 1 to 3, wherein the conductor layer is covered with the insulating layer except for a region where the electronic component is surface-mounted. The thick conductor substrate according to any one of claims 1 to 3, wherein an outer periphery of the conductor layer is covered with the same resin as that of the insulating layer. The contact surface of the said conductor layer and the said insulating layer is being fixed with the anchor formed with the same resin as the said insulating layer. The thick conductor board | substrate of any one of Claim 1 thru | or 3 characterized by the above-mentioned. . The thick conductor substrate according to claim 6, wherein the anchor fixes between the uppermost layer surface and the lowermost layer surface of the conductor layer. A groove is formed in the outermost conductor layer, and the anchor is connected so as to connect between an insulating layer formed by injection molding the resin in the groove and an insulating layer formed between the conductor layers. The thick conductor substrate according to claim 6, wherein the thick conductor substrate is formed. The thick conductor substrate according to any one of claims 1 to 8, wherein a surface of the conductor layer in contact with the insulating layer has a roughened structure. The conductor layer is divided into two or more conductor pieces on the same plane, and one end of each conductor piece is formed so that one of the two adjacent conductor pieces locks the other. The thick conductor substrate according to any one of claims 1 to 9, wherein the substrate is a thick conductor substrate. The conductor layer has an elastic portion having an elastic structure that can be deformed in a direction perpendicular to the surface of the conductor layer, and a joint portion whose tip side is joined to another conductor layer. The thick conductor substrate according to any one of claims 1 to 10, further comprising a connection portion for connecting in an automatic manner. The thick conductor substrate according to claim 11, wherein the elastic portion is provided on the conductor layer side of the connection portion. The two conductor layers having the connection part provided with the elastic part on the joint part side can be deformed in a direction perpendicular to the surface of the conductor layer by connecting the elastic parts at the joint part. The thick conductor substrate according to claim 11, wherein the substrate is a thick conductor substrate. The thick conductor substrate according to any one of claims 1 to 13, wherein a coil having a U-shaped cross section is formed in the conductor layer. The thick conductor substrate according to any one of claims 1 to 8, wherein the insulating layer is formed by injection molding of polyphenylene sulfide resin (PPS). A conductor layer connecting step of electrically connecting two or more conductor layers on which a circuit pattern is formed by processing a metal plate in advance;
A mold housing step of housing and fixing the two or more conductor layers in a mold for forming an insulating layer so as to reduce deformation due to thermal expansion corresponding to the circuit pattern;
An injection molding step of injecting a predetermined injection molding resin into the mold. A method for producing a thick conductor substrate, comprising:

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