JP7374613B2 - Resin mold circuit body, mold, manufacturing method, and circuit board - Google Patents

Description

The present invention relates to a resin molded circuit body used for a circuit board such as a metal-based circuit board, a mold for molding the resin molded circuit body, a method for manufacturing the resin molded circuit body, and a circuit board using the resin molded circuit body.

A conventional metal base circuit board 101 is completed by applying pressure and heating as shown in FIG . For example, each circuit 107 . / Heat treatment is performed to heat and harden the insulating layer 105.

However, as shown in FIGS. 25 and 26 , cracks Cr occur in the insulating layer 105 at the rising portions of the circuits 107 from the insulating layer 105, and bulges 105a of the insulating layer 105 between the circuits 107... However, there is a problem in that voids V are caused in the insulating layer 105.

In addition, there was also the problem that a gap _GA was created due to misalignment of the circuits 107, etc.

In addition, when a circuit is punched out from a copper plate material by top and bottom punching in precision punching, sagging Du occurs at the corners as shown in circuit 107 in FIG. There was also the problem of _GA occurring.

In particular, in order to improve the insulation reliability of metal-based circuit boards for power devices, it is important to improve the conditions for bonding the circuits 107 to the insulating layer 105, which affects the withstand voltage.

On the other hand, in the manufacturing method of FIG. 24 , the scope for improving the bonding conditions was narrow because the voids inherent in the insulating layer 105 remained uncompressed when the pressurizing force was reduced, and it was essential to improve the robustness.

To address this problem, a method for manufacturing a circuit board shown in FIG. 28 described in Patent Document 1 has been proposed.

This circuit board manufacturing method includes the steps of arranging the circuits 107 on the insulating layer 105 of the metal substrate, and forming a mold having convex portions 115a corresponding to the shape of the space between the circuits 107. The method includes a step of arranging the portion 115a in the space, a step of pressurizing and heating the mold , and a step of removing the mold .

In this method, since pressure is applied while the convex portions 115a of the mold are placed between the circuits 107, the positional deviation of the circuits 107 is small, and the insulating layer 105 between the circuits 107 is It is considered that the swelling of the mold is suppressed by the convex portion 115a of the mold , and the occurrence of cracks is also suppressed.

However, in this method, since the circuits 107 are accommodated in the recesses 115b of the mold , the insides of the recesses 115b of the mold are sealed by pressurization, and the circuits 107 are housed in the mold.・It was difficult to extract from the system, and there was a problem with its feasibility.

Publication No. 2018-182010

The problem to be solved is that although it may be possible to suppress problems such as swelling and cracking of the insulating layer, it is difficult to set and remove the mold, which poses a problem in feasibility.

An object of the present invention is to suppress swelling of an insulating layer between circuits and to suppress the occurrence of cracks in the insulating layer while making it possible to realize the same.

In order to achieve such an object, a resin molded circuit body according to the present invention includes a circuit arranged according to a circuit pattern and a resin molded part of a thermosetting resin that covers a peripheral side of the circuit, At least a part of the front and back circuit surfaces is exposed from the resin surface of the resin mold part, one of the front and back circuit surfaces and the resin surface is a bonding surface for bonding to an insulating layer, and the bonding surface is: The circuit surface is selectively protruded from the resin surface at a boundary where the resin surface contacts the circuit and is substantially flat, and the amount of protrusion is such that the bonding surface is flush with the insulating layer on the substrate. When the other of the front and back circuit surfaces and the resin surface is pressurized and heated, the pressure caused by the pressurization is dispersed to the circuit surface and the resin surface due to thermal expansion of the resin mold part, and the circuit surface is heated. The resin molded portion presses the insulating layer around the periphery, and the insulating layer is within a range where no cracks occur in the rising portion of the circuit from the insulating layer.

The mold used for manufacturing the resin molded circuit body of the present invention includes circuits arranged according to a circuit pattern and a resin mold part that covers the circumferential side of the circuit, and transfer molds the resin molded circuit body to be bonded to an insulating layer. The mold includes a first divided mold forming one side of a cavity for molding the resin molded circuit body, and has a size corresponding to the outer circumferential surface of the resin molded circuit body or a mold for molding the resin molded circuit body. The first split mold has a side periphery of the cavity larger than the outer peripheral surface of the molded circuit body, and the first split mold includes a positioning part for positioning the circuit within the cavity. shall be.

The method for manufacturing a resin molded circuit body of the present invention includes positioning and arranging the circuit in the positioning portion of the first split mold, forming the cavity including the first split mold, and preheating the circuit. The method is characterized in that a flowing resin is press-fitted into the cavity and then cured.

The circuit board of the present invention is characterized in that the resin molded circuit body is provided with the circuit surface and the resin surface of the bonding surface facing an insulating layer on the board.

According to the resin molded circuit body of the present invention, the circuits positioned according to the circuit pattern can be handled as a single resin molded circuit body, contributing to the realization of stable production by developing planned production activities. can do.

Resin molded circuit bodies that maintain accurate circuit patterns can be stocked as is.

The resin molded circuit body can also be made into a flat plate shape, and can be stocked in a space-efficient manner. Furthermore, the resin molded circuit body can be integrally formed into a flat plate, and can be easily handled during loading and unloading.

Since the resin molded circuit body maintains the circuit pattern using the resin molded portion, it can be used even if there is a floating island-shaped circuit in the circuit pattern.

Even thick circuits with a thickness exceeding 0.5 mm can be punched out by precision punching to meet the needs for large currents, making it possible to improve processing speed and improve response to needs for cost reduction. In this case, although the immediate circumferential surface of the circuit has sagging, it is possible to obtain a bonding surface that is molded substantially flat by the resin molded portion. By using the mold of the present invention, a resin molded circuit body is taken out from the mold or cut out from a semi-finished product taken out from the mold, and the resin molded circuit body is provided with circuits arranged according to the circuit pattern. can be easily obtained.

The method for manufacturing a resin molded circuit body of the present invention includes molding a circuit positioned and arranged according to a circuit pattern using the mold with a resin mold part, and exposing the circuit surface on the front and back sides, and the circuit surface on the front and back sides and the resin surface. A resin molded circuit body having a flat joint surface can be easily obtained.

In the circuit board using the resin molded circuit body of the present invention, since the resin molded circuit body including the circuit is pressurized, the stress caused by the pressure applied to the circuit is dispersed throughout the resin molded part and the insulating layer is heated. It is possible to suppress the swelling of the insulating layer around the circuit, suppress the occurrence of cracks, and improve insulation reliability. In the resin molded circuit body, since the resin molded portion remains as it is on the circuit board, the positional accuracy of the circuit can be easily maintained even after pressurization.

Further, since resin is present around the circuit as a circuit board, the insulation of the circuit can be improved. The resin around the circuit provides high insulation, and even if there are multiple circuits, the circuit density can be increased, and the circuit board can be made smaller. Heat generated by circuit elements connected to the circuit is also efficiently conducted through the resin surrounding the circuit, improving heat dissipation performance.

FIG. 3 is a cross-sectional view of a resin molded circuit body. (Example 1) FIG. 3 is a plan view of a resin molded circuit body. (Example 1) FIG. 3 is a perspective view of a resin molded circuit body. (Example 1) FIG. 2 is an enlarged cross-sectional view of a main part showing the relationship between a circuit and a resin molded part. (Example 1) FIG. 3 is a cross-sectional view of a mold used in the method for manufacturing a resin molded circuit body. (Example 1) FIG. 2 is a conceptual diagram of a pressurizing/heating process of a metal base circuit board using a resin molded circuit body. (Example 1) FIG. 2 is a cross-sectional view of a metal-based circuit board. (Example 1) FIG. 2 is an explanatory diagram showing enlarged locations in a cross-sectional view of a metal base circuit board of an example using a resin molded circuit body. (Example 1) 12 is an enlarged photograph of the enlarged portion indicated in FIG. 11. (Example 1) FIG. 7 is an explanatory diagram showing enlarged locations in a cross-sectional view of a metal-based circuit board of a comparative example without a resin molded portion. (Comparative example) (A) is an explanatory photograph indicating a portion to be further enlarged in the enlarged portion indicated in FIG. 13. (B) is an enlarged photograph of the enlarged area indicated in (A). (Comparative example) (A) is an explanatory diagram showing locations where withstand voltage is measured in a plan view of the metal base circuit board 29. (B) is a chart showing the withstand voltage at the measurement points. (Example 1) FIG. 3 is an enlarged sectional view of a main part of a metal base circuit board 29 employing a modified example of the circuit. (Example 1) 6 is a sectional view of a mold used in the method for manufacturing a resin molded circuit body, corresponding to FIG. 5. FIG. (Example 2) 2 is a sectional view of a resin molded circuit body corresponding to FIG. 1. FIG. (Example 2) 6 is a sectional view of a mold used in the method for manufacturing a resin molded circuit body, corresponding to FIG. 5. FIG. (Example 3) 2 is a sectional view of a resin molded circuit body corresponding to FIG. 1. FIG. (Example 3) 6 is a sectional view of a mold used in the method for manufacturing a resin molded circuit body, corresponding to FIG. 5. FIG. (Example 4) 2 is a sectional view of a resin molded circuit body corresponding to FIG. 1. FIG. (Example 4) 6 is a sectional view of a mold used in the method for manufacturing a resin molded circuit body, corresponding to FIG. 5. FIG. (Example 5) Corresponding to FIG. 1, it is a cross-sectional view taken along the line XXI-XXI in FIG. 22 of the resin molded circuit body. (Example 5) FIG. 2 is a plan view of a resin molded circuit body including circuits crossed in a bridge shape. (Example 5) FIG. 2 is a back view of a resin molded circuit body including circuits crossed in a bridge shape. (Example 5) It is a conceptual explanatory diagram showing the pressurization/heating process of the conventional metal base circuit board. (Conventional example) FIG. 3 is a cross-sectional view showing the relationship between a circuit that does not have a resin molded part and an insulating layer. (Conventional example) FIG. 3 is a cross-sectional view showing the relationship between a circuit that does not have a resin molded part and an insulating layer. (Conventional example) FIG. 3 is a cross-sectional view showing the relationship between a circuit that does not have a resin molded part and an insulating layer. (Conventional example) FIG. 3 is a cross-sectional view showing a process of applying pressure to a circuit pattern using a mold. (Conventional example)

The purpose of suppressing the swelling of the insulating layer and suppressing the occurrence of cracks in the insulating layer has been achieved as follows.

A resin molded circuit body according to the present invention includes a circuit arranged according to a circuit pattern, and a resin mold part that covers a circumferential side of the circuit, wherein at least a part of the front and back circuit surfaces of the circuit is made of the resin. One of the front and back circuit surfaces and the resin surface exposed from the resin surface of the mold part was used as a bonding surface for bonding to the insulating layer.

At least one of the front and back circuit surfaces of the circuit protrudes from the resin mold portion.

The circuits may be provided in multiples at uniform heights or may be provided in multiples at different heights.

The present invention provides a mold for transfer molding a resin molded circuit body to be bonded to an insulating layer, which includes a circuit arranged according to a circuit pattern and a resin molded portion covering a circumferential side of the circuit. a first split mold forming one side of a cavity for molding the resin-molded circuit body, the mold having a size corresponding to the outer circumferential surface of the resin-molded circuit body or a size larger than the outer circumferential surface of the resin-molded circuit body; The first split mold has a side periphery of the cavity, and the first split mold includes a positioning portion for positioning the circuit within the cavity.

The positioning portion is an adhesive layer, a positioning pin, or a counterbore provided on the first split mold on one side of the cavity.

The method for manufacturing a resin molded circuit body according to the present invention includes positioning and arranging the circuit in the positioning portion of the first split mold, configuring the cavity including the first split mold, and preheating. A flowing resin is press-fitted into the cavity and then cured.

The circuit board according to the present invention includes the resin molded circuit body with the circuit surface and resin surface of the bonding surface facing the insulating layer on the board.

[Resin mold circuit body]
FIG. 1 is a sectional view of a resin molded circuit body. FIG. 2 is a plan view of the resin molded circuit body. FIG. 3 is a perspective view of the resin molded circuit body.

As shown in FIGS. 1 to 3, the resin molded circuit body 1 is formed into, for example, a rectangular flat plate shape, and includes a circuit 3 and a resin molded portion 5. The shape of the resin molded circuit body 1 can be freely selected, such as a circular shape other than a rectangle, depending on the planar shape of the board.

Further, the resin molded circuit body 1 may have a shape in which lead terminals and the like are integrally drawn out.

The circuits 3 are arranged according to a circuit pattern. The circuit pattern includes a plurality of electrically independent circuits 3 in this embodiment. The configurations of the plurality of circuits 3 are formed according to the required characteristics of the circuit pattern. In Example 1, the circuit pattern has a floating island-shaped portion in the center. It is also possible to use a circuit pattern that does not have floating island-shaped portions. It is also possible to configure a circuit pattern using a single circuit 3.

The circuits 3 are made of copper, for example. The circuit 3... is formed of a circuit copper material with a thick copper pattern having a thickness exceeding 0.5 mm. The thickness of the circuit 3 can be selected from various values, and may be less than 0.5 mm.

The circuit 3 is formed so that front and back circuit surfaces 3a and 3b are flat. In this case, the side to be bonded to an insulating layer to be described later is the back circuit surface 3b, and the side opposite to the insulating layer to which circuit elements are bonded is the front circuit surface 3a. The front and back sides are expressions for convenience; the side to be bonded to the insulating layer may be the front side, and the side opposite to the insulating layer to which the circuit elements are bonded may be the back side.

The circuit surfaces 3b constitute a common plane among the plurality of circuits 3. Therefore, in this embodiment, the circuit surface being flat means that the individual surfaces of the circuit surfaces 3b... are flat among the plurality of circuits 3, and that the circuit surfaces 3b... form a common plane. It means both. However, in the case where the circuit 3 is single, it means that the single circuit surface 3b constitutes a plane.

In the first embodiment, the same applies to the circuit surfaces 3a... in the table above.

However, it is sufficient that the circuit 3 has at least a flat circuit surface 3b on the back side to be bonded to an insulating layer to be described later. Therefore, the circuit surfaces 3b on the back side to be bonded to the insulating layer constitute a common plane among the plurality of circuits 3, but the circuit surfaces 3a on the side opposite to the insulating layer constitute a common plane between the plurality of circuits 3 as will be described later. You can also set different heights between them.

That is, in addition to the configuration in which a plurality of circuits 3 are provided at a uniform height as in the first embodiment, a plurality of circuits 3 may be provided at different heights as described later.

In the circuit 3, the circumferential side surface 3c is formed by wire cutting, etching, shaving by precision shearing, etc., the front and back circuit surfaces 3a, 3b and the circumferential side surface 3c are perpendicular to each other, and both circuit surfaces 3a, 3b and the circumferential surface 3b is formed at a right angle. However, as will be described later, it is also possible to apply a form in which the corners have sag.

The resin molded portion 5 covers each circumferential side surface 3b of the circuits 3, and forms the overall rectangular shape of the resin molded circuit body 1.

The resin material used for the resin mold part 5 may be any resin that becomes fluid when heated and can be used for filling in transfer molding, which will be described later. In Example 1, epoxy resin, which is the same material as the insulating layer on the metal substrate to be described later, is used to improve adhesion to the insulating layer.

Other resin materials used for the resin mold part 5 include thermosetting resins such as phenol resin, urea resin, melamine resin, urethane resin, silicone resin, unsaturated polyester resin, acrylic resin, imide resin, and amide-imide resin. It will be done.

The resin used for filling may be composed of only one type, or may be composed of a combination of two or more types. From the viewpoint of electrical insulation and adhesiveness, the resin used for filling preferably contains at least one selected from the group consisting of epoxy resin, silicone resin, amide-imide resin, and urethane resin, and from the viewpoint of moisture resistance, epoxy It is preferable to include at least one selected from the group consisting of resin, acrylic resin, and amide-imide resin.

Further, the resin used for filling may contain components other than resin such as filler (powder, fiber, etc.) as necessary. In this example, in order to control the coefficient of thermal expansion and fluidity, the epoxy resin contains about 80 to 85 wt% of silica inorganic filler, so that the coefficient of thermal expansion is about the same as that of the copper circuit 3.

Similarly, other fillers may include inorganic materials such as alumina, boron nitride, aluminum nitride, carbon fiber, and glass fiber.

Only one type of these fillers may be included, or a combination of two or more types may be included.

Furthermore, fillers can be added to increase the volume, reinforce the material, and improve thermal conductivity and hygroscopicity. Examples of bulking agents include calcium carbonate, talc, silica, and clay. For reinforcement, wollastonite, potassium titanate, xonotrite, gypsum fiber, aluminum borate, MOS, aramid fiber, various fiber types, carbon fiber (carbon fiber), glass fiber (glass fiber), talc, mica, glass flakes , polyoxybenzoyl whiskers, etc. Examples of thermal conductivity include Al2O3 (alumina), AlN, BN, and BeO. Hygroscopic materials include water-absorbing polymer gels, calcium oxide, magnesium oxide, and the like.

Only one type of these fillers may be added, or a combination of two or more types may be added and included.

In addition, the resin material used for the resin mold part 5 may further contain, for example, a coupling agent, a dispersant, etc. in addition to the above-mentioned matrix resin and inorganic filler.

The resin mold part 5 is provided with a flat resin surface 5b to be bonded to the insulating layer substantially along a flat circuit surface 3b to be bonded to the insulating layer. The flat resin surface 5a on the side opposite to the insulating layer is also provided along the flat circuit surface 3a on the side opposite to the insulating layer. With these configurations, the resin molded circuit body 1 is formed into a flat plate shape as a whole.

However, it is sufficient that the circuit 3 and the resin molded part 5 are provided with at least flat circuit surfaces 3b to be bonded to the insulating layer and resin surfaces 5b substantially along each other. In a configuration in which a plurality of circuits 3 are provided at different heights, the resin surface 5a around each circuit surface 3a may have a step between the circuits 3 having different heights as described later.

In this flat resin molded circuit body 1, the front and back circuit surfaces 3a, 3b, . . . of the circuits 3 are both exposed from the resin mold portion 5.

The resin molded circuit body 1 has the circuit surface 3b on the back side and the resin surface 5b forming a bonding surface 1b for bonding to an insulating layer, which will be described later, and the circuit surface 3a on the front side to be bonded to an insulating layer, which will be described later. The joint surface was used as the joint surface.

Since the resin molded circuit body 1 of Example 1 is formed so that both the front and back sides are symmetrical and almost flat, both the front and back sides can be used as bonding surfaces to the insulating layer and can be arbitrarily selected at the time of bonding. It is possible to prevent incorrect assembly when assembling.

For example, it is also possible to use a configuration in which the circuit surfaces 3a... and the resin surface 5a on the front side are used as bonding surfaces for bonding to an insulating layer, and the circuit surfaces 3b... on the back side are used as bonding surfaces for circuit elements and the like.

However, the resin molded circuit body 1 can also be formed asymmetrically on the front and back, and one of the front and back sides can be specified as the bonding surface 1b, and the other can be specified as the bonding surface of the circuit element or the like.

FIG. 4 is an enlarged sectional view of main parts showing the relationship between the circuit and the resin molded part.

As shown in FIG. 4, in this embodiment, the circuits 3... have flat circuit surfaces 3a..., circuit surfaces 3b... on both the front and back surfaces of the resin molded portion 5. 5a, protruding from the resin surface 5b. The amount of protrusion is, for example, Pr=20 to 60 μm.

The protrusions of the circuit surfaces 3a, . . ., circuit surfaces 3b, . In this protrusion, both the front and back surfaces of the resin molded circuit body 1 are substantially flat, including the circuit surfaces 3a, . . . , the circuit surfaces 3b, . . . and the resin surfaces 5a, 5b.

The fact that at least one of the front and back surfaces of the resin molded circuit body 1 is flat is a configuration for maintaining adhesion to the insulating layer. Therefore, as long as adhesion can be maintained, the circuit surfaces 3a or 3b constituting the bonding surface to the insulating layer may be slightly recessed from the resin surface 5a or the resin surface 5b. However, it is preferable that the circuit surfaces 3a and 3b protrude from the resin surface 5a and the resin surface 5b or are formed flush with each other as described above.

The protrusion of at least one of the circuit surfaces 3a... or the circuit surfaces 3b... is performed by forming a counterbore in the mold as described later, and the circuit surfaces 3a... or the circuit surfaces 3b... It is also possible to make at least one of the resin surfaces 5a and 5b protrude from the flat resin surface 5a or 5b so that the resin surface is not flat.

In other words, the circuits 3... can have only the circuit surfaces 3a... or only the circuit surfaces 3b... protrude from the resin surface 5a or the resin surface 5b by counterboring. It is also possible to make both the circuit surfaces 3a, 3b, . . . protrude from the resin surfaces 5a and 5b by counterboring. Furthermore, a portion 3a or 3b of a plurality of front and back circuit surfaces 3a, . . . , circuit surfaces 3b, .

[Mold]
FIG. 5 is a sectional view of a mold used in the method for manufacturing a resin molded circuit body.

As shown in FIG. 5, the mold 7 is used for transfer molding a resin molded circuit body to be bonded to an insulating layer. As shown in FIG. 1, the resin molded circuit body 1 includes circuits 3 arranged according to a circuit pattern and a resin molded portion 5 that covers the circumferential side surface 3c of the circuits 3.

In the first embodiment, the mold 7 is composed of a combination of four first, second, third, and fourth split molds 9, 11, 13, and 15. The first, second, and third split molds 9, 11, and 13 form a cavity 17 for molding the resin molded circuit body 1. The fourth split mold 15 forms a transfer chamber 19.

The first split mold 9 forms one side of the cavity 17 in accordance with one side of the resin molded circuit body 1 . Further, the first split mold 9 includes an adhesive layer 21 as a positioning portion for positioning the circuit 3 within the cavity 17. For the positioning portion, instead of the adhesive layer 21, a positioning pin, a counterbore, or the like may be used as described later.

The positioning part can be configured to be provided in the second split mold 11. If the positioning portion does not have a large effect on the function of the bonding surface 1b of the resin molded circuit body 1, such as the adhesive layer 21 or counterbore, the configuration is provided in both the first and second split molds 9 and 11. It can also be done.

The adhesive layer 21 in the embodiment as a positioning part was provided on the surface inside the cavity 17 of the first divided mold 9, but it covered the entire upper surface including the surface inside the cavity 17 of the first divided mold 9. The peripheral edge of the adhesive layer 21 may be interposed between the layers of the first and third split molds 9 and 11. The same applies to the case where the adhesive layer 21 is provided on the second split mold 11. However, when the second split mold 11 is provided with the adhesive layer 21, it is formed so as not to block the gate 11a.

The adhesive layer 21 may be either fixedly provided on the first split mold 9 or the like or detachably provided.

The entire surface of the first split mold 9 facing the cavity 17 is flat. As the adhesive layer 21, a double-sided or single-sided adhesive tape using a heat-resistant silicone-based, acrylic-based, or urethane-based adhesive is used. The base material of the adhesive tape is preferably a PET film, an imide film, a metal foil (copper, aluminum), or the like.

The second split mold 11 constitutes the other side of the cavity 17 in accordance with the other side of the resin molded circuit body 1 . Further, the second split mold 11 includes a gate 11a that contacts the circuit surface of the circuit 3 within the cavity 17 and serves as a passage for the resin.

The entire surface of the second split mold 11 facing the cavity 17 is flat. However, depending on the specifications of the resin molded circuit body 1, the surface of the second split mold 11 on the cavity 17 side may be made into an uneven shape. Note that the interval between the cavities 17 formed by the first and second split molds 9 and 11 may be formed relatively narrow at the gate 11a to improve the fluidity of the resin throughout the cavities 17.

The third split mold 13 has flat upper and lower surfaces, its lower surface is positioned and coupled to the upper surface of the first split mold 9, and the lower surface of the second split mold 11 is positioned on the upper surface. The cavities 17 are formed by positioning and coupling. The thickness of the third split mold 13 is almost the same as that of the circuit 3 in Example 1, and the vertical dimension of the cavity 17 on the adhesive layer 21 is almost the same as that of the circuit 3.

In this way, the third split mold 13 is interposed between the first and second split molds 9 and 11, and has a size corresponding to the outer peripheral surface of the resin molded circuit body 1, and is formed around the side of the cavity 17. 17a. In this case, what is taken out from the cavity 17 becomes the resin molded circuit body 1 (FIG. 1).

However, the third split mold 13 may form the side periphery of the cavity 17 with a size larger than the outer peripheral surface of the resin molded circuit body 1. The side periphery of the cavity 17, which is larger than the outer peripheral surface of the resin molded circuit body 1, is formed so that the semi-finished product of the resin molded circuit body 1 including the resin molded circuit body 1 is slightly larger. In this case, the resin molded circuit body 1 is cut out from a semi-finished product.

The fourth split mold 15 is joined to the outer surface of the second split mold 11 to form the transfer chamber 19 . The transfer chamber 19 communicates with the gate 11a.

Note that the mold 7 only needs to be capable of transfer molding the resin molded circuit body 1, and only needs to include the first split mold 9 that forms one side of the cavity 17 for molding the resin molded circuit body 1. Therefore, it is not limited to the one having the first to fourth divided molds 9, 11, 13, 15, but the second to fourth divided molds 11, 13, 15 may be integrally formed, and the first divided mold It is also possible to have a two-part configuration with the mold 9.

[Method for manufacturing resin molded circuit body]
When manufacturing the resin molded circuit body 1, in the divided state of the first divided mold 9, the circuits 3 are positioned and arranged on the adhesive layer 21 according to the circuit pattern.

Although the arrangement of the circuits 3 can be automated by image processing, for example, it is also possible to use a semi-finished board material for a circuit board that has already been proposed by the present applicant. Alternatively, the circuits 3 may be formed by etching. In the etching process, a circuit is formed by chemical etching on a copper plate fixed on a carrier film with an adhesive or the like, and it can be used as is in a transfer mold. It can also be used in the present manufacturing method by transferring it to another adhesive film mentioned above.

In the case of the semi-finished board material for a circuit board, it has a flat plate shape and has a plurality of circuits positioned corresponding to a circuit pattern.

In other words, parts corresponding to multiple circuits are half-cut out from the copper plate material, and after half-cutting, the parts corresponding to multiple circuits are returned to the half-blanked positions in the scrap, and multiple circuits are fitted to the scrap. The entire structure is shaped like a flat plate and has almost the same shape as the original copper plate.

This semi-finished circuit board board material is positioned and arranged with respect to the first split mold 9, and is pressed out by a press device or the like and transferred onto the adhesive layer 21.

Next, the mold 7 is assembled by combining the first, second, third, and fourth split molds 9, 11, 13, and 15 to form the cavity 17 and the transfer chamber 19. At this time, the elasticity of the adhesive layer 21 can be used to press and hold the circuits 3 between the first and second split molds 9 and 11.

Next, the tablet-shaped resin is stored in the transfer chamber 19. This tablet-shaped resin is preheated in the transfer chamber 19 until the resin flows. At this time, the mold 7 is heated to, for example, 180°C.

The resin 23 flowing due to the preheating is pressed by a plunger with a pressure of about 7 MPa as shown by the arrow, and the resin 23 is forced into the cavity 17.

Note that in the press-fitting conditions, the preheating can be set in the range of 50 to 400° C. and the pressure can be set in the range of 1 to 20 MPa, depending on the material and viscosity of the resin used.

The press-fitted resin 23 is further heated while passing through the gate 11a, and its viscosity is reduced.

The resin 23 that has passed through the gate 11a flows within the cavity 17 and spreads throughout the space around the circuit 3. In this case, the mold 7 is provided with an air vent hole or an extra space into which the resin flows so that the resin 23 spreads throughout the space within the cavity 17 .

After that, a curing reaction is performed for about 3 minutes to harden the resin 23, and then the mold 7 is divided as appropriate, and the semi-finished products of the resin molded circuit body 1 are taken out. Note that the reaction time can be made faster than 3 minutes depending on the resin composition (epoxy resin, curing agent, catalyst, curing accelerator, etc.) and molding conditions.

In this embodiment, since the side periphery 17a of the cavity 17 has a size corresponding to the outer peripheral surface of the resin molded circuit body 1, what is taken out from the cavity 17 becomes the resin molded circuit body 1.

If the side periphery 17a of the cavity 17 is configured to be larger than the outer peripheral surface of the resin molded circuit body 1, the part taken out from the cavity 17, including the resin molded circuit body 1, is formed to be slightly larger. It becomes a semi-finished product. This semi-finished product is, for example, formed into a planar shape, such as a substantially circular shape, so that the resin can easily flow during molding.

In this case, the rectangular resin molded circuit body 1 shown in FIGS. 1 to 3 can be obtained by cutting the semi-finished product.

In the obtained resin molded circuit body 1, due to slight shrinkage of the resin in the resin molded portion 5 of the resin molded circuit body 1, the circuit surfaces 3a, 3b, . It protrudes from 5b.

However, it is also possible to set the circuit surfaces 3a, 3b, . . . and the resin surfaces 5a, 5b substantially flush by adjusting the content of filler in the resin molded portion 5, etc.

[Metal-based circuit board]
FIG. 6 is a conceptual diagram of a pressurizing/heating process for a metal base circuit board using a resin molded circuit body.

As shown in FIG. 6, in the pressurizing/heating step, pressurizing/heating treatment is performed to bond the resin molded circuit body 1 to the insulating layer 27 on the metal substrate 25. In this pressurization/heating treatment, a pressurization/heating plate and a flat pusher (see FIG. 24) are used.

When the pressure/heating plate descends, the upper surface of the resin molded circuit body 1 is pressed by the flat pusher, and the lower surface of the resin molded circuit body 1 is pressed against the insulating layer 27. At this time, the pressurizing force is distributed not only to the circuit but also to the entire resin molded part 5.

Due to this pressurization, the metal substrate 25, the insulating layer 27, and the resin molded circuit body 1 are pressurized between the pressurizing/heating plates, and are simultaneously heated to harden the insulating layer 27.

FIG. 7 is a cross-sectional view of the metal-based circuit board.

The metal base circuit board 29 in FIG. 7 is an example of a circuit board. The resin molded circuit body 1 is used for this metal base circuit board 29. In the metal base circuit board 29, the resin molded circuit body 1 is fixed to a rectangular flat metal substrate 25 via an insulating layer 27 by the manufacturing method described above.

That is, the resin molded circuit body 1 includes the insulating layer 27 on the metal substrate 25, the circuit surfaces 3b of the bonding surface 1b, and the resin surface 5b in a face-to-face relationship.

The metal substrate 25 is made of, for example, a single metal or an alloy. As the material of the metal substrate 25, for example, aluminum, iron, copper, aluminum alloy, or stainless steel can be used. The metal substrate 25 may further contain non-metal such as carbon. For example, the metal substrate 25 may include aluminum combined with carbon. Further, the metal substrate 25 may have a single layer structure or a multilayer structure.

Metal substrate 25 has high thermal conductivity. For example, for copper material, the heat is 370 to 400 W・m ⁻¹・K ⁻¹ , for aluminum material, 190 to 220 W・m ⁻¹・K ⁻¹ , and for iron material, 60 to 80 W・m ⁻¹・K ⁻¹ It has conductivity.

The metal substrate 25 may or may not have flexibility. The thickness of the metal substrate 25 is, for example, within a range of 0.2 to 5.0 mm. In the example, it was set to 2.0 mm.

The metal substrate 25 is an example of a substrate used as a circuit board, and its form can be selected from various types. Therefore, a heat sink shape having a plurality of fins or the like may be adopted as the substrate.

The thickness of the insulating layer 27 is set to 120 μm. However, the thickness of the insulating layer 27 can be variously set depending on the specifications of the metal base circuit board 29.

The insulating layer 27 not only serves to electrically insulate the circuit 3 from the metal substrate 25, but also serves as an adhesive for pasting them together. Therefore, resin is generally used for the insulating layer 27. Further, since the insulating layer 27 is required to have high heat resistance against the high heat generation of the elements mounted on the circuit 3 and high heat conductivity to transfer this heat generation to the metal substrate 25, the insulating layer 27 is inorganic. It is preferable to further contain a filler.

Examples of the matrix resin of the insulating layer 27 include epoxy resins such as bisphenol A epoxy resin, bisphenol F epoxy resin, and triazine epoxy resin; bisphenol E cyanate resin, bisphenol A cyanate resin, and novolac cyanate resin. Cyanate resins and the like can be used alone or in combination of two or more.

The inorganic filler contained in the insulating layer 27 preferably has excellent electrical insulation properties and high thermal conductivity, such as alumina, silica, aluminum nitride, boron nitride, silicon nitride, magnesium oxide, etc. It is preferable to use one or more selected from the following.

The filling rate of the inorganic filler in the insulating layer 27 can be appropriately set depending on the type of the inorganic filler. For example, it is preferably 85% by volume or less, more preferably 30 to 85% by volume, based on the total volume of the matrix resin contained in the insulating layer 27.

The insulating layer 27 may further contain, for example, a coupling agent, a dispersant, etc. in addition to the matrix resin and inorganic filler described above.

Note that a semi-cured insulating sheet can also be used as the insulating layer 27.

The details of the resin molded circuit body 1 are as described above.

FIG. 8 is an explanatory diagram showing a portion _IA to be enlarged in a cross-sectional view of the metal base circuit board 29 of the embodiment using the resin molded circuit body 1. As shown in FIG. FIG. 9 is an enlarged photograph of the enlarged portion indicated in FIG. FIG. 10 is an explanatory diagram showing a portion I _B1 to be enlarged in a cross-sectional view of a metal base circuit board 31 of a comparative example without a resin molded portion. FIG. 11(A) is an explanatory photograph that indicates a location I _B2 to be further enlarged in the photograph of the enlarged location I _B1 indicated in FIG. 13 . FIG. 11(B) is an enlarged photograph of the point _IB2 to be enlarged indicated in FIG. 11(A).

As shown in FIGS. 8 and 9, in the metal base circuit board 29 (with circuit sealing) manufactured using the resin molded circuit body 1 by the pressure/heat treatment, there is a dispersion of stress acting on the circuits 3... There were no cracks in the insulating layer 27 at the rising portions of the circuit 3 from the insulating layer 27.

On the other hand, as shown in FIGS. 10 and 11, in a metal base circuit board 31 (without circuit sealing) manufactured by pressurizing/heating the circuit 3 that is not molded with the resin mold part 5, stress is applied to the circuit 3. Cracks Cr occurred in the insulating layer 27 at the rising portions from the insulating layer 27. In FIG. 11, the white particles are the filler in the insulating layer 27, and the portions where the filler has not moved in the location _{IB2 of FIG. 11(A) and} the enlarged photograph of FIG. 11(B) are cracks Cr.

Note that in the enlarged photograph of the metal base circuit board 29 in FIG. There is. Even in this completed form, a resin molded circuit body 1 is used in which the circuit surfaces 3a, 3b, . . . protrude from the resin surfaces 5a, 5b as shown in FIG. As a result of the treatment, the circuit surface 3b and the resin surface 5b are now flush with each other.

This is considered to be because the resin molded portion 5 was further heated and pressurized after the circuit surfaces 3b of the circuits 3 came into contact with the insulating layer 27 during pressurization.

[Withstand voltage]
FIG. 12A is an explanatory diagram showing locations where withstand voltage is measured in a plan view of the metal base circuit board 29. FIG. 12(B) is a chart showing the withstand voltage at the measurement points.

As shown in FIG. 12(A), in the metal base circuit board 29 using the resin molded circuit body 1 of the example, the withstand voltage was measured in circuit numbers 1, 2, 3, 4, and 5. As shown in B), circuit number 1 is 9.3kv, circuit number 2 is 9.9kv, circuit number 3 is 8.7kv, circuit number 4 is 6.9kv, and circuit number 5 is 9.1kv. there were.

On the other hand, in the metal base circuit board 31 manufactured by pressurizing/heating the circuit 3 that is not molded with the resin mold part 5 as shown in FIG. 10, the withstand voltage of the circuit 3 was about 0.5 kV.

As is clear from this comparison, the metal base circuit board 29 of this example was able to improve the withstand voltage.

[Circuit modification example]
FIG. 13 is an enlarged sectional view of a main part of a metal base circuit board 29 employing a modified example of the circuit 3. As shown in FIG.

The circuit 3 of this modification is punched out by precision punching, and the peripheral surface is not subjected to any processing such as wire cutting or etching. Therefore, the circumferential side surface 3c of the circuit 3 is not sharp as shown in FIG. 4, but has a sag Du at the corner of the edge Si of the upper and lower circuit surfaces 3a, 3b in FIG .

Even in the circuit 3 where such sagging Du occurs, the resin of the resin molded portion 5 enters between the circuit 3 and the insulating layer 27 in the portion of the sag Du, and as for the resin molded circuit body 1, the bonding surface 1b is almost It becomes flat. Thereby, after bonding to the insulating layer 27, generation of a gap between the circuit 3 and the insulating layer 27 could be suppressed.

[Effects of Example 1]
Embodiment 1 of the present invention includes circuits 3... arranged according to a circuit pattern, and a resin molded portion 5 that covers the circumferential side surface 3c... of the circuits 3... The front and back circuit surfaces 3a..., 3b... are exposed from the resin surfaces 5a, 5b of the resin molded part 5, and the front and back circuit surfaces 3a..., 3b... and the resin surfaces 5a, 5b are One side was a bonding surface 1b for bonding to the insulating layer 27.

Therefore, the circuits 3 positioned according to the circuit pattern can be handled as one unit as the resin molded circuit body 1, and by developing them into planned production activities, it is possible to contribute to the realization of stable production. .

The resin molded circuit body 1 that maintains the accurate circuit pattern of the circuit 3 can be kept in stock as is.

The resin molded circuit body 1 can be made into a flat plate shape, and when it is made into a flat plate shape, it can be stocked in a space-efficient manner. Moreover, since the resin molded circuit body 1 is formed into a flat plate and integrated, it is easy to handle when carrying in and out.

Since the resin molded circuit body 1 maintains the circuit pattern of the circuits 3 .

The circuits 3 can be formed so that the front and back circuit surfaces 3 a , 3 b , . . . protrude from the resin mold part 5 .

Therefore, when bonding the resin molded circuit body 1 to the insulating layer 27 on the metal substrate 25 by pressure/heat treatment using a flat presser or the like, it is possible to apply pressure preferentially to the circuits 3 . can. Therefore, the pressing force of the circuit surfaces 3b against the insulating layer 27 becomes relatively high, which can contribute to improving the peel strength.

A plurality of the circuits 3 are provided at a uniform height or a plurality of circuits are provided at different heights.

If a plurality of circuits 3... are provided at a uniform height, the metal base circuit board 1 can be made into a flat plate, and if a plurality of circuits 3... are provided at different heights, the metal base circuit board 1 can be made into a flat plate shape. You can easily answer variations of 1.

Even if sag occurs at the edge corners of the upper and lower circuit surfaces 3a and 3b of the circuit 3 due to precision punching, the sag can be covered with the resin of the resin mold part 5, making the front and back surfaces flat. .

Therefore, even if sagging occurs at the edge corners of the upper and lower circuit surfaces 3a and 3b of the circuit 3, the circuit surfaces 3a, 3b, . However, the resin molded circuit body 1 having the substantially flat bonding surface 1b on the back side can be accurately formed.

Of course, when the corners of the circuits 3... are formed at right angles, the resin mold part 5 molds the side circumferential surfaces 3c of the circuits 3... and the side circumferential surfaces 3c are uniformly covered with the resin 23. It is possible to accurately form a resin molded circuit body 1 having circuit surfaces 3a, . . . , circuit surfaces 3b, .

Therefore, even if the circuit 3 is thicker than 0.5 mm to meet the needs for large currents, the circuit 3 can be obtained by using precision punching, and the processing speed can be improved. , can improve response to cost reduction needs.

Here, if the circuits 3... are processed by etching, it becomes difficult to reduce the mutual spacing between the circuits 3... to less than the thickness of the circuits 3....

On the other hand, in the case of precision punching, etc., the mutual spacing between the circuits 3... can be narrowed to less than the thickness of the circuits 3..., increasing the circuit density and reducing the size of the metal base circuit board 29. enable.

Of course, precision punching or the like can be similarly used for circuits with a thickness of less than 0.5 mm.

The mold for transfer molding the resin molded circuit body 1 includes first, second, and third divided molds 9, 11, and 13 for forming the cavity 17 for molding the resin molded circuit body 1, and a transfer mold. A fourth divided mold 15 is provided for forming a chamber 19, and the first divided mold 9 constitutes one side of the cavity 17 according to one side of the resin molded circuit body 1, and The second split mold 11 is provided with an adhesive layer 21 as a positioning part for positioning the circuit 3 in the cavity 17, and the second split mold 11 is arranged in the cavity 17 according to the other side of the resin molded circuit body 1. The third split mold 13 is provided with a gate 11a that forms the other side, contacts the circuit 3, and serves as a resin passage, and the third split mold 13 is located between the first and second split molds 9 and 11. The side periphery 17a of the cavity 17 is configured to have a size corresponding to the outer peripheral surface of the resin molded circuit body 1 or a size larger than the outer peripheral surface of the resin molded circuit body 1, and the fourth The split mold 15 was joined to the second split mold 11 to communicate the transfer chamber 19 with the gate 11a.

Therefore, in the divided state of the first divided mold 9, the circuit 3 is formed on the adhesive layer 21 exposed to the first divided mold 9 by automation through image processing or by using the semi-finished circuit board material. Position and place according to the pattern.

Next, the first, second, third, and fourth split molds 9, 11, 13, and 15 are combined to form the mold 7 to form the cavity 17 and the transfer chamber 19, and the resin that flows by preheating is assembled. 23 is press-fitted into the cavity 17, and when the resin 23 hardens, it can be taken out as the resin molded circuit body 1 or a semi-finished product of the resin molded circuit body 1.

For this purpose, the resin molded circuit body 1 is taken out from the mold, or the resin molded circuit body 1 is cut out from a semi-finished product taken out from the mold, and the resin molded circuit body 1 is provided with circuits 3 arranged according to the circuit pattern. can be easily obtained.

The positioning of the circuits 3 . . . can be easily carried out on the adhesive layer 21 while the first divided mold 9 is divided.

The thickness of the third split mold 13 is the same or almost the same as that of the circuit 3, and the vertical dimension of the cavity 17 can be made the same or almost the same as that of the circuit 3. The circuit surfaces 3a..., 3b... can be exposed accurately.

When the side periphery 17a of the cavity 17 is configured to have a size larger than the outer peripheral surface of the resin molded circuit body 1, the third split mold 13 adjusts the position of the resin flowing from the gate 11a into the resin molded circuit body 1. It is possible to improve the quality of the resin molded circuit body 1.

The positioning portion was an adhesive layer 21 provided on the first split mold 9 on one side of the cavity 17.

Therefore, the circuits 3 . . . can be easily positioned and arranged on the adhesive layer 21 of the first split mold 9 by automation through image processing or by using a semi-finished board material for a circuit board.

The method for manufacturing the resin molded circuit body 1 of Example 1 includes positioning and arranging the circuits 3 on the adhesive layer 21 which is the positioning part of the first divided mold 9, and The cavity 17 and the transfer chamber 19 are constructed by combining the first, second, third, and fourth divided molds 9, 11, 13, and 15 including the mold 9, and the mold 7 is heated and the The transfer chamber 19 accommodates tablet-shaped resin. This tablet-shaped resin is preheated in the transfer chamber 19 until the resin flows.

The resin 23, which has been softened until it flows due to preheating, can be press-fitted into the cavity 17 through the gate 11a using a plunger and then hardened.

In this case, since the circuits 3 are sandwiched between the first and second split molds 9 and 11 via the elasticity of the adhesive layer 21, the circuits 3 are held in the cavity 17 by the adhesiveness of the adhesive layer 21. positioning can be performed reliably.

For this reason, the circuits 3... positioned and arranged according to the circuit pattern are molded by the resin mold part 5, and the resin molded circuit body 1 with exposed circuit surfaces 3a..., 3b... on the front and back sides is easily obtained. be able to.

Note that when the circuits 3 are partially connected to each other by a bridge or the like, the front and back circuit surfaces 3a, 3b, etc. are exposed from the resin surface of the resin molded part 5, but the bridge, etc. It may be covered with a resin mold part 5. The bridge etc. constitute a part of the circuit, and the front and back sides of the bridge etc. constitute the circuit surface. By covering these bridges and the like with the resin mold part 5, the circuit has a structure in which at least a part of the front and back circuit surfaces are exposed from the resin surfaces 5a and 5b of the resin mold part 5. Specifically, this will be explained in Example 5 below.

When the cavity 17 has the side periphery 17a with a size larger than the outer peripheral surface of the resin molded circuit body 1, a semi-finished product of the resin molded circuit body 1 is formed within the cavity 17, and from the cavity 17 The resin molded circuit body 1 can be obtained by taking out the semi-finished product of the resin molded circuit body 1 and cutting it.

The resin molded circuit body 1 includes an insulating layer 27 on a metal substrate 25, a circuit surface 3b of the bonding surface 1b, and a resin surface 5b in a face-to-face manner.

Therefore, the resin molded circuit body 1 can be pressurized against the insulating layer 27 including the resin molded part 5, and the pressing force acting on the circuit can be dispersed over the entire resin molded part 5. Therefore, it is possible to suppress the swelling of the insulating layer 27 between the circuits 3... and suppress the occurrence of cracks at the rising portions of the insulating layer 27 of the circuits 3..., thereby improving insulation reliability. can.

Even when the circuit 3 is single, it suppresses the swelling of the insulating layer 27 around the circuit 3, suppresses the occurrence of cracks at the rising portion of the circuit 3 from the insulating layer 27, and similarly improves the insulation reliability. be able to.

In the resin molded circuit body 1, since the resin molded portion 5 remains as it is on the metal base circuit board 29, the positional accuracy of the circuit 3 can be easily maintained even after pressurization.

Further, as the metal base circuit board 29, the resin 23 is interposed between the circuits 3, so that the insulation between the circuits 3 can be improved, and the circuit density can also be increased. By increasing this circuit density, the metal base circuit board 29 can also be made smaller.

Further, the heat generated by the circuit elements connected to the circuits 3, etc. is efficiently conducted by the resin between the circuits 3, etc., and the heat dissipation performance can be improved as a whole.

This improvement in heat dissipation performance makes it possible to reduce the difference in thermal expansion between the insulating layer 27, the resin molded portion 5, and the circuit 3.

The resin molded portion 5 can also be used to prevent moisture absorption in the circuit 3 .

FIG. 14 and FIG. 15 show Example 2. FIG. 14 corresponds to FIG. 5 and is a sectional view of a mold used in the method for manufacturing a resin molded circuit body. FIG. 15 corresponds to FIG. 1 and is a sectional view of the resin molded circuit body.

In the second embodiment, a positioning pin 33 is used as a positioning portion of the circuit 3 with respect to the mold 7.

That is, in the first split mold 9 of Example 2, the adhesive layer 21 serving as the positioning portion of the circuit 3 in FIG. 5 was replaced with the positioning pin 33. Positioning The positioning pin 33 protrudes into the cavity 17 from the first split mold 9 . This positioning pin 33 is provided for each circuit 3 . The circumferential side surface 3c of the circuit 3 is engaged with the first split mold 9, and the circuit 3 is positioned with respect to the first split mold 9 in the XY direction.

When such a positioning portion using the positioning pin 33 is adopted, a hole 33a is formed in the front resin surface 5a of the resin molded circuit body 1, as shown in FIG. 15, where the positioning pin 33 is removed. No holes are generated on the surface 5b, and the bonding surface 1b can be bonded to the insulating layer 27 using a flat bonding surface 1b.

Further, by employing the positioning pin 33, the circuits 3 can be reliably positioned within the cavity 17.

It is also possible to adopt a configuration in which the position of the positioning pin 33 can be changed. For example, a hole for modification is formed in the first split mold 9, and the positioning pin 33 is replaced for use. Dummy pins can be inserted into unused holes.

In addition, the second embodiment can also provide the same effects as the first embodiment.

FIG. 16 and FIG. 17 show Example 3. FIG. 16 corresponds to FIG. 5 and is a sectional view of a mold used in the method for manufacturing a resin molded circuit body. FIG. 17 corresponds to FIG. 1 and is a sectional view of the resin molded circuit body.

In the third embodiment, a counterbore 35 is used as a positioning portion of the circuit 3 with respect to the mold 7.

That is, in the first split mold 9 of Example 3, the adhesive layer 21 serving as the positioning portion of the circuit 3 in FIG. 5 was replaced with a counterbore 35. The counterbore 35 is formed on the surface inside the cavity 17 of the first split mold 9. This counterbore 35 is provided for each circuit 3 , and the circuit surface 3b side of the circuit 3 is fitted into the first split mold 9 to position the circuit 3 with respect to the first split mold 9 in the XY direction.

The thickness of the third split mold 13 is formed to be relatively small with respect to the circuit 3, and the vertical dimension of the cavity 17 is smaller than the thickness of the circuit 3 by the depth dimension of the counterbore 35.

If such a positioning portion using the counterbore 35 is employed, the amount of protrusion of the circuit surface 3b of the resin molded circuit body 1 can be set as shown in FIG.

In this embodiment, the circuit surface 3a side has a protrusion amount due to slight shrinkage of the resin of the resin molded part 5 in FIG. 3b protrudes from the resin molded portion 5, and the protruding circuit surface 3b protrudes into the insulating layer 27.

In the metal base circuit board 29 (see FIG. 7 for the reference numeral) in which the circuit surface 3b penetrates into the insulating layer 27 (see FIG. 7 for the reference numeral), the strength of the bond between the circuits 3 and the insulating layer 27 is increased, and peeling is prevented. Strength can be increased.

Note that the depth of the counterbore 35 can be set to increase or decrease. Further, the counterbore 35 can be set in both the first and second split molds 9 and 11, or can be set only in the second split mold 11.

Furthermore, by employing the counterbore 35, the circuits 3 can be reliably positioned within the cavity 17. By setting the depth of the counterbore 35, the amount of protrusion of the resin molded portion 5 from the resin surface 5b of the circuit surface 3b can be arbitrarily set. This setting improves the peel strength and makes it possible to adjust it.

The third embodiment can also provide the same effects as the first embodiment.

FIG. 18 and FIG. 19 show Example 4. FIG. 18 corresponds to FIG. 5 and is a sectional view of a mold used in the method for manufacturing a resin molded circuit body. FIG. 19 corresponds to FIG. 1 and is a sectional view of the resin molded circuit body.

In the fourth embodiment, as shown in FIG. 18, an uneven shape is set on the surface of the second split mold 11 of the mold 7 on the cavity 17 side according to the difference in height of the circuits 3 .

The height of the circuit 3 can be freely selected. In Example 5, the heights of the other circuits 3 are set relatively lower than the height of the center circuit 3 in the figure.

The inner surface 11b of the second split mold 11 corresponding to the center circuit 3 is set the same as in FIG. 5 of Example 1, and the other inner surface 11c of the second split mold 11 is It is set to protrude from the inner surface portion 11b. Therefore, the other inner surface portion 11c of the second split mold 11 is fitted into the third split mold 13. There is a level difference between the central inner surface portion 11b and the other inner surface portions 11c between the circuits 3....

Due to the uneven shape of the inner surface of the second split mold 11, the resin molded circuit body 1 shown in FIG. 19 can be obtained.

In the resin molded circuit body 1 of FIG. 19, the resin surface 5a around the central circuit 3 has a height corresponding to the height of the circuit surface 3a of the central circuit 3 in the figure, and the resin The surface 5a becomes lower according to the height of the circuit surface 3a of the other circuit 3.

Therefore, in the fourth embodiment, the resin surface 5a has a stepped shape in the middle between the center circuit 3 and the circuits 3 on both sides.

By increasing the height of the circuit 3, it is possible to cope with an increase in the amount of heat generated by attached circuit elements.

Note that the height of the circuit 3... can be freely set, and the shape of the unevenness on the cavity 17 side of the corresponding second split mold 11 can also be changed in various ways according to the height setting of the circuit 3... .

The fourth embodiment can also provide the same effects as the first embodiment.

20 to 23 show Example 5. FIG. FIG. 20 corresponds to FIG. 5 and is a sectional view of a mold used in the method for manufacturing a resin molded circuit body. 21 is a sectional view taken along the line XXI-XXI in FIG. 22 of the resin molded circuit body, corresponding to FIG. 1. FIG. 22 is a plan view of a resin molded circuit body including circuits crossed in a bridge shape. FIG. 23 is a back view of a resin molded circuit body including circuits crossed in a bridge shape.

Embodiment 5, as shown in FIGS. 20 to 23, includes a pair of front and back circuits 3 . . . portions that partially cross each other in a bridge shape. In both cases, the circuit portions on both sides are connected by a bridge portion 3d.

The bridge portions 3d of the pair of circuits 3 are arranged facing each other and cross each other so as to straddle the other.

Both circuits 3 have linear circuit surfaces 3a and 3b on the front and back sides. Each circuit has island-shaped circuit surfaces 3a and 3b on the front and back sides on both sides of the bridge portion 3d.

Each circuit surface 3a, 3b is exposed from the resin surface 5a, 5b of the resin mold part 5, respectively.

In this manner, the circuit 3 of the fifth embodiment has a configuration in which at least a portion of the front and back circuit surfaces 3a, 3b are exposed from the resin surfaces 5a, 5b of the resin molded portion 5.

Note that the configuration in which at least a portion of the front and back circuit surfaces 3a, 3b are exposed from the resin surface of the resin molded portion is not limited to the bridge portion, but may be applied to other circuit configurations.

As shown in FIG. 20, the positioning portion of Example 5 was an adhesive layer 21. As in the first embodiment, the positioning portion of the first split mold 9 includes the adhesive layer 21 on one side of the cavity 17 on the first split mold 9.

In the method for manufacturing the resin molded circuit body 1 of the fifth embodiment, one circuit 3 is adhered to the adhesive layer 21 which is the positioning part of the first split mold 9, including the circuit surface 3a of the bridge part 3d. , positioned and arranged. The other circuit 3 is positioned across the bridge portion 3d with its circuit surfaces 3b on both sides adhered.

Note that the vertical arrangement of both circuits 3 with respect to the adhesive layer 21 is arbitrary.

The flow of the resin is the same as in the above embodiment, and the resin is press-fitted into the cavity 17 through the gate 11a, flows including between the bridge portions 3d of the circuit 3, and is cured to form the resin molded circuit shown in FIGS. 21 to 23. Body 1 is obtained.

In this embodiment as well, the same effects as in the above embodiment can be achieved.

1 Resin molded circuit body 1b Joint surface 3 Circuits 3a, 3b Circuit surface 3c Circumferential side 5 Resin mold parts 5a, 5b Resin surface 7 Mold 9 First split mold 11 Second split mold 11a Gates 11b, 11c Inner surface Part 13 Third split mold 15 Fourth split mold 17 Cavity 19 Transfer chamber 21 Adhesive layer (positioning part)
23 Resin 25 Metal substrate (substrate)
27 Insulating layer 29 Metal-based circuit board (circuit board)
33 Positioning pin (positioning part)
35 Counterbore (positioning part)
Du sauce

Claims (14)

A circuit arranged according to a circuit pattern,
a resin mold part of a thermosetting resin that covers the peripheral side of the circuit;
Equipped with
At least a portion of the front and back circuit surfaces of the circuit are exposed from the resin surface of the resin mold part,
One of the circuit surface and the resin surface on the front and back sides is a bonding surface for bonding to an insulating layer,
The bonding surface is substantially flat while causing the circuit surface to protrude from the resin surface, including a boundary where the resin surface contacts the circuit,
The protrusion amount of the protrusion is determined by the thermal expansion of the resin molded portion when the bonding surface is brought face to face with the insulating layer on the substrate and the other of the front and back circuit surfaces and the resin surface is pressurized and heated. The pressurizing force is distributed to the circuit surface and the resin surface, and the resin mold section presses the insulating layer around the circuit surface, causing cracks in the insulating layer at the rising portion of the circuit from the insulating layer. within the range where no occurrence of
A resin molded circuit body characterized by: The resin molded circuit body according to claim 1,
The protrusion amount of the protrusion is determined by the thermal expansion of the resin molded portion when the bonding surface is brought face to face with the insulating layer on the substrate and the other of the front and back circuit surfaces and the resin surface is pressurized and heated. A range in which the pressurizing force is distributed to the circuit surface and the resin surface, and the resin mold part presses the insulating layer around the circuit surface, so that the circuit surface and the resin surface are flush with each other in a completed form. is, The resin molded circuit body according to claim 2,
The amount of protrusion is 20 to 60 μm,
A resin molded circuit body characterized by: The resin molded circuit body according to any one of claims 1 to 3,
The other of the front and back circuit surfaces and the resin surface is provided with a plurality of the circuits at a uniform height or a plurality of circuits at different heights,
A resin molded circuit body characterized by: The resin molded circuit body according to any one of claims 1 to 4,
The circuit has corners formed at right angles or sag at the corners.
A resin molded circuit body characterized by: The resin molded circuit body according to any one of claims 1 to 5,
the circuit has a thickness of more than 0.5 mm;
A resin molded circuit body characterized by: A mold for transfer molding the resin molded circuit body according to claim 1 or 2 ,
a first split mold forming one side of a cavity for molding the resin molded circuit body;
having a side periphery of the cavity with a size corresponding to the outer peripheral surface of the resin molded circuit body or a size larger than the outer peripheral surface of the resin molded circuit body;
The first split mold includes a positioning part for positioning the circuit within the cavity.
A mold characterized by: The mold according to claim 7,
The positioning portion is an adhesive layer, a positioning pin, or a counterbore provided on the first split mold on one side of the cavity.
A mold characterized by: The mold according to claim 7 or 8,
comprising second and third split molds for forming the cavity and a fourth split mold for forming the transfer chamber,
The second split mold includes a gate that configures the other side of the cavity according to the other side of the resin molded circuit body, contacts the circuit, and serves as a passage for the resin,
The third split mold is interposed between the first and second split molds, and has a size corresponding to the outer peripheral surface of the resin molded circuit body or larger than the outer peripheral surface of the resin molded circuit body. The size constitutes the side periphery of the cavity,
The fourth split mold is joined to the second split mold to communicate the transfer chamber with the gate.
A mold characterized by: Using the mold according to claim 7 or 8,
positioning and arranging the circuit in the positioning part of the first split mold;
configuring the cavity including the first split mold,
Pressure-fitting a resin that flows by preheating into the cavity and then hardening it.
A method for manufacturing a resin molded circuit body, characterized in that: Using the mold according to claim 9,
positioning and arranging the circuit in the positioning part of the first split mold;
configuring the cavity and transfer chamber by combining the first, second, third, and fourth split molds,
heating the mold;
A tablet-shaped resin is stored in the transfer chamber and preheated until it flows,
Pressing the resin that flows due to the preheating into the cavity through the gate using a plunger and then hardening it.
A method for manufacturing a resin molded circuit body, characterized in that: A method for manufacturing a resin molded circuit body according to claim 10 or 11,
The cavity has the side periphery with a size larger than the outer peripheral surface of the resin molded circuit body,
A semi-finished product of a resin molded circuit body is formed in the cavity,
taking out the semi-finished product of the resin molded circuit body from the cavity and cutting it to obtain the resin molded circuit body;
A method for manufacturing a resin molded circuit body, characterized in that: A circuit board using the resin molded circuit body according to any one of claims 1 to 6,
The resin molded circuit body is provided with the circuit surface and the resin surface of the bonding surface facing the insulating layer on the substrate,
A circuit board characterized by: A circuit board using the resin molded circuit body according to claim 1,
The resin molded circuit body is provided with the circuit surface and the resin surface of the bonding surface facing the insulating layer on the substrate,
the circuit surface protrudes further into the insulating layer than the resin surface;
A circuit board characterized by:

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