JP6365360B2 - Electronic device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electronic device in which a circuit board on which electronic components are mounted is sealed with a mold resin, and a manufacturing method thereof.

  Conventionally, as an example of the electronic device as described above, there is a mold package disclosed in Patent Document 1. In the mold package, a resin film (hereinafter referred to as a protective resin) is provided between one surface of the circuit board and an end portion of the mold resin as an integrated material for covering the wiring. This protective resin includes a portion that is crushed by a mold during the molding process.

JP 2014-236114 A

  By the way, in the mold package, a protective resin is provided over the circuit board and the wiring outside the mold resin. That is, the protective resin includes a portion disposed on the wiring and a portion disposed on the circuit board without being disposed on the wiring outside the mold resin. For this reason, a difference arises in the amount of expansion and contraction between the two parts of the protective resin due to a change in ambient temperature. Therefore, the protective resin has a problem that stress concentrates and cracks occur due to the difference in the amount of expansion and contraction between the two parts.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic device that can suppress the occurrence of cracks in a protective resin, and a method for manufacturing the same.

In order to achieve the above object, the present invention provides:
A circuit board (10, 10a) in which wiring (12-15) is formed on an insulating base (11);
A circuit element (21, 22) mounted on a circuit board and electrically connected to the wiring;
A mold resin (30, 30a) for sealing the circuit element and a mounting surface on which the circuit element is mounted on the circuit board;
A dummy wiring (40) provided on the mounting surface of the circuit board, provided along the edge of the mold resin, and inside and outside the mold resin;
Protective resin (50, 50a) provided on the dummy wiring,
The protective resin is provided between the inside and the outside of the mold resin, and a portion arranged outside the mold resin covers the dummy wiring without touching the circuit board.

  Thus, the present invention covers the dummy wiring outside the mold resin without the protective resin touching the circuit board. For this reason, this invention can reduce the site | part which the difference in expansion-contraction amount produces in the protective resin provided in the exterior of mold resin. Therefore, this invention can suppress that a crack generate | occur | produces in protective resin.

Further features of the invention include
A circuit board (10, 10a) in which wirings (12-15) are formed on an insulating base (11); circuit elements (21, 22) mounted on the circuit board and electrically connected to the wiring; and circuit board A first structure including dummy wirings provided inside and outside the formation region along the edge of the formation region of the mold resin (30, 30a) on the mounting surface on which the circuit element is mounted ( 200a) preparing step;
Forming a protective resin on the dummy wiring over the inside and outside of the formation region, and forming the protective resin without touching the circuit board with a portion of the protective resin disposed outside the formation region; ,
Molding mold (400, 410, 400a, 410a) having a cavity corresponding to the outer shape of the molding resin is molded with the cavity facing the mounting surface of the structure on which the protective resin is formed. A mold process for sealing the circuit element, the mounting surface, and a part of the protective resin,
In the molding process, the molding resin is molded in a state in which the outside of the forming region of the protective resin is crushed by the pressing portion (400, 400a) that holds down the mounting surface side of the structure on which the protective resin is formed in the mold. There is in point to do.

  As described above, according to the present invention, when the protective resin is formed on the dummy wiring over the inside and outside of the formation region where the mold resin is formed, the portion of the protection resin disposed outside the formation region is It is formed without touching the circuit board. The present invention provides a pressing portion that holds down the mounting surface side of the structure in which the protective resin is formed in the mold, and in the state in which the outside of the formation region where the mold resin is formed is crushed in the protective resin. Mold the resin. For this reason, this invention can reduce the site | part which the difference in expansion-contraction amount produces in the protective resin provided in the exterior of mold resin. Therefore, the present invention can manufacture an electronic device in which cracks are unlikely to occur in the protective resin.

  The reference numerals in parentheses described in the claims and in this section indicate the correspondence with the specific means described in the embodiments described later as one aspect, and the technical scope of the invention is as follows. It is not limited.

It is a plane perspective view which shows schematic structure of the electronic device in embodiment. It is sectional drawing which follows the II-II line of FIG. It is sectional drawing which shows schematic structure of the 1st mold front structure of the electronic device in embodiment. It is sectional drawing which shows schematic structure of the 2nd mold front structure of the electronic device in embodiment. It is sectional drawing which shows the manufacturing process of the electronic device in embodiment. It is a plane perspective view which shows the mold structure before the division | segmentation in embodiment. 10 is a cross-sectional view illustrating a schematic configuration of an electronic device according to Modification 1. FIG. 12 is a cross-sectional view illustrating a manufacturing process of an electronic device according to Modification 1. FIG. 10 is a cross-sectional view illustrating a schematic configuration of an electronic device according to Modification 2. FIG.

  Hereinafter, a plurality of embodiments for carrying out the invention will be described with reference to the drawings. In each embodiment, portions corresponding to the matters described in the preceding embodiment may be denoted by the same reference numerals and redundant description may be omitted. In each embodiment, when only a part of the configuration is described, the other configurations described above can be applied to other portions of the configuration.

  The configuration of the electronic device 100 according to the present embodiment will be described with reference to FIGS. The electronic device 100 is mounted on a vehicle such as an automobile, and can be applied as a device for driving various devices for the vehicle.

  The electronic device 100 includes a circuit board 10, a semiconductor element 21 and a passive element 22, a mold resin 30, a dummy wiring 40, and a protective resin 50.

  The circuit board 10 is obtained by forming wiring on the insulating base material 11. The circuit board 10 has a semiconductor element 21 and a passive element 22 mounted on one surface. Therefore, it can be said that one surface of the circuit board 10 is a mounting surface S1. The circuit board 10 can employ a printed circuit board composed mainly of a resin such as an epoxy resin or a glass epoxy resin as the insulating base material 11, or a ceramic board composed mainly of ceramics as the insulating base material 11. The circuit board 10 can employ a through-hole board or a build-up board. Although not shown, the wiring is composed mainly of a metal such as copper.

  The semiconductor element 21 and the passive element 22 are mounted on the mounting surface S1, and correspond to circuit elements in the claims. The semiconductor element 21 and the passive element 22 are electrically connected to the wiring of the circuit board 10 via a conductive adhesive member such as solder. The semiconductor element 21 is a MOSFET, a microcomputer, a control element, or the like. The passive element 22 is a chip resistor, a chip capacitor, a crystal resonator, or the like. However, the present invention is not limited to this. The present invention can be adopted as long as it is a circuit element electrically connected to the wiring of the circuit board 10.

  The mold resin 30 seals the semiconductor element 21 and the passive element 22 and the mounting surface S1. The mold resin 30 is provided so as to reach the dummy wiring 40 and the protective resin 50. The mold resin 30 covers the semiconductor element 21 and the passive element 22, the mounting surface S <b> 1 of the circuit board 10, and a part of the protective resin 50 while being in close contact therewith. Thus, the electronic device 100 can be said to be a mold package having a half mold structure.

  The mold resin 30 can employ, for example, a thermosetting epoxy resin. Further, the mold resin 30 can be used even if the epoxy resin contains a filler such as alumina or silica in an epoxy resin as necessary. The mold resin 30 is formed by a transfer molding method, a compression molding method, or the like in a molding process described later.

  The dummy wiring 40 is a part that is pressed by the clamp part 400 of the mold during the molding process. The dummy wiring 40 is formed mainly of a metal such as copper and is provided on the mounting surface S1. The dummy wiring 40 is provided across the inside and outside of the mold resin 30 along the edge (in other words, the side wall) of the mold resin 30. In the present embodiment, two dummy wirings 40 that are provided along two opposite sides of the circuit board 10 and along the other two opposite sides are employed. Further, it can be said that the dummy wiring 40 includes a portion disposed in a region surrounded by a virtual plane along the side wall of the mold resin 30 and a portion provided outside the region.

  In this embodiment, a rectangular parallelepiped dummy wiring 40 is employed. Therefore, the corners of the dummy wiring 40 are formed inside and outside the mold resin 30. This corner can be rephrased as a shoulder.

  The dummy wiring 40 is not electrically connected to a circuit configured by the circuit board 10 and circuit elements such as the semiconductor element 21. The dummy wiring 40 is a conductor portion that is formed so as to protrude from the mounting surface S <b> 1 of the circuit board 10.

  The protective resin 50 is provided on the dummy wiring 40. Therefore, in the present embodiment, the protective resin 50 provided over two opposing sides of the circuit board 10 along the dummy wiring 40 is employed. Further, the protective resin 50 is provided between the inside and the outside of the mold resin 30, and a portion disposed outside the mold resin 30 covers the dummy wiring 40 without touching the circuit board 10. Therefore, a part of the protective resin 50 is covered with the mold resin 30 and the remaining part is exposed from the mold resin 30. Further, the portion of the protective resin 50 exposed from the mold resin 30 is provided only on the dummy wiring 40. In other words, the protective resin 50 is not formed on the shoulder portion of the dummy wiring 40 outside the mold resin 30.

  The protective resin 50 is a resin for suppressing a mold resin from leaking due to a gap between the circuit board 10 and the clamp part 400 of the mold during the molding process. In other words, the protective resin 50 is a resin for increasing the area facing the clamp unit 400.

  The portion of the protective resin 50 covered with the mold resin 30 may be formed on the shoulder portion of the dummy wiring 40 and may be in contact with the circuit board 10. Since the portion of the protective resin 50 covered with the mold resin 30 is covered with the mold resin 30, stress concentrates on the interface between the portion in contact with the circuit board 10 and the portion on the dummy wiring 40. Can be suppressed. Therefore, the electronic device 100 can secure an area where the clamp unit 400 contacts while suppressing the occurrence of cracks in the protective resin 50 in the mold resin 30.

  For example, an insulating solder resist can be employed as the protective resin 50. The circuit board 10 may have a solder resist formed around a solder connection portion such as the semiconductor element 21. The electronic device 100 is preferable because the solder resist and the protective resin 50 can be formed simultaneously. However, the present invention is not limited to this. Further, the protective resin 50 may be a resin such as polyimide, acrylic resin, or epoxy resin that is different from the solder resist provided around the solder connection portion or the like.

  In addition, the dummy wiring 40 and the protective resin 50 are portions pressed by the mold clamping unit 400 in a molding process described later, and can be called a mold stepping unit. Regarding this type stepping portion, refer to Japanese Patent Application Laid-Open No. 2014-220305 by the present applicant. The dummy wiring 40 and the protective resin 50 may be provided along the outline of the mold resin 30.

  As shown in FIG. 1, the electronic device 100 has a part of the circuit board 10 exposed from the mold resin 30. The part exposed from the mold resin 30 in the circuit board 10 can be said to be an ear part. Therefore, in the electronic device 100, a through hole may be formed in the ear portion. The through hole is a through hole that penetrates the circuit board 10 in the thickness direction and is covered with a conductor that is a part of the wiring, and is a connection portion used for electrical connection.

  Next, a method for manufacturing the electronic device 100 according to the present embodiment will be described with reference to FIGS. In this manufacturing method, a circuit board 10 in a multiple state in which a plurality of circuit boards 10 in the electronic device 100 are integrally connected is used. In this manufacturing method, the semiconductor element 21 and the passive element 22 are mounted on the circuit board 10 in a multiple state, and after the molding resin 30 is molded, the circuit board 10 is cut together with the molding resin 30 so that each electron The device 100 is divided into pieces. That is, this manufacturing method employs so-called MAP molding. However, the manufacturing method can be applied even when one circuit board 10 in the electronic device 100 is used. MAP is an abbreviation for Mold Array Package. Moreover, in FIG.3, FIG.4, FIG.6, the code | symbol of the component after individualization is provided to each component before individualization.

  First, the manufacturing method performs a preparation process for preparing the first pre-mold structure 200a shown in FIG. The first pre-mold structure 200a corresponds to the first structure in the claims. The first pre-mold structure 200 a includes a circuit board 10, a semiconductor element 21, a passive element 22, and a dummy wiring 40.

  The circuit board 10 has wiring in the insulating base material 11 and has a multiple state in which the circuit boards 10 in the three electronic devices 100 are integrated. The semiconductor element 21 and the passive element 22 are mounted for each region where the electronic device 100 is formed on the circuit board 10 by reflow soldering or the like. And the dummy wiring 40 is provided over the inside and outside of a formation area along the edge part of the formation area of the mold resin 30 in the mounting surface S1 of the circuit board 10 by patterning a conductor layer. Further, as shown in FIG. 3, the dummy wiring 40 is formed in an annular shape in the state of the first pre-mold structure 200a.

  Note that a two-dot chain line in FIG. 3 indicates a region where the mold resin 30 is formed. That is, in the molding process, the mold resin 30 is formed in a region sandwiched between the two-dot chain lines. Also, the two-dot chain line in FIG.

  Next, this manufacturing method performs the protective resin formation process which forms the 2nd pre-molding structure 200b shown in FIG. In the protective resin forming step, the protective resin 50 is formed on the dummy wiring 40 in the first pre-molding structure 200a by the well-known solder resist forming method or the like over the inside and outside of the molding resin 30 forming region. Further, as shown in FIG. 4, the protective resin 50 is formed in an annular shape in the state of the second pre-mold structure 200b.

  In the protective resin forming step, the protective resin 50 is formed without touching the circuit board 10 at a portion arranged outside the formation region. In the protective resin forming step, the second pre-mold structure 200b is thus formed. The second pre-mold structure 200b is the first pre-mold structure 200a on which the protective resin 50 is formed.

  Thus, in this manufacturing method, the 2nd pre-mold structure 200b can be manufactured by performing a preparation process and a protective resin formation process. This preparation process and protective resin formation process can be said to be a substrate manufacturing process with respect to the molding process described later. That is, in this manufacturing method, a preparation process and a protective resin formation process can be collectively called a substrate manufacturing process.

  Then, this manufacturing method performs the molding process shown in FIG. Here, the compression molding method is adopted. However, the present invention can be employed even with the transfer mold method.

  In the molding process, molding dies 400 and 410 having cavities corresponding to the outer shape of the mold resin 30 are used. Reference numeral 400 denotes a clamp portion that holds down the second pre-mold structure 200b. Reference numeral 410 denotes a movable portion that compresses the constituent material of the mold resin 30 disposed in the cavity. The clamp part 400 is corresponded to the press part in a claim. Further, the clamp part 400 is a part that holds down the mounting surface S1 side of the first pre-mold structure 200a.

  In the molding step, the mold resin 30 is heated and pressurized by the molds 400 and 410 while the cavity is opposed to the mounting surface S1 of the second pre-mold structure 200b. Is molded. In particular, in the molding process, the mold resin 30 is molded in a state where the outside of the formation region of the protective resin 50 is crushed by the clamp portion 400. Thus, in the molding process, the semiconductor element 21 and the passive element 22, the mounting surface S1, a part of the dummy wiring 40, and a part of the protective resin 50 are sealed. Thereby, this manufacturing method can manufacture the mold structure 300 shown in FIG. As shown in FIG. 6, in the mold structure 300, the protective resin 50 is provided between the inside and the outside of the mold resin 30, and a portion of the protective resin 50 arranged outside the mold resin 30 is a circuit board. The dummy wiring 40 is covered without touching 10. In this manufacturing method, the electronic device 100 can be manufactured by cutting the mold structure along the dicing line DL.

  As described above, the electronic device 100 covers the dummy wiring 40 without the protective resin 50 touching the circuit board 10 outside the mold resin 30. For this reason, the electronic device can reduce the part where the difference in expansion / contraction amount occurs in the protective resin 50 provided outside the mold resin 30. Therefore, the electronic device 100 can suppress the generation of cracks in the protective resin 50. In other words, even when the electronic device 100 is used in a cold environment, the protective resin 50 is less likely to cause a difference in expansion and contraction and can suppress the occurrence of cracks. The cold environment is an environment that repeatedly changes, for example, at a low temperature such as below freezing and at a high temperature exceeding 100 degrees.

  For example, when the protective resin is provided over the circuit board and the surface layer conductor outside the mold resin, cracks may occur as described above. In this case, in the electronic device, it is conceivable that stress is applied to the circuit board due to the occurrence of cracks in the protective resin. However, since the electronic device 100 can suppress the generation of cracks in the protective resin 50, it is possible to suppress the application of stress to the circuit board 10 due to the cracks in the protective resin 50.

  Further, as described above, in the present manufacturing method, when the protective resin 50 is formed on the dummy wiring 40 over the inside and outside of the formation region of the mold resin 30, the protection resin 50 is formed outside the formation region. The arranged portion is formed without touching the circuit board 10. Then, in the present manufacturing method, the mold resin 30 is molded in the state in which the outside of the formation region of the mold resin 30 in the protective resin 50 is crushed by the clamp portion 400. For this reason, this manufacturing method can reduce the site | part in which the difference in expansion-contraction amount arises in the protective resin 50 provided in the exterior of the mold resin 30. FIG. Therefore, this manufacturing method can manufacture the electronic device 100 in which the occurrence of cracks in the protective resin 50 is suppressed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention. Hereinafter, modifications 1 and 2 of the present invention will be described. The above-described embodiment and Modifications 1 and 2 can be implemented independently, but can also be implemented in appropriate combination. The present invention is not limited to the combinations shown in the embodiments, and can be implemented by various combinations.

(Modification 1)
Here, with reference to FIGS. 7 and 8, an electronic device 100 a according to Modification 1 and a method for manufacturing the same will be described. The electronic device 100a differs from the electronic device 100 in the shapes of the mold resin 30a and the protective resin 50a.

  As shown in FIG. 7, the mold resin 30 a includes a first taper portion 31 a that becomes wider on the dummy wiring 40 as it approaches the dummy wiring 40. The protective resin 50a includes a second tapered portion 51a that is inclined along the first tapered portion 31a. Such a shape is formed in the clamp part 400a used when performing a molding process.

  In the manufacturing method of this modification, as shown in FIG. 8, a clamp part 400a and a movable part 410a, which are molds, are used. In particular, the clamp portion 400a is formed with a mold taper portion 401a that is inclined so that the opening area of the cavity becomes wider as the dummy wiring 40 is approached.

  In the manufacturing method of this modification, since the mold configuration is performed using the clamp portion 400a, the releasability when the mold structure is released from the molds 410a and 400a can be improved. That is, in the manufacturing method of this modification, it is easy to remove the mold structure from the molds 410a and 400a after the molding process. Therefore, in the manufacturing method of this modification, it is possible to suppress stress from being applied to the electronic device 100a when the mold resin 30a is removed from the molds 410a and 400a.

  Note that the manufacturing method of the present modification can achieve the same effects as the manufacturing method of the electronic device 100. In addition, the electronic device 100a can achieve the same effects as the electronic device 100.

(Modification 2)
Here, the electronic apparatus 100b according to the second modification will be described with reference to FIG. The electronic device 100b is different from the electronic device 100 in the configuration of the circuit board 10a.

  The circuit board 10a includes a first surface layer wiring 14, an inner layer pattern 12, an interlayer connection portion 13, and a second surface layer wiring 15 as wirings. The first surface layer wiring 14 is provided inside the mold resin 30 and is electrically connected to the semiconductor element 21 and the passive element 22. That is, the first surface layer wiring 14 is sealed with the mold resin 30.

  The inner layer pattern 12 and the interlayer connection portion 13 correspond to the inner layer wiring in the claims. The inner layer pattern 12 is provided in the insulating base material 11 so as to intersect with the dummy wiring 40 via the insulating base material 11. The inner layer pattern 12 is electrically and mechanically connected to the interlayer connection portion 13. The interlayer connection portion 13 is electrically and mechanically connected to the first surface wiring 14 and is electrically and mechanically connected to the second surface wiring 15.

  The second surface layer wiring 15 is provided outside the mold resin 30 and is electrically connected to the inner layer pattern 12 through the interlayer connection portion 13. That is, the second surface layer wiring 15 is not sealed with the mold resin 30 and is exposed to the outside of the mold resin 30.

  Thus, even if the electronic device 100b has a structure in which the dummy wiring 40 is provided along the edge of the mold resin 30, the wiring connected to the semiconductor element 21 and the passive element 22 is connected to the outside of the mold resin 30. It can be pulled out. Note that the electronic device 100b can achieve the same effects as the electronic device 100. Modification 2 can also be implemented in combination with Modification 1.

  10, 10a Circuit board, 11 Resin base material, 12 Inner layer pattern, 13 Interlayer connection part, 14, 15 Surface layer wiring, 21 Semiconductor element, 22 Passive element, 30, 30a Mold resin, 31a First taper oblique part, 40 Dummy wiring , 50, 50a Protective resin, 51a Second tapered portion, 100, 100a, 100b Electronic device, 200a First pre-mold structure, 200b Second pre-mold structure, 300 Mold structure, 400, 400a Clamp portion, 410, 410a movable part, 401a mold taper part, S1 mounting surface, DL dicing line

Claims (5)

A circuit board (10, 10a) in which wiring (12-15) is formed on an insulating base (11);
Circuit elements (21, 22) mounted on the circuit board and electrically connected to the wiring;
A mold resin (30, 30a) sealing the circuit element and a mounting surface of the circuit board on which the circuit element is mounted;
Dummy wiring (40) provided on the mounting surface of the circuit board, and provided along the edge of the mold resin and inside and outside the mold resin,
A protective resin (50, 50a) provided on the dummy wiring,
The protective resin is provided between the inside and outside of the mold resin, and a portion arranged outside the mold resin covers the dummy wiring without touching the circuit board. An electronic device. The circuit board (10a) is used as the wiring (12 to 14).
A first surface layer wiring (14) provided in the mold resin and electrically connected to the circuit element;
Inner layer wiring (12, 13) provided in the insulating base material so as to intersect with the dummy wiring via the insulating base material and electrically connected to the first surface layer wiring;
The electronic device according to claim 1, further comprising a second surface layer wiring (15) provided outside the mold resin and electrically connected to the inner layer wiring. The mold resin (30a) includes, on the dummy wiring, a first taper portion (31a) that becomes wider as it approaches the dummy wiring,
The electronic device according to claim 1 or 2, wherein the protective resin (50a) includes a second taper portion (51a) inclined along the first taper portion. A circuit board (10, 10a) in which wiring (12-15) is formed on an insulating base (11), circuit elements (21, 22) mounted on the circuit board and electrically connected to the wiring, Dummy wiring (40) provided across the inside and outside of the formation region along the edge of the formation region of the mold resin (30, 30a) on the mounting surface of the circuit board on which the circuit elements are mounted; Preparing a first structure (200a) comprising:
A step of forming a protective resin on the dummy wiring over the inside and outside of the formation region, and a portion of the protection resin disposed outside the formation region is formed without touching the circuit board; A protective resin forming step;
A molding die (400, 410, 400a, 410a) having a cavity corresponding to the outer shape of the mold resin is made to face the mounting surface of the first structure on which the protective resin is formed. In the state, by molding the mold resin, it comprises a molding step for sealing the circuit element, the mounting surface, and a part of the protective resin,
In the molding step, a pressing portion (400, 400a) for pressing the mounting surface side of the first structure on which the protective resin is formed in the mold is crushed outside the formation region of the protective resin. A method of manufacturing an electronic device, wherein the molding resin is molded in a state where   The pressing part (400a) in the molds (400a, 410a) is formed with a mold taper part (401a) that is inclined so that the opening area of the cavity becomes wider as it approaches the dummy wiring. The method for manufacturing an electronic device according to claim 4.

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