JP2520429C - - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a printed wiring board used for mounting an electronic component such as an IC. BACKGROUND ART When mounting electronic components 2 such as ICs on a printed wiring board A, mounting recesses 9 are provided on the printed wiring board A. That is, as shown in FIG. 7, another wiring board 8 provided with the opening 7 is laminated on the wiring board 1 to form the printed wiring board A in which the mounting recess 9 is provided by the opening 7. And the wiring board 1
An electric insulating layer 4 is formed by applying and hardening an insulating resin or the like in order to secure electric insulation between the wiring substrate 8 and the wiring substrate 8.
The wiring substrates 1 and 8 can be laminated and adhered by the adhesive resin layer 6 by performing lamination molding in which heat is applied under heat. Here, openings 3 and 5 are also provided in the electrical insulating layer 4 and the adhesive resin layer 6 to form the mounting recess 9 respectively. When the size of the opening 3 of the electric insulating layer 4 is larger than the size of the opening 5 of the adhesive resin layer 6 as shown in FIG. 8, the recess 12 is formed in the mounting recess 9 at the portion where the adhesive resin layer 6 protrudes, as shown in FIG. However, when the recesses 12 are formed in this way, when cleaning the printed wiring board A, the cleaning liquid remains in the recesses 12, and the remaining cleaning liquid flows out after cleaning and may contaminate the circuit 13 of the printed wiring board A. When filling the electronic component 2 with the sealing resin in order to seal the inside of the mounting concave portion 9, voids are easily generated in the recess 12, and the sealing may be insufficient. In particular, when the lamination molding is performed, the protruding portion of the adhesive resin layer 6 hangs down as shown in FIG. Things. [Object of the Invention] The present invention has been made in view of the above points, and has as its object to provide a printed wiring board for mounting electronic components, which does not have a possibility of forming a recess in a mounting recess. is there. DISCLOSURE OF THE INVENTION Accordingly, the present invention provides an adhesive resin in which an opening 5 is provided at a mounting position of an electronic component 2 via an electrical insulating layer 4 having an opening 3 at the mounting position of the electronic component 2 on the wiring board 1. A mounting recess is also formed by laminating and adhering a wiring board 8 having openings 7 at the mounting positions of the electronic components 2 by the layer 6, and the openings 3, 5, 7 are vertically aligned. 9 relates to a printed wiring board A for mounting electronic components, in which the size of the opening 3 provided in the electrical insulating layer 4 formed by applying and curing a resin on the wiring board is determined by the size of the adhesive resin layer 6.
The opening 5 is characterized by being set smaller than the opening 5 of the electrical insulating layer 4 so that the edge of the opening 5 of the adhesive resin layer 6 does not protrude into the opening 3 of the electrical insulating layer 4. The size of the portions 3 and 5 is set so that no depression is formed in the mounting recess 9. Hereinafter, the present invention will be described in detail with reference to examples. FIG. 1 shows an embodiment of the present invention, in which a wiring board 1 is formed of a resin laminate such as a glass base epoxy resin laminate, and has a lower surface formed of a metal such as copper foil. Foil 14 is laminated and stretched. An electric insulating layer 4 is formed on the upper surface of the wiring board 1. The electric insulating layer 4 can be formed by applying and hardening a resin having excellent electric insulating properties such as an epoxy resin, for example, so that the wiring board 1 is exposed where electronic components 2 are mounted. An opening 3 is formed in the opening. Further, as the adhesive resin layer 6, for example, a bonding prepreg prepared by impregnating a glass substrate or the like with an epoxy resin or the like and drying the same can be used, and an opening 5 is formed at a place where the electronic component 2 is mounted. I have. Further, the wiring board 8 is formed in the same manner as the wiring board 1 described above, for example, formed of a resin laminate such as a glass base epoxy resin laminate, and has a metal foil such as a copper foil on the upper surface thereof. 14 are laminated and stretched, and an opening 7 is formed at a place where the electronic component 2 is mounted. Here, each of the openings 3, 5, and 7 is formed in the same plane shape such as a quadrangle, and the size (that is, the inner diameter) of the opening 3 of the electric insulating layer 4 is the It is formed so as to be smaller than the size of the portion 5 (that is, its inner diameter). Further, the size of the opening 5 of the adhesive resin layer 6 and the size of the opening 7 of the wiring board 8 are formed to be equal. Then, as shown in FIG. 1 (a), the adhesive resin layer 6 is placed on the wiring board 1 via the electric insulating layer 4 and the wiring board 8 is placed thereon, and the openings 3, 5, 7
By vertically pressing and heating and pressing in this state to perform lamination molding,
As shown in FIG. 1B, the wiring substrates 1 and 8 can be laminated and integrated by the adhesive resin layer 6, and the mounting recesses 9 can be formed by the openings 3, 5, and 7. Here, by roughening the surface of the electric insulating layer 4, the adhesiveness between the electric insulating layer 4 and the adhesive resin layer 6 can be improved. The surface roughening can be performed by mechanical surface roughening using liquid honing, sand blasting, sand paper, or the like, or by chemical roughening such as treatment with dichromic acids alone or in combination. Further, the printed circuit board A can be finished by forming the circuit 13 by etching the metal foil 14 of each of the wiring boards 1 and 8 and mounting the electronic component 2 such as an IC in the mounting recess 9. Circuit 13 and wire 1
The electronic component 2 can be mounted on the printed wiring board A by performing bonding at 5 or the like. In this case, the opening 5 of the adhesive resin layer 6 is
Is formed larger than the opening 3 of the adhesive resin layer 6, the periphery of the opening 5 of the adhesive resin layer 6 does not protrude inward of the opening 3 of the electric insulating layer 4, and therefore, the protrusion of the adhesive resin layer 6 The recess is not formed in the mounting recess 9. In the embodiment shown in FIGS. 2 and 3, the circuit board 1
3 is used between the wiring boards 1 and 8 by using a circuit board in which the circuit board 3 is formed in advance.
The electronic component 2 mounted in the mounting recess 9 is bonded to the circuit 13 of the wiring board 1 as an inner layer circuit with the wire 15 in addition to the circuit 13 of the wiring board 8. is there. In FIG. 2, reference numeral 16 denotes a through hole.
In the embodiment shown in FIG. 4, a wiring board 1 provided with a metal plate 17 for heat radiation at the bottom of the mounting recess 9 is used, and the wiring board 1 is fitted with the metal plate 17. The upper substrate 1b is formed by laminating the upper substrate 1b with the adhesive resin layer 18 on the lower substrate 1a. FIG. 5 shows an embodiment in which a through hole 19 is formed in the wiring board 1. In the embodiment shown in FIG. 6, a wiring board 1 having a metal plate 20 laminated as a core is used. [Effect of the Invention] As described above, in the present invention, the size of the opening provided in the electric insulating layer formed by applying and curing the resin on the wiring board is set smaller than the opening of the adhesive resin layer. Therefore, the peripheral portion of the opening of the adhesive resin layer does not protrude inward of the opening of the electrical insulating layer, and the recess of the adhesive resin layer does not form in the mounting recess. This eliminates the problem that cleaning water remains in the recess and voids occur during resin sealing.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) and (b) are cross-sectional views of one embodiment of the present invention, FIG. 2 is a cross-sectional view of another embodiment, and FIG. 4, 5, 5, and 6 are cross-sectional views of still another embodiment, FIG. 7 is a cross-sectional view of a conventional example, and FIG. 8 is an enlarged cross-sectional view of a part of the embodiment. 1 is a wiring board, 2 is an electronic component, 3 is an opening of an electric insulating layer, 4 is an electric insulating layer, 5
Is an opening of the adhesive resin layer, 6 is an adhesive resin layer, 7 is an opening of the wiring board, 8 is a wiring board, and 9 is a mounting recess.

Claims (1)

Claims: (1) An electric insulating layer having an opening at a mounting position of an electronic component on a wiring board is provided,
Similarly, a wiring board provided with an opening at the mounting position of an electronic component is formed by laminating and bonding with an adhesive resin layer having an opening at the mounting position of an electronic component, and each opening is formed so as to match up and down. in the electronic component mounting printed circuit board for the recess is provided mounted, the size of the opening provided in the electrical insulating layer formed by application of a resin cured wiring board from the opening of the adhesive resin layer A printed wiring board for mounting electronic components, characterized in that it is also set to be small.