JP6523039B2 - Printed wiring board and method of manufacturing the same - Google Patents

Description

  The present invention relates to a printed wiring board and a method of manufacturing the same.

In many package substrates and module substrates, semiconductor elements are directly mounted on a printed wiring board, and electrodes of the semiconductor elements and bonding pads on the printed wiring board are connected by a mounting method such as wire bonding or flip chip bonding. Furthermore, it is sealed with mold resin so that the mounted semiconductor element may be covered.
Therefore, when the adhesion between the mold resin and the printed wiring board is low, the two peel off, and even if the peeling does not occur, if there is a non-joining portion between them, the outside is generated. Due to the heat applied at the time of mounting on a circuit, a crack may be generated in the mold resin, which has an adverse effect such as causing breakage of a wire inside, and has a problem of reducing the reliability as a semiconductor device.

In Patent Document 1, in order to improve the adhesion between the mold resin and the printed wiring board, the surface of the printed wiring board is roughened by forming a large number of fine irregularities in the area sealed with the mold resin, Techniques have been described to improve the adhesion with the mold resin.
In the technique described in this patent document 1, a resin layer such as epoxy or polyimide is formed in a region where a mold resin of a printed wiring board is formed, and a large number of irregularities are formed in the resin layer to form a resin layer and a mold. Although the adhesion with the resin is improved, the adhesion between the resin layer and the printed wiring board is considered to be equivalent to the adhesion between the conventional mold resin and the printed wiring board.

Further, Patent Document 2 discloses a technique of forming a concave portion filled with a mold resin in a part of an electric circuit on the surface of a printed wiring board in a sealing area with a mold resin.
In this patent document 2, in the via hole forming step by laser processing, the concave portion is simultaneously formed in the region where the mold resin is formed, thereby forming the concave portion to be filled with the mold resin without increasing the number of steps. In the via filling process of the process, the formed recess is filled with a copper plating layer, and the copper plating layer is etched to remove a certain amount to form a recess again, and the recess is filled with a mold resin to obtain adhesion. Technology to improve

  However, this recess is the depth of the recess within the range that can be processed by the etching processing time to form the wiring, and not only the depth formed by laser processing can not be used, but also the metal layer with low adhesion Because of the formation, there is a problem that good adhesion between the mold resin and the printed wiring board can not be obtained.

Japanese Patent Application Publication No. 08-102583 JP, 2015-18934, A

  The present invention has been invented in view of the above-mentioned points, and provides a printed wiring board which improves the adhesion between a mold resin and a printed wiring board and prevents the occurrence of peeling of the mold resin, and a method of manufacturing the same. is there.

A printed wiring board according to the present invention is a printed wiring board having a wiring by a conductor and a semiconductor element mounted on the wiring on the surface of an insulating base material, and these are resin-sealed, and the printed wiring board In the resin-sealed area of the case, there is a recess in which the bottom filled with the mold resin reaches the insulating substrate, and in the recess, the inner wall is a printed surface whose side and bottom excluding the metal layer are the insulating substrate It is a wiring board.
Furthermore, the recess is a manufacturing method in which the conductor wiring is formed by etching and then processed by laser processing, and an opening for forming the recess is formed in part of the wiring when the conductor wiring is formed. It is a manufacturing method of a printed wiring board.

A first invention of the present invention is a printed wiring having on a surface of an insulating base material at least a wiring of a conductor and a semiconductor element mounted and fixed on the wiring, and including a molding resin for sealing the wiring and the semiconductor element It is a board, It is a resin sealing area which is a field in which a mold resin was provided in a printed wiring board, and it is a depth which has a crevice which fills mold resin in a part of the above-mentioned wiring inside a insulating base material. The printed wiring board according to the present invention is characterized in that the side surface of the surface of the recess excluding the conductor in the opening of the recess and the bottom surface of the recess are bare surfaces of the insulating base.

A second invention of the present invention is the method of manufacturing a printed wiring board, wherein the formation of the recess in the first invention is carried out after providing the conductor wiring by etching.

A third invention of the present invention is the method of manufacturing a printed wiring board, wherein the formation of the recess in the second invention is performed by laser processing.

According to a fourth aspect of the present invention, there is provided a printed wiring according to the second and third aspects, wherein the recess opening of the recess is formed in a part of the wiring after providing the wiring of the conductor by etching. It is a manufacturing method of a board.

  According to the present invention, when the recess is provided in the wiring area, the recess provided as the mold resin adhesion reinforcing hole is the recess side surface and the bottom excluding the metal layer of the recess side surface formed by the wiring is the insulating base Since it is comprised from the bare surface, adhesiveness with a printed circuit board can be improved by filling with a mold resin used for resin sealing in a crevice, and generating of exfoliation etc. can be prevented.

It is a fragmentary sectional view explaining an example of a printed wired board provided with a mold resin adhesion strengthening hole concerning the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining the manufacturing process of the printed wiring board of this invention, (a) is sectional drawing of the board | substrate for printed wiring boards which has a conductor layer on front and back of the insulation base material (insulation layer) prepared as a material of a printed wiring board. (B) is a cross-sectional view of a printed wiring board in which a via opening 4a is formed in the conductor layer 2 on the resin sealing side to form the via hole 4, (c) is a via hole along the via opening 4a by laser processing 4D is a cross-sectional view of the printed wiring board on which 4 is formed. (D) is to form a via hole by laser processing, perform via filling processing on the formed via hole, and form a metal layer on the inner wall thereof; (E) is a cross-sectional view of the printed wiring board in which the recess opening 5a is provided in the wiring at the same time when the conductor layer 2, 3 is used as the wiring. Figure , (F) is a sectional view of a printed wiring board bottom surface by laser machining to form a recess having an insulating substrate.

  The present invention relates to a printed wiring board in which a recess for a mold resin adhesion reinforcing hole is formed on a double-sided board provided with conductor layers on the front and back surfaces of an insulating base material and a method for manufacturing the same. It is possible to apply to the outermost layer part of a multilayer laminate.

FIG. 1 is a partial cross-sectional view for explaining an example of a printed wiring board provided with a mold resin adhesion reinforcing hole according to the present invention.
In FIG. 1, 1 is an insulating base (insulation layer), 2 is a conductor layer (wiring) on the resin sealing side, and is hereinafter also referred to as a conductor layer on the surface side, and 3 is a conductor layer (wiring) on the other side Hereinafter, the conductor layer on the back side is referred to as 4 via holes, 5 concave portions (mold resin adhesion reinforcing holes) 6 semiconductor elements, 7 solder, 8 mold resin, 9 resin sealing area, 20 printed wiring It is a board.

  As shown in FIG. 1, the printed wiring board 20 of the present invention is provided with a recess 5 whose bottom surface reaches the insulating base 1 in the resin-sealed area (resin-sealed area 9) of the printed wiring board substrate. The printed wiring board is improved in reliability by enhancing the adhesion between the mold resin 8 used for resin sealing and the printed wiring board.

Although the opening shape (including the size) and depth of the recess 5 which is a mold resin adhesion reinforcing hole are not specified or limited in manufacturing, the adhesion to the mold resin is higher than that of the metal conductor layer. It is preferable that the concave portion 5 is not in a penetrating state, and the concave portion bottom 5b is formed so as to reach the insulating substrate 1 because the insulating base mainly composed of is preferable.
With regard to the opening shape of the recess and the depth of the recess, pressure and heat are applied during resin sealing with a mold resin, so a thickness not broken at the time of sealing is required for the insulating base material as a remaining thickness. Similarly, it is specified in the range where the loss of the insulating base does not occur by the application of external force or thermal stress.

In addition to a commercially available core material and a prepreg, a sheet-like, film-like or semi-hardened liquid resin is used as the insulating base 1.
The resin component is not specified, and an epoxy resin, a phenol resin, a polyimide resin, a fluorine-containing resin, a polyester resin, a polyphenylene oxide resin or the like is used as a single substance or a mixture of a plurality of resins.
Furthermore, various additives and fillers may be prepared, or inorganic fibers such as glass, organic fibers such as polyester resin, polyimide resin and various natural fibers may be used as a reinforcing material.

[Method of manufacturing printed wiring board]
Next, with reference to FIG. 2, a method of manufacturing a printed wiring board according to the present invention will be described.
A printed wiring board substrate 10 provided with conductor layers 2 and 3 on both the front and back sides of the insulating base 1 is prepared (see FIG. 2A).

A predetermined resist mask for forming via openings 4 a for forming via holes (also referred to as via holes) 4 was formed on conductor layer 2.
Next, the via opening 4a was formed in the conductor layer 2 by etching (see FIG. 2 (b)).

Next, after peeling off the resist mask, a via hole 4 was formed by laser processing (see FIG. 2C).
A carbon dioxide gas laser, a UV laser, an excimer laser or the like can be used for this laser processing, but there is no particular specification as long as the resin can be removed. In the example, the conformal method is used, but it is also possible to perform laser processing directly on the opening.

  Next, the inner surface of the formed via hole 4 is plated with copper, and via filling processing is performed so that the conductor layers 2 and 3 on the front and back can be electrically connected (see FIG. 2D).

Next, in order to form the conductor layers 2 and 3 in the necessary wiring pattern, a resist mask (not shown) was formed on the conductor layers 2 and 3 and etching was performed to form the wirings 2 and 3.
The chemical solution used for this etching process is not specified, and may be selected from chemical solutions capable of etching copper such as sulfuric acid-hydrogen peroxide, ferric chloride, cupric chloride and the like.
At the time of this etching process, a part of the wiring 2 formed in the resin-sealed region 9 with the mold resin was formed as a wiring having the recess opening 5a as in the case of forming the via hole (see FIG. 2E).

Next, after peeling off the resist mask, the insulating substrate 1 is dug up by laser processing to form a non-penetrating via hole (having a bottom surface (having a recess bottom 5b) in the insulating substrate 1) of a predetermined depth. Thus, the concave portion 5 filled with the mold resin was formed (see FIG. 2 (f)).
Thereafter, after the semiconductor element is mounted and connected, the resin-sealed region is resin-sealed with a mold resin, and a desired printed wiring board 20 is manufactured.

1 Insulating substrate (Insulating layer)
2 Conductor layer on the front side (wiring)
3 Conductor layer on the other side (wiring)
4 via hole 4 a via opening 5 recess (hole for adhesion to mold resin)
5a recessed portion opening 5b recessed portion bottom 6 semiconductor element 7 solder 8 mold resin 9 resin sealing region 10 printed wiring board substrate 20 printed wiring board

Claims (4)

A printed wiring board comprising on a surface of an insulating base material at least a wiring of a conductor and a semiconductor element mounted and fixed on the wiring, wherein the printed wiring board comprises a mold resin sealing the wiring and the semiconductor element,
In the resin-sealed region which is the region where the mold resin is provided in the printed wiring board, and in a part of the wiring, a concave portion filled with the mold resin has a depth having a concave bottom inside the insulating base Equipped
A printed wiring board, wherein the side surface of the opening of the recess excluding the conductor and the bottom surface of the recess on the surface of the recess are bare surfaces of the insulating base.   The method for manufacturing a printed wiring board according to claim 1, wherein the formation of the recess is performed after providing a conductor wiring by etching.   The method for manufacturing a printed wiring board according to claim 2, wherein the formation of the concave portion is performed by laser processing.   The method for manufacturing a printed wiring board according to claim 2 or 3, wherein the recess opening portion of the recess is formed in a part of the wiring after providing a conductor wiring by etching.

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