JP2810604B2 - Manufacturing method of multilayer printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a plastic multilayer printed wiring board for high-density wiring.

[0002]

2. Description of the Related Art A multilayer printed wiring board is provided for the purpose of high-density wiring, and is manufactured, for example, as shown in FIG. First, as shown in FIG. 6 (a), a printed circuit board 17 formed by providing circuits 15 on both sides and conductingly connecting the circuits 15 on both sides by through holes 16 is superimposed via a prepreg 18 and further printed wiring boards. A metal foil 19 such as a copper foil is laid over the outside of the prepreg 17 via a prepreg 18, and the prepreg 18 is heated and pressed to form a laminate, as shown in FIG.
The printed wiring board 17 and the metal foil 19 are laminated and integrated by the insulating adhesive layer 18a formed by the above method to form a multilayer board 20, and through holes 21 penetrating through the multilayer board 20 from front to back.
Is provided by drilling or the like, and the inner periphery of the through hole 21 is plated with a through hole 22.
The circuit 23 is formed by performing a printing process such as an etching process on the printed circuit board 17 so that the circuit 15 of the inner layer and the circuit 23 of the outer layer provided on the printed wiring board 17 are electrically connected by the through hole 21 as shown in FIG. A connected multilayer printed wiring board can be manufactured.

As described above, the printed wiring board 17 and the metal foil 1
In addition to the method of producing a multilayer printed wiring board by laminating and molding the same, a circuit of the first layer is formed by printing a metal foil on one side using a double-sided metal foil-clad laminate.
A first photosensitive insulating layer is laminated on the circuit of the layer, a photo via hole is opened, and a metal plating such as copper plating is performed on the first photosensitive insulating layer by chemical plating or the like. Metal plating is printed to form a second layer circuit, and a second layer of photosensitive insulating layer is laminated on the second layer circuit to form a photovia hole, and then penetrate both sides. A method of manufacturing a multilayer printed wiring board in which a plurality of circuits are provided by drilling through holes and performing metal plating such as copper plating by chemical plating or the like has also been proposed.

[0004]

However, in the former method, the circuit in the inner layer and the circuit in the outer layer are electrically connected by through holes provided on the front and back surfaces. A large number is required, and as a result, there is a problem that the wiring density and the mounting density are reduced.

In the latter method, since the circuit is formed by an additive method of forming the circuit by metal plating, there is a problem that the adhesive strength of the circuit is low and the reliability of the circuit is low. The present invention has been made in view of the above points, and has as its object to provide a multilayer printed wiring board that can reduce the number of through holes and does not reduce the reliability of a circuit. It is.

[0006]

A first method of manufacturing a multilayer printed wiring board according to the present invention is a method for manufacturing a circuit of a printed wiring board 1.
The surface of the bottom portion of the non-penetrating via hole 6
After the application, the prepreg 4 provided with the through-hole 3 and the metal foil 5 provided with the through-hole 3 are superimposed on the surface of the printed wiring board 1 on which the circuit 2 is formed, with the two through-holes 3 aligned in this order. This is heated and pressed to form a prepreg 4 on the printed wiring board 1.
A metal foil 5 is laminated through the prepreg 4 and a through hole 3 of the metal foil 5 forms a non-penetrating via hole 6 in which the circuit 2 of the printed wiring board 1 becomes a bottom. The circuit 8 is formed by plating 7 and printing the metal foil 5.
That the composed and the circuit 2 of the printed wiring board 1 and electrically connected by non-through via hole 6 is characterized in.

[0007] The second method for manufacturing a multilayer printed wiring board according to the present invention, the non-through-bi of the circuit 2 of the printed wiring board 1
Gold plating was applied to the surface of the bottom of the hole 6
Thereafter, a prepreg 4 having a through-hole 3 provided on the surface of the printed wiring board 1 on which the circuit 2 is formed and a laminated board 9 having a metal foil 5 provided on the outer surface thereof and having the through-hole 3 are combined with each other. The laminates 9 are stacked in this order, and are heated and pressed to form a laminate 9 on the printed wiring board 1 via the prepreg 4, and the circuit 2 of the printed wiring board 1 becomes the bottom by the through holes 3 of the prepreg 4 and the laminate 9. A circuit 8 is formed by forming a non-penetrating via hole 6, applying a through-hole plating 7 to the inner periphery of the non-penetrating via hole 6 and printing the metal foil 5 of the laminated board 9. The above circuit 2 of 1
Are electrically connected to each other by a non-penetrating via hole 6.

[0008]

The circuit 2 of the printed wiring board 1 serving as the inner layer circuit and the circuit 8 serving as the outer layer circuit formed from the metal foil 5 are electrically connected to each other through a non-penetrating via hole 6. There is no need to use a large number of through holes. Since subjected to gold plating on the surface of the areas of the bottom of the blind via hole 6 of the circuit 2 of the printed wiring board 1,
The gold plating serves as a resist layer of the circuit 2 of the printed wiring board 1 so that the etching solution used in the printing process for forming the circuit 8 does not act on the circuit 2 of the printed wiring board 1 through the non-penetrating via hole 6. it can.

[0009]

The present invention will be described below in detail with reference to examples. FIG.
Shows an embodiment of the first manufacturing method of the present invention. The printed wiring board 1 uses an epoxy resin laminated board or the like in which a metal foil such as a copper foil is stretched on both sides, and a circuit 2 is provided on one side thereof.
And the other side is formed as a metal foil 25. Then, a metal foil 5 is overlaid on the surface of the printed wiring board 1 on which the circuit 2 is formed via a prepreg 4 as shown in FIG. The prepreg 4 may be a material prepared by impregnating a base material such as a glass cloth with a thermosetting resin such as an epoxy resin and drying. The prepreg 4 has through holes 3 at a plurality of locations. It is provided. Copper foil or the like can be used as the metal foil 5, and the through hole 3 is provided at the same location as the location provided on the prepreg 4. The prepreg 4 and the metal foil 5 are stacked on the printed wiring board 1 in a state where the through holes 3 of the prepreg 4 and the metal foil 5 are aligned.

As described above, the prepreg 4 and the metal foil 5 are stacked on the printed wiring board 1 in this order, and then heated and pressed to form a laminate, thereby forming the prepreg 4 as shown in FIG. The metal foil 5 can be laminated on the printed wiring board 1 with the insulating adhesive layer 4a. In stacking in this manner, the prepreg 4 and the through hole 3 of the metal foil 5 form an unpenetrated via hole 6 having the circuit 2 of the printed wiring board 1 as a bottom surface. Here, of the circuit 2 of the printed wiring board 1, gold plating is applied to the surface of the portion to be the bottom surface of the non-penetrating via hole 6.
Put .

As described above, the metal foil 5 is formed on the printed wiring board 1.
Then, the circuit 8 is formed by performing electroless plating or electrolytic plating to apply through-hole plating 7 to the inner periphery of the non-penetrating via hole 6, and then performing printing such as etching on the metal foil 5. Thus, the printed wiring board 1
A multilayer printed wiring board as shown in FIG. 1C having the circuit 2 serving as an inner layer circuit and the circuit 8 serving as an outer layer circuit provided on the printed wiring board 1 can be formed. 25 may be printed at the same time to form the circuit 26. And the printed wiring board 1
The circuit 2 serving as the inner layer circuit is electrically connected to the circuit 8 serving as the outer layer circuit through the through-hole plating 7.
The non-penetrating via hole 6 can be led out to the surface of the multilayer printed wiring board. Here, when the circuit 8 is formed by performing a printing process such as etching on the metal foil 5, the etchant acts on the circuit 2 of the printed wiring board 1 through the non-penetrating via hole 6. Since the surface of the bottom portion of the through via hole 6 is plated with gold as described above, there is no possibility that the gold plating becomes a resist layer and the circuit 2 is attacked by the etching solution. Therefore, it is not necessary to cover the non-penetrating via hole 6 with the etching resist when performing the etching.

Next, if necessary, a prepreg 4 provided with a through hole 3 and a metal foil 5 are stacked on the printed wiring board 1 in the same manner as described above, and heated and pressed to form a metal as shown in FIG. After laminating the foil 5 and forming the non-penetrating via hole 6, and forming a through-hole 27 penetrating on the front and back sides by drilling or the like, the through-hole plating 7 is applied to the inner periphery of the non-penetrating via hole 6, and the inner periphery of the through-hole 27 is formed. Through-hole plating 2
8 and print processing such as etching on the metal foil 5 to form the circuit 8, a multilayer printed wiring board having a four-layer circuit configuration as shown in FIG. 1 (e) can be produced. In this multilayer printed wiring board, the inner circuit 2 provided on the printed wiring board 1 is electrically connected to the outer layer circuit 8 through a non-through through hole, so that a through hole for conducting the circuits 2 and 8 is provided. 2
It is not necessary to provide a large number 7 through the front and back.

FIG. 2 shows another embodiment of the present invention. In this embodiment, a multilayer printed wiring board 1a having a multilayer circuit 2 is used as a printed wiring board 1.
It is designed to be made as a multilayer printed wiring board having a six-layer circuit configuration. FIG. 3 shows an embodiment of the second manufacturing method of the present invention. As shown in FIG. 3A, a prepreg 4 having a through hole 3 in a printed wiring board 1 and a laminate having a through hole 3 are provided. The plate 9 is overlapped. As the laminate 9, an epoxy resin laminate or the like in which a metal foil 5 such as a copper foil is laminated on the outside can be used, and the prepreg 4 is attached to the printed wiring board 1 with the through holes 3 aligned and aligned.
After laminating the laminated board 9 in this order, the laminated board 9 can be laminated on the printed wiring board 1 by performing heat and pressure molding and laminating. In performing such lamination, the prepreg 4 and The non-penetrating via hole 6 having the bottom surface of the circuit 2 of the printed wiring board 1 is formed by the through hole 3 of the laminated board 9. Then, after forming through holes 27 penetrating on the front and back sides by drilling or the like, a through hole plating 7 is applied to the inner periphery of the unpenetrated via hole 6, and a through hole plating 28 is applied to the inner periphery of the through hole 27. The circuit 8 is formed by performing a printing process such as etching on the metal foil 5 of FIG.
A multilayer printed wiring board can be produced as shown in FIG. In the embodiment shown in FIG.
Are used in a multilayer printed wiring board 1a.

FIG. 4 shows an example of a semiconductor device using a multilayer printed wiring board prepared according to the present invention as a package substrate A. In this embodiment, a concave portion 30 is provided on the lower surface of the package substrate A to form a concave portion. A semiconductor chip 31 such as an IC chip is mounted in the place 30, and the circuits 2, 8 and the semiconductor chip 31 are connected by wire bonding 32, and furthermore, the leads 33 of the lead frame are connected to the circuit 2. It is designed to be formed as a device.

In the embodiment shown in FIG. 5, an opening 34 is provided in the package substrate A so as to penetrate the package substrate A from front to back.
Is covered with a heat radiating plate 35 such as a metal plate, the semiconductor chip 31 is mounted in the opening 34 by bonding to the heat radiating plate 35, and the circuits 2, 8 and the semiconductor chip 31 are connected by wire bonding 32. By inserting the base of the terminal 36 into the through hole 27 and attaching the terminal pins 36 so as to protrude from the package substrate A, a PGA type semiconductor device is formed.

[0016]

As described above, according to the present invention, a prepreg provided with a through-hole and a metal foil provided with a through-hole are superimposed in this order on the surface of the printed wiring board on which the circuit is formed, with both the through-holes aligned. This is heated and pressed to form a metal foil on the printed wiring board via the prepreg, and a non-penetrating via hole in which the circuit of the printed wiring board is formed by the through hole of the prepreg and the metal foil is formed. A circuit is formed by applying through-hole plating to the inner periphery and printing the above metal foil to form a circuit, and the circuit and the circuit of the printed wiring board are electrically connected by a non-penetrating via hole, so that an inner layer circuit is formed. The circuit of the printed wiring board and the circuit that is the outer layer circuit made of metal foil are electrically connected by non-through via holes, and the circuit of the printed wiring board is drawn to the surface. Are those necessary to use a large number of through holes is not necessary to penetrate the front and back Sutame. Further, since the circuit can be formed by laminating the metal foils and printing as described above, the reliability of the circuit does not decrease as in the case of the additive method in which the circuit is formed by metal plating.

In addition, instead of laminating a prepreg having a through hole and a metal foil on a printed wiring board by laminating them, a prepreg having a through hole and a laminated plate having a metal foil provided on the outer surface and having a through hole are provided. Even when the printed circuit board is laminated with the both through holes aligned, the circuit of the printed circuit board that is also the inner layer circuit and the circuit that is the outer layer circuit made of metal foil are electrically connected with the non-through via hole And the same effect can be obtained. Since further subjected to gold plating on the surface of the blind become the bottom portion of the via hole of the circuit of the printed wiring board, the gold plating is a resist layer of a circuit of a printed wiring board, the etching solution used in the printing process for forming the circuit Can be prevented from acting on the circuit of the printed wiring board through the unpenetrated via hole, the circuit can be prevented from being attacked by the etchant, and it is not necessary to cover the nonpenetrated via hole with an etching resist when performing etching. It is.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a first manufacturing method of the present invention, and (a) to (e) are cross-sectional views, respectively.

FIG. 2 is a sectional view of another embodiment of the above.

FIG. 3 shows one embodiment of the second manufacturing method of the present invention, and (a) and (b) are cross-sectional views.

FIG. 4 shows a QF using a multilayer printed wiring board according to the present invention.
It is sectional drawing of a P-type semiconductor device.

FIG. 5 shows a PG using the multilayer printed wiring board according to the present invention.
It is sectional drawing of an A-type semiconductor device.

FIG. 6 shows a conventional example, and (a) to (c) are cross-sectional views, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed wiring board 2 Circuit 3 Through hole 4 Prepreg 5 Metal foil 6 Non-through via hole 7 Through-hole plating 8 Circuit 9 Laminate board

Claims (2)

(57) [Claims] 1. A non-penetrating via hole for a circuit of a printed wiring board.
After applying gold plating to the surface of the part that will become the bottom of the ル le, the prepreg with the through hole and the metal foil with the through hole are aligned on the surface where the circuit of the printed wiring board is formed Laminate and press-mold this to laminate the metal foil on the printed wiring board via the prepreg, and form a non-penetrating via hole where the circuit of the printed wiring board becomes the bottom by the through hole of the prepreg and the metal foil, and the non-penetration A circuit is formed by plating the metal foil and printing the above metal foil on the inner periphery of the via hole, and this circuit and the above circuit of the printed wiring board are electrically connected by a non-through via hole.
A method for manufacturing a multilayer printed wiring board, characterized by comprising: 2. A non-penetrating via hole for a circuit of a printed wiring board.
After applying gold plating to the surface of the bottom part of the metal plate, penetrate both the prepreg with a through hole on the surface where the circuit of the printed wiring board is formed and the laminated plate with metal foil on the outer surface and the through hole Align the holes, stack them in this order, heat and press mold them, laminate the laminated board on the printed wiring board via the prepreg, and make the circuit of the printed wiring board the bottom by the through hole of the prepreg and the laminated board. To form
A circuit is formed by applying through-hole plating to the inner periphery of the unpenetrated via hole and printing the metal foil of the laminated board to form a circuit, and this circuit and the circuit of the printed wiring board are electrically connected by the unpenetrated via hole. A method for manufacturing a multilayer printed wiring board, comprising: