JPH0556879B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a multilayer printed wiring board, and in particular, to a method for manufacturing a multilayer printed wiring board, and in particular to a method for manufacturing a multilayer printed wiring board.
The present invention relates to a method for manufacturing a multilayer printed wiring board having holes.

[Conventional technology]

In recent years, the performance and economic needs of electronic devices have led to an increase in the density of packaging.

For this reason, not only are electronic devices such as ICs and LSIs becoming more highly integrated and faster, but printed wiring boards on which these devices are mounted are also becoming more dense.

In conventional printed wiring boards, not only holes for inserting components but also via holes are penetrated, and a conductive layer is generally formed on the inner wall of the hole by plating or the like.

In addition, as multilayer printed wiring boards (hereinafter referred to as multilayer boards) become highly multilayered, some inner layers have inner layer via holes (inner layer via holes).
A design with a via hole is adopted. As one attempt, for example, Japanese Patent Application No. 58-049858 discloses a method for manufacturing a multilayer printed wiring board in which the space inside a blind via hole for connecting a conductive circuit is filled with resin.

This is the through hole 10 as shown in Figure 2.
two laminated plates 1A having a conductive layer on one side and a conductive circuit pattern on the other side,
Laminated board 1 on which a conductor circuit pattern between 1C is formed
b and a prepreg layer 5A sandwiching this laminate 1b,
5B and then heated and pressurized to form a multilayered substrate.

[Problem that the invention seeks to solve]

As a problem in manufacturing the above-mentioned multilayer board, two insulating plates 1A, each having a through hole 4 in the insulating plate and having a conductor circuit pattern formed on only one surface in advance,
1C is placed as the outermost layer, and after stacking the prepreg layers 5A and 5B with one or more insulating plates 1B on the inner side of which a conductor circuit pattern has been formed in advance, a multilayered board is formed by heating and pressurizing. , prepreg seeps out from the through holes 10 in the outermost layer, causing etching defects when forming the desired conductor circuit pattern on the conductor layer on the surface of the multilayer substrate in the subsequent process, reducing manufacturing yield and reliability. There is a problem.

An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board with improved manufacturing yield and reliability.

[Means for solving problems]

The method for manufacturing a multilayer printed wiring board of the present invention includes the steps of forming a conductive circuit pattern on one side of a first insulating plate having through holes and forming a photoresist film on the other side; The conductor circuit patterns of the first insulating plates are arranged as the outermost layer, facing each other, and at least one second insulating plate having the conductor circuit pattern formed inside the second insulating plate, and a prepreg layer sandwiching the second insulating plate. forming a multilayered substrate by stacking them and then heating and pressurizing them; forming a through hole in a predetermined portion of the multilayered substrate after removing the photoresist film on the surface of the multilayered substrate; and forming a through hole in a predetermined portion of the multilayered substrate The method includes the steps of forming a conductor layer on the surface of the multilayer substrate including the inner wall of the substrate, and then patterning the conductor layer to form a conductor circuit pattern.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1a to 1f are cross-sectional views for explaining one embodiment of the present invention.

First, as shown in Figure 1a, copper foil 2A is placed on both sides.
A through hole 4A is formed by a drill in the laminated plate 1A on which the hole 2B is formed.

Next, as shown in FIG. 1b, a conductor layer 6 is formed on the entire surface including the through holes 4A by known electroless plating and electroplating means.

Next, as shown in FIG. 1c, using a well-known tenting method, the entire upper surface and the lower surface are coated with a photosensitive dry film resist film 7 covering the desired circuit pattern portion, and then the upper surface is coated with a dry film resist film 7. The cover film of the film resist film 7 is not removed, and only the lower surface is subjected to development, etching, and peeling steps.
The circuit pattern 11 is formed only on the lower surface.

Next, as shown in FIG. 1d, the laminate 1A on which the dry film resist film 7 and the circuit pattern 11 have been formed and the laminate 1C treated in the same manner as the laminate 1A are placed so that the circuit pattern 11 faces each other. A laminate 1B with a circuit pattern formed on the inside thereof, and a prepreg layer 5 sandwiching this laminate 1B.
After stacking A and 5B, they are heated and pressurized to form an integrated structure, thereby forming the multilayer substrate 1. At this time, the through hole 4A is formed as a so-called non-penetrating blind via hole 4B, and the humidification and
The pressurized prepreg layers 5A and 5B are blocked by the dry film resist film 7 and do not flow to the outside.

Incidentally, it is preferable that the dry film resist film 7 is exposed to light because the strength thereof becomes greater.

Next, as shown in FIG. 1e, after removing the dry film resist film 7, a through hole 3 is formed by drilling a hole for inserting a component or a hole connecting to the inner layer pattern. Next, a conductor layer 6A is formed on the entire surface including the inner wall of the through hole 3 by known electroless plating and electroplating means.

Next, as shown in FIG. 1f, after covering the through hole 3 and the desired circuit pattern portion with a dry film resist using a known tenting method,
Unnecessary conductor layer 6A, underlying conductor layer 6, and copper foils 2A, 2F are etched away to complete a multilayer printed wiring board having blind via holes 4B.

The blind bias obtained in this way
The multilayer printed wiring board with holes has the following effects compared to conventional ones.

(1) When forming the desired circuit pattern on the outermost layer, there is no seepage from the prepreg through-holes, eliminating defects such as etching lumps and improving yield.

(2) Since there is no seepage from prepreg through holes, wiring boards can be formed with uniform lamination pressure.

(3) The outermost photosensitive dry film resist layer plays the role of a cushion between the end plate, which is the pressure medium during lamination, and reduces dent defects, which are poor lamination finishes, and improves yield.

In the above embodiment, a case has been described in which a laminate 1A having copper foil formed on both sides is used, but a laminate without copper foil on the surface covering the dry film resist film 7 may also be used. In this case, a laminated plate with a rough surface on which the dry film resist film is formed is used to facilitate electroless plating. Then, in the step shown in FIG. 1B, a conductor layer is formed on the entire surface of the laminate 1A, including the through holes 4A, by means of electroless plating and electroplating.

〔Effect of the invention〕

As explained above, the present invention forms a photoresist film on the surface of a first insulating plate having through holes, arranges this first insulating film as the outermost layer,
A multilayer printed wiring board with improved manufacturing yield and reliability can be obtained by stacking a prepreg layer and a second insulating plate having a circuit pattern on the inside and heating and pressurizing the prepreg layer to form a multilayer printed wiring board.

[Brief explanation of the drawing]

1A to 1F are cross-sectional views showing the order of manufacturing steps for explaining an embodiment of the present invention, and FIG. 2 is a cross-sectional view for explaining a conventional method for manufacturing a multilayer printed wiring board. 1...Multilayer substrate, 1A to 1C...Laminated board, 2
A to 2F...Copper foil, 3...Through hole, 4A...Through hole, 4B...Blind bias hole,
5A, 5B... prepreg layer, 6, 6A... conductor layer, 7... dry film resist film, 10...
Through hole, 11...Circuit pattern.

Claims (1)

[Claims] 1. Forming a conductive circuit pattern on one side of a first insulating plate having through holes and forming a photoresist film on the other side, and aligning the conductive circuit patterns of the two first insulating plates At least one second insulating board with a conductor circuit pattern formed inside the second insulating board and a prepreg layer sandwiching the second insulating board are stacked, and heated and pressurized to form a multilayer. a step of forming a through hole in a predetermined portion of the multilayer substrate after removing the photoresist film on the surface of the multilayer substrate, and a step of forming a through hole on the surface of the multilayer substrate including the inner wall of the through hole A method for producing a multilayer printed wiring board, comprising the steps of forming a conductor layer and then patterning it to form a conductor circuit pattern.