JPH02230797A - Multilayer type printed wiring board - Google Patents

Abstract

PURPOSE:To comparatively easily keep electric insulation for an inner layer circuit pattern layer positioned on the lower side of the bottom of a formed non-penetrating hole, by constituting a multilayer type printed wiring board in the manner in which an inner layer insulator layer in the region correspond ing with the bottom part of the non-penetrating hole to be formed is partly thickened. CONSTITUTION:In order to connect a circuit pattern layer 1a with an electrically connected inner layer circuit pattern 1c, e.g. a third layer circuit pattern 1b, a non-penetrating hole 2 is formed by drill working or the like. The thickness of an inner layer insulator layer 3' of a region corresponding with the bottom part of the non-penetrating hole, that is, the inner layer insulator layer 3' inter posed between the above mentioned third layer circuit pattern layer 1b and the next circuit pattern 1c' is previously constituted so as to be partly thick. As a result, even when there exsist some deviations in the depths of the formed non-penetrating holes 2, electric insulation for the next stage circuit pattern layer 1c' is not damaged.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a multilayer printed wiring board, in particular a multilayer printed wiring board in which a non-through hole for electrical connection, for example, is formed from one main surface side. The present invention relates to a multilayer printed wiring board.

(Prior Art) As is well known, multilayer printed wiring boards are being developed for the purpose of downsizing circuits or circuit components. In other words, by having a predetermined circuit pattern layer on one or both surfaces and arranging the required inner circuit pattern layer in multiple layers with an insulating layer interposed between the two surfaces (both main surfaces), the wiring density can be increased. The circuit itself and circuit components are becoming more compact. However, in this multilayer printed wiring board, due to the promotion of multilayering, compactness, or higher wiring density, a structure in which a thin insulator layer is disposed between the inner circuit pattern layers has been adopted. It's coming. Furthermore, in this type of multilayer printed wiring board, as schematically shown in FIG. 3, in order to connect the circuit pattern W1a on one main surface to, for example, the third inner circuit pattern layer 1b, A non-penetrating hole 2 is formed by drilling, and both circuit pattern layers 1a. It is often used by electrically connecting between lbs. In addition, in Figure 3,
1c is another inner circuit pattern layer forming the multilayer circuit pattern layer, 3 is an insulator layer interposed between the multilayer circuit pattern layers, and 4 is an insulating layer provided on the inner wall surface of the non-through hole 2 to connect between the circuit pattern layers 1a and lb. A conductor layer formed by plating to form an adhesive layer for electrical connection.

(Problems to be Solved by the Invention) However, the multilayer printed wiring board having the above structure has the following disadvantages. That is, as described above, for example, the circuit pattern layer 1a. Even if considerable care is taken when forming the required non-through hole 2 by drilling in order to electrically connect between lbs. It is practically difficult to accurately control the position of the inner circuit pattern layer 1 next to the inner circuit pattern layer 1b, as shown in FIG.
It is often not possible to maintain sufficient electrical insulation between C and the conductor layer 4 provided on the inner wall surface (bottom) of the non-through hole 2, which poses a problem in terms of reliability.

[Structure of the Invention] (Means for Solving the Problems) The present invention has been made in response to the above-mentioned circumstances, and consists of required circuit pattern layers being integrally stacked via an insulating layer, and In a multilayer printed wiring board in which a non-through hole is formed from one main surface side, the inner insulating layer is partially thickened in a region corresponding to the bottom of the non-through hole to be formed. This is the basic outline.

(Effect) As above. In the multilayer printed wiring board according to the present invention, the inner insulating layer is partially thickened in a region corresponding to the bottom of the non-through hole to be formed. Therefore, even when the non-through hole is formed by drilling, it is relatively easy to maintain electrical insulation between the inner circuit pattern layer located below the bottom of the formed non-through hole. Become.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view schematically showing the main parts of a multilayer printed wiring board according to the present invention, where la is a circuit pattern layer on one main surface, and b is a circuit pattern layer on the main surface. an inner circuit pattern layer electrically connected to 1a;
C is another circuit pattern layer forming the multilayer circuit pattern layer, 3 is the multilayer circuit pattern layer (la. lb, l
c) an insulating layer interposed between them. by the way,
In the multilayer printed wiring board according to the present invention, in order to connect the inner circuit pattern layer 1c electrically connected to the circuit pattern layer 1a, for example, to the third circuit pattern layer 1b, a non-contact structure is formed by drilling or the like. The inner insulating layer 3° in the area where the through hole 2 is formed and corresponding to the bottom of the non-through hole, that is, the third circuit pattern layer 1b.
The inner insulating layer 3° interposed between the circuit pattern layer 1c' and the next circuit pattern layer 1c' is partially thickened in advance. However, the multilayer printed wiring board with the above configuration,
Depending on the position and number of the required non-through holes 2 formed by drilling etc., and the depth of the required non-through holes 2, the corresponding portions of the inner insulating layer 3'' are formed. It can be manufactured by a normal method for manufacturing multilayer printed wiring boards, except that the thickness is selectively increased.

In the multilayer printed wiring board configured as described above, even when the required non-through holes 2 are formed, the corresponding portions of the inner insulating layer 3 are selectively thickened, so that the formed non-through holes 2 are thickened selectively. Even if there is a slight deviation in the depth (bottom position) of the through hole 2, the electrical insulation between it and the next (next stage) circuit pattern layer 1c' will not be easily impaired (it will ensure that the required insulation is maintained). - Therefore, even when the two circuit pattern layers 1a and lb are electrically connected via the formed non-through hole 2, for example, by the conductor layer 4 formed by plating, it can be put into practical use with peace of mind. You will get it.

[Effects of the Invention] As described above, the multilayer printed wiring board according to the present invention has the following effects:
The inner insulating layer is partially thickened in a region corresponding to the bottom of the non-through hole to be formed. Therefore, even when the non-through hole is formed by drilling, the electrical insulation between the inner circuit pattern layer located below the bottom of the formed non-through hole is easily and reliably maintained. Shitsuru. In other words, even if a non-through hole is formed and a conductive layer is placed on the inner wall surface of the non-through hole to make an electrical connection with the required inner layer circuit pattern, a highly reliable recessed path or circuit component can be achieved. can be configured.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view schematically showing a configuration example of a multilayer printed wiring board according to the present invention, and FIG. Fig. 3 is a cross-sectional view showing a state in which a conductive layer is disposed on a wall surface, and Fig. 3 is a cross-sectional view showing a state in which a non-through hole is formed in a conventional multilayer printed wiring board and a conductive layer is disposed on the inner wall surface. be. 1a...Surface circuit pattern layer 1b...Inner layer circuit pattern l corresponding to the bottom of the non-through hole
c...Inner circuit pattern layer 2...Non-through hole 3...Inner insulator layer 3'...Inner insulator layer 4 corresponding to the bottom of the non-through hole...
・Applicant for conductor layer connected to inner layer circuit pattern
Toshiba Corporation Agent Patent Attorney Saichi Suyama

Claims (1)

[Scope of Claims] A multilayer printed wiring board in which required circuit pattern layers are integrally stacked with an insulating layer interposed therebetween, and a non-penetrating hole is formed from one main surface side. A multilayer printed wiring board, wherein the inner insulating layer in a region corresponding to the bottom of the formed non-through hole is partially thickened.