JPS5893300A - Method of producing multilayer printed board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for manufacturing a multilayer printed board.

(2) Background of the Technology Multilayer printed boards on which electronic circuit patterns are printed are used in various electronic devices. With the miniaturization of electronic devices and diversification of functions, printed circuit board wiring and! As the density of turns increases, there is a demand for highly reliable multilayer printed circuit boards with superior quality such as cut-off of glue and distortion of i4 turns.

(3) Prior Art and Problems FIG. 1 shows a cross-sectional view of a two-layer printed board manufactured by a conventional multilayer printed board manufacturing method. In conventional manufacturing methods,
First, a first conductive pattern layer 2 is printed on a substrate 1, and then an insulating layer 3 is formed. Subsequently, a second conductor pattern layer 4 electrically connected to the first conductor/gut pattern layer 2 is printed on the insulating layer 3 by IM to an appropriate extent. In such a conventional method, unevenness is formed on the surface of the insulating layer 3 according to the shape of the first conductor or the turn latch 2, so that the i22 conductive pattern layer 4
Printing was not done uniformly, and the conductor pattern that should be formed continuously was cut off in the four parts of the insulating layer 3, and the thickness of the pattern was not equal between the convex parts. In addition, the problem of erroneous contact with the adjacent pattern occurs because the no.e-turn printed on the convex portion becomes thicker, and the problem arises that the signal transmission characteristics of the trench cannot be obtained.

(4) Purpose of the Invention The present invention addresses the drawbacks of the above-mentioned prior art, and addresses the problem of pattern breakage in a single-layer conductor pattern, T1 depth, and thickness of the pattern due to unevenness on the surface of the insulating layer. The disparity of -
The purpose of the present invention is to provide a method for manufacturing a multilayer printed board that can form a highly reliable conductor pattern by eliminating such problems.

(5) Structure of the Invention In order to achieve this object, the present invention provides a method for manufacturing a multilayer cylinder board in which at least two conductor pattern layers are laminated on a substrate with an insulating layer interposed therebetween, in which the conductor pattern is formed on layers other than the top layer. The method is characterized in that it includes a step of later covering a portion other than the conductor pattern forming portion with an insulating layer having the same thickness as the conductor pattern.

(6) Embodiments of the Invention Fig. 2 is a cross-sectional view of a two-layer printed board manufactured by the method of the present invention, and Figs. 3 to 7 show printed boards in different steps of the method of the present invention. It is a top view shown in order.

A first conductor pattern layer 11 is formed by screen printing on a substrate 10 made of an enameled material obtained by enameling a ceramic, iron, or aluminum substrate with an insulating material such as glass.
(Figure 3). 1st. After drying the conductive pattern layer 11 or after drying and baking, this first conductive pattern layer 11
The negative pattern (3), that is, the part outside the 14th body pattern layer 11 bt is printed with an insulating paste to form an insulating layer 12 (FIG. 4).
. Such a screen printing mask with a negative pattern can be easily made using a mask film having the first conductor or turn layer.

The mesh 71 of the screen, the material of the insulating paste, the number of times of printing, etc. are appropriately selected so that the thickness of the insulating layer 12 is the same as the thickness of the first conductor nozzle layer 11.

After firing this insulating layer 12, a conductive layer 13 for conduction between conductor layers is formed on the land of the fourteenth body turn layer 11 by screen printing (FIG. 5). Subsequently, in the same way as the insulating layer 12 shown in FIG. 4, an insulating layer 14 of the negative turns of the conductive layer 13 is formed by screen printing using an insulating paste (FIG. 6). Subsequently, this insulating layer 14
A second conductor four-turn layer 15 is formed thereon by screen printing. This insulating layer 12.14 is the negative node of 11.13? '#E explained as a turn, iZ turn width of 11.13, 12.14 for the conduction hole diameter mfkX 0.
It may be configured to be approximately 2 ruts larger, in which case it is possible to prevent the land diameter and pattern width from becoming smaller due to inflow during printing of the insulating layer 12° (4) 14.

A multilayer printed board having three or more layers may be constructed by further repeating the process of laminating the conductor pattern layers as described above. Further, the order of the process of forming the conductive layer 13 shown in FIG. 3 and the process of forming the insulating layer 14 shown in FIG. 4 may be reversed.

(7) As described in detail of the invention, in the method for manufacturing a multilayer printed board according to the present invention, after forming the lower layer conductor mother turn 11, the portion other than the conductor pattern forming portion is removed from the conductor pattern 1.
By covering with an insulating layer 12 having the same thickness as 1, the heights of the surface of the conductor pattern and the surface of the surrounding insulating layer are made equal. Therefore, the insulating layer 14 provided on the conductor pattern layer 11 is formed flat as shown in FIG. 2, and does not have an uneven surface as in the conventional case. Therefore, this insulating layer 14
The upper conductor/lean layer 15 is a highly reliable multilayer printed board with uniform and excellent quality wiring without causing turn breakage, distortion of turns, uneven pattern thickness, etc. is obtained.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a multilayer printed board manufactured by the conventional method 1-7, Fig. 2 is a sectional view of a multilayer printed board manufactured by the method of the present invention, and Figs. FIG. 3 is a plan view sequentially showing printed boards in different steps. 10... Substrate, 11... First conductor pattern layer, 12
゜14... Insulating layer, 15... Second conductor pattern layer. Patent applicant: Fujitsu Limited Patent application agent: Akira Aoki, patent attorney: Kazuyuki Nishidate, patent attorney: Yukio Uchida, patent attorney: Akira Yamaguchi

Claims (1)

[Claims] ■Insulate at least two layers of conductor/thousand turns on the board N
A method for manufacturing a multilayer printed board laminated via i, including a step of covering a portion other than the conductor pattern forming portion with an insulating layer having the same thickness as the conductor or turn after forming a conductor pattern on a layer other than the top layer. A method for manufacturing a multilayer printed board characterized by: