JPS61230394A - Manufacture of multilayer printed circuit board using heatproof base material - 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 [Industrial Field of Application] The present invention relates to a method for manufacturing a multilayer printed circuit board using a heat-resistant base material.

[Conventional technology]

Conventionally, the manufacturing method for multilayer printed circuit boards using heat-resistant base materials involves stacking multiple outer layer materials and inner layer materials on which logical patterns are formed, sandwiching adhesives such as bonding films, and integrating them under pressure. This is what I did. Furthermore, logic patterns that require conduction between layers are electrically connected using through holes.

However, in order to take advantage of the electrical properties of the base material, bonding only through holes is insufficient), and it is necessary to directly bond the logic patterns to reduce electrical loss.

In order to improve this problem, there is a method of directly joining the logical patterns of each layer.

A method is used in which solder is coated on the necessary logical patterns of a double-sided printed circuit board, one combination is positioned, and then the solder is reflowed while applying an appropriate pressure to join the parts.

In this manufacturing method, in the solder coating process, large variations occur in the solder film thickness due to differences in the surface area of the logic pattern on one side of the board and the copper foil on the other side, and therefore, in the solder reflow process, Solder often overflows from the top of the logic pattern to the side, causing short circuits with other logic patterns and impairing electrical characteristics, which is a major drawback in the production of multilayer printed circuit boards.

Therefore, creating a stable manufacturing method for multilayer substrates using heat-resistant substrates will cut into limited applications.
It is something that opens things up and contributes to technological development.

[Problem that the invention seeks to solve]

This invention was made for the purpose of improving the technical problems related to the above-mentioned manufacturing method. An object of the present invention is to provide a manufacturing method in which electrical characteristics are not impaired even when exposed to heat.

[Means for solving problems]

As a result of extensive research, the method of manufacturing a multilayer printed circuit board using a heat-resistant base material according to the present invention has been developed so that when coating with solder, the surface area of one side of the base material and the other side of the base material are the same. It is characterized in that a portion of the copper foil on the side with a relatively large surface area is removed and solder coated, and a heat-resistant insulating material is provided around the logical pattern on one side of the base material. .

The present invention will be explained in more detail below.The method for manufacturing a multilayer printed circuit board using the heat-resistant base material of the present invention first involves a necessary hole drilling process, a through-hole plating process, and a developing process, and then an etching process. A logical pattern is formed on one side of the base material, and unnecessary steel foil is removed from the other side of the base material so that the surface area on both sides is the same.

9. Next, in the method of manufacturing a multilayer printed circuit board using a heat-resistant base material of the present invention, after forming a logic pattern on the base material and removing unnecessary copper foil, the logic pattern on one side of the base material is coated with solder. A frame made of heat-resistant insulator is provided around the patterned area.

Such a method is preferably a screen printing method◎ [Function] In this invention, one side of the base material is made the same as the other side during solder coating, so variation in solder thickness is suppressed. It is possible to prevent melted solder from flowing out.

Even in the unlikely event that solder leaks, a heat-resistant insulator is provided around the logic patterns, which prevents the logic patterns from shorting out and damaging electrical characteristics due to melted solder flowing out.

〔Example〕

The present invention will be explained in more detail below with reference to Examples.

FIG. 1 is a diagram showing an embodiment according to the present invention.

FIG. 1(a) shows the signal pattern plane, and FIG. 1(b) shows the ground plane B.

In the figure, (1) is a Teflon base material, (2) is a copper foil pattern that does not require soldering, (3) is a pattern that requires solder, and (4) is a through hole. After making p9Ti holes, a plating film is attached to the holes by a conventional method. Then, after developing a desired pattern on the Teflon substrate (1) using a desired film, unnecessary copper foil is removed. At this time, base material (1)
A signal pattern surface (a) is formed on one side of the base material, and a pattern (b) with unnecessary copper foil removed is formed on the other surface of the base material, so that the surfaces of both sides of the base material are almost the same. That's what I do.

Then, a resist film is attached to the copper foil pattern (2) that does not require solder, and the pattern (3) that requires solder is attached.
After applying the required plating pre-treatment in the same state, solder is coated. 5).

Figure 2 is a diagram showing an assembly diagram of a multilayer printed circuit board. Figure 2 (a) is a diagram showing a cross section of a double-sided printed board using a heat-resistant base material, and Figure 2 (b) is a diagram showing a cross-section of a double-sided printed board using a heat-resistant base material. FIG. 2 is a diagram showing a cross section of a multilayer printed circuit board using the material.

In the figure, (Pt). (p, ), (Pg) are double-sided printed boards using a heat-resistant base material, -(Lt),
(LJ, (Ls), (L4), (Lρ, (L
is the circuit layer.

Combination of double-sided printed board (P+), (P public), (P3).

A state in which a six-layer multilayer printed circuit board is manufactured by reflowing the solder and joining pattern (3) with appropriate pressure and temperature after positioning the pattern (3) that requires solder. shows.

At this time, the heat-resistant insulator (5) is on top, so that either -(Ls) or (1,) may be on top.
It is located on the bottom.

Moreover, the solder of pattern (3) of (L and (Ls)) is melted, and PI and P are directly joined on pattern (3).

At this time, even if the molten solder (6) flows from the pattern (3), it is blocked by the heat-resistant insulating material (5), and the molten solder (6) flows from the same song in the pattern (3). This prevents it from flowing out and short circuiting with pattern (2).

This prevents variations in solder film thickness.

This is a double preventive measure that prevents melted solder from flowing out and prevents seepage.

〔Effect of the invention〕

As explained above, this invention is designed to obtain the strength necessary for adhesion of a multilayer board when coating with solder.
By making the surface area of one side and the other side of a double-sided printed circuit board equal, variations in solder film thickness are suppressed.
This has the effect of preventing molten solder from flowing out, and even if molten solder should flow out, the heat-resistant insulator prevents short circuits between patterns.

Due to this effect, electrical characteristics are not impaired.

The additional effect of stabilizing the manufacturing process can also be expected.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment according to the present invention. @1 Figure (a) is a diagram showing the signal pattern drawing, g1 (b)
) is a diagram showing the ground plane B, FIG. 2 is a diagram showing an assembly diagram of a multilayer printed circuit board, and FIG. 2(a) is a diagram showing a cross section of a double-sided printed board using a heat-resistant base material. FIG. 2(b) is a diagram showing a cross section of a multilayer printed circuit board using a Fi heat-resistant base material. In the figure, (1) is a Teflon base material, (2) is a copper foil pattern that does not require soldering, (3) is a pattern that requires soldering, (4) is a through hole, and (5) is a heat-resistant insulator. The proposition,
1b) Molten solder overflowing from the ri pattern.

Claims (2)

[Claims] (1) A logic pattern is formed on one side of a heat-resistant base material, and the other side is coated with solder on the logic pattern and copper foil on the substrate with copper foil as it is for the outer layer and inner layer. In a method of manufacturing a multilayer printed circuit board using solder reflow by combining two double-sided printed circuit boards, when coating with solder, a part of the copper foil on the other side of the base material is removed, and one side of the double-sided printed circuit board is coated with solder. 1. A method for manufacturing a multilayer printed circuit board using a heat-resistant base material, characterized in that the solder coating is applied so that the surface area of one side and the other side are the same. (2) After forming a logic pattern on one side of the base material and coating it with solder, provide a frame made of heat-resistant insulator around the logic pattern to join the predetermined logic patterns while preventing solder from flowing out. A method for manufacturing a multilayer printed circuit board using a heat-resistant base material according to claim (1).