JPS6088492A - Printed circuit 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] Industrial applications The present invention relates to a semiconductor element, a resistive element, and a capacitive element.

The present invention relates to the structure of a printed wiring board suitable for connecting chip components such as inductance elements by wire bonding technology.

Follower vehicle ω Luha *1. #Punishment T-C [Punishment] In the past, there were some conventional examples of chip-on-board technology, which refers to the state in which chip components are mounted on a printed wiring board. That is, as a first example, as shown in FIG. There is a method in which a foil 5 is bonded and then the conductor portion 5 is selectively etched with copper foil, and the conductor portion 5 is plated with nickel 6 or gold 7, and an aluminum wire is wire-bonded.

As a second example, as shown in FIG. 2, copper foil is directly adhered to the glass cloth base epoxy resin laminate 12, and then gold plating is applied to the selectively etched portions 13 of the copper foil. There are bonded parts 1 and 4 and wire bonding parts.

The problems with these conventional methods are that in the first example, moisture is adsorbed or trapped in the alumite treated perforated parts, lowering the insulation of the board and causing electrical short circuits, and it is difficult to bond together gold wire and aluminum wire. Otherwise, selective etching of copper foil and bath processes during nickel plating are complicated and costly, and residual ionic substances in the bath can contaminate semiconductor chips and shorten their lifespan. There are many things that are likely to happen. Unfortunately, in the second example, because the copper foil was applied directly, the mesh of the glass fiber cloth in the laminate was replicated on the copper foil surface, creating unevenness and hindering the smooth operation of the wire bonding mechanism. Problems include the contamination of the plating bath and the high cost of gold.

OBJECTS OF THE INVENTION The present invention is directed to metal plates, and aims to eliminate the drawbacks of the conventional examples described above and to obtain a simple and economical printed wiring board for wire bonding.

Structure of the Invention As a structure of the present invention, firstly, a flexible insulating resin paste having good affinity with metal is directly printed on a metal plate. f. forming a resin layer; secondly, selectively printing a highly insulating rigid resin paste on the surface of the first resin layer to form a second resin layer; and thirdly, selectively printing the second resin layer. A third resin layer is provided in which a resin paste containing conductive particles is selectively printed in an area that extends beyond the printed surface. The reason why printing technology is used to form each resin layer is to maintain the required printing thickness of 10 to 150 microns with high precision of ±2 to 6 microns. In addition, the printing of the second and third resin layers is 0.00% not only in the thickness direction but also in the horizontal direction.
In order to keep the width tolerance within 1 to 0.1 w, mesh screen plate making technology is effective. Note that the configuration of the present invention includes a first degree, a second degree, and a second degree. After printing each third resin layer, 60
After preheating to ~80°C, there is an accompanying step of curing by heating in air at a temperature of 120-220″C.

DESCRIPTION OF THE EMBODIMENT FIGS. 3 and 4 are cross-sectional views of the embodiments of the present invention. First, an aluminum plate 2 with a thickness of 1 Omm and a size of 60 x 60 is wiped off with an acetone solution to remove dirt, dust, etc. .

Then, on this aluminum plate 22, the 1411th fat layer 2
As 3, viscosity 3 is obtained by adding 60 phr of aromatic amine adduct resin (H-84 manufactured by Nippon Gosei Kako Co., Ltd.) to an epoxy resin (for example, 828, a product name of Shell Oil Co., Ltd.).
Using a 50-void solvent-free resin paste lattetron mesh screen with a thickness of 20±
The first resin layer 23 has a thickness of 14±1μ, and its hardness is 4H or more on a pencil hardness, which prevents warpage in the center of the entire bridge board. It has the flexibility to withstand 10 degrees of deviation, and has an adhesive strength of 1.
It is as high as 6 kg/- at 20°C.

As the second resin layer 24, an epoxy resin (Shell Oil Company 8
Using a solvent-free resin paste with a viscosity of 1100 poise to which 60 phr of aromatic amine duct resin (H-90 manufactured by Nippon Gosei Kogyo Co., Ltd.) was added to 28), Tetron's 160
Selective resist film on mesh screen to thickness 6o±2μ
selectively to a thickness of 35±2μ using
The second resin layer 24 is printed on top of the first resin layer 23 and cured in the atmosphere for 180 minutes at 150'' GK.The thickness of the second resin layer 24 is 24±2μ, the hardness is 6H or more on the pencil hardness, and it is hardened with glass. Although the transition temperature TG is 180°C, the metal plate does not have the flexibility to withstand a warping deviation of 10 mm at the center.

As the third resin layer 26, the average size of flaky silver powder is 1
86% epoxy resin (with a weight ratio of ~6μ)
10o1 (manufactured by Shell Oil Company) and 80 phr of modified acid anhydride (H-106, manufactured by Nippon Gosei Kako Co., Ltd.) as a curing agent was added to the resin paste using a mixer to obtain a viscosity of 16.
Using 0 poise conductive I4 fat paste, selectively print to a thickness of 19±2μ using a Tetron 180 mesh screen with a selective resist film formed to a thickness of 25±2μ and 150″C. Cure in air for 60 minutes.

The third resin layer 26 has a thickness of 14±2μ, a pencil hardness of 8H or more, and a glass transition temperature (Ta) of 210″.
C and the conductor resistance value is 10 mΩ/mouth. Increased hardness of the second and third resin layers appears to be effective in preventing dissipation of ultrasonic energy.

Using a commercially available wire bonding device for semiconductor ICs, an ultrasonic thermocompression bonding device for gold wire is used.
Bonding the thin gold wire 26 and the thin aluminum wire 28,
The results of the strength test are shown in the table below, and a practical standard of 6 g or more was obtained.

Note that the bonding properties can be further improved by scraping the surface of the conductive resin layer 26 to make it flat.

At the same time, tin-lead containing 2% silver (61/37)
The adhesion of the semiconductor chip 31 with the solder 30 is 220~2
80'C can be done in a few seconds.

Effects of the Invention According to the present invention, sufficient adhesive strength can be obtained without applying special processing such as alumite treatment to the surface of the metal plate, eliminating the possibility of moisture adsorption or trapping during treatment. It is possible to bond gold wires and aluminum wires together, and the ability to form conductors). The problem of contamination of semiconductor chips and deterioration of life characteristics can be avoided.The surface of the conductive resin layer is still flat, and mirror polishing is also possible. As described above, the printed wiring board according to the present invention can be formed by insulating the metal base and directly printing the conductor instead of etching, using the dryer method, and can be used to bond the wires of surface mount devices. It is a technologically and economically superior technology that has made bonding possible.

[Brief explanation of the drawing]

FIGS. 1 and 2 are sectional views of a conventional example, and FIGS. 3 and 4 are sectional views of each embodiment of the present invention. 22... Aluminum plate, 23... Insulating resin first layer, 24... Insulating resin second layer,
26... Conductive third layer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3', ゛,・ Figure 4 O-22

Claims (1)

[Claims] a first resin layer in which an insulating resin paste is printed on a metal plate;
A second resin layer was printed with an insulating resin paste selectively overlapping the first resin layer, and a conductive resin paste was printed on the second resin layer either in the same area or in an area that did not protrude from the second resin layer. 1. A printed wiring board comprising a third resin layer, and a gold wire or aluminum wire for connecting an electrode of a semiconductor chip is thermocompression bonded to the third resin layer.