JPH02242513A - Conductor paste - Google Patents

Abstract

PURPOSE:To prevent a VIA hole from being broken and lower the resistivity of the conductor paste so as to reduce its cost by mixing a conductor powder with a vehicle consisting of a resin and a solvent, the conductor having silver powder, paradium powder and tin powder in a specific ratio and having its total weight specified. CONSTITUTION:A conductor powder having 50.35 to 57.84 parts by weight of silver powder, 2.65 to 3.04 parts by weight of paradium, and 3.20 to 9.35 parts by weight of tin powder, the total amount of which is 62.35 to 64.09 parts by weight, is kneaded with a vehicle consisting of a resin and a solvent so as to form a conductor paste. The amount of paradium is thus reduced and tin is added thereto, whereby contraction of the conductor 1 within a VIA hole 2 can be restrained and the conductor 1 between VIA portions is prevented from opening, and also, low-cost tin is used to reduce the amount of paradium which is expensive. The cost of the conductor is thereby reduced, and besides the resistivity of the conductor is lowered.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a conductive paste, and particularly to a conductive paste suitable for use in through-hole connections often used in printed circuits.

(Prior Art) Recently, in the field of hybrid IC boards, multi-layered boards have been used that can increase the density of circuit packaging in order to reduce the size or cost.

In this case, the circuits provided on the substrates of each layer are connected to each other by via holes.

A conventional example of producing such a multilayer board will be described below with reference to FIG. First, MgO24.3wt%.

Nb20S 56.7 wt%, ZnO9, Owt
%, Bi2O36, Owt%, a resin binder is added to the ceramic mixed powder to form a slurry, and a ceramic green sheet 3 is produced from this slurry by a doctor blade method or the like. Next, this sheet is cut into a predetermined shape and a hole 2 for via hole connection is formed.Next, silver powder is added to form a predetermined circuit pattern on the notebook.
8.5wt%, Pd powder 6.5wt% and vehicle 35w
The conductive paste mixed at a ratio of t% is screen printed, the required number of sheets are stacked, and vacuum thermocompression bonded.
It is co-fired with the conductor at 950°C in the atmosphere to create a multilayer board (Figure 1). Also, at this time, in order to connect the patterns of the upper and lower layers when stacked, the green sheet is coated with conductive paste at the same time as the pattern when printed in the via hole.
is filling in.

(Problems to be Solved by the Invention) When the current multilayer board is fired at the same time as the conductor paste, there is a difference in shrinkage between the conductor paste and the multilayer board main body, and the conductor in the part A of the process shrinks more. A large gap 4 is created in the via 2, and the conductor becomes open between the vias, causing the circuit to lose its function (FIG. 2). VI at this time
There were as many as 1.50 defects out of 1000 devices due to A opening (see the conventional product column in Table 1). In addition, Pcl is expensive (it affects the price of the conductor paste, and furthermore, it increases the specific resistance with the conductor).

(Means for Solving the Problems) In order to solve the above problems, in the present invention, silver powder 50.35~
57.84 wt% and palladium 2.65-3.04
wt% and tin powder 3.20-9.35 wt% for a total of 6
A conductor paste was prepared by kneading 2.35-64.09% by weight of conductor powder with a resin and bath additive mixture.

(Function) By reducing the amount of palladium and adding tin, the shrinkage of the conductor inside the VIA hole can be suppressed, and the conductor between the VIA holes can be prevented from becoming open. By reducing the amount of palladium, the price of the conductive paste was reduced, and the specific resistance of the conductor was also reduced.

(Example) Conductor pests were prepared using mixed conductor powders consisting of Ag powder, Pd powder, and Sn powder at the compounding ratios shown in samples Nα1 to Nα3 in Table 1. That is, ■Ag 57.84 wt%, Pd3
．． 04wt%, Sn 3.20wt%, Vehicle 3
5.91 wt%, ■Ag 54.04 wt%, Pd
2.84 wt%, Sn 6.32 wt%.

Vehicle 36.79 wt%, ■Ag 50.35 w
t%, Pd2.65 wt%, Sn 9.3
5 wt% and vehicle 37.65 wt%.
, Pd, and Sn were mixed in a dry state, and then a vehicle was created by kneading the mixture with a resin and a solvent. After mixing, three types of conductor paste were created by mixing them with three rolls.
Each was printed on a sheet with a VIA hole open therein, followed by vacuum thermocompression bonding and baking to produce a multilayer substrate. As a result V
The disconnection rate of the IA hole was O, and the void 4' inside the VIA hole at that time was also small as shown in FIG.

(Effects of the invention) By reducing the amount of palladium and adding tin, disconnections in via holes are eliminated and the price of conductor paste is reduced.
Furthermore, the specific resistance, which is important for circuit conductors, has been lowered, so it can be used for harmonics, computer wiring, and other circuits, and yields due to circuit disconnections can be improved.950
We were able to make an inexpensive paste that can be fired at ℃.

[Brief explanation of drawings]

FIG. 1 shows a cross section of a via hole in a multilayer board using the conductive paste of the present invention, and FIG. 2 shows a conventional example.

Claims (1)

[Claims] 50.35-57.84% by weight of silver powder and palladium powder2.
65-3.04% by weight and tin powder 3.20-9.35% by weight
A conductor paste prepared by kneading conductor powder having a total weight of 62.35 to 64.09% with a vehicle comprising a resin and a solvent.