JPS61174696A - Manufacture of ceramic multilayer interconnection 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 application field) The present invention relates to a method for manufacturing a ceramic multilayer wiring board.

(Prior art) Conventional ceramic multilayer wiring boards are made by punching ceramic green sheets (hereinafter referred to as green sheets) to form an outer shape, and then punching, drilling, etc. to form holes, and then inserting tungsten or molybdenum.

A conductor paste containing high-melting point metal powder such as manganese is filled into the holes printed on the green sheet to form a conductor part.First, an insulator is formed on the top surface of the conductor part, and then an insulator is formed on the top surface and the hole again. A conductor portion is formed, these steps are repeated several times to obtain a multilayer structure, and the product is then simultaneously fired at a temperature of 1500 to 1700° C. in a weakly reducing atmosphere.

(Problems to be Solved by the Invention) However, in this method, the shrinkage of the green sheet during firing causes a variation of about 1% in the external dimensions, hole dimensions, and positional accuracy. Furthermore, since the conductor paste, green sheet, etc. are simultaneously sintered and formed in one batch, if there is a change in the pattern, the punch mold etc. must be changed, resulting in disadvantages such as increased costs.

An object of the present invention is to provide a method for manufacturing a ceramic multilayer wiring board that has high dimensional accuracy and is inexpensive.

(Means for Solving the Problems) As a result of various studies on the above-mentioned drawbacks, the present inventors have found that two ceramic substrates each having at least two conductor layers therein.
Mechanically or with energy, the two internal conductor layers are partially exposed by penetrating the front and back sides or forming a hole halfway, plating the exposed internal conductor, and then applying conductive paste to the plated part. It has been confirmed that the above problem can be solved by making conductivity with other plating or the like and exposing that part to the surface.

In the present invention, a ceramic substrate having at least two internal conductor layers is made to penetrate through the front and back sides, or to form a hole halfway, so that a part of the two internal conductor layers is exposed using mechanical force or energy. With the process.

The present invention relates to a method for manufacturing a ceramic multilayer wiring board, which comprises a step of plating the exposed internal conductor, and a step of making the plated portion conductive and exposing the conductive portion to the surface.

In the present invention, tungsten, molybdenum, manganese, etc. are used as the high melting point metal powder forming the conductor layer.
Green sheets are used as materials for forming insulators,
A ceramic slip or the like is used before being made into a green sheet.

Mechanical or energy methods for drilling holes include ultrasonic waves, lasers, electron beams, etc.
The method is not limited to the above method as long as a hole can be formed in a sintered ceramic substrate.

Although there are no particular restrictions on the type and thickness of plating on the internal conductor exposed by drilling, nickel plating is preferably applied.

Copper, gold, and silver are the materials used to connect the plated part after plating and expose that part to the surface.

Platinum or the like is used, and these may be formed by printing a paste or by plating, although there are no particular restrictions.

Example C) The present invention will be described in detail below with reference to the drawings.

Example 1 A conductive paste (trade name 3TW-1200, manufactured by Asato Kagaku Kenkyusho Co., Ltd.) containing tungsten powder as a main component was printed on the upper and lower surfaces of the green sheet 1 shown in (a) of Fig. 1. (b) After forming the conductor layer 2 as shown in K, an insulating paste having the same composition as the green sheet was printed on both surfaces thereof to form an insulating layer 3 as shown in FIG. 1(C). Thereafter, the conductor layer 2' is sintered in a slightly reducing atmosphere at a temperature of 1600°C for 1 hour to form a sintered conductor layer 2' as shown in FIG. 1(d).
A ceramic substrate was obtained with an inner layer of

Next, as shown in FIG. 1(e), a through hole 4 is formed using ultrasonic waves, and as shown in FIG. Plating 5 was applied to a thickness of 3 μm, and then curing type copper paste (manufactured by Asahi Chemical Research Institute, trade name ACP-
030) through the above-mentioned through hole 4. A surface conductor 6 as shown in FIG. 1(g) was formed by coating the nickel plating 5 and parts of both surfaces in contact with the ends of the through holes 4. Thereafter, a ceramic multilayer wiring board was obtained by mechanical work to a predetermined size.

Example 2 3 parts by weight of methyl cellulose and a solvent were added to 100 parts by weight of a mixture of 80% by weight of molybdenum powder with an average particle size of 1.5 μm and 20% by weight of manganese powder on the upper and lower surfaces of the green sheet 1 shown in Figure 2 (Extension) K. A suitable amount of butylcarbyl acetate was added thereto and mixed uniformly, and a conductor paste was printed to form a conductor layer 2 as shown in Fig. 1(b).9 Then, other green sheets were coated on both surfaces. They were sandwiched together, thermocompressed and laminated, and then molded as shown in FIG. 2(C). Thereafter, it was fired in a weakly reducing atmosphere at a temperature of 1600 DEG C. for 1 hour to obtain a ceramic substrate having a sintered conductor layer 2' as shown in FIG. 2(d).

Next, as shown in FIG. 2 (e) t/c, a through hole 4 is formed using a laser, and as shown in FIG. After applying plating 5 to a thickness of 3 μm and sensitizing and activating the through hole 4 portion, steel plating is applied to the through hole 4 I and the portion where nickel plating 5 has been applied and the through hole. A surface conductor 6 having a thickness of 5 μm was formed on a portion of both surfaces which were in contact with the ends of the conductor 4, as shown in FIG. 2(g). Thereafter, it was processed to a predetermined size to obtain a ceramic multilayer wiring board.

In the example, the surface conductor on the ceramic substrate was formed of copper, but low-temperature fired Ag/Pd was formed on the enamel substrate etc.
A conductor may also be formed. However, in this case, it is necessary to form an oxidation-resistant film on the inner layer conductor, such as by performing nickel plating and then gold plating.

(Effects of the Invention) According to the present invention, since through-holes are formed in sintered ceramics using ultrasonic waves, lasers, etc., there is no need to prepare a punch mold even if the pattern is changed. Furthermore, the dimensional accuracy of the through holes is such that variations in sintering shrinkage of ceramics can be ignored, making it possible to obtain an inexpensive ceramic multilayer wiring board with high dimensional accuracy.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the manufacturing process of a ceramic multilayer wiring board according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the manufacturing process of a ceramic multilayer wiring board according to another embodiment of the invention. It is a diagram. Explanation of symbols 1...Green sheet 2...Conductor layer 3...Insulating layer 4...Through hole 5...Nickel plating 6...Surface conductor'T-t Figure Y2 Figure

Claims (1)

[Claims] 1. A process of penetrating the front and back of a ceramic substrate containing at least two conductive layers internally or forming a hole halfway so that a part of the two internal conductive layers is exposed by mechanical or energy. A method for manufacturing a ceramic multilayer wiring board, comprising the steps of: plating the exposed internal two-layer conductor; and connecting the plated portion to the conductive portion to expose the conductive portion to the surface.