JPS6024093A - Method of producing ceramic 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] The present invention relates to a method for manufacturing a ceramic wiring board,
It is mainly aimed at manufacturing ceramic packages for sealing ICs (integrated circuit devices).

In the production of ceramic packages, after the high-temperature firing process of the ceramic, a plating process is performed to attach the semiconductor pellet, external lead wire, and sealing cap, and a Ni and Au plating film is formed on the surface of the metallized wiring layer. .

Conventionally, there are two methods for plating wiring layers: electroplating and electroless plating. However, with the latter electroless plating method, it is troublesome to selectively apply only to the wiring layer. Since it is also difficult, a method using electroplating is generally adopted. Such a method is disclosed, for example, in Japanese Patent Publication No. 48-52177.

By the way, when using the electroplating method, if the wiring lines are separated from each other, it is impossible to plate them at the same time, so the structure is such that the wiring lines are connected to each other using the blank space of the ceramic substrate.

After firing, the wiring layer is plated using a portion of the conductive portion as a plating electrode.

After that, unnecessary portions of the conductive wiring layer (auxiliary wiring layer) are cut, separation grooves are formed along the boundary line separating the ceramic wiring board into individual small substrates, and then, along the line grooves, Cut it to make the specified ceramic cage.

However, the ceramic substrate after firing is hard and it is difficult to form accurate and deep separation grooves on this substrate. Therefore, the reliability of the subsequent cutting and separation was poor, resulting in a large number of defective products. In addition, a diamond cutter is used to form the separation grooves, but as the ceramic substrate after firing is hard as mentioned above, the cutter wears out and the cutter needs to be replaced more frequently, resulting in the manufacturing cost of the ceramic wiring board. The problem was that it was expensive.

As a countermeasure to the above problem, it may be possible to form a separation groove in the unfired ceramic wiring board before firing, but when this separation groove is formed, the plating conductive wiring layer in that area will be cut at the same time. Therefore, it is not possible to plate the wiring layer afterwards (ゝ0 Therefore, in the past, after baking and plating,
Separation grooves must be formed on the ceramic wiring board,
The above-mentioned problems could not be avoided.0 The present invention was made to solve the above-mentioned difficult problems. To provide an inexpensive ceramic wiring board that makes it possible to easily and reliably cut a ceramic board by plating the wiring layer by electroplating while preventing the wiring layer from being cut. be.

The basic structure of the present invention to achieve the above object is to separate unit wiring layer patterns from each other on a large ceramic substrate in an unfired state, which will be separated into individual rectangular substrates along boundary lines in a later process. A plurality of wires are formed vertically and horizontally, extending along the boundary line on the ceramic substrate separating adjacent unit wiring layer patterns, and electrically commonly connecting the unit wiring layer patterns. A through-hole conductor layer is provided at a position corresponding to the boundary line for each wiring layer of the unit wiring layer pattern that the boundary line crosses, and a through-hole conductor layer is formed to pass through the through-hole conductor layer. After forming a separation groove narrower than the through-hole conductor layer along the boundary line, the large substrate is fired, and then electricity is applied to the unit wiring layer pattern through the auxiliary wiring layer and the through-hole conductor layer. Plated,
The method is characterized in that the large substrate is cut into square individual substrates along the separation groove.

An embodiment of the present invention will be specifically described below with reference to the drawings.

(1) A green ceramic sheet is punched out into a predetermined shape by punch cutting to form large-sized green ceramic substrates (upper layer, middle layer, lower layer) 1.2.3, and a predetermined pattern is formed on the surface of each substrate. Wiring layers (conductor layers) 4, 5, 6 are formed, and a through-hole conductor layer 7 is also formed in the through-hole portion.

Auxiliary wiring layers 8 and 9 for interconnecting independent wiring layers (conductor layers) 4 and 6 are formed in the respective margins of the upper surface of the upper layer board 1 and the lower surface of the lower layer board 3 when laminated at the same time. And three layers of unfired ceramic plates 1, 2.3
are laminated to form a large green ceramic wiring board as shown in FIG. The through-hole conductor layer 7 is connected to the wiring layer 5 formed on the upper surface of the ceramic plate 2 on the one hand and the wiring layer 6 formed on the lower surface of the ceramic plate 3 on the other hand.
They are arranged along boundary lines X and Y lines in the X and Y directions that separate each substrate.

(21) On the bottom surface of the unfired ceramic wiring boards laminated next, a second
As shown in the figure, a separation groove 10 having a depth of about 1/10 of the thickness of the substrate is formed. The separation groove 10 may be formed at the same time when the green ceramic wiring board is formed by hot pressing. The separation groove 10 passes through the center of each through-hole conductor layer 7 at the same time. Note that the formation of this separation trench 10 does not cut the auxiliary wiring layer 9 interconnecting each wiring layer.

(3) Next, heat the large unfired wiring board to 1100°C to 12°C.
It is fired at 00°C to make a fired ceramic wiring board. The auxiliary wiring layers 8 and 9 interconnecting the descendant wiring layers 4 and 6 are used as electrodes for electroplating, respectively, and Ni or Au plating is applied to the upper surfaces of the wiring layers 4 and 5.6 exposed on the substrate. Thereafter, the fired large-sized ceramic wiring board is cut into the separation groove 10 to obtain a ceramic package as shown in FIG.

According to the present invention as explained in the embodiments above, the above object can be achieved for the following reasons.

That is, according to the present invention, even if a separation groove is formed for each ceramic substrate in the state of an unfired ceramic wiring board, since the separation groove is formed on the through-hole conductor layer, the through-hole conductor layer The plating auxiliary wiring layer, which is internally connected and connects the wiring to each other, will not be cut.

Therefore, the wiring layer can be plated by subsequent firing and electroplating using one end of the wiring as an electrode.

In addition, since the fired descendant ceramic wiring board is cut using the deep separation grooves formed in the unfired ceramic substrate as a base line, the cutting can be done easily and reliably.

Furthermore, according to the present invention, since the separation grooves are formed in the unfired ceramic substrate, there is no need to use a diamond cutter (and there is no shoulder wear on the cutter. Therefore, it is possible to provide an inexpensive ceramic wiring board. can.

Furthermore, according to the present invention, the ends of the unit wiring layer pattern to be cut into squares can be electrically connected to the auxiliary wiring layer through the through-hole conductor layer, so that the through-hole conductor layer of the unit wiring layer pattern should be formed. The width of the wiring section can be reduced. That is, the terminals of the unit wiring layer pattern can be installed at high density. Since the auxiliary wiring layer can be arranged in a comb-like manner between adjacent unit wiring layer patterns, the electrical connection pattern between the auxiliary wiring layer and the unit wiring layer pattern can be made simple.

The present invention is not limited to the above-mentioned embodiment51, but can be implemented in other forms as described below.

In the above embodiment, a separation groove was formed to separate each ceramic wiring board in the through-hole conductor layer that interconnected the two wiring layers between the upper and lower layers. Alternatively, a through-hole conductor layer may be provided to prevent cutting of the auxiliary wiring layer interconnecting each wiring layer, and a separation groove may be formed in this through-hole conductor layer.

Further, the separation grooves formed in the unfired ceramic wiring board may be formed on both sides of the board. In this case, the wiring pattern is such that the plating auxiliary wiring layer interconnecting each wiring layer is not cut due to the formation of the separation groove.

Generally, the present invention can be used to form a simple ceramic wiring board in addition to a package, and can be used not only for manufacturing a multilayer ceramic wiring board but also a single-layer ceramic wiring board. −

[Brief explanation of the drawing]

FIG. 1 shows an unfired ceramic wiring board manufactured by the manufacturing process of the present invention, (a) is a plan view, (b) is a sectional view taken along line A-A, and (c) is a top view.
2 is a bottom view, FIG. 2 is an enlarged cross-sectional view showing a state in which isolation grooves are formed in the manufacturing process of the present invention, and FIG. 3 is a ceramic wiring board obtained by the present invention. )
(c) shows a cross-sectional view, and (c) shows a bottom view. 1.2.3... Ceramic plate, 4.5.6... Wiring layer, 7... Through-hole conductor layer, 8, 9... Auxiliary wiring layer, 10... Separation groove. Figure 1 (Figure 2 Figure 3 Figure 8

Claims (1)

[Claims] 1. On a large ceramic substrate in an unfired state, a plurality of unit wiring layer patterns to be separated into rectangular individual substrates along boundary lines in a later process are formed vertically and horizontally, spaced apart from each other, and adjacent unit wiring patterns are formed. An auxiliary wiring layer is formed on the ceramic substrate separating the layer patterns, extending over the boundary line and for electrically connecting the unit wiring layer patterns in common, A through-hole conductor layer is provided at a position corresponding to the boundary line for each wiring layer of the unit wiring layer pattern that is crossed by After forming a narrow separation groove, the large substrate is fired, and then electroplating is applied to the unit wiring layer pattern through the auxiliary wiring layer and the through-hole conductor layer, and the large substrate is formed along the separation groove. A method for manufacturing a ceramic wiring layer board, which is characterized by cutting a shaped board into square individual boards.