JPS5922390B2 - Ceramic circuit board manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a ceramic circuit board, and more particularly to a method of manufacturing a ceramic circuit board with finer press pins and a higher mounting density.

As a manufacturing method for obtaining electrical continuity between the front and back sides of a ceramic circuit board, a method of filling a green sheet with conductor balls and stacking them to form a multilayer structure has been implemented, and there is a tendency for miniaturization to continue. FIG. 1 is a sectional view showing a conventional method of filling a green sheet with conductor balls.

In the figure, a hole 3 having the diameter of a plurality of conductor balls 2 is located on the upper surface of a green sheet 1 at a position where a plurality of conductor balls 2 are to be embedded.
The metal masks 4 provided with the above are placed one on top of the other, and the conductor balls 2 are inserted into the holes 3. Thereafter, the green sheet 1 is filled with the conductor balls 2 by applying pressure from above the mask 4 with a press die 6 having a convex portion 5 at a position facing the conductor balls 2 . The material of the press die 6 is usually molybdenum or stainless steel, and the press pin 5 is made to protrude by etching. However, if the above conventional etching method is used, a phenomenon as shown in FIG. 2 occurs.

In other words, in the figure, the press die 6 is formed sequentially from the tip of the press pin 5 by etching, so the etching time is longer for the tip, and the culm at the root is shorter, so it is side etched, resulting in a tapered or extreme shape like 5' or 2'. In this case, it becomes conical.

Therefore, there was a problem in that it was not possible to form fine pins having the required length. The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a ceramic circuit board that enables the formation of press pins having a minute diameter and has a high packaging density. In order to achieve the above object, the present invention is characterized in that in the production of a ceramic circuit board in which a green sheet is filled with conductor balls, the material of the press pin for filling the conductor balls is made of a SiO2-LiCO3-Al2O3 glass composition. The conductor balls are filled with a filling jig obtained by using photosensitive glass and performing etching after irradiation with ultraviolet rays.

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

A powder having the composition shown in the table was collected as a raw material powder for the press shown in FIG. 1.

The raw material powder with the above composition was collected in a platinum crucible, heated at 1450°C for 3 hours to melt it, and then poured into a carbon mold and rapidly cooled.
An At2O3-based glass substrate can be obtained.

Ultraviolet rays are irradiated onto the glass substrate using an irradiation mask to areas other than the pins 5 of the ball filling jig.

After irradiation, heat at 620℃ for 2 hours, then 1
Etch in 0% AF solution. The above SlO2
-Li2O2-At2O3 glass has a difference in solubility ratio to HF of about 30 times between the ultraviolet irradiated part and the non-irradiated part, and only the irradiated part is etched and the non-irradiated part is hardly etched. It is. By etching the pins 5 of the press die 6 in this manner, the amount of side etching is extremely small, making it possible to form fine press pins.

As a result of experiments regarding the etching of the above-mentioned press-type pins, it was possible to obtain pins with almost no side etching by forming a press-type pin with a diameter of pin 5 of 80 μm and a height of 1 pin of 100 μm. It was possible to embed a conductor ball 2 with a diameter of 80 μm in a green sheet 1 with a thickness of 150 μm. As explained above, in the method of manufacturing a ceramic circuit board according to the present invention, a photosensitive glass having a glass composition of SlO2-LiCO3-AL2O3 is used as the material of the push pin for filling the conductor balls, and ultraviolet rays are irradiated. Later, by making a filling jig with etching and filling the conductor balls with this jig, it became possible to fill with fine conductor balls and obtain a ceramic circuit board with a small via hole diameter. The effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a method of filling a green sheet with conductor balls, and FIG. 2 is a cross-sectional view showing the relationship between the side-etched shape of the press pin and the conductor balls. In the figure, 1... green sheet, 2... conductor ball, 3... hole into which the conductor ball fits, 4... metal mask, 5... protrusion (pin), 5', da. . . . Pin after etching, 6 . . . Indicates a press mold.

Claims (1)

[Claims] 1. In manufacturing a ceramic circuit board in which a green sheet is filled with conductor balls, a photosensitive glass having a glass composition of SiO_2-LiCO_3-Al_2O_3 is used as the material of the push-type pin for filling the conductor balls, and ultraviolet rays are irradiated on it. 1. A method for manufacturing a ceramic circuit board, characterized in that conductive balls are filled with a filling jig obtained by etching the ceramic circuit board.