JPS6362120B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method of filling conductor balls into a ceramic substrate.

When manufacturing ceramic multilayer circuit boards used for high-density packaging of semiconductor devices such as LSIs and VLSIs, the ceramic substrates constituting each layer of the multilayer board have electrical conductors that penetrate between the two main surfaces of the board. A road must be established. As a conductive path penetrating this substrate, micro conductive balls made of a highly conductive metal such as gold are filled in the ceramic substrate, and these conductive balls connect the conductive circuits formed on the two main surfaces of the substrate. Structures for electrical connection have already been proposed.

To fill a ceramic substrate with the conductive balls, first, guide holes are made in an unfired ceramic substrate (hereinafter referred to as green ceramic sheet) called a green sheet, and then guide holes are formed in the lower mold of a die unit (pressing device). The raw ceramic sheet is fixed on the lower mold by inserting the guide pin into the guide hole, and the raw ceramic sheet is opened while having the same guide hole thereon and maintaining a predetermined mutual positional relationship based on the guide hole. A ball arranging guide plate having a large number of ball arranging holes is covered, and then conductor balls are inserted and arranged one by one into the arranging holes, and these balls are placed in the upper mold in correspondence with the arranging holes. A method of pressing with a pressure pin was used.

Such conventional conductor ball filling methods require a large number of steps and have the disadvantage that it is not always easy to reliably insert the balls one by one into the arrangement holes.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for filling conductor balls, which allows guide holes to be opened and conductor balls to be filled accurately in one step. Therefore, the present invention provides an upper mold having a punch for punching a guide hole and a vacuum suction port formed in a predetermined mutual positional relationship with the punch, and a predetermined conductive ball is attracted to the vacuum suction port. Then, a raw ceramic sheet is placed on a lower mold having a die corresponding to the punch,
The present invention is characterized in that guide holes are formed in the raw ceramic sheet and filled with conductor balls by operating the die unit consisting of the upper mold and the lower mold.

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

FIG. 1 is a front view for explaining one embodiment of the conductor ball filling method of the present invention, and a section is partially shown. In the figure, 1 is a raw ceramic sheet, 2
3 and 4 are a lower mold and an upper mold, respectively, and they constitute a die unit. 5 is the upper mold 4.
A vacuum suction port opened on the pressurizing surface (bottom surface in the figure) is connected to a vacuum evacuation device (not shown) via a manifold 6. Reference numeral 7 designates a punch which is provided in an accurate mutual positional relationship with the vacuum suction port, 8 a die corresponding to the punch, and 9 a cutter.
Further, 10, 11, 12, and 13 are a lower base, an upper base, a pole, and a shank, respectively, of the die set.

As shown in the figure, first, the vacuum suction port 5 of the upper mold 4
The conductor ball 2 is attracted to the conductor ball 2. The diameter of this vacuum suction port 5 is approximately 80 mm of the outer diameter of the conductive ball to be sucked.
% is practically preferable. By making the diameter of the vacuum suction port slightly smaller than the outer diameter of the conductive ball in this way, if a conductive ball with an extremely small outer diameter gets mixed in, it will be possible to remove it by suction. It is possible to prevent problems such as poor conduction between the upper and lower main surfaces of the ceramic substrate caused by excessive heat transfer.

On the other hand, the raw ceramic sheet 1 is placed on the lower mold 3. It goes without saying that this raw ceramic sheet may be larger than the ceramic substrate to be produced, or may be a continuous sheet.

After doing this, by operating the die set and lowering the upper die 4, the punch 7 and die 8 open the guide hole, the cutter 9 cuts the outer shape, and the conductive balls 2 are filled in one shot. It can be done with

FIG. 2 is a cross-sectional view showing a ceramic sheet filled with conductive balls as described above, where 1 is a raw ceramic sheet, 2 is a filled conductive ball, 1
4 is a drilled guide hole.

In this embodiment, as already clear from the above description, filling of the conductor balls 2 and guide holes 14 are performed.
Since the opening of the hole and the cutting of the outer shape can be performed in one shot, the process is significantly simplified. Further, the mutual positional relationship between the guide hole 14 and the conductor ball 2 can be made uniform and accurate with no variation from shot to shot by manufacturing the upper mold with high precision. Furthermore, since only one conductor ball 2 is attracted to one vacuum suction port 5, a plurality of conductor balls 2 are not filled in the same place.

Although the upper mold 4 is shown as an integral part for convenience of explanation in FIG. 1, it is of course possible to use a split mold, and since the pressing force required to fill the conductor balls 2 is very small, the above-mentioned The portion of the pressurizing surface of the mold 4 where the vacuum suction port 5 is provided may be made of a thin metal plate such as stainless steel. Therefore, the present invention can also be used when manufacturing a plurality of types of ceramic substrates having different numbers and positions of conductive balls 2.

As explained above, according to the present invention, it is possible to accurately and easily fill conductor balls into a raw ceramic sheet, and the process is significantly simplified.

[Brief explanation of drawings]

FIG. 1 is a front view for explaining an embodiment of the conductor ball filling method of the present invention, and FIG. 2 shows a ceramic sheet filled with conductor balls according to the above embodiment. In the figure, 1 is a raw ceramic sheet, 2 is a conductor ball, 3 is a lower die, 4 is an upper die, 5 is a vacuum suction port, 7 is a punch, 8 is a die, and 14 is a guide hole.

Claims (1)

[Claims] 1 A plurality of conductive balls are adsorbed to the pressurizing surface of the upper die of the die unit in which a punch is disposed on the pressurizing surface of the upper die, and the balls are placed on the unfired ceramic substrate placed on the surface of the lower die of the die unit. A method for filling conductor balls into a ceramic substrate, characterized in that guide holes are bored in the unfired ceramic substrate and filled with the conductor balls by applying pressure with the upper die.