JPH0136278B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a jig used for forming via holes in a ceramic circuit board by a conductor ball filling method, and particularly to a method of manufacturing a jig with excellent precision.

With the increasing density of semiconductor devices such as ICs and LSIs, the circuit boards on which these devices are packaged are also becoming increasingly dense.
There is a demand for higher wiring density. To this end, efforts are being made to make conductor circuits smaller in line width and multilayered. When forming via holes in this multilayered ceramic substrate, there are usually two steps: drilling and filling the holes, and the drilling is performed using equipment such as punching, drilling, laser, etc. on the raw sheet.

However, the minimum perforation by these methods, for example, by punching and drilling, is about 0.5 mm, and it is difficult to obtain a punching die and drill that can make holes with high precision.On the other hand, by laser drilling, the minimum perforation is about 0.5 mm. Although it is possible, there are problems such as the long time required for drilling, making it unsuitable for microfabrication.
Moreover, as mentioned above, it is difficult to achieve accuracy.

A method has already been proposed that solves these problems and forms via holes with excellent alignment accuracy on a raw sheet in a single process. (Special application 1972-
130113, etc.) This is called the conductor ball filling method, and its characteristics are that metal balls are arranged on the insulating layer using a ball placement jig, and then the metal balls are placed into the insulating layer using pressure using the jig and a press mold. Via holes are formed by filling metal balls.

Figures 1a and 1b are principle diagrams explaining the via hole forming method using the conductor ball filling method.
0.1mm〓 Au ball, 4 is 0.12mm thick raw sheet,
5 indicates a receiving mold, and 6 indicates a recess of the receiving mold.

First, as shown in Fig. 1a, the raw sheet 4 is sandwiched between the Au ball placement jig 2 and the receiving mold 5, and the Au balls 4 are placed appropriately on the ball placement jig 2. By vibrating the ball placement jig 2, the Au
Ball 3 is loaded. Next, extra Au ball 3
is removed, and the press mold 1 is set on the upper part of the ball placement jig 2 using guide pins (not shown) provided at the four corners of the receiving mold 5.

Next, the entire set was pressurized for 5 minutes at a pressure of 100 kg/cm ² using a hydraulic press heated to 80°C. As shown in Fig. 1b, the Au balls 3 were filled into the green sheet 4, and the green sheet The debris falls into the recess of the mold 5. The upper part of the Au ball 3 is in contact with the press mold 1.

Next, when the push mold 1, ball placement jig 2, and receiving mold 5 are removed, the green sheet 4 is filled with Au balls 3 and via holes are formed.

As described above, a thick film pattern is formed on the raw sheet 4 with via holes formed to create a circuit board, and the circuit boards are stacked and pressed to form a multilayer, and then baked at 900°C. Make a multilayer circuit board.

According to this method, the alignment accuracy can be made much better than the accuracy when printing and filling a perforated green sheet with a conductor.

However, since the jigs used in this method conventionally, the press die 1 and the ball placement jig 2 (also called metal mask), were manufactured separately by etching, the alignment accuracy between the two was not sufficient and it was not always necessary to fill the conductor balls. The problem was that the characteristics of the system could not be satisfied. That is, there was a drawback in that positional deviation between the press die 1 and the ball placement jig 2 occurred, which greatly affected the positional accuracy of filling the conductor balls. In addition, since the press die 1 was manufactured by etching, the tip became needle-like due to side etching, which caused the filled conductor balls to be misaligned.

The present invention eliminates the above-mentioned conventional drawbacks, greatly improves the positional accuracy of the ball placement jig 2 and the press die 1, and provides a method for manufacturing a via hole forming jig in which the tip of the press die can be made flat. It is an object.

According to the present invention, this purpose is to form a predetermined hole by etching a metal plate in a method for manufacturing a ball placement jig and a pressing die for forming a via hole by filling conductor balls in an insulating layer. A via hole forming jig comprising the steps of: obtaining a ball placement jig; and pouring resin or metal into the holes of the ball placement jig, and then heat curing or cooling solidification to obtain a press mold. This is achieved by providing a method for manufacturing a tool.

An embodiment of the present invention will be described in detail below with reference to the drawings.
FIGS. 2a to 2d are diagrams illustrating a method for manufacturing a via hole forming jig according to an embodiment of the present invention,
In particular, it is a diagram showing the manufacturing process of the pressing mold 1.

FIG. 2a shows the ball placement jig 2, and 6 shows its positioning guide hole. The ball placement jig 2 is manufactured by coating a 0.3 mm thick stainless steel plate with photoresist, exposing it to light, and then etching it from both sides using a shower spray method. This allows a hole with a diameter of 0.4 mm to be formed at a predetermined position.

Next, as shown in FIG. 2b, the ball placement jig 2
is fixed to a Teflon mold 9 using guide pins 8, and the thermosetting epoxy resin 7 is fixed to the ball placement jig 2.
Pour into the hole. The state after pouring is shown in Figure 2c. After drying, ball placement jig 2
The hardened resin was removed from the This resin becomes the mold 1. This mold 1 has a diameter of 0.4 mm and a height of
It has a convex shape with a flat tip of 0.3 mm. Note that 10 indicates a guide hole for positioning.

FIGS. 8a and 8b show the shapes of pressing dies manufactured by the conventional manufacturing method and the manufacturing method of the present invention.

According to the manufacturing method of the present invention as described above, since the press mold 1 is manufactured in accordance with the ball placement jig 2, the positional accuracy of both jigs is greatly improved, and via holes can be formed with excellent accuracy. is possible. While the conventional positional accuracy was ±20 μm, the present invention improved it to ±5 μm.

In addition, when manufacturing the press mold, it is also possible to use molten solder instead of thermosetting resin. The effect is similar.

[Brief explanation of drawings]

Figures 1a and b are diagrams explaining a via hole forming method using a conductor ball filling method, Figure 2 is a diagram explaining a method for manufacturing a via hole forming jig according to an embodiment of the present invention, and Figure 3 is a diagram explaining a method for manufacturing a via hole forming jig according to an embodiment of the present invention. It is a figure explaining the effect of this invention. In the figure, 1 is a pressing mold, 2 is a ball arrangement jig, 3 is a conductor ball, 4 is an insulating layer raw sheet, and 7 is a thermosetting resin.

Claims (1)

[Scope of Claims] 1. A receiving mold with a recess provided at the via hole forming location and a ball placement jig with a hole provided at the via hole forming location are set through a raw sheet so that the recess and the hole correspond to each other. Then, a conductive ball is loaded into the hole of the ball placement jig, and a press mold with a convex portion corresponding to the hole of the ball placement jig is set on the ball placement jig loaded with the ball. Receiving mold, raw sheet,
In the method of forming a via hole in which a set of a ball placement jig, a ball, and a press mold is pressurized to fill a raw sheet with conductive balls to form a via hole, a metal plate is photoetched as the ball placement jig. Using a mold with a predetermined hole formed therein, one surface thereof is brought into contact with the flat surface of the pouring mold as the pressing mold, and the hole is shaped into a concave shape with the opening on one surface being closed by the flat surface. A thermosetting resin or metal is poured into the casting mold to which the ball placement jig is fixed, and the thermosetting resin is thermosetted or the metal is cooled and solidified to form the convex portion with a flat tip at the location corresponding to the hole. 1. A method for forming a via hole, the method comprising using a mold formed with a mold.