JPS61258744A - Manufacture of multilayer ceramic substrate - 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 (Field of Industrial Application) The present invention relates to a method for manufacturing a multilayer ceramic substrate.

(Background Art and its Problems) Some ceramic packages for semiconductor devices have a multilayer ceramic structure in which green sheets are laminated and fired. FIG. 4 shows an example of a green-toned laminate after being divided into individual pieces. Generally, to form a green sea lion laminate, green sheets for each layer are punched out into the desired shape, the necessary conductor patterns are printed, and then stacked, and the pressed surface follows the uneven shape of the surface of the stacked green sheets. Pressure is applied using a pressing jig having a pressure jig to closely laminate the materials.

By the way, since the conductor patterns described above have recently become extremely dense, it is undesirable for foreign matter such as powder of alumina or the like constituting the green sheet, dust, etc. to adhere to the exposed portions of the conductor patterns. This is because it becomes a hindrance when wire bonding to the conductor pattern is performed later, making normal bonding impossible. Therefore, in order to prevent the adhesion of these foreign substances, a conventional method is to apply an adhesive tape to the surface of the green sheet after the lamination process. However, when using this method, the process of applying adhesive tape to the surface of the green sheet is extremely tedious, which is not only inefficient, but also requires that the adhesive tape has both appropriate adhesion and removability. However, there is a problem that it is expensive. Also,
It has been found that adhesion of foreign matter such as alumina powder to the conductor pattern on the surface of the green sheet often occurs when the green sheet is pressed into close contact with a pressing jig.

Therefore, if adhesive tape is applied after the lamination process, the effect of preventing foreign matter from adhering will be halved.

(Summary of the Invention) The present invention has been made in view of the various problems mentioned above, and its purpose is to provide a multilayer ceramic that can effectively prevent the adhesion of foreign substances and can be made at low cost. The present invention provides a method for manufacturing a substrate.

In addition, its feature is that in the manufacturing method of multilayer ceramic substrates, in which multiple green sheets formed into a desired shape are laminated under pressure and then fired, a thin protective film is simultaneously applied when the multiple green sheets are pressed together. The purpose is to bring the material into close contact with the surface of the laminate.

(Embodiments) Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

1 to 3 are explanatory diagrams showing the manufacturing process of the present invention.

Reference numeral 10 denotes a green sheet, which, as described above, is formed into a desired shape, a necessary conductive pattern is formed, and the required number of green sheets are stacked one on top of the other. Up to this stage, the process is the same as the conventional process.

Reference numeral 12 denotes a pressing jig, the lower pressing surface of which is formed in a shape that follows the uneven shape of the surfaces of the stacked green sheets.

A characteristic feature of the present invention is that an extremely thin protective film 14 made of polyester or the like with a thickness of about 5 mm is interposed between the surface of the stacked green sheets 10 and the pressing jig 1z, and the pressing jig 1z is The green sheets 10 are laminated in close contact with each other by applying pressure using a tool 12.

As a result, the protective film 14 is stretched to the shape of the lower surface of the pressing jig 12, and is simultaneously brought into close contact with the slightly sticky surface of the green sheet.

As mentioned above, the protective film 14 is extremely thin with a thickness of about 5A, so even if it is slightly wrinkled and adhered as it is, it will not cause any dents on the surface of the green sheet and will not cause any problems in terms of appearance. It won't happen.

The protective film 14 may be cut into a required size in advance, or the remaining portion may be cut off after the protective film 14 is adhered.

As described above, the surface of the green sheet can be protected from the time of lamination to the stage before firing, and the adhesion of foreign matter can be prevented.

At the time of baking, it is preferable to perform the baking with the protective film 14 separated by #, but it is also possible to bake it in the oven as it is without peeling it off. This is because the baking is performed at a high temperature of about 1500° C. to 1600° C., so the protective film 14 is decomposed and scattered in a gaseous state. Especially the protective film 14 is 54
Since it has an extremely thin wall of about 4A, it hardly causes long decomposition and does not cause any functional problems.

Although the above description has been made using a ceramic tape for semiconductor devices as an example, it goes without saying that the present invention is not limited to this.

(Effects of the Invention) As described above, according to the method for manufacturing a multilayer ceramic substrate according to the present invention, a protective film is formed between the green sheet and the pressing jig when the green sheet is pressed into close contact with the green sheet, where foreign matter is likely to adhere. Since this is interposed, adhesion of foreign matter can be effectively prevented.

It also effectively prevents the adhesion of foreign matter up to the subsequent firing process.

Furthermore, since the protective film is attached at the same time as the green sheet is attached under pressure, there is no particular increase in the number of manufacturing steps, and this is very effective in reducing costs.

[Brief explanation of the drawing]

1 to 3 are process explanatory diagrams of a method for manufacturing a multilayer ceramic substrate according to the present invention. FIG. 4 is a schematic diagram of a ceramic package for a semiconductor device. lO... Green sheet, 12... Pressing jig,
14...Protective film. N1 Figure 3 Figure 4 Figure 2

Claims (1)

[Claims] 1. In a method for manufacturing a multilayer ceramic substrate in which a plurality of green sheets formed into a desired shape are laminated under pressure and then fired, a thin protective film is simultaneously applied to the laminate when the plurality of green sheets are laminated under pressure. A method for producing a multilayer ceramic substrate characterized by closely adhering it to the surface.