JPS63242604A - Manufacturing method of ceramic green sheet - 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 [Summary] A modified hot melt resin that is solid at room temperature and whose viscosity drops to 80,000 CP or less at 200 to 300°C is used as an organic binder, and after heating and kneading it with ceramic powder without using a solvent, A method of obtaining green sheets with good precision and excellent workability by hot pressing.

[Industrial application field]

The present invention relates to a method for manufacturing a ceramic green sheet with improved workability.

Due to the need to process large amounts of information at high speeds, information processing technology has advanced significantly, and in response to this demand, semiconductor devices that form the main body of information processing equipment have increased in capacity from LSI to VLSI. Also, the mounting method has been improved and the entire chip is mounted on a ceramic circuit board.

In other words, advances in thin film formation technology and photolithography have enabled the pattern width of conductor lines to become smaller, and advances in passivation technology have made it possible to mount large capacitance elements on circuit boards in the form of chips. It has become possible.

Here, the size of the chip is at most 10+n square, and electronic devices are formed by arranging such chips in a matrix, but since each chip has a large number of constituent elements, the size of each chip is The number of conductor lines that connect terminals to circuits has become enormous, and therefore the circuit board on which they are mounted is necessarily a multilayer wiring board with fine wiring.

The present invention relates to a method of manufacturing a ceramic green sheet constituting such a multilayer substrate.

[Conventional technology]

1. Chips such as SI and VLSI generate heat even when the rated voltage is applied, so cooling methods such as fins are generally used. On the other hand, the substrates on which such chips are directly mounted are made of heat-resistant materials. This is an essential condition, and the substrate is made of ceramics such as alumina (α-a1g03) and borosilicate glass as a constituent material.

That is, an organic binder and a plasticizer are added to these ceramic powders, and the mixture is kneaded with a solvent to form a slurry (5 lu
rry slurry-like), make a green sheet (raw sheet) by tape casting method, and make a via hole (V
After forming ia-holes and patterning conductor lines, a multilayer ceramic circuit board is manufactured by aligning and stacking green sheets, pressurizing them to integrate them, and then firing them.

Here, the commonly used slurry constituent materials are as follows.

Organic binder: butyral resin, acrylic resin.

Cellulose, vinyl acetate, etc. Plasticizers: Dibutyl phthalate (abbreviated as DOP), dibutyl phthalate (abbreviated as DBP), etc. Organic solvent: Isopropyl alcohol (abbreviated as fLIpa).

such as ethyl alcohol, Additionally, water may be used as a solvent.

Next, the tape casting method is also called the doctor blade method, in which an extruder (doctor blade) with a blade kept at a predetermined gap is installed on top of the moving polyester film, and while supplying slurry to the extruder, the polyester is This method continuously forms green sheets with a predetermined thickness by moving the film.

After drying the green sheet formed in this way, it is separated from the polyester film, six via holes are opened and a conductor pattern is screen printed, and then laminated and integrated while aligning, and then heated at high temperature. Multi-layer circuit boards are made by firing.

However, the dimensions of the green sheet change due to evaporation of the solvent and changes in viscosity due to temperature, etc. before lamination processing, making it difficult to precisely form ceramic circuit boards with fine patterns. there were.

[Problem that the invention seeks to solve]

As mentioned above, for multilayer circuit boards, thin green sheets are made using the tape casting method, and after drying and peeling, holes are processed and conductive patterns are printed, and the multiple green sheets are aligned. However, the dimensions and positions of the punched holes and screen-printed conductor patterns vary during the lamination process, making it difficult to achieve a multilayer circuit board with good positional accuracy. The problem is that it cannot be formed with a high yield.

[Means for solving problems]

The above problem is caused by the organic binder in the ceramic powder.

Instead of the conventional method of adding a plasticizer and an organic solvent, kneading it, making it into a slurry, and then forming a green sheet by tape casting, we use an organic binder that is solid at room temperature and has a viscosity of 80,000 CP or less at 200-300℃. This problem can be solved by a method for manufacturing a ceramic green sheet, which uses a modified hot melt resin, heat-kneads it without using a solvent, and forms the green sheet by a hot press method.

[Effect]

The present invention uses a modified hot melt resin, which is solid at room temperature but whose viscosity drops to 80,000 CP or less at 200 to 300°C, as an organic binder that is a component of the green sheet. A green sheet is obtained by a pressing method.

In other words, the cause of dimensional changes and collapse of conductor patterns in the conventional Grin Sheet after it is manufactured by tape casting and before the lamination process is due to the gradual evaporation of the solvent contained in the Grin Sheet and the gradual evaporation of the organic binder. is dissolved in a solvent and becomes a gel, which causes viscosity changes due to temperature fluctuations, causing dimensional changes and changes over time.

Since the presence of a solvent causes dimensional changes, the present invention does not use a solvent, but instead uses a modified hot melt resin such as modified polyester or modified polyamide, which melts when heated and becomes low in viscosity. , which is kneaded with ceramic resin at high temperature to make a green sheet.

Note that it is effective to add a plasticizer or lubricant to increase moldability.

Next, if the green sheet forming material is solid at room temperature, the conventional tape casting method cannot be applied.

Therefore, a green sheet is formed by a hot press method.

The green sheet thus formed does not contain a solvent and is solid at room temperature, so it has good workability in forming via holes and screen printing, and does not shrink.

In this way, the viscosity of the resin used in the present invention is adjusted to 200 to 300.
The reason why the viscosity is limited to 80,000 CP or less at °C is because workability during kneading deteriorates if the viscosity is higher than this, and the reason why a modified resin is used is that such a reduction in viscosity cannot be achieved unless it is a modified product.

〔Example〕

Example 1: Alumina (α
-AIVzOs) was used.

The composition ratio of the materials used is as follows.

Ceramic powder: Alumina powder...100 parts Modified polyester resin: Trade name Aronmelt PPET (manufactured by Towa Gosei Chemical Co., Ltd.)...10 parts Lubricant Nistearic acid...10 parts Plasticizer Nidibutyl phthalate...5 parts These After sufficiently kneading the materials using a kneader at a temperature of 220°C, the mixture was kneaded at 100°C using a hot press machine with a Teflon-based mold release agent applied to the press surface.

Pressing was carried out for 5 minutes to form a green sheet of steel with a thickness of 500μ.

・This green sheet has a dimensional change of less than 0.05% even after being left for 10 days after being formed, compared to the dimensional change of about 0.5% with conventional tape casting.
/lO or less.

In addition, via holes could be formed with good workability.

Example 2: Aluminum nitride (AIN) with a particle size of 5 μm or less was used as the ceramic powder.

The material composition is as follows.

Ceramic powder: AIN powder...100 parts Modified boricimide: Macromelt 6238 (manufactured by Henkel Japan)
...15 parts Lubricant Nistearic acid ...10 parts Plasticizer Nidibutyl phthalate ...5 parts These materials were thoroughly kneaded at 200° C. using a kneader.

Next, a hot press machine coated with a mold release agent was used to heat the mold at 130℃ for 5 minutes.
A green sheet of steel having a thickness of 300 μm was formed by pressing under conditions of 300 μm.

This green sheet has a dimensional change of less than 0.05% even after being left for 10 days after formation, compared to conventional tape casting, which has a dimensional change of about 0.5%.
We were able to reduce the number to below 10.

〔Effect of the invention〕

According to the present invention, a green sheet can be manufactured without using a solvent, so no shrinkage occurs even if it is left as it is, and therefore dimensional changes can be suppressed to a minimum, making it possible to produce a green sheet with good dimensional and processing accuracy. You can make sheets.

Claims (1)

[Claims] Instead of the conventional method of adding an organic binder, a plasticizer, and an organic solvent to ceramic powder, kneading it, making it into a slurry, and then forming a green sheet by tape casting, we use an organic binder that is solid at room temperature and has a density of 200 to 300 ml.
A method for producing a ceramic green sheet, which comprises using a modified hot melt resin whose viscosity drops to 80,000 CP or less at °C, heating and kneading without using a solvent, and forming a green sheet by a hot press method.