JPH05286749A - Production of green sheet - Google Patents

Abstract

PURPOSE:To produce a green sheet with the uniformity in thickness improved by adjusting a slurry to a viscosity appropriate to form a tape in a short time. CONSTITUTION:A ceramic material, a sintering assistant, a water-soluble resin, a plasticizer, water and alcohols or ketones are mixed, the mixture is adjusted to an appropriate viscosity, and a tape is formed from the mixture to produce a green sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a green sheet, and more particularly to a method for producing a green sheet using water as a main component of a solvent added to the green sheet.

[0002]

2. Description of the Related Art In recent years, semiconductor elements (LSI, IC, etc.) are mounted on a laminated substrate containing alumina particles as a main component to form small electronic components, which are used in communication devices, computers, etc. The speed, performance, miniaturization, and thinning of products have been rapidly promoted.

Conventionally, in the production of a laminated substrate, a green sheet is produced by a doctor blade method or the like, and the green sheet is processed into a form according to each purpose and use,
It is carried out by firing a laminated product.

The green sheet is prepared by mixing alumina powder with additives such as a sintering aid, a butyral resin, a plasticizer and a solvent (xylene, etc.) to form a slurry, and then performing a tape forming process called a doctor blade method. It was produced by. However, in this case, since xylene or the like is used as a solvent, there is a problem in terms of safety for human body and manufacturing cost.

Therefore, in order to solve such a problem, a water-soluble binder is used in the production of the green sheet without using butyral resin, and water is used in place of an organic solvent such as xylene. A method has also been proposed to reduce the manufacturing cost and improve the safety during the manufacturing process.

[0006]

As described above, in the method for producing a green sheet in which water is used instead of an organic solvent such as xylene, since the evaporation temperature of water is high, the viscosity of the slurry is not suitable for tape forming. There is a problem that it takes a long time to adjust the viscosity. There is also a problem that the thickness of the green sheet is not uniform even if the green sheet is manufactured by tape-molding a slurry having an appropriate viscosity.

The present invention has been made in view of these problems, and it is possible to adjust the viscosity of the slurry to an appropriate viscosity required for tape molding in a short time, and to make the thickness of the green sheet uniform. It is an object of the present invention to provide a method for manufacturing a green sheet that can

[0008]

In order to achieve the above-mentioned object, a method for producing a green sheet according to the present invention comprises a ceramic raw material, a sintering aid, a water-soluble resin, a plasticizer, water and alcohols or ketones. Is mixed, and after the mixture has an appropriate viscosity, tape molding is performed.

[0009]

According to the above method, a ceramic raw material, a sintering aid, a water-soluble resin, a plasticizer, water and alcohols or ketones are mixed to form a slurry. After that, when degassing the slurry, the evaporation temperature of alcohols and ketones is lower than the evaporation temperature of water, so alcohols or ketones evaporate faster than water, and the viscosity of the slurry is adjusted in a short time. It becomes possible to do.

The mixture of water and alcohols or ketones has the effect of reducing the temperature difference between the upper surface and the lower surface of the green sheet, and as a result, the entire green sheet has a uniform viscosity and the thickness of the green sheet is small. It is considered that the variation in the height becomes small.

[0011]

EXAMPLES AND COMPARATIVE EXAMPLES Examples and comparative examples of the green sheet manufacturing method according to the present invention will be described below. First, 13 parts of sintering aid was added to 100 parts by weight of alumina powder.
Parts by weight are added, water is further added, and the mixture is pulverized and mixed in a ball mill for 24 hours and dried. Then, the mixture was crushed, 10 parts by weight of a water-soluble resin, 3 parts by weight of a plasticizer, and water and alcohols shown in Table 1 below and a solvent in which water and ketones were mixed at various ratios were added, and a ball mill was used. And mix to form a slurry.

[0012]

[Table 1]

[0013]

[Table 1-2]

Thereafter, the slurry is defoamed, the slurry is tape-formed by using a doctor blade method, and then dried in a temperature range of 60 ° C. to 120 ° C. to produce a green sheet.

Table 1 shows the time required for the viscosity of the slurry to reach 100 ps (poise) and the variation value of the thickness of the produced green sheet in the method for producing the green sheet.

The variation value is a value calculated based on the following equation (1). However, the 1 cm portions on both edges are excluded.

[0017]

[Equation 1]

As is apparent from Table 1, the test No. The comparative example shown in FIG. 1 is a case where only water was used as the solvent as in the conventional case, and the test No. 2-45 have shown the Example. When the results of this comparative example and those of the example are compared, the time required until the viscosity of the slurry reaches 100 ps (poise) is longer in the comparative example, and the variation value of the thickness of the green sheet is also larger in the comparative example. It was great.
As described above, in the example, the viscosity can be adjusted in a shorter time, and the thickness of the green sheet can be made uniform.

As described above, since the evaporation temperature of alcohols and ketones is lower than the evaporation temperature of water, alcohols or ketones evaporate faster than water, and when the slurry is defoamed, the slurry The viscosity of can be adjusted to an appropriate viscosity required for tape molding in a short time. In addition, the thickness of the green sheet can be made uniform.

[0020]

As described in detail above, in the method for producing a green sheet according to the present invention, a ceramic raw material, a sintering aid, a water-soluble resin, a plasticizer, water and alcohols or ketones are mixed. Obtain a slurry. After that, when defoaming the slurry, the evaporation temperature of alcohols and ketones is lower than the evaporation temperature of water, so alcohols or ketones evaporate faster than water, and the viscosity of the slurry is tape-formed. The required viscosity can be adjusted in a short time. Moreover, the uniformity of the thickness of the green sheet could be improved.

Claims (1)

[Claims] 1. A ceramic raw material, a sintering aid, a water-soluble resin, a plasticizer, water and alcohols or ketones are mixed, and after the mixture has an appropriate viscosity, tape molding is performed. Green sheet manufacturing method.