JPS63210071A - Sheet for burning ceramic - 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] Purpose of the Invention (Field of Industrial Application) Although the present invention can be used for firing general ceramic products, it particularly relates to a ceramic firing sheet used for microcircuit boards for electronic A devices. It is.

(Prior art) Conventionally, circuit boards have been made by placing substrates such as alumina substrates and capacitor substrates on a ceramic base plate, stacking the same substrates in multiple stages, and applying high melting point oxide between the substrates by machine or hand. The product was used by sprinkling powder particles and firing the powder. In this method, the powder particles of the high melting point oxide are not uniformly dispersed, causing warping and waviness of the substrate, and adhesion of the substrates to each other, so that a satisfactory circuit board cannot be obtained. Moreover, the number of manufacturing steps increases, resulting in higher costs.

In order to improve these defects, a sheet of combustible paper or organic resin sheet with dispersed powders of magnesium oxide, silicon dioxide, alumina, zirconium dioxide, etc. adhered to the surface of the alumina substrate is used. A method of inserting the capacitor between capacitor boards has been proposed (Japanese Patent Laid-Open No. 122282/1982).

(Problems to be Solved by the Invention) However, even in the method using such a sheet, as in the case of spreading powder, the powder adheres to the substrate after baking.
Then, it is necessary to remove the bedding powder by soaking it in water, which increases the number of manufacturing steps and increases the manufacturing cost.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention employs a structure in which a material made of amorphous inorganic fiber is molded into a thin plate shape.

Here, the material made of amorphous inorganic fiber refers to a material made of amorphous inorganic fiber and other materials.

The above-mentioned amorphous inorganic fiber is non-crystalline and includes ceramic fiber, glass fiber, and the like.

For example, ceramic fibers are made by electrically melting natural alumina-silica compositions, kaolin, bauxite, kyanite, fireclay, etc., and blowing the fine particles out with high-pressure air or steam to form fibers.

In addition, other materials include inorganic powder, organic fiber, organic binder, etc. used as a powder for ceramic firing.

As the ceramic firing powder, conventionally known powders of alumina, zirconia, magnesia, silica, etc. are used. Their particle size is on the order of tens to hundreds of micrometers. Examples of organic fibers include wood pulp and synthetic pulp. Examples of organic binders include natural and synthetic glues, such as starch, gelatin, sodium alginate, and rubber latex; examples of synthetic glues include acrylic resins, synthetic latex, and carboxymethyl cellulose (
CMC), methylcellulose, etc.

The thickness of the amorphous inorganic fiber sheet is 0.
A range of OL=10 mn+ is appropriate. If the thickness is less than 0.01 mm, the substrates tend to adhere to each other, and sheeting is also a problem; if it exceeds 10 mm+, the performance will not improve and the manufacturing cost will increase.

Furthermore, as a method for forming amorphous inorganic fibers into sheets, a conventional technique for making paper from wood fibers is employed.

(Function) By adopting the above configuration, there is no adhesion between the substrates due to the difference in crystalline state between the sheet made of amorphous inorganic fibers and the substrate such as an alumina substrate or a capacitor substrate during firing, and there is no adhesion between the substrates. reaction is prevented, and the sheet can be easily peeled off from the substrate.

(Example 1) An example embodying the present invention will be described below with reference to the drawings.

As shown in the figure, an unfired ceramic substrate 1 is laminated on a ceramic base plate 3 for firing with a ceramic fiber sheet 2 interposed therebetween. The unfired ceramic substrate l is 10
Laminated in tiers.

As the unfired ceramic substrate 1, a commercially available alumina substrate having a thickness of 1III11 was used. Its composition is as follows.

8ho396% by weight, Ti0□ 2.0% by weight 5iOz
1.0% by weight, MgO0.8% by weight Cr2O,0,
Double ht% The ceramic fiber sheet 2 is formed into a sheet by a conventional method of paper making using commercially available ceramic fibers. That is, the sheeting is performed using equipment similar to a paper machine, which includes a paper rope section that forms a wet sheet, a dewatering section that dewaters the sheet, and a drying section. The sheet thus obtained is paper-like and has a uniform thickness, and can be made to any desired thickness.

The ceramic fiber sheet 2 was formed by punching into the same shape as the green ceramic substrate 1. Its thickness was 0.25n+n+ and 5Qg/m.

The laminate as described above was fired at about 1600° C. for 2 hours.

Then, a fired circuit board was obtained.

The ceramic base plate 3 for firing is a commercially available one, and is made of alumina and has a thickness of about 15 mm. Further, the unfired ceramic substrate l can be heated to 20% by firing.
%, but ceramic fiber sheet 2 also followed this shrinkage.

The circuit board thus obtained consists of a ceramic fiber sheet 2 and a ceramic substrate l adjacent to both sides of the ceramic fiber sheet 2.
Therefore, there is no adhesion or reaction between the ceramic cut plates I.

In addition, since no bedding powder is used, there is no warping or waviness of the board due to unevenness of the bedding powder, and when peeling the board 1) 1t, there is no need to immerse it in water and one step can be omitted, reducing costs. can be measured.

(Example 2) To the ceramic fiber of Example 1 above, 30% by weight of alumina powder (average particle size 40 μm), which has been used as a bedding powder for ceramic firing, was added to the ceramic 7 fiber. They were added and mixed and formed into a sheet in the same manner as in Example 1 to form a thin plate with a thickness of 0.5 mm and a width of 10.degree.

As a result, the same actions and effects as in Example 1 were obtained.

The present invention is not limited to the above embodiments, but can be configured as follows.

(1) Although an alumina substrate was used as the ceramic substrate l in the above embodiment, a magnesia substrate, a capacitor substrate, a steatite substrate, etc. can be used instead.

(2) In the above example, the firing conditions were approximately 1600"C and 2
In the case of the magnesia substrate, capacitor substrate, and steatite substrate, approximately 1350℃ was adopted.
The 2 hour condition is adopted.

(3) The ceramic firing sheet of the present invention can be used by applying the ceramic firing powder described above to a sheet obtained by molding an amorphous inorganic fiber into a thin plate shape.

Effects of the Invention The ceramic firing sheet of the present invention does not warp the alumina substrate or capacitor substrate during firing, and the substrates can be easily released from the mold after firing, and the manufacturing process can be easily simplified. It has the excellent effect that fired products can be obtained at low cost.

[Brief explanation of the drawing]

The figure is a sectional view showing a laminate of ceramic substrates according to an embodiment of the present invention. Patent Applicant Tanaka Paper Industries Co., Ltd. Agent Patent Attorney OnITI Hakusen Voluntary Procedures Nett Official Book February 27, 1988

Claims (1)

[Scope of Claims] 1. A ceramic firing sheet formed by forming a material made of amorphous inorganic fiber into a thin plate shape. 2. The sheet for ceramic firing according to claim 1, wherein the amorphous inorganic fiber is a ceramic fiber or a glass fiber. 3. The sheet for ceramic firing according to claim 1, wherein the material made of amorphous inorganic fiber is a mixture of ceramic fiber or glass fiber with inorganic powder as a powder for ceramic firing.