JPS62128973A - Method of burning 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 [Technical Field] The present invention belongs to the field of ceramic substrate manufacturing technology, and more specifically to the field of ceramic substrate firing technology.

[Background Art] Ceramic substrates are usually fired using a continuous firing furnace, as shown in FIG.
A green sheet 4 is placed (1 to 10 sheets stacked) and a ceramic support 2 is placed around the green sheet 1, which is stacked in several tiers (Figure 2 shows an example of two tiers stacked). ing).

However, in the firing of ceramic substrates, warping occurs during firing, resulting in problems such as deterioration of printing characteristics and deterioration of suitability for automated lines.

Therefore, reducing the warpage of the ceramic substrate is strongly desired from the viewpoint of improving reliability in subsequent processes.

Conventionally, for products with large warpage after firing, re-firing was carried out by placing a weight on the product and utilizing the high-temperature creep phenomenon of the ceramic substrate, but this method increases manufacturing costs and is not preferred.

Additionally, a method of firing with a weight board placed on top of the green sheet is being considered, but if a board with the weight required to sufficiently suppress warping is placed, the distance between the green sheets during firing is This has the disadvantage of causing a defect in the shape of the ceramic substrate, that is, a defect in dimensional accuracy, due to seizure due to sintering or inhibition of uniform shrinkage.

[Object of the Invention] An object of the present invention is to provide a method for suppressing warpage during firing of a ceramic substrate while overcoming the above problems.

[Disclosure of the Invention] The present inventors have discovered that during sintering shrinkage of a ceramic L-shaped substrate green sheet, the shrinkage progresses smoothly as before, and then the warpage that occurs during sintering is eliminated by utilizing the high-temperature creep phenomenon of the ceramic substrate. In addition, we have invented a method that can reduce warpage in one firing step by utilizing the effect of a weight plate.

That is, the present invention has completed a ceramic substrate firing method characterized by applying a load using a weight plate from around the firing temperature at which the shrinkage of the green sheet in the first stage of the firing process is almost completed. .

The following description will be made based on FIG. 1 shown as an example.

In the present invention, a calcined ceramic strut 2a having the following characteristics is used as the firing strut 2a, and a weight plate 3 is placed on the calcined ceramic strut 2a for firing. In terms of temperature, it is desirable that the shrinkage rate of the green sheet 4 in the height direction is greater than the shrinkage rate of the green sheet 4 in the thickness direction. Furthermore, it is preferable that the shrinkage start temperature is higher than that of the green sheet 4. A calcined alumina column is used as the column 2a having such characteristics. Examples will be described below.

Example 1 A calcined ceramic pillar is made of alumina as a main component, and talc, clay, etc. is used as a flux, and the shrinkage start temperature, shrinkage rate, and shrinkage speed are determined by adjusting the alumina particle size, the blending ratio of talc and clay, and The amount was changed by examining the blending amount, molding pressure, and amount of organic binder. As a calcined ceramic pillar, the shrinkage start temperature is 1200℃,
A material with a shrinkage rate of about 20% at 1600°C was prepared.

The green sheet is made of 96% alumina and the remainder is talc and clay, and the alumina has an average particle size of about 2 μm.
The one manufactured using the one was used. The dimensions after firing were 4 inches square and 0.8N thick. The experiment was carried out by stacking 10 of these alumina green sheets and using 250 g as a weight plate.

The results of the above firing are shown in Table 1. In addition, the data is
The average value for +-1oo sheets is shown.

Example 2 It was carried out under the same conditions as Example 1. However, as a heavy slope, 4
00g was used. In this case, the warpage rate is 10
0%, and the dimensional accuracy was also good.

[Effects of the Invention] The present invention is characterized in that, in the firing method for ceramic substrates, the load by the weight plate is applied from around the firing temperature at which the shrinkage of the green sheet in the first stage of the firing process is almost completed, so that warping is prevented. We were able to provide a firing method that produces a ceramic substrate with a small amount of heat and good dimensional accuracy.

[Margin below] Table 1

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an outline of a firing method according to the present invention, and FIG. 2 is a schematic diagram showing a firing method according to a conventional example. 1: Center 2: Calcined ceramic Support column 3: Weight plate 4: Green sheet Patent applicant: Matsushita Electric Works Co., Ltd. Patent attorney Toshikuro Takemoto (and 2 others) Figure 1 Figure 2

Claims (3)

[Claims] (1) A method for firing a ceramic substrate, characterized in that a load is applied by a weight plate from around the firing temperature at which the shrinkage of the green sheet in the first stage of the firing process is almost completed. (2) Around the green sheet to be fired, place a calcined ceramic product whose shrinkage rate is higher than that of the green sheet at the firing temperature of the ceramic substrate green sheet as a support, and place a weight plate on top of it. 2. The method of firing a ceramic substrate according to claim 1, wherein the load of the weight plate is applied to the green sheet by contraction of the pillar. (3) Claim 2, characterized in that a support whose shrinkage start temperature is higher than that of the green sheet is used.
A method for firing a ceramic substrate as described in Section 1.