JPS63222043A - Low-temperature sintering ceramic - Google Patents

Abstract

PURPOSE:To obtain a low-temperature sintering ceramic having low sintering temperature to enable sintering together with an electrode material such as Cu, Ni and Ag, by combining a glass layer and a number of crystal particles including aluminum nitride crystal particles having aluminum oxide layer on the surface. CONSTITUTION:Aluminum nitride powder is mixed with pure water, boiled and separated by suction filtration to obtain aluminum nitride powder having aluminum oxide layer on the surface. The aluminum nitride powder coated with aluminum oxide is mixed with specific amounts of CaO-B2O3-SiO2 glass powder, polyvinyl butyral resin, DBP, acetone and oleic acid and stirred in a ball mill to obtain a homogeneous slurry. The objective low-temperature sintering ceramic composed of AlN crystal particles 1 having Al2O3 layer 2 and a glass layer 3 can be produced by heat-treating and calcining the slurry. The ceramic exhibits thermal conductivity close to that of high-temperature sintering alumina substrate in addition to the above-mentioned characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to low-temperature sintered porcelain used for circuit boards, multilayer wiring boards, integrated circuit packages, and the like.

[Prior Art and its Problems] As insulating substrates, high-temperature sintered alumina porcelain substrates, low-temperature sintered glass-containing alumina porcelain substrates, aluminum nitride substrates, and the like are known.

High-temperature sintered alumina porcelain substrates have high density and relatively high thermal conductivity, but the firing temperature is 1500-160℃.
Since the temperature is as high as 0°C, Mo
, W and other expensive metals must be used, and the firing cost is high.

Glass-containing low-temperature sintered alumina porcelain substrate
Since it can be obtained by firing at 1000℃), it can be fired simultaneously with base metal electrode materials such as CU, and has the advantage of low sintering cost I. 0.01 [cal cm/s 'Cc
J] has the disadvantage of being low.

Aluminum nitride substrates have the advantage of extremely high thermal conductivity, but on the other hand, the sintering temperature is high (approximately 1800°C).
Therefore, there are disadvantages in that W, Mo, etc. must be used in the place where the electrodes are simultaneously fired, and in that the firing cost and product cost increase by 1-.

Therefore, the purpose of the present invention is to
- It is an object of the present invention to provide a low-temperature sintered porcelain that has a low sintering temperature that allows electrode materials such as Pd to be co-fired, and has a thermal conductivity close to that of a high-temperature sintered alumina substrate.

[Means for Solving the Problems] To achieve the above object, the present invention provides a low-temperature sintered porcelain consisting of a large number of crystal grains and a glass layer, in which at least a part of the large number of crystal grains is on the surface. The present invention relates to low-temperature sintered porcelain characterized by aluminum nitride crystal grains having an aluminum oxide layer.

[Function] Aluminum nitride crystal particles contribute to improving thermal conductivity. Even if a glass component is mixed into the aluminum nitride crystal particles themselves, sintering is impossible or difficult, and a dense and highly thermally conductive sintered body cannot be obtained. In the case of aluminum crystal particles, a dense sintered body with high thermal conductivity can be obtained.

This is because aluminum oxide on the surface of aluminum nitride crystal particles has good wettability with glass.

[Example] Next, Examples (including comparative examples) of the present invention will be described. First, aluminum oxide (A
1203) AIN powder 200 with an average particle size of 1 μm to obtain aluminum nitride (AIN) crystal grains with layers
g with 500 ml of pure water, boiled at 100° C. for 10 minutes, and filtered with suction to separate the powder to obtain aluminum nitride powder having an aluminum oxide layer on the surface.

Next, the obtained aluminum oxide coated AIN powder 100
The weight part contains CaO-B2O3-8i0 with an average particle size of 2 μm.
2.00 parts by weight of glass powder, 14 parts by weight of polyvinyl butyral resin, 14 parts by weight of dibdelphthalate, 60 parts by weight of acetone, and 1 part by weight of oleic acid were added and stirred with a ball mill to prepare a uniform slurry.

Next, the obtained slurry is used to make a thickness of 0.25 ml 1 liter.
A ceramic green sheet was prepared using a doctor blade method and cut into a size of 10CI11×100rrl.

Next, the obtained green sheet was punched out into a disk shape with a diameter of 16 m111 to prepare a first sample piece. In addition, 17 sheets of the obtained Green Sea I. (thickness approximately 4 mm) were piled up and crimped, and then cut into a size of 36 ml 1 x 4 rr 1 m to prepare a second sample piece.

Next, the first and second sample pieces were heated in the air in a heat treatment furnace to 600°C at a rate of 100°C/min, and the atmosphere in the furnace was replaced with a reducing atmosphere of 1% H3vol-1% N297v01. , the temperature was raised to 950° C. at a rate of 100° C./min, held for 3 hours, and cooled to room temperature while maintaining the same atmospheric conditions to obtain first and second sintered body samples. Each sintered body consists of AIN crystal particles 1 having an A I 203 layer 2 on the surface and a glass layer 3, as shown in FIG.

Next, an In-Ga alloy was applied to the bifacial surfaces of the first sintered sample, and an electrode with a diameter of 10+I1 m was provided.
ra] was measured. At this time, the relative dielectric constant ε is 25° at room temperature.
Q is calculated from the capacitance measured at a frequency of 1 MHz at C, and Q is measured under the same conditions as the capacitance above. Further, the resistivity ρ was calculated from the insulation resistance value after applying a DC voltage of 500 V for 60 seconds.

Furthermore, the thermal conductivity [Cal C11l/S 'Ca
&]. Furthermore, regarding the second sintered body sample, the linear expansion coefficient α[1/'C
] was measured.

The boiling column of AIN in Table 1 shows the boiling time for forming an Al2O3 layer on the surface of the AIN powder by boiling it in pure water. The column Parts by Weight of AIN indicates the proportion of AIN powder to be mixed with the glass. A
In the column I 203, the proportion of A1203 powder in parts by weight to obtain the At 2 O crystal particles 4 of FIG. 2 is shown. In the glass column, the proportion of glass powder for obtaining the glass layer 3 is shown. The firing temperature column shows the firing temperature in a reducing atmosphere. Table 2 shows the thermal conductivity, thermal expansion coefficient, ε, Q, and ρ of each sample.

In sample numbers 2 to 5, as is clear from Table 1,
Only the boiling time of the AIN powder was changed from 30 to 180 minutes. A sintered body was otherwise produced under the same conditions as Sample No. 1, and its properties were measured under the same conditions.

For sample numbers 6 to 11, as is clear from Table 1, the sintered bodies were made in the same manner as sample number 1, except that the boiling time was varied and the average grain size of the AIN crystal particles was changed to 5 μm. were prepared and their properties were measured using the same method.

In sample numbers 12 to 15, the boiling time was 30 minutes, and in addition to the Al203N-coated AIN crystal particles, AI 203 powder with an average particle size of 1 μm was mixed with glass and sintered in the same manner as sample number 1. Create a body and measure its properties in the same way. The sintered bodies of sample numbers 12 to 15 are composed of AIN crystal particles 1 covered with an Al2O3 layer 2, Al2O3 particles 4, and a glass layer 3, as shown in FIG.

For sample numbers 16 to 23, AI should not be boiled for 30 minutes.
N crystal particles are fixed at 100 parts by weight, and the glass is 0 to 3 parts by weight.
A sintered body was prepared in the same manner as Sample No. 1, except that the amount was varied within a range of 0.00 parts by weight, and the properties were measured in the same manner.

For sample numbers 24 to 27, sintered bodies were created in the same manner as sample number 1, except that the boiling time was 30 minutes and the firing temperature was varied in the range of 700 to 1200°C, and the characteristics were measured in the same manner. did.

Table 1 Table 1 (Continued) Table 2 Table 2 (Continued) The thermal conductivity of sample number 1 is 0, 033 cal c mark/
°C-, which is significantly larger than that of conventional glass-containing low-temperature sintered alumina substrates. This is because the sintered body contains AIN crystal particles with high thermal conductivity. By the way, the desired sintered body cannot be obtained simply by including AIN crystal particles in the sintered body. That is, as shown in sample number 28, since the boiling time is zero, Al2
A mixture of AIN powder and glass powder that does not have the O3 layer 2 cannot be sintered at 950°C.

When AIN powder with an average particle size of 1 μm is boiled for 10 to 180 minutes as shown in sample numbers 1 to 5, and AIN powder with an average particle size of 5 μm as shown in sample numbers 6 to 11 is boiled for 5 to 240 minutes, a thickness of 0. 01~0.1μm AI 203 scrap 2 is A
Formed on the surface of the IN crystal particles 1, this contributes to improved wettability with glass and enables low-temperature sintering.

When the glass component of sample numbers 16 to 18 is 0 to 40 parts by weight, it cannot be sintered at 950°C. Therefore,
The amount of glass is desirably 60 parts by weight or more.

As shown in sample number 24, sintering does not occur when the firing temperature is 700°C. Therefore, it is desirable that the firing temperature is 800°C or higher.

As is clear from sample numbers 12 to 15, even when AIN crystal grain 1 and AI 203 crystal grain 4 coexist, AI
It is possible to obtain the effect of N crystal particles.

In sample numbers 1 to 15.19 to 23.25 to 27, thermal conductivity, coefficient of thermal expansion, ε, Q, and ρ all have values that are satisfactory as circuit boards.

[Modifications] The present invention is not limited to the above-described embodiments, and, for example, the following modifications are possible.

(1) Although the electrode material was not fired at the same time in the example, in order to form a multilayer wiring board, an integrated circuit package, etc., a paste of the electrode material may be printed on a green sheet and fired at the same time.

(2) As a glass, also used for Ca0-B ○ -3i○ -A1203 series glass, Ba0-B O-9iO-AI203 series glass, BOS i 02 series glass, A12o3-B2O2-8iO2 series glass, etc. can do.

(3) When making a mixture, the type of vehicle (such as a liquid, a dispersant, a solvent, etc.) can be varied.

(4) Al2O3 debris 2 on the surface of the A I N crystal particle 1
In order to create
Alternately, the AIN powder may be heated in air to form an aluminum oxide layer on the surface.

[Effects of the Invention] As is clear from the above, according to the present invention, it is possible to provide insulator porcelain with a high thermal conductivity of 0, even though it is of a low temperature sintering type.

Figure 1

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the principle of a part of the porcelain according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the principle of a part of the porcelain according to another embodiment of the invention. 1...AIN crystal particles, 2...Al203m, 3...
...Glass layer.

Claims (1)

[Claims] A low-temperature sintered porcelain comprising a large number of crystal grains and a glass layer, characterized in that at least some of the large number of crystal grains are aluminum nitride crystal grains having an aluminum oxide layer on the surface. Low temperature sintered porcelain.