JPH03163173A - Conductive paste for aluminum nitride substrates - 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] Regarding the conductor paste for aluminum nitride substrates, the purpose is to put into practical use a conductor paste with a low conductor resistance value. The conductor paste used to form the conductor pattern is made by adding 0.2 to 0.7% by weight of aluminum nitride powder to tungsten powder, adding a binder and a solvent to the powder, and kneading the mixture. Characteristically, the conductive paste for aluminum nitride substrates is constructed.

[Industrial application field]

The present invention relates to a conductor paste for aluminum nitride substrates having low conductor resistance.

Due to the need to process large amounts of information at high speed, information processing devices are becoming smaller and larger in capacity, and the semiconductor integrated circuits that make up the main component of these devices have improved in integration, and LSI and VLS have been put into practical use. .

These integrated circuits are then mounted on a ceramic chip mounting board (interposer) to create an LSI module, which is then mounted on a printed circuit board or the like as a replacement unit. There is a lot of momme.

As described above, as the degree of integration of semiconductor integrated circuits increases and high-density packaging is performed, the amount of heat generated by devices is increasing at an accelerating pace.

That is, initially, the amount of heat generated per IC chip (approximately 3.
The amount of heat generated per LSI chip has increased to about 10W, which used to be as low as about 5W, and when a large number of LSI chips are installed in a matrix, the amount of heat generated is enormous, and this is expected to increase further. There is a tendency K to do so.

Conventionally, chip mounting boards for mounting LSI chips, etc., have been made of aluminum-t (Al20), which has high thermal conductivity and excellent heat resistance.
3) has been used.

However, alumina has excellent thermal conductivity\20W/
ml<, which is insufficient as the material for the above-mentioned chip mounting substrate piece.

Therefore, AI has a thermal conductivity of 320 W/mK (theoretical value) and a coefficient of thermal expansion close to that of silicon (Si)!
N has attracted attention, and efforts are being made to put this substrate into practical use.

In addition to its excellent thermal conductivity, AIN also has a thermal expansion coefficient of 4.4
(7) It has the advantage of being close to the coefficient of thermal expansion (3.6x 10-@/'C).

[Conventional technology]

The method for manufacturing ceramic multilayer circuit boards is to make a slurry by kneading ceramic powder with a sintering aid, binder, plasticizer, and dispersant, and then use the doctor blade method to make a grit sheet. A via-hole is made by drilling a hole, and a conductive paste is screen printed on the via-hole to fill the via-hole and form a conductor line.

Then, a multilayer ceramic circuit board is produced by laminating the Kaharu Green sheets while accurately positioning them, pressurizing them to integrate them, and then firing them at a high temperature.

Since AiN has a high melting point of 22QO'C and requires a high firing temperature of 1600℃ or higher, high-melting point metals such as tungsten (W) and molybdenum (Mo) are recommended as constituent materials for conductor lines. CRefactory-
metal) is used.

A W conductor paste whose main constituent is W powder is already commercially available.

However, this W conductor paste is intended for use with alumina substrates, and there is a problem in that even if it is applied directly to an Aj7N substrate, the adhesion is poor and a highly reliable conductor pattern cannot be formed. It has been reported that the conductor resistance of a W conductor paste for AAN can be minimized by adding 1% by weight of An powder to the W paste.

(Hamaguchi et al. Proceedings of the 1986 Ceramics Association Annual Meeting p305, 1
(986) However, according to experiments conducted by the inventors, the addition of 1% by weight of AIN increases the conductor resistance.

The reason for this is that A47N has a high resistivity of >lQl3Ω・am and is an insulator, and the specific gravity of AIN is 3.26, whereas the specific gravity of W is 19.3, which is about 6 times larger. I think that the.

[Problem to be solved by the invention]

The resistivity of W is 4.9μΩ・cm (0℃) and that of Cu is 1.5
It is more than three times larger than 5 μΩ·cm (0° C.), and therefore, the conductor line obtained by screen printing the W conductor paste has a large resistance, and there is a problem that power loss cannot be ignored.

Therefore, reducing the resistance of conductor lines is an issue when putting AIN multilayer circuit boards into practical use.

[Means to solve the problem]

The above challenges are AI! The conductor paste used to form a conductor pattern by screen printing on an N green sheet and baking it to form a conductor pattern contains 0.2 to 0.2 to 0.2 to 0.2 AfN to W powder.
This problem can be solved by constructing a conductor paste for AIN substrates, which is characterized by adding Q, 7-layer ji96, adding a binder and a solvent to this powder, and kneading the powder.

[Function] The inventors developed AI for W conductor paste! As a result of researching the effect of adding N, it was found that when AIN powder is added to W paste and sintered, the W conductor becomes more dense than when no additive is added.

However, when Aj7N powder is added, the resistivity increases because it is an insulator.

Therefore, the inventors investigated the relationship between the relative density and volume resistivity of the W conductor with respect to the amount of AIN added, and found that 0.2% by weight
It was found that the above addition resulted in densification, and that the resistivity was lower than that without additives up to the addition of 0.8 weight 96.

〔Example〕

Add AIN powder to the W powder in a range of 0 to 5% by weight, and to 100 parts by weight, triple ffi 96 ethyl cellulose as an organic binder, 15% by weight of butyl carbitol and 100% by weight of methyl ethyl ketone as a solvent.
In addition, 17 types of W pastes were prepared by kneading using a ball mill, a mulch mill, and a three-mouth remill.

This paste was printed on an AIN green sheet with a thickness of approximately 500 μm, heated to 600°C in a N2 stream to degrease it, and each sample was baked at 1700°C in a N2 stream for 9 hours to form an AlN wiring board. was formed, and the sheet resistance of each wiring board was measured.

Table 1 shows the relationship between the amount of AlN added to W and the sheet resistance. As the amount of AfN increases, the sheet resistance gradually decreases, reaches a low value with the addition of 0.5% by weight, and then starts to rise. FIG. 1 illustrates this relationship.

Here, the sheet resistance is less than 13 mΩ/mouth and AI! The range where the value is much lower than when no N powder is added is 0.
．． 2 to 0.7 weight 96, and this range of AIN
I can see if adding powder is effective.

〔Effect of the invention〕

0.2 to 0.7 weight of A47N powder to W powder? 6
By implementing the invention using a doped conductor paste,
It is possible to manufacture an AfN multilayer ceramic circuit board having conductor lines with lower resistance than conventional ones.

Table 1 4.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the effect of adding An to W conductor paste. Figure 1 showing the effect of 0 effect of W Dokyu Paste vs. Naro AIN

Claims (1)

[Claims] The conductor paste used to form a conductor pattern by screen printing on an aluminum nitride green sheet and baking it to form a conductor pattern has aluminum nitride powder added in an amount of 0.2 to 0.7% by weight based on tungsten powder. A conductor paste for an aluminum nitride substrate, characterized in that it is made by adding a binder and a solvent to the powder and kneading the mixture.