JPS58213671A - Manufacture of high heat transmission ceramics - 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 The present invention relates to a method for producing ceramics that significantly improves thermal conductivity and maintains high insulation properties.

For example, printed wiring boards made of thin plates of high-aluminum porcelain have had higher heat dissipation density in recent years as the mounting density of electronic circuits has increased, so there is a strong demand for materials with high heat dissipation. Even in the case of high alumina porcelain, which is commonly used because it is inexpensive and exhibits high thermal conductivity, there is an upper limit for mass production. ! 0.07c even for high purity products
However, the above requirements could not be met.

The present invention has established a method for producing highly thermally conductive ceramics that significantly improves thermal conductivity without significantly reducing the insulation resistance of various types of ceramics, including the above-mentioned printed wiring boards. explain.

Example 1 (a) Alumina sol (#koO0, alumina content iochi9 Nissan Chemical) /301 0aCO3 (commercial product) average particle size 0. Cop O
, cofMgCOs (commercial product) average particle size o, iμ
o, ty silicic anhydride (commercial product) average particle size 0.3μ
0. A nonionic surfactant (Nonion E-230° HLB value tzs, NOF) is added to the ceramic raw material fine powder (first raw material powder) consisting of /f! 2 Blend 40 cc of water core and mix by magnetic stirrer to make the first % dispersion.

(b) Fears (commercial product, average particle size 0.jp)
#JfMoss (commercial product, average particle size 0.jp
) Polyethylene oxide (water-soluble particle binder) /f water 41-
10 cc was mixed using the same magnetic stirrer to create a second dispersion frost. (c) Ethylene tetrachloride (water-insoluble solvent) / #6O
f Nonionic surfactant (OP-rob.

HI, B value 3, Nippon Oil & Fats) Ff are mixed using a magnetic stirrer as before to make non-aqueous solvent 0. The second raw material powder is dispersed in water using a surfactant and then emulsified in a non-aqueous solvent to create a W2-〇 emulsion in which countless W2 lumps are dispersed in θ.

(E) W2-0 construction! The W2-0 emulsion and the above-mentioned components are mixed with stirring, and a -0-Wt composite emulsion is prepared using the W2-0 emulsion and a nonionic surfactant having a different HLB value, which is blended into the first dispersion Wi.

This %-0-% composite emulsion consists of the first dispersion W
The second dispersion W2 coated with the non-aqueous solvent 0 was dispersed in the form of a slurry.

(f) The slurry-like %-0-glum composite emulsion was molded by a doctor blade method.

(G) This molded product was held and fired at 14!20°C for 1 hour in a hydrogen atmosphere with a dew point of J0°C.
Xj OHx O,6m Otlh Crystalt” 11
Ta.

The sintered product is sintered using powder metallurgy and is made up of countless polyhedrons of aO to 601t consisting of fine particles of 9-Fe and Zinc with a film thickness of 4! ~7μ
It had a dense cross-sectional shape that was firmly bonded by the front and rear sintered alumina insulating layers.

Table 1 shows the results of measuring the properties of the sintered product thus obtained.

From the above table, it can be seen that the sintered product obtained by the above embodiment of the present invention has a
It suppresses the feared decrease in insulation resistance to a negligible level and significantly increases the target thermal conductivity, making it ideal for printed wiring boards that require particularly high heat dissipation. The thermal conductivity of the enamel board, which is made by baking glass onto an iron plate, is said to be excellent in terms of quantity and quality. /12 & shira・sea
・TaO@ is also high relative to °C, and the packaging density of electronic circuits can be significantly increased.

In addition, in the above Example 1, CaCO5*MgCO3,5 was added as a mineralizer to alumina sol as the first raw material powder.
Although a small amount of iOz was added, some or all of these were added to calcium stearate, magnesium stearate,
By replacing it with a water-insoluble organic compound such as ethyl silicate and blending it with the non-aqueous solvent O, the function of the non-aqueous solvent is enhanced, and in the sintering process, a CaO-MgO-Sing system glass is produced and sintered with nine Fe, It is possible to further improve the adhesion between the Mo fine powder and the alumina insulating layer covering it. Granulated by spray drying by adding 0.3- or less! A thin layer of gel-like alumina fine powder covering the surface of the N grains is hardened to make handling easier, and a trace amount of ethyl cellulose or the like is added as a water-insoluble particle binder to the non-aqueous solvent 0. It is also effective.

Example Coforsterite porcelain (4 electric 0-8 iOz) Raw material fine powder Average particle size 0. ! μlOf nonionic surfactant (Noigun HA-770, HLB value 17, Daiichi Kogyo Seiyaku) ≠2 water
First dispersion W1 consisting of a mixture of 000 cc of Fe2Og (commercial product, average particle size 0.3fi)
//3ft polyvinyl alcohol (Ten force B-
or) (water-soluble particle binder) /1 water
'! '00 ee diluted dispersion consisting of a mixture of ethylene dichloride (a water-insoluble solvent) and a nonionic surfactant (Noogen EA-ss, HLB value≠1 Daiichi Kogyo Seiyaku) 11. Non-aqueous solvent consisting of a mixture 0
Similar to the previous example, a slurry-like %-0-% emulsion was made by three people, and after casting in a plaster mold, it was heated to 14410°C and 0.5°C in a hydrogen atmosphere with a dew point of -2j°C.
A sintered product of ■φX/mt obtained by firing under conditions of holding for 1 hour consists of a polyhedron of jo to 609 made of a sintered body of fine particles of metallic iron, and an insulating layer of 7 orsterite porcelain of around jμ. It exhibited a cross-sectional shape that was strongly connected.

As shown in Table 2, this sintered product showed remarkable effects in greatly improving the thermal conductivity of forsterite porcelain without having any adverse effects on its properties.

Embodiments 1 and 2 above are both intended for printed wiring boards, but since the present invention can also be cast as in embodiment 1, it requires particularly high heat dissipation properties as well as insulation resistance and other properties of ceramics. The present invention can be applied to the production of thick-walled ceramics such as IC packages, etc., not only to plate-shaped bodies but also to cylindrical rods and the like.

In addition, it is possible to further improve heat dissipation by using beryllia, which has particularly high thermal conductivity, as the highly insulating first raw material fine powder, and as the highly thermally conductive second raw material fine powder. is Fe20s m shown in the example
In addition to oxides that are metallized by firing such as Mo5s, other compounds or metals may be used directly, and carbides such as h stc and BN that are stable in a non-oxidizing atmosphere.

Although nitrides can also be used, the first and second raw material fine powders have similar coefficients of thermal expansion and sintering temperatures (the following combinations of materials are preferred).

Therefore, the insulating layer formed from the above-mentioned first raw material fine powder exhibits sufficient specific characteristics even at an extremely thin film thickness of about 2 μm, and even when it is thickened, it exhibits heat dissipation properties according to the film thickness. Although not particularly limited, it is preferably about 3 to tμ, and the blending ratio of the first raw material fine powder and the second raw material fine powder is determined depending on the desired film thickness.

Next, the preferable conditions for producing a satisfactory %-0-Wl emulsion are: first, the content of O and O is equal to or less than the cancer (volume ratio, hereinafter the same), and the relationship between W2 and O is as follows: Also, W2 is equivalent to //II with respect to O, and furthermore, the surfactant in Wl is o, io, z% with respect to water, and the surfactant in 0 is a water-insoluble solvent. For O, Co ~ Co%, %
The first raw material fine powder inside is 2 to 4% based on water.

The nonionic surfactants added to Oni and 0 are:
As mentioned above, depending on their HLB value, the former is for adding oil to water and emulsifying it, the latter is for adding oil to oil and emulsifying it, and the former is for adding a nonionic surfactant to the light. The HLB value is 13 or more, and the HLB value of the nonionic surfactant added to the latter O! It is as follows.

Procedural amendment (voluntary) dated May 6, 1958 Kazuo Wakasugi, Commissioner of the Patent Office1, Indication of the case: Patent Application No. 97373 of 1982, Title of the invention: Process for manufacturing highly thermally conductive ceramics, 3, Amendments made. Relationship with the Patent Case Patent Applicant Address 14-18 Takatsuji-cho, Mizuho-ku, Nagoya Name (
454) NGK Spark Plug Co., Ltd. Representative: Shuho Ogawa 4, Agent Address: Postal Code: 467 Name: 4-3-3-5, Takada-cho, Mizuho-ku, Nagoya City, Subject of Amendment 1, Specification, Page 5 In line 13 and in line 11 of page 9, ``innumerable polyhedra'' has been corrected to ``innumerable lumps.''

2, page 7, line 9, Correct "140%" to "70%".

3, page 8, lines 4 to 6, "The thin layer of gel-like alumina fine powder bundles that coat the surface of the granules granulated by spray drying is hardened to facilitate handling." Delete.

4. The 4th to last line of page 12 will be corrected as follows.

“The blending ratio of the first raw material fine powder and the second raw material fine powder is determined according to the desired film thickness.

Next, W2-O-W should be added by 1, and the preferable conditions for producing an emulsion are: First, the total amount of W2 and O is equal to Wl to 1/4 (capacity ratio, the same applies hereinafter), Wi and 0 The relationship between W2 and O is equal to 1/4, and the first and second raw material powders are dispersed in the form of a slurry in the first dispersion W1 and the -second dispersion W2, respectively. The blending ratio with respect to water is determined so that the amount of metal is about 10 to 40% by weight of both metals. Further, the surfactant in the first dispersion W is in the range of 0.1 to 0.5% by weight based on the water content, and the surfactant in the non-aqueous solvent is in the range of 0.1 to 0.5% by weight based on the water-insoluble solvent. It is 0.2 to 2% by weight.

In addition, the nonionic surfactant added to Wl and 0 is as follows:
As mentioned earlier, depending on their HLB value, the former is for adding oil to water and emulsifying it, and the latter is for adding water to oil and emulsifying it. It is preferable that the HLB value is 15 or more, and the HLB value of the nonionic surfactant added to the latter O is 5 or less. ” Above 389-

Claims (1)

[Claims] (a) A fine powder of a ceramic raw material having high insulating properties is used as a first raw material powder, and a nonionic surfactant and water are added and mixed to form a first dispersion. The process of making a sparrow. (b) Above 18, the first raw material powder also has one or more fine powders selected from inorganic materials such as metals, metal compounds that can be metallized by firing, carbides, and nitrides, which have high thermal conductivity. A step of preparing a second dispersion W2 by adding and mixing a water-soluble particle binder and water to the first raw material powder. (C) Water-insoluble solvent and (B) nonionic surfactant) are also nonionic surfactants with low HLB value) W2 above
The process of mixing and emulsifying W*-0 with 0 to create a W*-0 emulsion. (f) A slurry-like composite emulsion made by mixing the above W2-0 process and Wl and dispersing Uma-0 throughout the prefecture%-〇-
Process of making W1. (f) A step of molding a desired element body using the slurry-like composite emulsion % -0-Wi by a doctor blade method or a casting process. (g) A process of sintering in a non-oxidizing atmosphere. A method for producing highly thermally conductive ceramics consisting of