JPS6049149B2 - Manufacturing method of white alumina/ceramic for electronic parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a ceramic for electronic parts, such as a white alumina ceramic for electronic parts used for IC boards, circuit boards, packages for integrated circuits, and the like.

Generally, ceramics for electronic parts use high melting point metals such as Mo and W, and are metallized by making the atmosphere during firing either in a reducing state or in a slightly oxidizing state and involving a chemical reaction.

In recent years, simultaneous firing technology has been developed that allows ceramic sintering and metallization to be performed simultaneously to eliminate the process. the current,
Multilayer alumina ceramics typically consist of multiple ceramic substrates in combination with internal metallized regions, with 15
It is sintered at high temperatures ranging from 00 to 17000C. Therefore, there is a drawback that the life of the electric furnace, the substrate firing service, the time required for firing the substrate, and the amount of time required to burn the electric furnace increase. Furthermore, white alumina ceramics for electronic parts are desired to have a smooth surface, but the above-mentioned high-temperature firing often has the disadvantage that excellent surface smoothness cannot be obtained due to crystal grain growth. The present invention was made to eliminate such drawbacks, and is an alumina ceramic for electronic parts that can significantly lower the firing temperature of conventional ceramics and that can provide excellent surface smoothness as an alumina ceramic for electronic parts. The present invention provides a method for manufacturing white alumina ceramic, thereby reducing firing costs and improving the surface roughness of the ceramic.

In accordance with this purpose, the method for producing white alumina ceramic for electronic components according to the present invention includes an Al content of 80 wt% or more.
. O. and point A) 10:20:70 where average 00:MgO:5i00 (wt%) is 50:20:30 in the composition diagram.
A composition consisting of additives consisting of B2O3, MgO, and SiO2 powders having a Ξ-gonal composition connecting points B and C of 10:60:30 is prepared, and the particle size of the composition is adjusted to 2 μm. It is characterized by the following adjustment and firing. Examples of the present invention will be described below. Composition example of O alumina ceramic (wt%) Crosspiece O.

, MgO, SiO. The composition diagram of additives A-L is shown in the figure. The composition table is shown in Table 1. Prepare an additive having the composition shown above.

As Ae2O3, alpha alumina with a purity of 99 wt% or more is used. O Preparation of alumina/ceramic green sheet Add the above-mentioned composition up to Additive A to Af2O3,
A composition with an Ae2O3 purity of 80, 85, 90, 95, 99 wt% is put into a ball mill, and a solvent, plasticizer, and binder are added to all samples in the following proportions.

Ae2O3 + B2O3, MgO, SlO2 Additives 10 parts Binder polyvinyl butyral 5 Plasticizer di-octyl phthalate 3 Solvent methanol
10〃Toluene
12〃Cyclohexane 20〃Samples were directly slip-cast using the above combination of ceramic, binder, plasticizer, and solvent until the average particle size of the ceramic particles was 0.5, 1, 2, or 3μ to obtain a slip-cast composition. Thoroughly mix and grind.

The slip cast composition thus formed is doctor bladed onto a Mylar substrate using known casting techniques to a width of 10C77. , to form a sheet with a thickness of 0.57rn. This sheet was then dried in a drying oven for 1 time to remove volatile solvents.
It was dried at 00℃ for 3 times and peeled off from the Mylar substrate.
Cut into 5C7n square sheets. For comparison with conventional θ products, CaO:MgO:SiO2=20:10:70 (
The additive composition (Wt% ratio) was changed to the same α-
Using Ae2O3, A'203 purity 80, 85, 90
,95,99 Wt% alumina ceramic powder,
The powder was reduced to an average particle size of 50.5, 1, 2 by the same means as above.
, 3μ of ceramic particles. ○ 1300 and C, 13500C, 14 under firing reducing atmosphere
Bake at 00°C and 1450°C for 3 hours.

) Alumina/ceramic sheet using Additive A and conventional alumina ●Tables 2 to 2 show the relationship between alumina purity, average particle size of ceramic particles in raw sheet, firing temperature, and degree of sintering in the case of ceramic sheet. It is shown in Table 4.

The degree of sintering is determined by the fuchsin test (dip the ceramic in fuchsin liquid, and if the fuchsin liquid does not penetrate into the ceramic after 1 sintering, the product is good), and the water absorption rate test (dip the ceramic in water, and after 1 hour of vacuum defoaming, the water absorption rate is 0. If it is less than .1%, it is a good product),
As a result of the porosity test (ceramic is mirror-polished and its porosity is measured using a porosimeter, if it is within 5%, it is considered to be a good product. shall be. From this B
When the alumina ceramic using 2O3-MgO-SiO2 additives A-G has an Ae2O3 purity of 80 wt% or more and the average particle size of the ceramic particles is 2μ or less, a significant decrease in the firing temperature is observed.

803-Ae using MgO-SlO2-based additives A-G
Alumina ceramic with 2O3 purity of 95wt% and Al2
Table 5 shows the relationship between the ceramic average particle diameter and surface roughness in the raw sheet of a conventional product with an O3 purity of 95 Wt%.

The firing temperature is as follows in order to prevent surface roughness from deteriorating due to crystal grain growth due to over-firing. A-
G Conventional product 0.5μ, 1μ: 1380℃ 14800C2μ
〃 1450℃ 1550℃ 3μ 〃 1500℃
1600°C From this, it can be seen that the white alumina ceramic obtained by the present invention has improved surface roughness compared to the conventional product.

As detailed above, the white alumina ceramic obtained by the method of manufacturing white alumina ceramic for electronic components of the present invention has the advantage of significantly lower firing temperature and surface roughness compared to conventional products. has.

[Brief explanation of the drawing]

The drawing is a ternary composition diagram of the B2O3-MgO-SiO2 additive of the present invention.

Claims (1)

[Claims] 1 80wt% or more Al_2O_3 and B_2O_3
:SiO_2 (wt%) is 50:20 in the composition diagram:
30 point A, 10:20:70 point B, 10:60:3
B_2O_3,M which has a triangular composition connecting point C of 0
A method for producing white alumina ceramic for electronic components, which comprises preparing a composition comprising additives consisting of gO, SiO_2 powder, adjusting the powder diameter of the composition to 2 μm or less, and firing.