JPH0333027A - Glass paste for manufacture of ceramic substrate - Google Patents

Abstract

PURPOSE: To form a glass paste for manufacture of a ceramic substrate which is possible to be plasticized at low temp., has an excellent substrate surface and is excellent in printability, drying rate, plasticizing rate, etc., by compourding a specific vehicle into PbO-B₂O₃-ZnO system noncrystal glass powder having a low softening point.

CONSTITUTION: The glass paste for use in the manufacture of the ceramic substrate is formed by mixing A) 75 to 95 wt.% glass powder having a low melting point (melting point: ≤400°C, consisting of PbO: 60 to 85%, B₂O₃: 5 to 10%, ZnO: 2 to 25%, SiO₂: 1 to 15%, Al₂O₃: 5 to 15%) with B) 5 to 30 wt.% vehicle [consisting of 1) a binder (a mixture of isobutyl methacrylate and nitrocellulose): 1 to 20 wt.% and 2) a solvent (≥ one kind selected from ester based alcohol, ethyleneglycolmonobutylether and terpineol): 80 to 99 wt.%.].

COPYRIGHT: (C)1991,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a glass paste used for manufacturing ceramic substrates, and particularly to a glass paste that can be plasticized at low temperatures.

(Prior technology) A paste layer containing glass as the main component is applied thinly to the surface of an alumina (Ah(h)) substrate for use in integrated circuits.
Ceramic substrates obtained by plasticizing this have features such as the roughness of the surface, excellent hue and smoothness of the sealing glass itself, and excellent adhesive properties, making it possible to reduce the bonding thickness of the substrates. Widely used.

In order to manufacture such a plastic ceramic substrate, −
For boat fishing, a screen printing method is used to apply a paste made by mixing a PbO-BzOs-ZnO based low melting point glass composition powder, a combination of ethyl cellulose or nitrocellulose, and an isoamyl acetate solvent onto a ceramic substrate such as alumina, barium, etc. A method is used in which a glass paste is applied to a ceramic substrate through a drying and plasticizing process, and then bonded to a ceramic substrate.

Recently, considering the simplification of the printing process and the danger to workers,
Various wood stuffing agents and high boiling point solvents are used in a way that volatilizes and decomposes at temperatures above room temperature and can be stored and used for long periods of time. The types include acrylic resin, ester alcohol, butyl cellosolve, etc. These solvents evaporate at 150°C to 200°C, and
The decomposition and scattering of the binder occurs at high temperatures of 0°C or higher in an oxidizing atmosphere.

(Problems to be Solved by the Invention) Such conventional bonding pastes for ceramic substrates are dried in an oxidizing atmosphere at high temperatures (200 to 330 degrees Celsius) to make them plastic, in consideration of workability and toxicity. When adhering to the surface of a substrate, the decomposition temperature of the hydrocarbon solvent and adhesive is higher than or equal to the transition point or softening point of the glass composition, which is the main raw material for paste production, and a certain increase in temperature is required. If the temperature speeds do not match, the solvent and adhesive used will not decompose and will carbonize.
Since carbon substances remain on the surface of the ceramic substrate or the bonded contents, problems such as blackening of the surface color and deterioration of adhesive strength and airtightness due to this have been pointed out.

In order to solve these problems, the present invention was developed as a result of research efforts, and by decomposing the transition point and softening state at a lower temperature than the low melting point glass composition for bonding, carbonized substances are formed on the surface of the ceramic substrate. We found a new m-acid ratio in a vehicle that does not leave any residue, and as a result, we were able to obtain a paste for ceramic substrates that has excellent substrate surface and internal effects, such as printability, drying speed, plasticity speed, etc. Therefore, an object of the present invention is to provide such a paste for ceramic substrates.

(Means for Solving the Problems) The present invention provides a) PbO-
B2O3-ZnO-based amorphous glass powder 70-95% by weight
and) A mixture of isobutyl methacrylate resin and nitrocellulose, or binders 1 to 2 containing each of these.
0% by weight, and 80 to 99% by weight of one or more solvents selected from the group of ester alcohols, ethylene glycol monobutyl ether (hereinafter abbreviated to the trade name butyl cellosolve), and terpineol.
30% by weight of the glass paste for manufacturing ceramic substrates.

The present invention will be explained in detail below.

The glass paste according to the present invention is a glass molded body made of a low-melting glass powder having a softening point of 400° C. or less and a vehicle made of a hydrocarbon, and the vehicle is made of a binder and a solvent.

The low melting point bonding glass used in the present invention is a PbQ-BzO+-ZnO-based amorphous glass powder with a softening temperature of 400°C or less, and its composition content is 60 to 85% PbO,
B20, 5~1O%, ZnO2~25%, 5i (h 1
~15%, A1□035~15%, and the particle size used is 100 mesh or less.

The vehicle used in the present invention sufficiently evaporates and decomposes at temperatures below 300°C, and the residual content has low chemical energy activity, so even if heated while still in the sealing glass, it will not cause chemical damage to the sealing material. It has a strong property of binding glass powder particles together without causing physical or physical changes, and is composed of hydrocarbons that are in a solid state.

An example of a hydrocarbon with such properties is the molecular formula C
nHzn+z (n=15-30) or C-B211
-2 (n=15~30), Cn)12,1(n=
6 to 24), but here, if the number of carbon atoms in C4IH2n*2 or Cnfhn-z is less than 15, even in a solid state at room temperature, the number of carbon atoms is 30.
If it exceeds this value, carbon may remain in the adhesive layer during heating, resulting in a black surface and generation of bubbles, which is undesirable. Also, C, In2. If the number of carbon atoms in , is less than 6, solidification will occur at room temperature, and if it exceeds 24, carbon will remain in the adhesive layer upon heating, and bubbles will remain.

Examples of hydrocarbons that satisfy these conditions include isobutyl methacrylate resin, nitrocellulose, etc., which can be used as a binder, and ester alcohol solvents, butyl cellosolve, terpineol, etc., which can be used as a solvent.

When a conventional general resin binder is used instead of the binder and solvent used in the present invention, the durability and adhesive strength are high, but there are drawbacks such as a wide range of required decomposition and scattering, and a large amount of residual hydrocarbons. Therefore, it is limited in its use in applications requiring a high degree of integration.

On the other hand, the vehicle solution according to the present invention consists of 1-20% binder and 80-99% solvent;
If it is lower than 20%, the molding and bonding strength of the low melting point glass powder will be reduced, and if it is higher than 20%, there will be a residue after plasticity, which will be liberated on the surface and the sealing strength will drop during the sealing process. This is the main cause of bubble formation at the interface with the substrate.

When bonding the glass paste according to the present invention to a ceramic substrate, after adding a small amount of ester or ether solvent to the glass paste, a molded rod of the composition is manufactured by silk screen printing method, and this is dried. First, the solvent is evaporated and decomposed, and then the predetermined molded object is bonded to the ceramic substrate using a plasticizing method.

(Effects of the Invention) According to the present invention, a ceramic substrate that can be plasticized particularly at low temperatures, has no carbonized substance remaining on the surface of the ceramic substrate, provides an excellent substrate surface, and has excellent printability, drying speed, plasticity speed, etc. A glass paste for manufacturing a substrate can be provided.

(Example) Hereinafter, the present invention will be specifically explained based on Examples.

Example 1 Ester alcohol (trade name, TEXANOL: C
+zHz40*) 50g of acrylic resin binder (trade name, ELVACIT11! 2045: isobutyl methacrylate CaHzO□) was dissolved in 200g of solvent, and after aging until no viscosity change occurred, further dissolved in solvent 2
00g was added.

Subsequently, PbO 60-85%, B, 0.5-20%, Z
n0z 25%, Sing 1-15%, Al2O35
Add 400 g of PbO-BxQ*-ZnO-based low melting point glass (softening point 380°C) powder with a weight ratio of ~15%,
Mix for 3 hours to avoid layer separation of the product.
It was fully aged for 7 days using a roller with a rotation speed of 5-20.

This was placed on a mask with the same shape as the ceramic substrate shape, printed on the ceramic material located below, and then dried in an oxidizing atmosphere at a temperature of 100°C to 200°C for 5 to 15 minutes, and further in a plastic furnace. After the adhesive was decomposed and scattered, it was bonded to a ceramic substrate by maintaining the adhesive at about 30° C. higher than the softening temperature.

The viscosity of the adhesive and solvent after aging in the above method was 4000 centipoise at 25°C. Further, the viscosity after mixing the low melting point glass powder and sufficiently ripening was 150,000 centipoise at 25°C.

In addition, the drying temperature after printing molding is 100℃, 130℃, 1
5 minutes each at 50℃, 170℃, 190℃, 200℃, 1
After drying for 0 minutes, 15 minutes, and 20 minutes, dry at 380°C again.
The glass powder particles were made plastic by increasing the temperature to 400°C, 420°C, and 450°C.

Examples 2 to 7 Examples were carried out in the same manner as in Example 1 above, except that the compositions of the binder and solvent were changed as shown in Table 1 below.

Internal pores due to residual organic hydrocarbons in the ceramic substrates manufactured according to Examples 1 to 7 above.
In order to confirm the degree of discoloration, each fracture surface was analyzed using a scanning electron microscope, and the degree of surface discoloration of the adhesive composition was observed with the naked eye. The results are shown in Table 1 below.

I: Isobutyl methacrylate resin N: Nitrocellulose E: Ester-based alcohol B Nibutyl cellosolve T: Terpineol (TERPINBOL) As can be seen from Table 1, the glass paste for manufacturing ceramic substrates according to the present invention requires a high temperature compared to the conventional one. The decomposition and scattering temperature was lowered to about 400°C, and the low energy and residual amount resulted in an excellent surface pattern, fewer internal pores, and greatly improved adhesive strength.

Claims (1)

[Claims] A) PbO-B_2O_ whose softening temperature is 400°C or less
3-70 to 95% by weight of ZnO-based amorphous glass powder, b) a mixture of isobutyl methacrylate resin and nitrocellulose, or 1 to 20% by weight of a binder containing each of these, and ester-based alcohol, ethylene glycol monomer. A glass paste for producing ceramic substrates, characterized in that it comprises 80-99% by weight of one or more solvents selected from the group of butyl ether and terpineol, and 5-30% by weight of a vehicle.