JP3424219B2 - Low melting point sealing composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low melting point sealing composition, and more specifically, a ceramic package for an IC or a crystal unit, a display device such as a CRT for color TV, a fluorescent display tube, a plasma display panel and the like. The present invention relates to a low melting point sealing composition suitable for sealing the above.

[0002]

2. Description of the Related Art Conventionally, a sealing material using a low melting point glass has been widely used for sealing ceramic packages and display devices.

Main characteristics required for such a sealing material
The sealing temperature is low and the coefficient of thermal expansion is suitable for the adherend.
It has good mechanical strength and chemical durability.
There are such things. Therefore, P is generally used as the sealing material.
PbO-B with high bO content ₂ O₃ Low melting point glass
It is used for adjusting the thermal expansion coefficient and improving the mechanical strength.
Therefore, refractory filler powder is mixed. For example
No. 2-229738 has PbO-B₂ O₃ Low melting point
Dot glass powder and refractory filler powder (lead titanate ceramic
Mick powder and low expansion ceramic powder)
Fees are proposed.

[0004]

By the way, in recent years, PbO
For using a low melting point glass containing a large amount of
It has been pointed out that there is a problem in the living environment, and these glasses should have a PbO content as low as possible (preferably Pb
It is desired to substitute O) -free glass).

The present invention has been made in view of the above circumstances, and an object thereof is to provide a low melting point sealing composition capable of satisfying various properties required while reducing the PbO content. To do.

[0006]

Means for Solving the Problems In order to reduce PbO, Bi in which a part or all of PbO is replaced with Bi ₂ O ₃ is used.
It is conceivable to use a ₂ O ₃ -B ₂ O ₃ (-PbO) type glass, but this type of glass tends to have a higher viscosity than the PbO-B ₂ O ₃ type glass, and is simply PbO.
It is not possible to obtain a sealing material that can be sealed at a low temperature simply by substituting Bi ₂ O ₃ for.

In the case of Bi ₂ O ₃ --B ₂ O ₃ (--PbO) type glass, the effect of the content of B ₂ O ₃ on the viscosity of the glass is very large, and the lower the content of B ₂ O ₃ , the lower the viscosity. Glass can be easily obtained. However, since B ₂ O ₃ is a component that has a large effect of stabilizing the glass, if it is too small, the glass becomes unstable and devitrification easily occurs, resulting in poor fluidity. Therefore, stabilizing the glass while reducing the B ₂ O ₃ content as much as possible is an issue in composition development.

Therefore, as a result of various studies by the present inventors, in Bi ₂ O ₃ --B ₂ O ₃ (--PbO) based glass, Fe ₂ O ₃ has a very large effect on stabilizing the glass. Yes, by incorporating this in glass, B ₂
It was found that a glass having stable and excellent fluidity can be obtained even if the content of O ₃ is reduced, and is proposed as the present invention.

That is, the low melting point sealing composition of the present invention has a weight percentage of Bi ₂ O _{3 of} 45 to 90% and B ₂ O _{3 of} 1 to 20.
%, Fe ₂ O ₃ 0.3-8%, PbO 0-44.9
%, SiO ₂ + Al ₂ O ₃ 0-5%, ZnO + CuO
0-15%, Cs ₂ O 0-10%, TeO ₂ 0-4
%, Characterized in that it consists of glass powder containing F ₂ 0%.

The low melting point sealing composition of the present invention has a weight percentage of Bi ₂ O _{3 of} 45 to 90% and B ₂ O _{3 of} 1 to 20.
%, Fe ₂ O ₃ 0.3-8%, PbO 0-44.9
%, SiO ₂ + Al ₂ O ₃ 0-5%, ZnO + CuO
0-15%, Cs ₂ O 0-10%, TeO ₂ 0-4
%, Glass powder 45-95 containing F ₂ 0-10%
It is characterized in that it is composed of 5% by volume of refractory filler powder and 55% by volume of refractory filler powder.

[0011]

In the low melting point sealing composition of the present invention, the reason why the glass composition is limited as described above will be described below.

Bi ₂ O ₃ is the main component of glass and has the effect of stabilizing the glass, and its content is 45 to 90.
%, Preferably 45 to 85%. Bi ₂ O ₃ is 45
%, PbO is added to obtain a glass having a low melting point.
Must be contained in a large amount, and if it exceeds 90%, the glass becomes unstable.

B ₂ O ₃ is a component having a large effect of stabilizing the glass, and the content thereof is 1 to 20%, preferably 3 to 12%. If the content of B ₂ O ₃ is less than 1%, stable glass cannot be obtained, devitrification occurs and the fluidity decreases. On the other hand, when B ₂ O ₃ is more than 20%, the viscosity of the glass becomes high and the sealing temperature becomes high.

Fe ₂ O ₃ is a component having the effect of stabilizing the glass with almost no increase in viscosity, and its content is 0.3 to 8%, preferably 1 to 4%. F
If the content of e ₂ O ₃ is less than 0.3%, there is no effect, and 8%
If the amount is larger, the glass tends to devitrify and the fluidity decreases.

From the environmental point of view, it is preferable to use as little PbO as possible, but since it is a component that has a large effect of lowering the melting point of glass, it is necessary to add it to 44.9%, preferably 30%. Can be used.

SiO ₂ and Al ₂ O ₃ are components that have the effect of stabilizing the glass, and their content is 0-5 in total.
%, Preferably 0 to 3%. If the content of these components is more than 5%, the viscosity of glass becomes high.

ZnO and CuO have the effect of improving the chemical durability of the glass with almost no increase in viscosity, and the total content is 0 to 15%, preferably 1 to 10%. If the total amount of these components is more than 15%, the glass tends to devitrify, and the fluidity decreases.

Cs ₂ O is a component having a large effect of reducing the viscosity of glass, and its content is 0 to 10%, preferably 0 to 5%. If the Cs ₂ O content exceeds 10%, the chemical durability of the glass will deteriorate.

If TeO ₂ is added in a small amount, it has the effect of stabilizing the glass, but if it exceeds 4%, devitrification is likely to occur and the fluidity deteriorates. The preferable addition amount of TeO ₂ is 0 to 2%
Is.

F ₂ is a component having a large effect of lowering the viscosity of glass, and its content is 0 to 10%, preferably 0 to
4%. If F ₂ is more than 10%, stable glass cannot be obtained.

In addition to the above components, V ₂ O of 5% or less is also used.
₅ , Ag ₂ O, SrO, BaO, P ₂ O ₅ , Co ₂ O
₃ , Mo ₂ O ₃ , WO ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , C
eO ₂ , Ga ₂ O ₃ , Sb ₂ O ₃ , SnO ₂ and a rare earth oxide can be contained.

However, addition of highly toxic components such as Tl ₂ O and CdO should be avoided.

The glass having the above composition is an amorphous or crystalline glass having a low glass transition point of 400 ° C. or lower and exhibiting good fluidity. Further, the coefficient of thermal expansion at 30 to 250 ° C. is 90 × 10 ⁻⁷ / ° C. or higher, and it is possible to seal a high expansion material compatible with this at a low temperature of 540 ° C. or lower.

On the other hand, in the case of sealing various packages or display devices made of materials having incompatible thermal expansion coefficients, a refractory filler powder is mixed and used in order to correct the difference in thermal expansion coefficient with the adherend. It is possible to Further, when the mechanical strength is insufficient, the refractory filler powder can be used.

When the refractory filler powder is mixed, the mixing ratio is preferably 45 to 95% by volume of glass powder and 55 to 5% by volume of refractory filler powder. The reason why the ratio of the two is limited in this way is that if the refractory filler powder is less than 5% by volume, its effect is not exerted, and if it exceeds 55% by volume, the fluidity is deteriorated.

As the refractory filler powder, powders of lead titanate type ceramics, willemite type ceramics, β-eucryptite, cordierite, zircon type ceramics, tin oxide type ceramics, mullite, quartz glass, alumina and the like are used alone. , Or a combination is preferably used.

[0027]

EXAMPLES The low melting point sealing composition of the present invention will be described below based on Examples.

Tables 1 and 2 show examples of the low melting point sealing composition made of glass according to the present invention.

[0029]

[Table 1]

[0030]

[Table 2]

Each sample was prepared as follows. First, raw materials were mixed so as to have the composition shown in the table, put in a platinum crucible, and melted at 900 to 1000 ° C. for 1 to 2 hours. Next, this was shaped into a thin plate, crushed, and then passed through a 250-mesh sieve to obtain a sample having an average particle size of 4 μm. The glass transition point, the sealing temperature and the coefficient of thermal expansion of the obtained sample were measured. As is clear from Tables 1 and 2, Sample A
~ I has a glass transition point of 300 to 396 ° C and 430
It was found that sealing was possible at ~ 540 ° C. The coefficient of thermal expansion was 93 to 122 × 10 ⁻⁷ / ° C. Sample A,
F and G were crystalline glasses, and other samples were amorphous glasses.

Tables 3 and 4 show Examples (Sample Nos. 1 to 9) of the present invention prepared by mixing the samples of Tables 1 and 2 with the refractory filler powder.

[0033]

[Table 3]

[0034]

[Table 4]

As is clear from Tables 3 and 4, sample N
o. Nos. 1 to 9 have a sealing temperature of 460 to 550 ° C, and it can be seen that they can be sealed at a low temperature. Also, the bending strength is 500 ~
It was 650 kg / cm ² , which was a sufficient value as a sealing material. Furthermore, the coefficient of thermal expansion is 65-100 × 10 ^-7 / ° C.
Alumina (70 × 10 ⁻⁷ / ° C.), window glass (85 × 10 ⁻⁷ / ° C.), CRT glass (100 × 10
^-7 / ° C).

These facts indicate that the low melting point sealing composition of the present invention satisfies various conditions required for a sealing material for various packages and display devices, can be sealed at a low temperature of 550 ° C. or lower, and has a fire resistance. By including an appropriate amount of filler powder, the thermal expansion coefficient of alumina, window glass, CR
It shows that it can be adjusted to suit T glass and the like.

The glass transition point is determined by differential thermal analysis (DT
Determined according to A). The sealing temperature was the temperature at which the button having an outer diameter of 20 mm and a height of 5 mm prepared from each sample was heated to flow and the outer diameter became 21 mm or more. The coefficient of thermal expansion was measured using a push rod type thermal expansion measuring device. The bending strength was obtained by sintering the sample and then forming it into a prism of 10 × 10 × 50 mm, and then measuring it by a three-point load measuring method.

The refractory filler powders shown in Tables 3 to 4 were prepared as follows.

The willemite-based ceramic powder includes zinc white, optical stone powder, and aluminum oxide in a weight percentage of ZnO 7
It was prepared to have a composition of 0%, SiO ₂ 25% and Al ₂ O ₃ 5%, and after mixing, it was baked at 1440 ° C. for 15 hours, and then this baked product was crushed and passed through a 250 mesh stainless sieve. I used what I did.

The lead titanate-based ceramic powder contains litharge, titanium oxide, and calcium carbonate in PbO 6 by weight%.
5%, TiO ₂ 30%, CaO 5% were mixed and mixed, and after the mixture was fired at 1100 ° C. for 5 hours, the fired product was crushed with an alumina ball, and a 350 mesh stainless sieve was used. It was made to pass through and made into a powder form with an average particle size of 5 μm.

As the cordierite powder, magnesium oxide, aluminum oxide and optical stone powder are used as 2MgO.2Al ₂
Prepare so that the ratio of O ₃ · 5SiO ₂ is, and after mixing,
It was fired at 1400 ° C. for 10 hours, then the fired product was crushed and passed through a 250-mesh stainless sieve.

The zircon ceramic powder was prepared as follows. First, natural zircon sand is once decomposed with soda, dissolved in hydrochloric acid, and then repeatedly concentrated and crystallized to obtain zirconium oxychloride having extremely small amounts of U and Th which are α-ray emitting substances, neutralized with an alkali, and then heated. Purified ZrO ₂ was obtained. Furthermore, high-purity silica stone powder and ferric oxide were added to this purified ZrO ₂ in a weight% of ZrO ₂ 66%, SiO _2.
2 32% and Fe ₂ O ₃ 2% were mixed,
After mixing, the mixture was fired at 1400 ° C. for 16 hours, then the fired product was crushed and passed through a 250-mesh stainless sieve.

The tin oxide ceramic powder is Sn in weight%.
O ₂ 93%, TiO ₂ 2%, MnO ₂ 5% were mixed to obtain a composition, and after mixing, fired at 1400 ° C. for 16 hours,
Next, this fired product was crushed and passed through a 250-mesh stainless sieve.

[0044]

As described above, the low melting point sealing composition of the present invention can be used for a package for an IC or a crystal unit,
Satisfying the various characteristics required for the sealing material for display devices such as color TV CRTs, fluorescent display tubes, plasma display panels, etc. In particular, it is possible to seal at low temperature while reducing the amount of PbO used. Therefore, it is suitable as a sealing material.

Claims (2)

(57) [Claims] 1. Bi ₂ O ₃ 45-90% by weight,
_{B 2 O 3 1~20%, Fe} 2 O 3 0.3~8%, PbO
0-44.9%, SiO ₂ + Al ₂ O ₃ 0-5%, Zn
_{O + CuO 0~15%, Cs 2} O 0~10%, Te
A low melting point sealing composition comprising a glass powder containing O ₂ 0 to 4% and F ₂ 0 to 10%. 2. Bi ₂ O ₃ 45-90% by weight,
_{B 2 O 3 1~20%, Fe} 2 O 3 0.3~8%, PbO
0-44.9%, SiO ₂ + Al ₂ O ₃ 0-5%, Zn
_{O + CuO 0~15%, Cs 2} O 0~10%, Te
A low melting point sealing composition comprising 45 to 95% by volume of a glass powder containing 0 to 4% of O _{2 and} 0 to 10% of F ₂ and 55 to 5 % by volume of a refractory filler powder.