JPH04357132A - Composition for low-melting sealing - Google Patents

Abstract

PURPOSE:To obtain a sealing composition satisfying characteristics required for a sealing material such as IC package or display device, capable of sealing especially at <=400 deg.C. CONSTITUTION:A composition for low-melting sealing consists of 45-80vol.% glass powder having a composition of 65.0-85.0wt.% PbO, 1.0-11.0wt.% B2O3, 0.2-10.0wt.% Fe2O3, 1.0-15.0wt.% Bi2O3+ZnO+CuO, 0-5.0wt.% SiO2+Al2O3, 0-5.0wt.% V2O5, 0-6.0wt.% F2O and 0-5.0wt.% SnO2 and 20-55vol.% refractory filler powder such as lead titanate-based ceramics, willemite-based ceramics, beta-eucryptite, codierite, zircon-based ceramics, tin oxide-based ceramics, mullite- based ceramics, quartz glass alumina or titanium oxide.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a low melting point sealing composition, and more specifically to a low melting point sealing composition suitable for sealing electronic components such as ceramic packages for ICs and display devices. It is.

0002

[Prior Art] Sealing materials used for sealing IC packages and display devices have the ability to seal at low temperatures so as not to adversely affect ICs, crystal resonators, etc., and have thermal expansion coefficients such as those of ceramics and windows. It is required that it conform to that of plate glass. In addition to these conditions, sealing materials for IC packages in particular must have high mechanical strength, good insulation properties to prevent signal current leakage, and
If an IC element is irradiated with alpha rays, a soft error will occur, so it is necessary to satisfy conditions such as containing as little material that emits alpha rays as possible.

[0003] Conventionally, as a product that satisfies the above conditions,
PbO-B2O3 system, PbO-B2O3 -ZnO
Various types of low-melting point glasses, such as those of the BACKGROUND ART type, and sealing materials made by adding fire-resistant fillers to these glasses have been proposed. For example, JP-A No. 2-229738, which was invented by the present inventors, discloses a sealing material made by adding lead titanate-based ceramic powder and low-expansion ceramic powder to PbO-B2O3-based glass. .

0004

[Problem to be solved by the invention] Generally, PbO-B2
It is known that in O3-based glasses and PbO-B2O3-ZnO-based glasses, the lower the content of B2O3, the lower the transition point and the lower the sealing temperature. However, since B2 O3 must be contained in a certain amount or more to stabilize the glass, there is a limit to lowering the melting point of sealing materials using these glasses.
It is difficult to keep the sealing temperature below 400°C. Therefore, these sealing materials have the problem of not being able to be used for sealing packages and devices equipped with highly heat-sensitive elements, such as highly integrated ICs and special crystal oscillators. There is.

[0005] The present invention has been made in view of the above circumstances.
The object of the present invention is to provide a sealing composition that satisfies various properties required of sealing materials for IC packages, display devices, etc., and is particularly capable of sealing at a temperature of 400° C. or lower.

[0006]

[Means for Solving the Problems] As a result of various studies conducted by the present inventors, it was found that Fe2 O3 is very effective in stabilizing the PbO-B2 O3 glass, and therefore Fe2 O3 containing Fe2 O3 is very effective in stabilizing the glass. B by letting
It has been discovered that the content of 2 O3 can be reduced, and this is proposed as the present invention.

That is, the low melting point sealing composition of the present invention contains 65.0 to 85.0% PbO and B2O in weight percentage.
3 1.0-11.0%, Fe2O3 0.2-10
．． 0%, Bi2O3 +ZnO+CuO 1.0~1
5.0%, SiO2 + Al2 O3 0-5.0%,
V2 O5 0-5.0%, F2 0-6.0%, Sn
It is characterized by consisting of 0 to 5.0% O2.

[0008] The low melting point sealing composition of the present invention also contains 65.0 to 85.0% PbO and B2O3 in weight percentages.
1.0-11.0%, Fe2O3 0.2-10.
0%, Bi2O3 +ZnO+CuO 1.0~1
5.0%, SiO2 + Al2 O3 0-5.0%,
V2 O5 0-5.0%, F2 0-6.0%, Sn
It is characterized by consisting of 45-80% by volume of glass having a composition of 0-5.0% O2 and 20-55% by volume of refractory filler.

[0009]

[Operation] The low melting point sealing composition of the present invention is PbO-B2
Part of B2 O3 of O3 glass is converted to Fe2 O3
The content of B2 O3 is reduced.

The reason for limiting the glass composition as described above in the low melting point sealing composition of the present invention will be described below.

[0011] The content of PbO is 65.0 to 85.0%,
Preferably it is 70.0 to 83.0%. PbO is 65
．． If it is less than 0%, the viscosity of the glass will increase to 400℃.
If the temperature is below 85.0%, the glass will not flow sufficiently, and if it exceeds 85.0%, crystallization will become significant during sealing and the glass will not flow.

[0012] The content of B2 O3 is 1.0 to 11.0.
%, preferably 2.0 to 10.0%. B2 O3
If it is less than 1.0%, the glass will become unstable and crystallization will be significant during sealing and will not flow, and if it is more than 11.0%, the viscosity of the glass will be high and it will not flow sufficiently at temperatures below 400°C. I won't.

[0013] Fe2 O3 has the function of stabilizing glass, and its content is 0.2 to 10.0%, preferably 0.5 to 8.5%. Fe2O3 is 0.2%
If the amount is less than 10.0%, the above-mentioned effect will not be obtained, and crystallization will become significant during sealing, and the glass will not flow properly.If it is more than 10.0%, the viscosity of the glass will become high and the glass will not flow sufficiently at temperatures below 400°C.

Bi2 O3, ZnO and CuO are components that stabilize the glass without increasing its viscosity, and are contained in a total amount of 1.0 to 15.0%. Bi2 O3
If the total amount of , ZnO, and CuO is less than 1.0%, crystallization will become significant, fluidity will decrease, and sealing will not be possible at temperatures below 400°C. Moreover, if the amount is more than 15.0%, crystal precipitation becomes significant during sealing, resulting in a decrease in fluidity. Among these components, Bi2 O3 has the above-mentioned effect particularly, and is preferably contained in an amount of 1.0 to 15.0%. In addition, the contents of ZnO and CuO are respectively 0 to 0.
10.0%, preferably in the range of 0 to 5.0%.

[0015] SiO2 and Al2O3 have the effect of preventing devitrification, and their total content is 0 to 5.0%,
Preferably it is 0 to 3.0%. SiO2 and Al2
If the total amount of O3 is more than 5%, the viscosity of the glass will increase and the fluidity will deteriorate.

V2O5 is a component that lowers the surface tension of glass and improves its fluidity, and its content ranges from 0 to 5.
0%, preferably 0-3.0%. If the V2 O5 content is more than 5.0%, the crystallization of the glass will become significant and the glass will not flow.

F2 has the function of lowering the sealing temperature of glass, and its content is 0 to 6.0%, preferably 0 to 4.0%.
It is 0%. If the F2 content is more than 6.0%, crystallization becomes significant during sealing, making it difficult to flow.

[0018] SnO2 is added to stabilize the glass.
-5.0%, preferably 0-2.0%. SnO
When 2 is more than 5.0%, the viscosity of the glass becomes high and it becomes difficult to flow.

[0019] In addition to the above components, 5% or less of Ag2
O, SrO, BaO, P2 O5, Co2 O3
, 3% or less Mo2 O3, Rb2 O, Cs2
O, Nb2O5, Ta2O3, ZrO2, Ce
It is possible to contain rare earth oxides such as O2, NiO, Cr2O3, Sb2O3, and La2O3 as other components.

[0020] Glass having the above composition has a low glass transition point of 240 to 300°C, is stable as a glass, and exhibits good fluidity, so it is a sealing material that can be sealed at low temperatures. A wearable composition. However, 30-2
Thermal expansion coefficient at 50°C is 110 to 140 x 10-7
and alumina (70×10-7/℃), aluminum nitride (45×10-7/℃), window glass (85×10-7
/°C), so it is necessary to adjust the coefficient of thermal expansion in order to seal IC packages, display devices, etc. using these materials.

The low-melting point sealing composition of the present invention can obtain a thermal expansion coefficient suitable for sealing IC packages, display devices, etc. by containing the refractory filler within the above-mentioned range. As the refractory filler, powders such as lead titanate ceramic, willemite ceramic, β-eucryptite, cordierite, zircon ceramic, tin oxide ceramic, mullite ceramic, quartz glass, alumina, and titanium oxide are used. It is preferable to use them alone or in combination.

[0022] In the present invention, the reason why the mixing ratio of glass and refractory filler is limited as described above will be explained below.

[0023] If the glass content is less than 45%, that is, if the refractory filler content is more than 55%, the fluidity will be poor and sealing will not be possible at temperatures below 400°C. On the other hand, when the glass content is more than 80%, that is, when the fire-resistant filler content is less than 20%, the above-mentioned effects cannot be obtained.

Next, a method for producing the low melting point sealing composition of the present invention will be described. First, each raw material is mixed to have a desired composition, melted at 700 to 1000°C for 1 to 2 hours, and then formed into a plate shape. Next, this plate-like material is pulverized using a ball mill or the like, and then classified to a predetermined particle size to obtain powdered glass. Further, if necessary, the glass powder thus obtained and the refractory filler are mixed in a predetermined ratio.

[0025]

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

(Example 1) Table 1 shows PbO-B2 O3
This is to explain the effect of Fe2 O3 on glass based on sample No. a is general PbO-B2O
3 series glass, sample No. b is sample No. PbO- with the B2 O3 content reduced by 4% from the composition of a.
B2 O3 type glass, sample No. c is sample No.
2 shows a low melting point sealing composition of the present invention in which 2% of Fe2O3 is added to b.

[0027]

[Table 1]

The samples in Table 1 were prepared as follows.

[0029] Mix raw material powder to have the composition shown in the table,
The mixture was mixed, placed in a platinum crucible, and melted at 900° C. for 1 hour, formed into a thin plate, pulverized, and passed through a 250-mesh stainless steel sieve to obtain a sample with an average particle size of 4 μm.

As is clear from Table 1, sample No. 1 with a reduced content of B2 O3. b has a glass transition point of 2
The temperature was 85°C, and sample no. Although the temperature was lowered by 20°C compared to a, the fluidity and stability were poor. On the other hand, Fe
Sample No. 2 O3 added. Sample No. c has a glass transition point of 287°C. It shows a low value equivalent to that of sample No. b, and the fluidity is as low as that of sample No. It was superior to A and had good stability.

These facts show that even if the content of B2 O3 is reduced in order to lower the glass transition point, Fe2
This shows that by adding O3, good fluidity and stability can be obtained, and a sealing composition that can be sealed at low temperatures can be obtained.

[0032] The glass transition point was measured using a differential thermal analyzer (DT).
A). In addition, the fluidity was measured at an outer diameter of 20 m from the sample.
After making a button with a height of 5 mm, it was heated at 380°C for 10
Heated it under the conditions of 1 minute, and the diameter of the button at this time was 23 mm.
Good if over 20 to 23 mm, OK if over 20 m
Those less than m were not accepted. Stability was determined by visually observing the surface of the sample after the fluidity test, and those in which no crystals were observed were graded as good, and those in which any crystals were observed were graded as poor.

(Example 2) Table 2 shows examples of low melting point sealing compositions made of glass according to the present invention.

[0034]

[Table 2]

As is clear from Table 2, sample No. A
~F had a glass transition point of 246 to 295°C, a thermal expansion coefficient of 115 to 132 x 10-7/°C, and all exhibited good fluidity.

[0036] Each sample in Table 2 was prepared in the same manner as in Example 1.

Tables 3 and 4 show examples (sample Nos. 1 to 9) of low melting point sealing compositions for IC packages prepared by mixing each sample in Table 2 with a fire-resistant filler. be.

[0038]

[Table 3]

[0039]

[Table 4]

As is clear from Tables 3 and 4, sample N
o. Nos. 1 to 9 have a sealing temperature of 360 to 400°C, a bending strength of 590 to 680 kg/cm2, and an insulation resistance of 13.
2 to 14.8 Ω・cm, alpha ray emission amount is 0.11 to 0.2
It showed a good value of 5 counts/cm2·hr. In addition, the thermal expansion coefficient of sample No. 1 to 6 is 60 to 73 x 1
0-7/℃, sample no. 7 to 9 is 51 to 55 x 10-
7/℃, and alumina (70×10-7/℃), respectively.
), showed a value close to that of aluminum nitride (45 x 10-7/°C).

Table 5 shows examples (Samples Nos. 10 to 12) of low melting point sealing compositions for display devices prepared by mixing the samples in Table 2 with a refractory filler.

[0042]

[Table 5]

As is clear from Table 5, sample No. 1
0 to 12 has a low sealing temperature of 380 to 390°C, and a thermal expansion coefficient of 73 to 78 x 10-7/°C, which is a value close to that of window glass (85 x 10-7/°C). Indicated.

These facts demonstrate that the low melting point sealing composition of the present invention satisfies the various conditions required for sealing materials for IC packages and display devices, can be sealed at low temperatures of 400°C or less, and is fire resistant. This shows that by containing an appropriate amount of filler powder, the coefficient of thermal expansion can be adjusted to suit alumina, aluminum nitride, window glass, etc.

The coefficient of thermal expansion was measured using a push rod type thermal expansion measuring device. In addition, the outer diameter 20 made from each sample
A button with a diameter of 5 mm and a height of 5 mm was heated to flow, and the temperature at which the outer diameter became 21 mm or more was defined as the sealing temperature. The bending strength was determined by sintering the sample, forming it into a 10 x 10 x 50 mm square column, and using a three-point load measurement method. Insulation resistance was measured at 150° C. using a megohmmeter, and α-ray emission was measured using a ZnS scintillation counter.

The fire-resistant fillers shown in Tables 3 to 5 were produced in the following manner.

The lead titanate ceramic contains litharge, titanium oxide, and calcium carbonate in a weight percent of PbO of 65%.
, 30% TiO2, and 5% CaO, and after mixing, it was fired at 1100°C for 5 hours, and then the fired product was crushed with an alumina ball and passed through a 350 mesh stainless steel sieve. It was made into a powder with an average particle size of 5 μm.

The willemite ceramic contains zinc white, optical stone powder, and aluminum oxide in a weight percent of ZnO of 70%.
, 25% SiO2 and 5% Al2O3, and after mixing, baked at 1440°C for 15 hours,
Next, this fired product was pulverized and passed through a 250 mesh stainless steel sieve before being used.

β-eucryptite is lithium carbonate,
Alumina, optical stone powder Li2 O・Al2 O3 ・2
Mixed to have a composition of SiO2, and after mixing, 125
Calcinate at 0°C for 5 hours, then crush the fired product,
The material that passed through a 0 mesh stainless steel sieve was used.

The zircon ceramic was produced as follows. First, natural zircon sand is decomposed with soda, dissolved in hydrochloric acid, and then concentrated and crystallized repeatedly to produce zirconium oxychloride with extremely low U and Th content, which are α-ray emitting substances. After neutralization with alkali, the mixture is heated. Purified ZrO2 was obtained. Furthermore, high-purity silica powder and ferric oxide were added to this purified ZrO2 in weight percentages of 66% ZrO2 and Si.
The composition was prepared to have a composition of 32% O2 and 2% Fe2O3, and after mixing, it was fired at 1400°C for 16 hours, and then the fired product was pulverized and passed through a 250 mesh stainless steel sieve and used.

[0051] The tin oxide ceramic contains SnO2 in weight%.
93% TiO2, 2% MnO2, and 5% MnO2. After mixing, it was fired at 1400°C for 16 hours, and then the fired product was crushed and passed through a 250 mesh stainless steel sieve. .

[0052] Mullite ceramic is prepared by mixing aluminum oxide and optical stone powder to have a composition of 3Al2O3.2SiO2, and after mixing, firing at 1600°C for 10 hours, then crushing the fired product, and molding it into 250 mesh stainless steel. The material that passed through a sieve was used.

Cordierite is magnesium oxide,
Aluminum oxide, optical stone powder 2MgO・2Al2O
3.5SiO2, and after mixing, it was fired at 1400°C for 10 hours, and then the fired product was crushed and passed through a 250 mesh stainless steel sieve and used.

[0054]

Effects of the Invention As explained above, the low melting point sealing composition of the present invention satisfies various properties required for sealing materials for IC packages, display devices, etc., and is particularly effective at low temperatures below 400°C. can be sealed.

Claims (2)

[Claims] Claim 1: PbO 65.0-8 in weight percentage
5.0%, B2 O3 1.0-11.0%, Fe2
O3 0.2-10.0%, Bi2 O3 +ZnO+
CuO1.0-15.0%, SiO2 +Al2O3
0-5.0%, V2 O5 0-5.0%, F2 0
6.0% and SnO2 0 to 5.0%. Claim 2: PbO 65.0 to 8 in weight percentage
5.0%, B2 O3 1.0-11.0%, Fe2
O3 0.2-10.0%, Bi2 O3 +ZnO+
CuO1.0-15.0%, SiO2 +Al2O3
0-5.0%, V2 O5 0-5.0%, F2 0
6.0%, SnO2 0 to 5.0% by volume, and 20 to 55 volume% of a fire-resistant filler.