JP2001106550A - Sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sealing material which does not contain toxic materials and is capable of sealing packages at <=330 deg.C without exerting burden thereon. SOLUTION: This sealing material is prepared by mixing 45 to 90 vol.% low melting composition powder and 10 to 55 vol.% refractory material powder. This low melting composition powder has a composition consisting of 25 to 50% Ag2O, 25 to 45% P2O5, 5 to 30% PbO+ZnO and 0 to 10% TeO2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing material, and more particularly to a sealing material suitable for hermetically sealing a package on which heat-sensitive elements such as a semiconductor integrated circuit and a quartz oscillator are mounted. is there.

[0002]

2. Description of the Related Art A sealing material using a low-melting glass is used for hermetic sealing of a highly reliable package on which elements such as a semiconductor integrated circuit and a quartz oscillator are mounted.

Conventionally, the PbO-B ₂ O ₃ -based glass powder as a sealing material, lead titanate, and that the addition of low expansion refractory material powder such as willemite is widely known, the glass of this system Since it is difficult to reduce the sealing temperature of the used sealing material to 400 ° C. or lower, the characteristics may be deteriorated depending on the element.

[0004] Under these circumstances, development of a sealing material which can be sealed at a lower temperature has been advanced in recent years. For example, Kohyo Sho _{63-502583, PbO-V 2 O 5} -Bi
A sealing material using ₂ O ₃ -based glass is disclosed, and JP-A-63-315536 discloses PbO-Tl ₂ O-B ₂ O.
Sealing materials using ₃ based glass is disclosed.

[0005]

Problems to be Solved by the Invention The above-mentioned Japanese Patent Application Publication Sho 63-50
The sealing material disclosed in No. 2583 can lower the sealing temperature to about 330 ° C. However, in order to seal at such a low temperature, a considerable load must be applied by a metal clip or the like at the time of sealing.
On the other hand, the sealing material of JP-A-63-315536 can also have a sealing temperature of about 330 ° C., but contains a large amount of highly toxic Tl ₂ O. There is a practical problem, such as the need for equipment to prevent the scattering of dust.

An object of the present invention is to provide a sealing material which does not contain a toxic substance and which can seal a package at a temperature of 330 ° C. or less without applying a load.

[0007]

The sealing material of the present invention comprises 45 to 90% by volume of the low melting point composition powder and 1 part of the refractory substance powder.
0-55 it was mixed volume%, low melting point composition powder in _{mol%, Ag 2 O25~50%, P} 2 O 5 25~45
%, PbO + ZnO 5-30%, TeO ₂ 0-10%
Characterized by having the following composition:

[0008]

In the sealing material of the present invention, the low melting point composition takes any form of an amorphous glass, a crystalline glass, and a crystal. Amorphous glass and crystalline glass have a transition point of 150
It is very low at ~ 230 ° C and flows sufficiently when heated at 300-330 ° C. The crystalline material has a very low melting point,
It remelts by heating at 330 ° C. to become a low viscosity liquid. The crystalline material is obtained by first melting the raw material, then cooling it to precipitate a crystal, and then pulverizing the crystal.

The reason why the composition range of the low melting point composition in the sealing material of the present invention is limited as described above will be described below.

[0010] Ag ₂ O is the main component of the low melting point composition and is very insoluble in water, so that it has the effect of increasing the chemical durability of the composition. When the content of Ag ₂ O is less than 25%, the viscosity of the low melting point composition becomes high, and the chemical durability decreases. On the other hand, when the content is more than 50%, it becomes difficult to melt. For the same purpose, silver halide can be further added. In this case, the total amount of Ag ₂ O and silver halide is 85%.
Limited to:

P ₂ O ₅ is a main component of the low melting point composition together with Ag ₂ O. If the total amount of the P ₂ O ₅ components is less than 25%, it becomes difficult to melt, and if it exceeds 45%, the viscosity of the low melting point composition becomes high. For the same purpose, GeO
₂ , WO ₃ and MoO ₃ can be added. In this case, the total amount of P ₂ O ₅ , GeO ₂ , WO ₃ and MoO ₃ is 50%
Limited to:

PbO and ZnO are effective in increasing the stability of the low melting point composition, improving the chemical durability, and reducing the coefficient of thermal expansion. If the total amount of these components is less than 5%, the effect is not obtained. If the total amount is more than 30%, the viscosity of the low melting point composition increases. For the same purpose, halides of Pb and Zn and oxides and halides of Ba, Sr, Ca, Cu, Mn and Bi can be further added. in this case,
The total amount of oxides and halides of Pb, Zn, Ba, Sr, Ca, Cu, Mn, and Bi is limited to 40% or less.

[0013] TeO_TwoIs the P_TwoO_FiveAssists the work of
It is a component that does. TeO_TwoIf more than 10%, low melting point group
The viscosity of the product increases. For the same purpose, V_Two
O_Five, B _TwoO_Three, Nb_TwoO_Five, Ta_TwoO_Five, Fe_TwoO_Three, Si
O_Two, Al_TwoO_ThreeCan be added. In this case, T
eO_Two, V_TwoO_Five, B_TwoO_Three, Nb_TwoO_Five, Ta_TwoO_Five, Fe_TwoO
_Three, SiO_Two, Al_TwoO_ThreeIs limited to 25% or less in total
You.

The halide in the present invention is a fluoride, chloride, bromide or iodide. When the metal elements are the same, the use of these elements is more effective than the case of using an oxide. Further, the viscosity of the glass can be reduced.

Incidentally, the low melting point composition having the above composition has a very high coefficient of thermal expansion at 30 to 150 ° C. (or 200 ° C.) of 150 to 220 × 10 ⁻⁷ / ° C. and has insufficient mechanical strength. It is. Therefore, it is necessary to adjust the coefficient of thermal expansion so as to be compatible with the package to be sealed or to increase the mechanical strength.

The sealing material of the present invention is obtained by mixing a powder of the low melting point composition with a powder of a refractory substance, so that a thermal expansion coefficient suitable for a package to be sealed can be obtained. In addition, it has sufficient mechanical strength.

Among the refractory materials, those which mainly lower the coefficient of thermal expansion include NbZr (PO ₄ ) ₃ and Sr _0.5 Z
NaZr ₂ (PO ₄ ) ₃ type solid solution such as r ₂ P ₃ O ₁₂ , lead titanate and its solid solution, willemite, cordierite,
Zircon, tin oxide, β-eucryptite, zirconium phosphate, niobium pentoxide, quartz glass, mullite, aluminum titanate and the like can be used.

In addition, alumina, zirconia, titania, zinc stannate,
Magnesia, quartz, spinel, garnite and the like can be used.

The refractory material powder as described above is
Two or more kinds may be used as a mixture.

Next, the reason why the mixing ratio of the low melting point composition powder and the refractory substance powder in the sealing material of the present invention is limited as described above will be described below.

When the low melting point composition powder is more than 90% by volume, that is, when the refractory substance powder is less than 10% by volume, the above effects cannot be obtained. On the other hand, when the low melting point composition powder is less than 45% by volume, that is, when the refractory substance powder is more than 55% by volume, the sealing material does not flow.

[0022]

EXAMPLES The sealing material of the present invention will be described below based on examples.

As the low melting point composition powder, an amorphous glass powder prepared as follows was used.

Ag ₂ O 45% in mole%, P ₂ O ₅ 40
%, ZnO 10%, and TeO ₂ 5% were mixed with silver oxide, orthophosphoric acid, zinc phosphate, and tellurium dioxide, melted at 800 ° C. for 2 hours using a platinum crucible, and vitrified. . Next, after molding this molten glass, it is ground and
The mixture was passed through a 50-mesh sieve to obtain glass powder having an average particle size of 7 μm. The obtained glass powder has a transition point of 220.
° C, thermal expansion coefficient at 30-200 ° C is 155 × 10
⁻⁷ / ° C.

Further, as the refractory substance powder, MgO
NbZr (PO ₄ ) ₃ ceramic powder to which weight% was added was used.

NbZr (PO ₄ ) ₃ ceramic powder is prepared by mixing niobium pentoxide, low α-ray zirconia, ammonium dihydrogen phosphate, and magnesia, firing at 1450 ° C. for 16 hours, pulverizing, and crushing to obtain an average particle size of 5 μm. The powder was used.

Next, 60% by volume of glass powder and NbZr
A sample was obtained by mixing 40% by volume of (PO ₄ ) ₃ ceramic powder. The sample thus obtained had a sealing temperature of 330
° C, the coefficient of thermal expansion at 30 to 200 ° C is 78 × 10 ^-7
/ ° C.

Using this sample, alumina (thermal expansion coefficient)
When an IC package made of 70 × 10 ⁻⁷ / ° C.) was sealed, a highly airtight sealed product was obtained.

The transition point and the coefficient of thermal expansion were determined using a quartz push rod type thermal dilatometer.

[0030]

As described above, the sealing material of the present invention does not contain toxic substances and can be used without a load.
Since sealing can be performed at an extremely low temperature of 0 to 330 ° C., it is suitable for sealing a package on which a semiconductor integrated circuit or a crystal oscillator which is sensitive to heat is mounted.

Claims (1)

[Claims] 1. A low melting point composition powder of 45 to 90% by volume,
It is a mixture of 10 to 55 vol% refractory material powder, low melting point composition powder in mol%, Ag ₂ O 25 to 50%,
_{P 2 O 5 25~45%, PbO} + 5~30% ZnO,
Sealing material characterized by comprising a composition of TeO ₂ 0%.