JPS61191540A - Glass for low-temperature sealing - Google Patents

Abstract

PURPOSE:To provide titled glass having excellent leak resistance, adhesive strength, moisture resistance and water resistance by consisting said glass of specifically composed PbO, PbF2, B2O3, GeO2 and SiO2. CONSTITUTION:The titled glass compsn. which can make sealing while suppressing cracking at <=500 deg.C is obtd. by mixing and melting 65-88wt% PbO, 0.1-5wt% PbF2, 1-15wt% B2O3, 1-15wt% GeO2, 1-20wt% SiO2 and, if necessary, low expandable ceramic powder as a filler. The glass is pulverized and is made into a pasty state with an org. solvent. Sealing in executed by using such glass paste.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to Which the Invention Pertains] The present invention relates to a glass for low-temperature sealing, and particularly to a glass used for sealing semiconductor devices.

[Conventional technology and its problems]

Packages that shield semiconductor chips from the outside air and mechanically protect semiconductor chips and lead wires are particularly important for semiconductor devices with fine circuit patterns, such as highly integrated ultra-large semiconductor integrated circuits (ultra LSIs). , has become an important presence.

For example, in a mounting method using a ceramic package,
The method of airtight sealing by interposing glass between the lead wires connected to the semiconductor chip and the ceramic package is widely used because it is not moisture permeable, has excellent airtightness, and is mechanically robust. It is being

Conventionally, most of the glass used for such sealing must be heated to 500η or more during sealing, and low-temperature treatment may reduce the strength after bonding or reduce water resistance @'z moisture resistance. There were problems such as a decrease in

However, if encapsulation is performed at a high temperature of 500°C or higher, the built-in semiconductor chip may be adversely affected, resulting in deterioration of characteristics, which may lead to a decrease in device yield and reliability. Therefore, it has been strongly desired to realize a sealing glass that can be sealed at the lowest possible temperature, has sufficiently high strength after bonding, and has excellent water resistance and moisture resistance.

[Purpose of the invention]

The present invention was made in view of the above-mentioned circumstances, and
An object of the present invention is to provide a low-temperature sealing glass that can be sealed with the following properties and has excellent adhesive strength, water resistance, and moisture resistance.

[Summary of the invention]

Therefore, the sealing glass of the present invention is made of lead oxide (PbO6).
5-88 heavy weight percent, lead fluoride (PbF,) 0
．． 1 to 5% of boron oxide (BtOs), 1 to 15% of germanium oxide (GeOl), and 1 to 20% of silicon oxide (8i0.).

Here, lead oxide is a network-modifying oxide that lowers the pour point of glass, but if the content is less than 65%, it has no effect, and if it is more than 8 parts, the glass will crystallize and devitrify. .

In addition, lead fluoride is the hydrogen (H,) or hydroxyl group (O) in glass.
H group), and this effect is 0.
If it is less than 1%, it hardly exists, and if it is more than 5%, the glass will actually devitrify.

Furthermore, boron oxide works to lower the thermal expansion coefficient of glass, and its effect is small below 1 q.
If it is higher than b, the pour point of the glass becomes high and it becomes impossible to use it for low-temperature sealing.

Historically, germanium oxide has the function of preventing devitrification and increasing water resistance, but if it is less than 1%, it has no effect, and if it is more than 1%, the pour point increases.

In addition, silicon oxide has the function of assisting vitrification and lowering the thermal expansion coefficient, and if it is less than 1 ts, its effect is small, and if it is more than 20%, the pour point becomes significantly high.

In addition, the above-mentioned lead oxide 65-88%, lead fluoride 0.1-5%
%, boron oxide 1-15%, germanium oxide 1-1
By mixing and sealing glass consisting of 5% silicon oxide and 1 to 20% silicon oxide and a low thermal expansion ceramic as a filler, the occurrence of cracks can be significantly reduced.

〔Effect of the invention〕

The low-temperature sealing glass of the present invention is a packaging material with good sealing properties and excellent leak resistance.

That is, when sealing a semiconductor device such as an LSI using the low-temperature sealing glass of the present invention, it is possible to seal a semiconductor device such as an LSI with a sealing temperature of about 400 mm, and a package with excellent adhesive strength, moisture resistance, and water resistance can be obtained. can do.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIGS. 1 and 2 are a cross-sectional view and a partially broken perspective view of the mounted state when the low-temperature sealing glass of the embodiment of the present invention is used for sealing a glass-sealed surdeep (ceramics package) of an LSI, respectively. 2 is a diagram illustrating a lead frame assembly structure configured by connecting a semiconductor chip 3 to a lead frame 1 via wires 2.
The alumina base 4 and the alumina cap 5 sandwich the alumina base 4 and the alumina cap 5 with the external extraction terminals (pins) protruding, and between the alumina base 4 and the alumina cap 5, A sealing glass 6 is interposed to airtightly seal the space in which the semiconductor chip exists.

(Implementation fl, 11) First, the weight ratio is 84% lead oxide, 1% lead fluoride, 7.5% boron oxide, 2% germanium oxide, and 5.5% silicon oxide.
% and 5oo1 for 2 hours in a platinum crucible.
: Forms glass by heating and melting. The glass thus formed is powdered and made into a paste with an organic solvent such as acetone to produce a glass paste.

Then, with the lead frame assembly structure installed on the alumina base, the glass paste is applied as a sealing glass to the upper edge of the alumina base, the alumina cap is covered, and the alumina cap is heated at 400° C. for 20 minutes. .

In the package thus formed, the adhesive strength of the glass was 40 kg/cm2, and there was almost no occurrence of glass cracking. Furthermore, since the content of hydroxyl groups in the glass is small, it can be sealed extremely airtight, and the leakage between pins was about 20 μA with respect to an applied voltage of 5 V.

(Example 2) First, the weight ratio is 75% lead oxide and 2% lead fluoride.

Mix 15% boron oxide, 2% germanium oxide, and 6% silicon oxide and heat at 85% for 2 hours in a platinum crucible.
Glass is formed by heating to 0 and melting.

Next, this glass is pulverized and mixed with cordierite crystals in a one-to-one ratio, and this is made into a paste with an organic solvent to produce a glass paste.

The glass paste thus formed is used as a sealing glass to perform sealing 1F in the same manner as in Example 1. At this time, the sealing temperature is set at 450°C.

In the package formed in this way, the adhesive strength of the glass was 35 Kg/cm'', and there were almost no cracks in the glass.Also, because the hydroxyl group content in the glass was small, an applied voltage of 5V could be applied. On the other hand, the leakage between pins was about 25 μA.

(Example 3) First, in weight ratio, lead oxide 70%, lead fluoride 3%, boron oxide 10%, germanium oxide 7%, silicon oxide 10qb
are mixed and heated to 90 l for 3 hours in a platinum crucible and melted to form a glass. The glass is then ground into a fine powder and barium titanate crystals are mixed in a ratio of 1:1. Make a glass paste by making it into a paste with an organic solvent.

The glass paste thus formed is used as a sealing glass to perform sealing in the same manner as in the case 111.

In the package formed in this way, the adhesive strength of the glass was 50 kg/cm'', and no cracks occurred in the glass.Also, because the hydroxyl group content in the glass was small, it , the pin-to-pin leakage is 4
It was 0μA.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are a cross-sectional view and a partially broken perspective view of a mounted state when the low-temperature sealing glass of an embodiment of the present invention is used for sealing a glass-sealed surdeep ceramic package for an LSI, respectively. It is a diagram. DESCRIPTION OF SYMBOLS 1... Lead frame, 2... Wire, 3... Semiconductor chip, 4... Alumina base, 5... Alumina cap, 6... Glass for sealing.

Claims (2)

[Claims] (1) Lead oxide 65-88%, lead fluoride 0.1-5% by weight
%, boron oxide 1-15%, germanium oxide 1-15%
%, and 1 to 20% silicon oxide. (2) Lead oxide 65-88%, lead fluoride 0.1-5% by weight
%, boron oxide 1-15%, germanium oxide 1-15%
%, a glass powder containing 1 to 20% silicon oxide;
A low-temperature sealing glass characterized by being made of a mixture with a low thermal expansion ceramic powder.