JP7522386B2 - Glass composition and sealing material - Google Patents

Description

The present invention relates to a glass composition that does not contain harmful lead, has weather resistance, and can be hermetically sealed by low-temperature firing, and a sealing material that uses the glass composition.

Sealing materials are used in semiconductor integrated circuits, quartz crystal oscillators, metal components, flat panel displays, glass terminals for LEDs, etc.

The above sealing materials require chemical durability and heat resistance, so glass-based sealing materials are used instead of resin-based adhesives. Sealing materials are also required to have properties such as mechanical strength, fluidity, and weather resistance, but sealing electronic components that are equipped with elements that are sensitive to heat requires that the sealing temperature be as low as possible. Specifically, sealing at 400°C or lower is preferable. Therefore, lead borate glass, which contains a large amount of PbO, which has an extremely large effect of lowering the softening point, has been widely used as a glass that satisfies the above properties (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 63-315536 JP 2019-202921 A

Environmental problems have been pointed out regarding the PbO contained in lead borate glass, and it is desirable to replace lead borate glass with glass that does not contain PbO. For this reason, various low-softening point glasses have been developed as substitutes for lead borate glass. However, in general, as the softening point of glass decreases, the weather resistance of the glass tends to deteriorate, so achieving both is a technical challenge. The CuO-TeO ₂ -MoO ₃ glass described in Patent Document 2 was expected to be a candidate for replacing lead borate glass, but although it has weather resistance, further lowering of the sealing temperature is required in consideration of the heat resistance of the above-mentioned element.

In view of the above, the present invention aims to provide a glass composition that is weather resistant and can be sealed by low-temperature firing, and a sealing material using the same.

The glass composition of the present invention is characterized by containing, in mol %, 1-30% MgO+CaO+SrO+BaO+ZnO, 30-80% TeO ₂ , and _5-30 % MoO 3. Here, "MgO+CaO+SrO+BaO+ZnO" means the total amount of MgO, CaO, SrO, BaO, and ZnO.

The glass composition of the present invention achieves a low softening point while retaining the weather resistance of glass by making the total content of MgO, CaO, SrO, BaO and ZnO 1% or more. Generally, when the softening point of glass is low, vitrification becomes difficult or phase separation occurs, making it difficult to obtain homogeneous glass. However, in the present invention, the content of _TeO2 is set to 30% or more and the content of _MoO3 is set to 5% or more, so that the glass is stabilized and homogeneous glass can be obtained.

Furthermore, the glass composition of the present invention preferably contains, in mol %, 1 to 30% of Li ₂ O + Na ₂ O + K ₂ O. Here, "Li ₂ O + Na ₂ O + K ₂ O" means the total amount of Li ₂ O, Na ₂ O and K ₂ O.

Furthermore, the glass composition of the present invention preferably contains, in mole percent, 1 to 30% BaO.

Furthermore, the glass composition of the present invention preferably contains, in mol %, 0 to 10% of TiO ₂ +Al ₂ O ₃ , where "TiO ₂ +Al ₂ O ₃ " means the total amount of TiO ₂ and Al ₂ O ₃ .

Furthermore, the glass composition of the present invention preferably contains, in mol %, 1 to 10% Al ₂ O ₃ .

Furthermore, the glass composition of the present invention preferably contains, in mol %, CuO 0-30%, WO ₃ 0-20%, and P ₂ O ₅ 0-10%.

Furthermore, the glass composition of the present invention preferably contains, in mole percent, 1 to 30% CuO.

The sealing material of the present invention is characterized by containing 40 to 100 volume % of glass powder made of the above glass composition and 0 to 60 volume % of refractory filler powder.

In the sealing material of the present invention, the refractory filler powder preferably contains Zr ₂ WO ₄ (PO ₄ ) ₂ .

In the sealing material of the present invention, the fire-resistant filler powder is preferably approximately spherical.

The sealing material of the present invention is preferably used to package quartz crystal oscillators.

The sealing material paste of the present invention is characterized by containing the above-mentioned sealing material and a vehicle.

The present invention provides a glass composition that can be sealed by low-temperature firing without containing lead, which is harmful to the environment, and a sealing material that uses the glass composition.

FIG. 2 is a schematic diagram showing a measurement curve obtained by a macro-type differential thermal analyzer.

The glass composition of the present invention contains, in mole percent, 1-30% MgO+CaO+SrO+BaO+ZnO, 30-80% TeO ₂ , and 5-30% MoO ₃ . The reasons for limiting the glass composition as above are as follows. In the following description of the content of each component, "%" means "mol percent" unless otherwise specified.

MgO, CaO, SrO, BaO and ZnO are components that expand the vitrification range and improve the weather resistance of glass. MgO + CaO + SrO + BaO + ZnO is 1 to 30%, preferably 3 to 25%, more preferably 5 to 20%, even more preferably 8 to 18%, and particularly preferably 10 to 15%. If there is too little MgO + CaO + SrO + BaO + ZnO, vitrification becomes difficult. In addition, the weather resistance of the glass deteriorates, and the glass becomes thermally unstable, making it more likely to devitrify when melted or fired. On the other hand, if there is too much MgO + CaO + SrO + BaO + ZnO, the glass becomes thermally unstable and more likely to devitrify when melted or fired.

The preferred ranges for the contents of MgO, CaO, SrO, BaO and ZnO are as follows:

MgO is a component that expands the vitrification range and improves the weather resistance of glass while suppressing an excessive increase in the softening point of glass. The MgO content is 1 to 30%, preferably 3 to 25%, more preferably 5 to 20%, even more preferably 8 to 18%, and particularly preferably 10 to 15%. If the MgO content is too low, vitrification becomes difficult, the weather resistance of the glass deteriorates, and the glass becomes thermally unstable, making it prone to devitrification when melted or fired. On the other hand, if the MgO content is too high, the glass becomes thermally unstable and prone to devitrification when melted or fired.

CaO is a component that expands the vitrification range and improves the weather resistance of glass while suppressing an excessive increase in the softening point of glass. The CaO content is 1 to 30%, preferably 3 to 25%, more preferably 5 to 20%, even more preferably 8 to 18%, and particularly preferably 10 to 15%. If the CaO content is too low, vitrification becomes difficult, the weather resistance of the glass deteriorates, and the glass becomes thermally unstable, making it prone to devitrification when melted or fired. On the other hand, if the CaO content is too high, the glass becomes thermally unstable and prone to devitrification when melted or fired.

SrO is a component that expands the vitrification range and improves the weather resistance of glass while suppressing an excessive increase in the softening point of glass. The SrO content is 1 to 30%, preferably 3 to 25%, more preferably 5 to 20%, even more preferably 8 to 18%, and particularly preferably 10 to 15%. If the SrO content is too low, vitrification becomes difficult, the weather resistance of the glass deteriorates, and the glass becomes thermally unstable, making it prone to devitrification when melted or fired. On the other hand, if the SrO content is too high, the glass becomes thermally unstable and prone to devitrification when melted or fired.

BaO is a component that significantly expands the vitrification range, significantly lowers the softening point of glass, and significantly improves the weather resistance of glass, compared to MgO, CaO, SrO, and ZnO. The BaO content is 1 to 30%, preferably 3 to 25%, more preferably 5 to 20%, even more preferably 8 to 18%, and particularly preferably 10 to 15%. If the BaO content is too low, vitrification becomes difficult, the softening point does not decrease, making low-temperature sealing difficult, and the glass becomes thermally unstable, making it prone to devitrification when melted or fired. It also becomes difficult to maintain the weather resistance of the glass. On the other hand, if the BaO content is too high, the glass becomes thermally unstable, making it prone to devitrification when melted or fired.

ZnO is a component that expands the vitrification range and improves the weather resistance of glass while suppressing an excessive increase in the softening point of glass. The ZnO content is 1 to 30%, preferably 3 to 25%, more preferably 5 to 20%, even more preferably 8 to 18%, and particularly preferably 10 to 15%. If the ZnO content is too low, vitrification becomes difficult, the weather resistance of the glass deteriorates, and the glass becomes thermally unstable, making it prone to devitrification when melted or fired. On the other hand, if the ZnO content is too high, the glass becomes thermally unstable and prone to devitrification when melted or fired.

_TeO2 is a component that forms a glass network and improves weather resistance. The content of _TeO2 is 30 to 80%, preferably 35 to 75%, more preferably 40 to 70%, even more preferably 45 to 65%, and particularly preferably 50 to 60%. If the content of _TeO2 is too small, the glass becomes thermally unstable, the glass becomes easily devitrified when melted or fired, and the weather resistance is easily reduced. On the other hand, if the content of _TeO2 is too large, the viscosity (softening point, etc.) of the glass becomes high, low-temperature sealing becomes difficult, the glass becomes thermally unstable, and the glass becomes easily devitrified when melted or fired. In addition, the thermal expansion coefficient of the glass tends to become too high.

MoO ₃ is a component that forms a glass network and improves weather resistance. The content of MoO ₃ is 5 to 30%, preferably 7 to 27%, more preferably 10 to 25%, even more preferably 12 to 22%, and particularly preferably 15 to 20%. If the content of MoO ₃ is too small, the glass becomes thermally unstable, the glass becomes easily devitrified when melted or fired, and the viscosity (softening point, etc.) of the glass becomes high, making low-temperature sealing difficult. On the other hand, if the content of MoO ₃ is too high, vitrification becomes difficult. In addition, the glass becomes thermally unstable, the glass becomes easily devitrified when melted or fired, and the thermal expansion coefficient of the glass tends to become too high.

In addition to the above components, the glass composition of the present invention may contain the following components in the glass composition.

Li ₂ O, Na ₂ O and K ₂ O are components that reduce the viscosity (softening point, etc.) of glass. Li ₂ O + Na ₂ O + K ₂ O is preferably 1 to 30%, more preferably 2 to 25%, even more preferably 5 to 20%, and particularly preferably 8 to 15%. If _{Li 2} O + Na ₂ O + K ₂ O is too little, the viscosity (softening point, etc.) of the glass increases, making low-temperature sealing difficult, and the glass becomes thermally unstable, making the glass more likely to devitrify during melting or firing. On the other hand, if Li ₂ O + Na ₂ O + K ₂ O is too much, the glass becomes thermally unstable, making the glass more likely to devitrify during melting or firing.

Li ₂ O is a component that significantly reduces the viscosity (softening point, etc.) of glass compared with Na ₂ O and K ₂ O. The content of Li ₂ O is preferably 1 to 30%, more preferably 2 to 25%, further preferably 3 to 20%, and particularly preferably 5 to 18%. If the content of Li ₂ O is too low, the viscosity (softening point, etc.) of the glass becomes high, making low-temperature sealing difficult. On the other hand, if the content of Li ₂ O is too high, the glass becomes thermally unstable and is prone to devitrification during melting or firing.

Na ₂ O is a component that lowers the viscosity (softening point, etc.) of glass compared with K ₂ O. The content of Na ₂ O is preferably 1 to 20%, more preferably 2 to 15%, further preferably 3 to 12%, and particularly preferably 5 to 10%. If the content of Na ₂ O is too low, the viscosity (softening point, etc.) of the glass increases, making low-temperature sealing difficult. On the other hand, if the content of Na ₂ O is too high, the glass becomes thermally unstable and is prone to devitrification during melting or firing.

K ₂ O is a component that reduces the viscosity (softening point, etc.) of glass. The content of K ₂ O is preferably 1 to 30%, more preferably 2 to 25%, further preferably 3 to 20%, and particularly preferably 5 to 18%. If the content of K ₂ O is too low, the viscosity (softening point, etc.) of the glass increases, making low-temperature sealing difficult. On the other hand, if the content of K ₂ O is too high, the glass becomes thermally unstable and is prone to devitrification during melting or firing.

Furthermore, in order to lower the softening point of the glass by the alkali mixing effect, the molar ratio of Li ₂ O/K ₂ O is preferably 0.3 to 5, more preferably 0.4 to 4, 0.5 to 3, even more preferably 0.6 to 2, and particularly preferably 0.7 to 1.5. If Li ₂ O/K ₂ O is too small, the viscosity (softening point, etc.) of the glass increases, making low-temperature sealing difficult and the glass becomes thermally unstable, making it easy for the glass to devitrify during melting or firing. On the other hand, if Li ₂ O/K ₂ O is too large, the glass becomes thermally unstable, making it easy for the glass to devitrify during melting or firing.

_TiO2 and _Al2O3 are components that improve weather resistance. _{TiO2 + Al2O3} is preferably 0 to 10%, more preferably 0.1 to 8%, further preferably 1 to 6%, and particularly preferably 2 to 5%. If _TiO2 + _Al2O3 is too much, the viscosity (softening point _{, etc.} ) of the glass increases, making low-temperature sealing difficult and making the glass thermally unstable, which makes the glass more susceptible to devitrification during melting or firing.

The preferred ranges of the contents of _{TiO2 and Al2O3} are as follows.

The content of _{TiO2 is} preferably 0-8%, more preferably 0.1-6%, even more preferably 1-5%, and particularly preferably 2-4%. The content of _Al2O3 is preferably 0-8%, more preferably 0.1-5%, even more preferably 0.5-3%, and particularly preferably 1-2%.

CuO is a component that reduces the viscosity (softening point, etc.) of glass and also reduces the thermal expansion coefficient of glass. It is also a component that improves the adhesive strength between glass and metal when sealing metal. The details of this mechanism are unclear at this time, but it is believed that because Cu atoms have high diffusivity, Cu atoms diffuse from the surface layer of the metal to the inside, making it easier for the glass and metal to be integrated. There is no particular restriction on the type of metal to be sealed, but examples include iron, iron alloys, nickel, nickel alloys, copper, copper alloys, aluminum, and aluminum alloys. The CuO content is preferably 0-30%, 0-10%, 0.1-5%, 0.5-3%, and especially 1-2%. The CuO content when sealing metal is preferably 1-30%, more preferably 1-20%, even more preferably 3-15%, and especially preferably 5-10%. If the CuO content is too high, the glass becomes thermally unstable, and metallic Cu may precipitate from the glass surface during the sealing process, adversely affecting the sealing properties and electrical properties. In addition, the glass is prone to devitrification during melting or firing.

_WO3 is a component that reduces the thermal expansion coefficient of glass. The content of _WO3 is 0 to 20%, 0.1 to 10%, and particularly 1 to 5%. If the content of _WO3 is too high, the glass becomes thermally unstable, the glass becomes easily devitrified during melting or firing, and the viscosity (softening point, etc.) of the glass increases, making low-temperature sealing difficult.

P ₂ O ₅ is a component that forms a glass network and thermally stabilizes the glass. The content of P ₂ O ₅ is preferably 0 to 10%, more preferably 0.1 to 5%, further preferably 0.2 to 2%, and particularly preferably 0.5 to 1%. If the content of _{P 2} O ₅ is too high, the viscosity (softening point, etc.) of the glass increases, making low-temperature sealing difficult and facilitating a decrease in weather resistance.

Ag ₂ O is a component that reduces the viscosity (softening point, etc.) of glass. The content of Ag ₂ O is preferably 0 to 10%, more preferably 0.1 to 5%, further preferably 0.2 to 3%, and particularly preferably 0.5 to 2%. If the content of Ag ₂ O is too high, the glass becomes thermally unstable and is prone to devitrification during melting or firing. In addition, there is a risk that metallic Ag will precipitate from the glass depending on the firing atmosphere.

AgI is a component that reduces the viscosity (softening point, etc.) of glass. The AgI content is preferably 0-10%, more preferably 0.1-5%, even more preferably 0.2-2%, and particularly preferably 0.5-1%. If the AgI content is too high, the thermal expansion coefficient of the glass tends to be too high.

Nb ₂ O ₅ is a component that thermally stabilizes glass and improves weather resistance. The content of Nb ₂ O ₅ is preferably 0 to 10%, more preferably 0.1 to 5%, further preferably 0.2 to 2%, and particularly preferably 0.5 to 1%. If the content of Nb ₂ O ₅ is too high, the viscosity (softening point, etc.) of the glass increases, making low-temperature sealing difficult.

V ₂ O ₅ is a component that forms a glass network and reduces the viscosity (softening point, etc.) of the glass. The content of V ₂ O ₅ is preferably 0 to 10%, more preferably 0.1 to 5%, even more preferably 0.2 to 3%, and still more preferably 1 to 2%. If the content of V ₂ O ₅ is too high, the glass becomes thermally unstable, and the glass is likely to devitrify during melting or firing, and the weather resistance is likely to decrease.

Ga ₂ O ₃ is a component that thermally stabilizes the glass and improves the weather resistance. However, since it is very expensive, it is preferable that the content be less than 0.01%, and in particular that no Ga 2 O 3 is contained.

_SiO2 , _GeO2 , _Fe2O3 , _NiO , _CeO2 , _B2O3 , _Sb2O3 , and _ZrO2 are components _that thermally stabilize the glass and suppress devitrification, and each can be added up to less than 2%. _If the content of these is too high, the glass becomes thermally unstable and is prone to devitrification during melting or firing.

For environmental reasons, it is preferable that the glass composition of the present invention contains substantially no PbO. Here, "substantially no PbO" refers to a glass composition containing 1% or less PbO.

The sealing material of the present invention contains glass powder made of the above glass composition. The sealing material of the present invention may contain a refractory filler powder in order to improve the mechanical strength or adjust the thermal expansion coefficient. The mixing ratio is preferably 40 to 100 volume % of glass powder and 0 to 60 volume % of refractory filler powder, more preferably 50 to 99 volume % of glass powder and 1 to 50 volume % of refractory filler powder, even more preferably 60 to 95 volume % of glass powder and 5 to 40 volume % of refractory filler powder, and particularly preferably 70 to 90 volume % of glass powder and 10 to 30 volume % of refractory filler powder. If the content of the refractory filler powder is too high, the proportion of the glass powder will be relatively small, making it difficult to ensure the desired fluidity.

The refractory filler powder preferably contains Zr ₂ WO ₄ (PO ₄ ) _2. Zr ₂ WO ₄ (PO ₄ ) ₂ does not easily react with the above-mentioned glass powder, and can efficiently reduce the thermal expansion coefficient of the sealing material.

In addition, the sealing material of the present invention may use a refractory filler powder other than Zr ₂ WO ₄ (PO ₄ ) ₂ as the refractory filler powder. As the other refractory filler powder, powders consisting of NbZr (PO ₄ ) ₃ , Zr ₂ MoO ₄ (PO ₄ ) ₂ , Hf ₂ WO ₄ (PO ₄ ) ₂ , Hf ₂ MoO ₄ (PO ₄ ) ₂ , zirconium phosphate, zircon, zirconia, tin oxide, aluminum titanate, quartz, β-spodumene, mullite, titania, quartz glass, β-eucryptite, β-quartz, willemite, cordierite, Sr _0.5 Zr ₂ (PO ₄ ) ₃ , etc. may be used alone or in combination of two or more.

It is preferable that the refractory filler powder is substantially spherical. In this way, when the glass powder softens, the fluidity of the glass powder is less likely to be hindered by the refractory filler powder, and as a result, the fluidity of the sealing material is improved. In addition, it is easier to obtain a smooth glaze layer. Furthermore, even if a part of the refractory filler powder is exposed on the surface of the glaze layer, since the refractory filler powder is substantially spherical, the stress of this part is dispersed, and even if the sealed object is brought into contact with the glaze layer during sealing, undue stress is unlikely to be applied to the sealed object, and as a result, it is easier to ensure airtightness. In addition, the "substantially spherical" in the present invention is not limited to a perfect sphere, but refers to a refractory filler powder in which the value obtained by dividing the shortest diameter passing through the center of gravity of the refractory filler powder by the longest diameter is 0.5 or more, preferably 0.7 or more.

The particle size of the refractory filler powder is preferably such that the average particle size _D50 is about 0.2 to 20 μm.

The softening point of the sealing material of the present invention is preferably 350°C or less, particularly preferably 340°C or less. If the softening point is too high, the viscosity of the glass increases, so that the sealing temperature rises to meet a predetermined fluidity, and there is a risk of the element being deteriorated by the heat during sealing. The lower limit of the softening point is not particularly limited, but is practically 180°C or more. Here, the "softening point" refers to a value measured by a macro-type differential thermal analyzer using a sealing material having an average particle size _D50 of 0.5 to 20 μm as a measurement sample. The measurement conditions are that the measurement is started from room temperature and the heating rate is 10°C/min. The softening point measured by a macro-type differential thermal analyzer refers to the temperature (Ts) of the fourth bending point in the measurement curve shown in FIG. 1.

The thermal expansion coefficient (30 to 150° C.) of the sealing material of the present invention is preferably 20×10 ⁻⁷ /° C. to 200×10 ⁻⁷ /° C., more preferably 30×10 ⁻⁷ /° C. to 160×10 ⁻⁷ /° C., even more preferably 40×10 ⁻⁷ /° C. to 140×10 ⁻⁷ /° C., and particularly preferably 50×10 ⁻⁷ /° C. to 120×10 ⁻⁷ /° C. If the thermal expansion coefficient is too low or too high, the difference in thermal expansion with the sealed material makes the sealed portion prone to damage during or after sealing.

The sealing material of the present invention, which has the above-mentioned characteristics, is particularly suitable for packaging quartz crystal oscillators, which require sealing at low temperatures.

Next, we will explain an example of a method for producing glass powder using the glass composition of the present invention, and a method for using the glass composition of the present invention as a sealing material.

First, the raw material powder prepared to have the above composition is melted at 800 to 1000°C for 1 to 2 hours until a homogeneous glass is obtained. Next, the molten glass is formed into a film or the like, pulverized, and classified to produce glass powder made of the glass composition of the present invention. The average particle size _D50 of the glass powder is preferably about 1 to 20 μm. If necessary, various fire-resistant filler powders are added to the glass powder to produce a sealing material.

Next, a vehicle is added to the glass powder (or sealing material) and kneaded to prepare a glass paste (or sealing material paste). The vehicle mainly consists of an organic solvent and a resin, and the resin is added to adjust the viscosity of the paste. If necessary, surfactants, thickeners, etc. can also be added.

The organic solvent is preferably one that has a low boiling point (for example, a boiling point of 300° C. or less), leaves little residue after firing, and does not alter the glass, and the content is preferably 10 to 40% by mass. As the organic solvent, it is preferable to use propylene carbonate, toluene, N,N'-dimethylformamide (DMF), 1,3-dimethyl-2-imidazolidinone (DMI), dimethyl carbonate, butyl carbitol acetate (BCA), isoamyl acetate, dimethyl sulfoxide, acetone, methyl ethyl ketone, or the like. It is more preferable to use a higher alcohol as the organic solvent. Since higher alcohols themselves have viscosity, they can be made into a paste without adding a resin to the vehicle. In addition, pentanediol and its derivatives, specifically diethylpentanediol (C ₉ H ₂₀ O ₂ ), also have excellent viscosity and can be used as a solvent.

The resin preferably has a low decomposition temperature, leaves little residue after firing, and is not likely to alter the glass, and its content is preferably 0.1 to 20% by mass. The resin preferably used is nitrocellulose, polyethylene glycol derivatives, polyethylene carbonate, acrylic esters (acrylic resins), etc.

Next, the glass paste (sealing material paste) is applied to the sealing points of the objects to be sealed, which are made of metal, ceramic, or glass, using an applicator such as a dispenser or screen printer, dried, and glazed at 300 to 350°C. The objects to be sealed are then brought into contact with each other and heat-treated at 350 to 400°C, causing the glass powder to soften and flow, sealing the two objects.

The glass composition of the present invention can be used for purposes other than sealing, such as coating and filling. It can also be used in forms other than paste, such as powder, green sheet, tablet (press frit, which is a sintered body of powder), etc.

The present invention will be described in detail based on examples. Tables 1 and 2 show examples of the present invention (samples No. 1 to 17) and comparative examples (samples No. 18 to 21).

First, glass raw materials such as various oxides and carbonates were mixed to obtain the glass compositions shown in the table to prepare glass batches, which were then placed in platinum crucibles and melted in air at 800 to 1000° C. for 1 to 2 hours. The molten glass was then formed into a film using water-cooled rollers, and the film-like glass was pulverized using a ball mill and passed through a sieve with 75 μm openings to obtain glass powder with an average particle size D ₅₀ of about 10 μm.

Then, the obtained glass powder and the refractory filler powder were mixed as shown in the table to obtain a mixed powder.

The refractory filler powder used was roughly _{spherical Zr2WO4} ( _PO4 ) ₂ (referred to as ZWP in the table) and NbZr( _PO4 ) ₃ (referred to as NZP in the table). The average particle size _D50 of the refractory filler powder was about 10 μm.

Samples No. 1 to 21 were evaluated for glass transition point, thermal expansion coefficient, softening point, fluidity, presence or absence of devitrification, weather resistance, and adhesion to metals.

The glass transition point and thermal expansion coefficient (30-150°C) were evaluated as follows. The mixed powder sample was placed in a rod-shaped mold and press-molded, then sintered at 380°C for 10 minutes on an alumina substrate coated with a release agent. The sintered body was then processed into a specified shape and measured using a TMA device.

The softening point was measured using a macro differential thermal analyzer, and the fourth inflection point was taken as the softening point. The measurement was performed in air, the heating rate was 10°C/min, and the measurement was started from room temperature.

The flowability was evaluated as follows. The weight of the mixed powder sample corresponding to the composite density was placed in a mold with a diameter of 20 mm, press molded, and then fired on a glass substrate at 380°C for 10 minutes. Fired bodies with a flow diameter of 19 mm or more were marked as "○", and those with a flow diameter of less than 19 mm were marked as "×".

The presence or absence of devitrification was evaluated as follows: The surface of the fired body prepared above was visually observed, and those that did not have a glassy luster were rated as "present" devitrification, and all other cases were rated as "absent" devitrification.

Weather resistance was evaluated by an accelerated deterioration test using the PCT (Pressure Cooker Test). Specifically, the fired bodies prepared above were kept in an environment of 121°C, 2 atm, and 100% relative humidity for 24 hours, and then visually observed to determine whether there was any precipitate on the surface of the fired bodies, and whether there was an "O" or "X" rating.

The adhesion to metal was evaluated as follows. A weight equivalent to the density of the glass powder sample was placed in a mold with a diameter of 20 mm, press molded, and then fired on a stainless steel SUS304 substrate at 380°C for 10 minutes in a nitrogen atmosphere. After firing, the surface opposite to the surface to which the fired SUS304 body was sealed was attached so that it was in close contact with a wall perpendicular to the horizon. If the fired body did not peel off from the SUS304 substrate due to its own weight even after 24 hours, it was marked as "○", and if it peeled off and fell off, it was marked as "×".

As is clear from the table, the samples No. 1 to No. 17, which are examples of the present invention, had excellent fluidity due to their low softening points. They also had excellent weather resistance. On the other hand, the sample No. 18, which is a comparative example, had a content of MgO+CaO+SrO+BaO+ZnO that exceeded the specified amount, so the glass was devitrified during firing and had poor fluidity. The sample No. 19, which is a comparative example, did not vitrify because the content of _MoO3 exceeded the specified amount. The samples No. 20 and No. 21, which are comparative examples, did not contain MgO, CaO, SrO, BaO, or ZnO, so their weather resistance was poor.

The glass composition of the present invention is suitable for sealing semiconductor integrated circuits, quartz crystal oscillators, flat panel displays, glass terminals for LEDs, and aluminum nitride substrates. It can also be used as a sealing material for metals.

Claims (12)

A glass composition comprising, in mole percent, 1-30% MgO+CaO+SrO ₊ BaO+ZnO, _30-80 % TeO2, 5-30% _MoO3 , and 1-30% Li2O +Na2O ₊ K2O _, with a molar ratio of Li2O _/ K2O _being 0.3-5 . 2. The glass composition according to claim 1 , containing, in mol %, 1 to 30% Li ₂ O. 3. The glass composition according to claim 1, further comprising, in terms of molar ratio, 1 to 30% of BaO. 4. The glass composition according to claim 1 , further comprising, in mol %, 0 to 10% of TiO ₂ +Al ₂ O ₃ . The glass composition according to any one of claims 1 to 4 , further comprising, in mol %, 1 to 10% of Al ₂ O ₃ . 6. The glass composition according to claim 1 , further comprising, in mol %, 0 to 30% CuO, 0 to 20% WO ₃ , and 0 to 10% P ₂ O ₅ . 7. The glass composition according to claim 1 , further comprising, in mol %, 1 to 30% of CuO. A sealing material comprising 40 to 100 volume % of a glass powder made of the glass composition according to any one of claims 1 to 7 , and 0 to 60 volume % of a refractory filler powder. The sealing material according to claim 8 _, characterized in that the refractory filler powder contains _Zr2WO4 ( _PO4 ) ₂ . 10. The sealing material according to claim 8 , wherein the refractory filler powder is substantially spherical. The sealing material according to any one of claims 8 to 10 , which is used for a quartz crystal oscillator package. A sealing material paste comprising the sealing material according to any one of claims 8 to 11 and a vehicle.