JP2001199740A - Lead-free glass and composition for sealing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain glass which contains no lead component so as to reduce load of environment, is usable at a sufficiently low temperature to seal and coat an electronic part and stands a practical use. SOLUTION: This lead-free glass has a composition comprising 5.1-60 mol% calculated as CuO of copper, 25-75 mol% P2O5 and 1-60 mol% RO (RO is one or more kinds selected from the group consisting of ZnO, BaO, CaO, MgO, SrO, SnO, NiO, FeO and MnO) based on oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead-free glass, and more particularly to a lead-free low-melting glass composition used at low temperatures for sealing and coating electronic members.

[0002]

2. Description of the Related Art Heretofore, glass containing PbO as a main component has been used as a glass for sealing and coating electronic members at a low temperature. Specifically, for example, it is used as a sealing material for a ceramic package for protecting a semiconductor. Since semiconductors are extremely sensitive to moisture and impurities, they are generally housed in a package and hermetically sealed to protect them. For this reason, packages are required to have high airtightness and weather resistance, and ceramics such as alumina are used. Further, since semiconductors are weak to heat, it is required that the sealing material of the package can be used at a low temperature in addition to airtightness and weather resistance.

For sealing and coating of electronic members, a PbO-based low-melting glass is used, an organic solvent and a binder are mixed to form a paste, applied by a dispenser or screen printing, dried, and degreased to 400 ° C. to 600 ° C. The heat treatment of ° C was performed. Glasses containing a high concentration of a lead component have been used for these conventional sealing glasses. In recent years, there has been a demand for a glass composition containing no lead component to reduce environmental load. In order to meet this demand, bismuth-based glass (JP-A-6-234547) and zinc-based glass (JP-A-6-23447)
-220375), phosphoric acid-based glass (JP-A-6-325)
863) has been developed.

[0004]

However, when the above-mentioned lead-free glass is used for sealing and coating electronic members, it may not be practically used because it cannot be used at a sufficiently low temperature, or crystallization is likely to occur. An object of the present invention is to provide a stable glass which does not contain a lead component for reducing the environmental load and which can be used at a sufficiently low temperature to be used for sealing and coating of electronic members and which can withstand practical use. And

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a copper content of 5.1 to 60% in terms of CuO, expressed as mol% on an oxide basis, of P _2. O ₅ :
25 to 75%, RO: 1 to 60% (where RO is Zn
O, BaO, CaO, MgO, SrO, SnO, Ni
A lead-free glass having a composition of at least one selected from the group consisting of O, FeO and MnO). Note that, as described later, the present invention does not exclude the inclusion of components other than the above-mentioned composition.

Further, the lead-free glass is 40 to 99% by volume.
And 1 to 60% by volume of an inorganic filler.

The present inventor has proposed CuO-P_TwoO_FiveSystem lead-free glass
As a result of intensive research, CuO_x−P_TwoO _Five-RO glass
Can be used at a sufficiently low temperature for sealing and coating electronic components.
Found to be a stable glass without crystallization
I did. Here, "can be used at a sufficiently low temperature" means the working temperature
It means that the temperature is 600 ° C. or less.

As a glass containing copper, J.I. No
n-Cryst. Solids, 201, 222-23
Describes a CuO _x -P ₂ O ₅ based glass to 0 (1996). However, when glass of this composition is used for sealing electronic components, crystallization is likely to occur and fluidity is insufficient, so that sufficient airtightness with an object to be sealed may not be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the lead-free glass of the present invention will be described in detail with reference to preferred embodiments. Copper is a main component of the lead-free glass of the present invention and is essential. When the content of copper in terms of CuO is less than 5.1 mol%, the chemical durability of the glass is remarkably reduced, and the glass is not practical. It is preferably at least 10 mol%, more preferably at least 20 mol%. If it exceeds 60 mol%, vitrification becomes difficult. It is preferably at most 50 mol%, more preferably at most 40 mol%.

[0010] The glass properties can be changed by changing the oxidation state of copper in the lead-free glass of the present invention. When the oxidized state is monovalent copper oxide and contained in the glass, it has the effect of lowering the softening point of the glass. When the oxidized state is divalent copper oxide and contained in the glass, the glass is stabilized and crystallized. This has the effect of suppressing the formation.

The glass properties can be changed by combining monovalent and divalent copper oxides in the glass. When the heat resistance of the electronic component to be sealed and coated is not high, a glass may be prepared and used so as to contain a large amount of monovalent copper oxide. When the sealed and coated glass is exposed to a high temperature, the glass may be produced so as to contain a large amount of divalent copper oxide in order to increase the stability of the glass.

The oxidation state of copper, ie, the ratio between monovalent and divalent, can be adjusted by the atmosphere in which the glass is melted and the amount of the reducing agent. To obtain lead-free glass containing a large amount of monovalent copper oxide,
What is necessary is just to add a reducing agent to the raw material and melt the glass in a reducing atmosphere, and to obtain a lead-free glass containing a large amount of divalent copper oxide, it is sufficient to melt the glass in an air atmosphere without adding a reducing agent.
The reducing agent is not particularly limited, but saccharose and glucose are preferred. The addition amount of the reducing agent is preferably 0.1 to 3% by weight. In the present invention, the mass percentage is expressed by weight%.
Notation.

P ₂ O ₅ is a component constituting a glass network and is essential. When the content of P ₂ O ₅ is less than 25 mol%, vitrification becomes difficult. It is preferably at least 35 mol%, more preferably at least 40 mol%. P ₂ O ₅
When the content exceeds 75 mol%, the chemical durability is significantly reduced. It is preferably at most 70 mol%, more preferably at most 60 mol%.

ZnO, BaO, CaO, MgO, Sr
O, SnO, NiO, FeO and MnO are components for improving the stability of the glass, and the lead-free glass of the present invention must contain at least one of these nine components. If the total content of these nine components is less than 1 mol%, the effect of stabilizing the glass cannot be obtained. It is preferably at least 5 mol%, more preferably at least 10 mol%. Also, 60
If it exceeds mol%, the softening point becomes too high, the fluidity of the glass becomes poor, and sealing and coating at low temperatures cannot be performed. It is preferably at most 40 mol%, more preferably at most 30 mol%.

The lead-free glass of the present invention contains, in addition to the above components, Al ₂ O ₃ , B ₂ O ₃ , La ₂ O ₃ , Li ₂ O, Na ₂ O, K
The components (other components) such as ₂ O, CeO ₂ , SiO ₂ , TiO _2, etc. are used to improve the chemical durability, adjust the thermal expansion coefficient, improve the glass melting property or suppress the crystallization. You may make it contain in the range which does not spoil. The total content of these other components is preferably 30 mol% or less, more preferably 10 mol% or less.

The lead-free glass of the present invention can be manufactured by a known method, and the manufacturing method is not particularly limited. For example, a raw material is mixed in a predetermined amount, and the atmosphere is adjusted as necessary.
The mixture is heated and melted at a temperature of 00 to 1400 ° C., and the melt is poured into a mold to obtain a glass block. When powder is used, it is pulverized using a ball mill or the like.

The lead-free glass of the present invention has a thermal expansion coefficient of 80 ×
It is preferably from 10 ^{−7 to} 150 × 10 ⁻⁷ / ° C. When the lead-free glass of the present invention is used for sealing, coating, or the like, if the coefficient of thermal expansion does not match that of the object to be sealed or coated, the sealed object or the coating may peel off, or the sealed object may break. I do. The lead-free glass of the present invention can be used for sealing or coating as it is if the thermal expansion coefficient of the material to be sealed or coated is matched, but if the thermal expansion coefficient is not matched, inorganic The thermal expansion coefficient can be adjusted by adding a filler.

Next, the sealing composition of the present invention will be described. The sealing composition of the present invention contains the lead-free glass of the present invention as an essential component in the range of 40 to 99% by volume. Preferably it is 50 to 99% by volume. The inorganic filler is essential in the sealing composition of the present invention, and its content is from 1 to
60% by volume. When the content of the inorganic filler exceeds 60% by volume, the glass component becomes too small, and the fluidity of the sealed product becomes poor, so that the treatment at a low temperature cannot be performed. Preferably it is 50% by volume or less.

When the sealing composition of the present invention is used for sealing, it is lead-free so that the calcined product has a coefficient of thermal expansion of 0 to -10 × 10 ^-7 / ° C with respect to the coefficient of thermal expansion of the material to be sealed. Mixing glass and an inorganic filler is preferable because sealing with excellent airtightness can be performed.

The inorganic filler in the sealing composition of the present invention not only adjusts the coefficient of thermal expansion but also has mechanical strength, moisture resistance,
Effective for improving water resistance. For this reason, in order to obtain a desired sealed product in terms of thermal expansion coefficient, moisture resistance, mechanical strength, and the like, a plurality of inorganic fillers may be contained in combination.

Examples of the inorganic filler include zircon, cordierite, alumina, mullite, silica, β-eucryptite, β-spodumene, β-quartz solid solution, zirconium phosphate, zirconium phosphate solid solution, tin oxide, and tin oxide. Titanium oxide solid solution, magnesium phosphate, fluorite, forsterite, aluminum nitride, silicon nitride, silicon carbide and niobium oxide are preferred, and these may be used alone or in combination of two or more.

The lead-free glass and the sealing composition of the present invention can be used for sealing and coating of electronic members. Specific applications are semiconductor packages, crystal oscillator packages, cathode ray tubes, plasma display panels, fluorescent display tubes, and liquid crystals. Backlight, sealing material for sheathed heater, plasma display panel, dielectric layer of fluorescent display tube, plasma display panel, partition material of fluorescent display tube, conductive paste additive, and not electronic material, but vacuum of stainless steel thermos It is also used as a sealing material.

When the lead-free glass and the sealing composition of the present invention are used for a semiconductor alumina package, for example, the lead-free glass powder of the present invention is sieved to 150 mesh to have an average particle size of about 4 to 10 μm. For the purpose of reducing the thermal expansion coefficient, cordierite having an average particle size of 5 to 10 μm is blended and mixed as an inorganic filler so that the fired product has a thermal expansion coefficient of 70 × 10 ⁻⁷ / ° C.

When used as a partition wall material of a plasma display panel, for example, the lead-free glass of the present invention has a maximum particle size of 10 μm and an average particle size of 1 to 2 μm. Silica to make it smaller, Cu-Cr-Mn to make it black
A pigment is mixed and used with a particle size substantially equal to that of lead-free glass.

When used for vacuum sealing of a stainless steel thermos, for example, the coefficient of thermal expansion of the fired product is 120 × 10 ⁻⁷ / ° C.
The composition is adjusted so as to be in the order of magnitude and molded to form a bulk body. Further, it is cut into a size of 2 mm square, placed on a sealing portion, placed in a vacuum firing furnace, evacuated, and then heated and sealed.

[0026]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples. Raw materials were prepared so as to have the composition shown in the column from CuO to glucose in Table 1. For the components from CuO to MnO, the content in mol% is shown, and for the glucose as a reducing agent, the addition amount in weight% is shown. The prepared raw materials were put into a quartz crucible, and heated and melted in an electric furnace at 1100 ° C. for 1 hour in an atmosphere shown in Table 1, and then melted.
It was quenched and formed into a plate to obtain a plate-shaped glass block.
In Table 1, the atmosphere described as "atmosphere" is the one in which the quartz crucible was not covered at the time of the melting, and the one described as "reduction" was covered with the quartz crucible at the time of the melting. It was done.

Next, the glass block was pulverized with a ball mill to obtain a glass powder. The glass powders of Examples 1 to 7 are the powders of the lead-free glass of the present invention, and Examples 8 and 9 are comparative examples. In Example 9, no glass was obtained.

Further, the glass powders of Examples 5 to 7 and the inorganic fillers shown in the column of the filler in Table 1 were mixed to prepare the sealing composition of the present invention. The content of the glass powder is shown in the column of glass, and the content of the inorganic filler is shown in the column of the filler in volume%. Glass powders of Examples 1-4 and 8 and Examples 5
7, the glass transition point T _g (unit:
° C), coefficient of thermal expansion α (unit: 10 ^-7 / ° C) and fluidity were measured. The results are shown in Table 1, and the measuring method is shown below.

Glass transition point: Measured using a differential dilatometer. Heating was performed at a heating rate of 10 ° C./min, and the first inflection point was read as the glass transition point. Coefficient of thermal expansion: Measured using a differential dilatometer. Heating rate 1
It heated at 0 degreeC / min, and calculated the average linear expansion coefficient in 30-250 degreeC.

Fluidity: The sample was press-molded into a 12.7 mm cylindrical shape to obtain a measurement sample. This firing temperature (unit: ° C.) described in the column of T _B of Table 1 was calcined by holding for 10 minutes. The measurement sample flowed by this firing. The diameter of the obtained fired product was measured to evaluate the fluidity. When used for sealing electronic parts, the diameter is preferably 20 mm or more. If the diameter is 20 mm or more, it is good, and if it is less than 20 mm, it is bad.

For Examples 1 to 7, stable lead-free glasses were obtained. In addition, sufficient fluidity was obtained for the glass powders of Examples 1 to 4 and the sealing compositions of Examples 5 to 7. In contrast, the glass powder of Example 8 had a sufficiently low glass transition point, but the glass was unstable and the fluidity was poor.

[0032]

[Table 1]

[0033]

As described above, since both the lead-free glass and the sealing composition of the present invention do not contain a lead component, the working environment is improved. Furthermore, there is no need to take measures against lead when treating waste containing these materials. Moreover, since it can be used at a sufficiently low temperature, it can be used for sealing and coating electronic components.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Jun Toshima 2-1915-5, Kamitomiokacho, Nagaoka City, Niigata Prefecture (72) Atsushi Hiroi 1-50-1 Gyoda, Funabashi City, Chiba Prefecture Asahi Techno Glass Co., Ltd. F-term in Nakayama Plant (reference) 4G062 AA08 AA09 BB09 CC10 DA01 DB01 DC01 DD04 DD05 DD06 DD07 DE02 DE03 DE04 DE05 DE06 DF01 EA01 EB01 EC01 ED02 ED03 ED04 ED05 ED06 EE02 EE03 EE04 EE05 EE06 EF02 EF03 EF03 EF02 EF03 EF02 EF03 FB01 FC01 FD01 FE02 FE03 FE04 FE05 FE06 FF01 FG01 FH01 FJ01 FK01 FL01 GA01 GA10 GB01 GC01 GD01 GE01 HH01 HH03 HH04 HH05 HH07 HH09 HH10 PPHH11 HH12 HH13 HH15 HH17 KK01 JJ01 KK JJ JJ JJ KK PP09 PP10 PP11

Claims (3)

[Claims] 1. Copper expressed as mol% on an oxide basis, calculated as CuO: 5.1 to 60%, P ₂ O ₅ : 25 to 75%, R
O: 1 to 60% (RO means ZnO, BaO, Ca
O, MgO, SrO, SnO, NiO, FeO and Mn
(Lead-free glass) having a composition of at least one selected from the group consisting of O). 2. A sealing composition comprising 40 to 99% by volume of the lead-free glass according to claim 1 and 1 to 60% by volume of an inorganic filler. 3. The inorganic filler is zircon, cordierite, alumina, mullite, silica, β-eucryptite, β-spodumene, β-quartz solid solution, zirconium phosphate, zirconium phosphate solid solution, tin oxide, tin oxide -Titanium oxide solid solution, magnesium phosphate, fluorite,
3. The sealing composition according to claim 2, wherein the composition is at least one selected from the group consisting of forsterite, aluminum nitride, silicon nitride, silicon carbide, and niobium oxide.