Acid resistant low melting point material

Abstract

To provide a sealing material containing a glass composition which contains neither lead oxide nor vanadium oxide, can be fluidized by firing at a low temperature, and is excellent in acid resistance of a fired body.SOLUTION: A sealing material comprising a tellurium oxide-based glass composition substantially free of any of lead oxides and vanadium oxides, wherein the tellurium oxide-based glass composition comprises, as represented by mol% in terms of oxides, 44 to 70% of TeO2, 2 to 25% of Nb2O5, 3 to 20% of ZnO, and 0 to 15% in total of one or more of MgO, CaO, SrO, and BaO.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a material that can replace lead-based glass, and more specifically to a material for adhering metal powder (conductor powder) such as silver or copper used to form electrodes on electronic components to the surface of a substrate, or a material used to cover electrodes, resistors, etc. that have already been formed on electronic components for the purposes of protecting or insulating them (collectively referred to as "sealing material" hereinafter), which can be used at low temperatures without substantially containing lead or vanadium oxide. [Background technology]

[0002] Materials used as carriers for forming electrodes on electronic components, in which metal powders (conductor powders) such as silver and copper are applied to the surface of a substrate and then baked to adhere, must soften at as low a temperature as possible, have sufficient fluidity during baking, and be resistant to deterioration even when immersed in a plating solution.

[0003] Similarly, materials used to cover previously formed electrodes and resistors for purposes such as protection and insulation are also required to be able to be fired at low temperatures.

[0004] PbO-B2O3 and PbO-B2O3-Bi2O3 glasses have been commonly used as materials that can be used for sealing and coating by firing at low temperatures. However, in recent years, the use of these lead-containing glasses has been avoided from an environmental perspective, and they have been replaced by lead-free glasses.

[0005] Known lead-free low-melting-point glasses include phosphate glass, alkali silicate glass, bismuth-based glass, tellurium oxide-based glass, etc. Among these, bismuth-based glass has attracted attention from the viewpoint of weather resistance, and many bismuth-based glasses with various compositions have been developed to date. However, these glasses have poorer acid resistance than lead-based glasses, and therefore cannot replace lead-based glasses in some applications.

[0006] Furthermore, tellurium oxide-based glass compositions such as those disclosed in Patent Documents 1 and 2 also have insufficient acid resistance and have the same problems as bismuth-based glasses, and have not been improved. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 10-29834 [Patent Document 2] Patent Publication No. 2015-44728 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a sealing material comprising a glass composition that does not contain lead oxide or vanadium oxide, can be fluidized by firing at a low temperature, and has excellent acid resistance when fired.

[0009] Vanadium oxide (V2O5) is known to be one of the components that form glass and lower the softening point, but vanadium is a component that has an effect on the human body (it is subject to the Ordinance for Prevention of Harm from Specified Chemical Substances under the Industrial Safety and Health Act). For this reason, it should not be included in glass components, particularly from the perspective of avoiding concerns about workers being exposed to vanadium during the glass manufacturing process. [Means for solving the problem]

[0010] The present inventors have discovered that a tellurium oxide-based glass composition that is substantially free of lead oxide and vanadium oxide and that contains niobium pentoxide in a specified content range and other components in a specified content range exhibits fluidity when fired at a low temperature and at the same time exhibits excellent acid resistance, and have completed the present invention.

[0011] 1. A sealing material comprising a tellurium oxide-based glass composition that is substantially free of lead oxide and vanadium oxide, wherein the tellurium oxide-based glass composition contains, in mole % calculated as oxide, TeO2: 44-70%, Nb2O5: 2-25% ZnO: 3 to 20%, and One or more of MgO, CaO, SrO, and BaO, 0 to 15% in total; A sealing material comprising: 2. The tellurium oxide-based glass composition has, in mole percent in terms of oxide, TeO2: 48-70%, Nb2O5: 4~25% ZnO: 5 to 19%, and One or more of MgO, CaO, SrO, and BaO, 3 to 12% in total; 2. The sealing material according to claim 1, characterized in that it contains: 3. The tellurium oxide-based glass composition has, in mole percent in terms of oxide, TeO2: 50-70%, Nb2O5: 6-25% ZnO: 7 to 16%, and One or more of MgO, CaO, SrO, and BaO, total of 4 to 8% 2. The sealing material according to claim 1, characterized in that it contains: 4. The sealing material according to any one of 1 to 3 above, wherein the tellurium oxide-based glass composition contains 10 mol % or less of Bi2O3, expressed as mol % calculated as oxide. 5. The sealing material according to any one of 1 to 4 above, wherein the tellurium oxide-based glass composition contains 25 mol % or less of B2O3, expressed as mol % calculated as oxide. 6. A sealing material according to any one of 1 to 5 above, wherein the tellurium oxide-based glass composition and ceramic filler powder in powder form are mixed in an amount of: 100 to 60% by weight of the tellurium oxide-based glass composition in powder form, and Ceramic filler powder: 0 to 40% by weight A sealing material comprising: 7. A sealing material comprising the sealing material according to 6 above, an organic binder, and a solvent. [Effects of the Invention]

[0012] According to the present invention having the above-described configuration, it is possible to obtain a sealing material comprising a lead-free tellurium oxide-based glass composition, which can be made to flow well by firing at a low temperature, and even when in the form of a mixture with a ceramic filler, no crystal precipitation occurs during firing, ensuring good flowability, and forming a fired body with excellent acid resistance after cooling and solidifying. DETAILED DESCRIPTION OF THE INVENTION

[0013] The sealing material of the present invention will be described below with regard to the components in terms of oxides in the glass composition constituting the sealing material, the contents of these components, the type of filler in the case of a mixture of the glass composition pulverized into powder and a filler powder, and the blending ratio of the glass composition powder and the filler powder, etc. Note that the component contents of the glass composition are all expressed in mol% below.

[0014] As used herein, the term "low temperature" in relation to firing refers to a temperature not exceeding 550°C, more preferably not exceeding 520°C, and even more preferably not exceeding 500°C.

[0015] 1. Glass composition TeO2 is a glass-forming oxide, and in the present invention, the content of TeO2 in the glass composition can be in the range of 44 to 70% in relation to other components. If the TeO2 content is less than 44%, glass may not be formed. Even if glass is formed, the glass may have a high softening point, making it impossible to obtain a low-melting-point glass that flows during firing. Furthermore, if the TeO2 content exceeds 70%, the acid resistance of the fired body obtained after firing may be reduced. In the present invention, taking into consideration the effects on glass formability, flowability during firing, and acid resistance, the TeO2 content is preferably 44% or more, more preferably 48% or more, even more preferably 50% or more, and preferably 70% or less, more preferably 65% ​​or less, and even more preferably 60% or less.

[0016] Nb2O5 is a component that has been found to act to improve the acid resistance of the glass composition of the present invention, and the effect of improving acid resistance is observed at a content in the range of at least 2 to 25%. Furthermore, if the content exceeds 25%, there is a risk that Nb2O5 will remain undissolved during glass production. In consideration of these points, the Nb2O5 content is preferably 2% or more, more preferably 4% or more, even more preferably 6% or more, particularly preferably 11% or more, and is preferably 25% or less, more preferably 22% or less, even more preferably 20% or less, particularly preferably 18% or less.

[0017] ZnO is a component that enhances glass formability. In the glass composition of the present invention, if the ZnO content is less than 3%, the glass forming effect may be insufficient, and glass may not be obtained. Furthermore, if the ZnO content exceeds 20%, the acid resistance of the glass may be reduced. In consideration of glass formability, acid resistance, etc., the ZnO content is preferably 3% or more, more preferably 5% or more, even more preferably 7% or more, particularly preferably 10% or more, and is preferably 20% or less, more preferably 19% or less, and even more preferably 16% or less.

[0018] Although MgO, CaO, SrO, and BaO are not necessarily contained, they are components that function to enhance glass formability in the present invention, and therefore, one or more of them may be contained in the glass composition of the present invention. However, if the total content of these components exceeds 15%, it may be impossible to obtain glass, and a high content of these components may have a negative effect on the acid resistance of the glass. In consideration of these points, the total content of one or more of MgO, CaO, SrO, and BaO is preferably 0% or more, more preferably 3% or more, and even more preferably 4% or more, and is preferably 15% or less, more preferably 12% or less, and even more preferably 8% or less.

[0019] Bi2O3 is a component that stabilizes the glass state in the glass composition of the present invention and contributes to lowering the melting point. Bi2O3 does not necessarily have to be contained in the glass composition of the present invention, but if it is contained, the content is preferably 10% or less, more preferably 7% or less, and even more preferably 4% or less.

[0020] B2O3 is a component that forms glass, and it does not have to be contained in the glass composition of the present invention. However, if it is contained, the content is preferably 25% or less, more preferably 24% or less, even more preferably 20% or less, and particularly preferably 12% or less.

[0021] In addition to the above components, the glass composition of the present invention may contain one or more of lanthanoid compounds (La2O3, Y2O3, Yb2O3, CeO2), MoO3, WO3, CuO, TiO2, and ZrO2 in a total amount of 0.01 to 3 mol % for the purposes of improving the stability of the glass state during glass production, suppressing crystallization, and adjusting the thermal expansion coefficient.

[0022] In the glass composition of the present invention, in order to improve the stability of the glass during production and to prevent crystallization during the firing process, the total content of the essential components (TeO2 + Nb2O5 + ZnO) among the above-mentioned components in the glass composition is preferably 76% or more, more preferably 78% or more, and even more preferably 80% or more. The total content of the essential components can be 96% or more.

[0023] In the present invention, the glass composition is substantially free of lead oxide (PbO) and vanadium oxide (VO). Here, "substantially free" means that raw materials containing lead oxide (PbO) and vanadium oxide (VO) as major components are not used, and does not exclude trace amounts of lead oxide (PbO) and vanadium oxide (VO) from the raw materials for the components that make up the glass, or from other sources. In other words, it does not mean that materials simply contained as impurities are not included within the scope of the present invention. More specifically, PbO and VO are considered impurities if their contents are 500 ppm or less.

[0024] When used, the sealing material of the present invention may be a powder of the tellurium oxide-based glass composition described above, or a mixture of the powder with a ceramic filler powder described below.

[0025] 2. Ceramic filler If necessary, the sealing material of the present invention can be in the form of a mixture of a powder of the above-mentioned glass composition and a powder of a ceramic filler, in order to adjust the thermal expansion coefficient of the fired body formed by firing the sealing material of the present invention in order to reduce the difference in thermal expansion between the sealing material and the substrate to which it is applied, and / or to additionally improve the strength of the fired body.

[0026] Examples of ceramic fillers that can be used include, but are not limited to, β-eucryptite, cordierite, zircon, zirconium phosphate, zirconium tungstate phosphate, aluminum titanate, mullite, β-spodumene, alumina, celsian, willemite, and silica (α-quartz, cristobalite, tridymite).

[0027] When the sealing material of the present invention is a mixture of the above-mentioned glass composition powder and ceramic filler powder, the blending ratio of the ceramic filler powder can be in the range of up to 40% by weight of the mixture (100% by weight) of the two, and the blending ratio of the filler can be appropriately adjusted to 10%, 20%, 30%, etc. depending on the thermal expansion coefficient of the glass used and the target strength and thermal expansion coefficient of the fired body.

[0028] 3. Organic binders, organic solvents The sealing material of the present invention may be in the form of a paste, which is convenient for use. To prepare the paste, an organic binder and an organic solvent are added to and mixed with a powder of the glass composition of the present invention or a mixture of the powder of the glass composition and a filler powder.

[0029] Examples of organic binders include, but are not limited to, cellulose resins such as ethyl cellulose, copolymers of methyl methacrylate as a main component with various acrylates, methacrylates, acrylamide, styrene, acrylonitrile, etc., and acrylic acid, methacrylic acid, etc., and copolymers to which various unsaturated groups have been added.

[0030] The organic solvent may be appropriately selected depending on the type of organic binder, etc., and examples thereof include, but are not limited to, alcohols such as ethanol, methanol, isopropanol, etc., as well as terpineol (α-terpineol or a mixture of β-terpineol and γ-terpineol with α-terpineol as the main component), butyl carbitol, butyl carbitol acetate, ethylene glycol alkyl ether, etc. These solvents may be used alone or in combination of two or more.

[0031] In addition to the above, known additives such as plasticizers, thickeners, sensitizers, surfactants, dispersants, etc. may be appropriately added to the paste, if necessary. [Example]

[0032] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.

[0033] (Manufacture of glass and glass powder) Example 1 The raw materials used were tellurium oxide, niobium oxide, zinc oxide, and barium carbonate, and were prepared and mixed to obtain the glass composition shown in Table 1. The resulting mixture was placed in a platinum crucible and melted at 950°C for 1 hour. Most of the melt was rapidly cooled using a twin-roll method to obtain glass flakes. The remaining melt was poured into a block onto a preheated carbon plate and slowly cooled in an electric furnace set at a temperature approximately 50°C higher than the expected glass transition point to produce a glass block. The glass flakes were then placed in a pot mill and pulverized to produce glass powder.

[0034] Examples 2 to 35 Raw materials were prepared and mixed to obtain the glass compositions of Examples 2 to 35 shown in Tables 1 to 7, and melted at a melting temperature of 900 to 1000°C in the same manner as in Example 1 to produce glass flakes, glass powder, and glass blocks.

[0035] (Comparative Example 1) The raw materials used were tellurium oxide, zinc oxide, barium carbonate, and bismuth oxide, and were mixed in the proportions shown in Table 8. The resulting mixture was placed in a platinum crucible and melted at 950°C for 1 hour. Most of the melt was rapidly cooled using a twin-roll method to obtain glass flakes. The remaining melt was poured into a block onto a preheated carbon plate, placed in an electric furnace set at a temperature approximately 50°C higher than the expected glass transition point, and slowly cooled to produce a glass block. The glass flakes were then placed in a pot mill and crushed to produce glass powder.

[0036] (Comparative Example 2) The raw materials used were bismuth oxide, boric acid, silicon oxide, aluminum hydroxide, and copper oxide, which were compounded and mixed in the proportions shown in Table 8, and glass flakes, glass powder, and glass blocks were produced under the same conditions as in Comparative Example 1.

[0037] (Preparation of mixed powder with filler) Examples 36 to 42 Glass powder and ceramic filler powder were blended and mixed in the proportions shown in Examples 36 to 42 listed in Tables 9 and 10 to prepare mixed powders.

[0038] (Test items and test methods) For each of the glass compositions of Examples 1 to 35 and Comparative Examples 1 and 2 (Tables 1 to 8), the glass transition point, softening point, crystallization temperature, and flow diameter of the green compact were measured using glass powder, and the thermal expansion coefficient and acid resistance of the glass were measured using a glass block, according to the methods described below. Furthermore, for the mixed powders with fillers prepared in Examples 36 to 42 (Tables 9 and 10), green compacts were prepared and fired, and the flow diameter and the thermal expansion coefficient of the fired compacts were measured. The results are shown in Tables 1 to 10.

[0039] (1) Glass transition temperature Tg, softening point Ts, crystallization temperature Tp Approximately 60 to 80 mg of the glass powders produced in Examples 1 to 35 and Comparative Examples 1 and 2 were filled into platinum cells, and the glass transition point (°C), softening point (°C), and crystallization temperature (°C) were measured by raising the temperature from room temperature at a rate of 20°C / min using a DTA measurement device (Rigaku Thermo Plus TG8120).

[0040] (2) Flow diameter of glass powder compact Approximately 8 g of the glass powder produced in Examples 1 to 35 and Comparative Examples 1 and 2 was placed in a mold with an inner diameter of 20 mm and dry-pressed (10 to 20 MPa) to form a green compact. Each green compact was heated to 450°C, 520°C, or 550°C over 2 hours as shown in Tables 1 to 8, and then held at these temperatures for 15 minutes to obtain a fired body. The diameter of the fired body was measured and recorded as the flow diameter (mm) of the glass green compact.

[0041] (3) Thermal expansion coefficient α of glass The glass blocks prepared in Examples 1 to 35 and Comparative Examples 1 and 2 were cut into samples of approximately 5 × 5 × 15 mm and polished to prepare samples for measurement. The thermal expansion coefficients (×10) of the samples were determined from the thermal expansion curves obtained by increasing the temperature from room temperature at a rate of 10°C / min using a TMA measuring device. -7 / °C) was calculated.

[0042] (4) Acid resistance of glass The glass blocks prepared in Examples 1 to 35 and Comparative Examples 1 and 2 were cut into samples of approximately 10 × 15 × 3 mm for measurement. These samples were immersed in 5% sulfuric acid and allowed to stand at room temperature for 2 hours. The weight loss rate (wt%) of the glass blocks after immersion relative to before immersion was determined.

[0043] (5) Flow diameter of glass-ceramic mixed powder compact Approximately 8 g of the mixed powders produced in Examples 36 to 42 were dry-pressed to form green compacts under the same conditions as in the test for the flow diameter of glass green compacts in (2) above. The green compacts were heated to the temperatures shown in Table 9 or Table 10 over two hours and held at those temperatures for 15 minutes to obtain fired bodies. The diameters of the fired bodies were measured and recorded as the flow diameters (mm).

[0044] (6) Thermal expansion coefficient α of glass-ceramic mixed powder compact and sintered body The fired body obtained in (5) above was cut into a size of approximately 5 × 5 × 15 mm to prepare a sample for measurement. The thermal expansion coefficient (×10) of each sample was measured at two points, 50 °C and 300 °C, in the same manner as in (3) above. -7 / °C) was calculated and compared with the thermal expansion coefficient of the glass used.

[0045] [Table 1]

[0046] [Table 2]

[0047] Table 3

[0048] Table 4

[0049] Table 5

[0050] Table 6

[0051] Table 7

[0052] Table 8

[0053] Table 9

[0054] Table 10

[0055] Tables 1 to 7 confirm that the flow diameters of the glasses of Examples 1 to 35 all exhibit sufficient fluidity during firing. Furthermore, as shown in Table 8, the weight loss rates of the glasses of Comparative Examples 1 and 2 after immersion in 5% sulfuric acid for 2 hours were 0.70% and 1.30%, respectively, whereas the weight loss rates of the glasses of Examples 1 to 35, which are sealing materials of the present invention, under the same conditions were in the range of 0.00 to 0.38%, and all but one example (Example 14) were in the range of 0.00 to 0.20%, indicating that the glasses that are sealing materials of the present invention have extremely high acid resistance.

[0056] The sealing materials of Examples 36 to 42, which are mixtures of glass and ceramic filler, also exhibit sufficient fluidity during firing, as shown in Tables 9 and 10, and are free from the problem of reaction with the filler that would lead to crystal formation during firing, which would inhibit fluidity. In addition, the difference in thermal expansion coefficient from the glass used indicates that the thermal expansion coefficient can be adjusted over a wide range by blending ceramic fillers. [Industrial Applicability]

[0057] The sealing material of the present invention exhibits good fluidity when fired at low temperatures of 550°C or less. Even when it contains a filler, it maintains its fluidity without reacting with the filler. Therefore, it can be used as a sealing material with mechanical strength and adjustable thermal expansion coefficient relative to the surface to be sealed. Furthermore, the fired product after cooling and solidification has remarkably high acid resistance, eliminating the risk of deterioration even when exposed to plating solutions. Furthermore, the thermal expansion coefficient can be adjusted by blending fillers. Therefore, it can also be used as a sealing material suitable for sealing electronic components such as IC packages and quartz oscillator packages.

Claims

1. A sealing material comprising a tellurium oxide-based glass composition that is substantially free of both lead oxide and vanadium oxide, wherein the tellurium oxide-based glass composition contains, in mole % calculated as oxide, Tet ２ :44~70%, Nb ２ O ５ :2~25%、 ZnO: 3 to 20%, and one or more of MgO, CaO, SrO, and BaO in a total amount of 0 to 15%; A sealing material comprising:

2. The tellurium oxide-based glass composition has, in mole % in terms of oxide, Tet ２ : 48-70%, Nb ２ O ５ :4~25% ZnO: 5 to 19%, and one or more of MgO, CaO, SrO, and BaO in a total amount of 3 to 12%; The sealing material according to claim 1, comprising:

3. The tellurium oxide-based glass composition has, in mole % in terms of oxide, Tet ２ : 50-70%, Nb ２ O ５ :6~25%、 ZnO: 7 to 16%, and one or more of MgO, CaO, SrO, and BaO in a total amount of 4 to 8%; The sealing material according to claim 1, comprising:

4. The tellurium oxide-based glass composition contains, in mole percent in terms of oxide, Bi ２ O ３ The sealing material according to claim 1, characterized in that it contains 10 mol % or less of

5. The tellurium oxide-based glass composition has, in mole percent in terms of oxide, B ２ O ３ 2. The sealing material according to claim 1, wherein the content of the above is 25 mol % or less.

6. The sealing material according to any one of claims 1 to 5, wherein the tellurium oxide-based glass composition and the ceramic filler powder in powder form are mixed in an amount of: 100 to 60% by weight of the tellurium oxide-based glass composition in powder form, and Ceramic filler powder: 0 to 40% by weight A sealing material comprising:

7. A sealing material comprising the sealing material of claim 6, an organic binder, and a solvent.

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