Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
  • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/083—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound
  • C03C3/085—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal
  • C03C3/087—Glass compositions containing silica with 40% to 90% silica, by weight containing aluminium oxide or an iron compound containing an oxide of a divalent metal containing calcium oxide, e.g. common sheet or container glass
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
  • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C3/00—Glass compositions
  • C03C3/04—Glass compositions containing silica
  • C03C3/076—Glass compositions containing silica with 40% to 90% silica, by weight
  • C03C3/089—Glass compositions containing silica with 40% to 90% silica, by weight containing boron
  • C03C3/091—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium
  • C03C3/093—Glass compositions containing silica with 40% to 90% silica, by weight containing boron containing aluminium containing zinc or zirconium
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
  • C03C8/00—Enamels; Glazes; Fusion seal compositions being frit compositions having non-frit additions
  • C03C8/02—Frit compositions, i.e. in a powdered or comminuted form

Definitions

• the present invention relates to glass for covering semiconductor elements and a material for covering semiconductor elements using the same.
• Semiconductor elements such as silicon diodes and transistors generally have their surfaces, including the P-N junctions, covered with glass. This stabilizes the surface of the semiconductor element and prevents deterioration of characteristics over time.
• the properties required for glass used to cover semiconductor elements include (1) a thermal expansion coefficient that matches that of the semiconductor element to prevent cracks due to differences in thermal expansion coefficients with the semiconductor element, (2) the ability to cover the semiconductor element at low temperatures (e.g., 900°C or lower) to prevent deterioration of the characteristics of the semiconductor element, and (3) the absence of impurities such as alkaline components that adversely affect the surface of the semiconductor element.
• zinc-based glasses such as ZnO-B 2 O 3 -SiO 2- based glasses and lead-based glasses such as PbO-SiO 2 -Al 2 O 3 -based glasses and PbO-SiO 2 -Al 2 O 3 -B 2 O 3 -based glasses have been known as glasses for covering semiconductor elements.
• lead-based glasses such as PbO-SiO 2 -Al 2 O 3- based glasses and PbO-SiO 2 -Al 2 O 3 -B 2 O 3 -based glasses are becoming mainstream (for example, see Patent Documents 1 to 4).
• the lead component in lead-based glass is harmful to the environment.
• the zinc-based glass mentioned above contains small amounts of lead and bismuth, so it cannot be said to be completely harmless to the environment.
• zinc-based glass has the problem of being inferior in chemical durability and easily corroded during the acid treatment process after the coating layer is formed. For this reason, it was necessary to further form a protective film on the surface of the coating layer and then perform the acid treatment.
• the content of SiO2 in the glass composition is increased, the acid resistance and reverse voltage resistance of the semiconductor element are improved.
• the firing temperature of the glass increases, which may degrade the characteristics of the semiconductor element in the coating process.
• the present invention has been made in consideration of the above circumstances, and its technical objective is to provide a lead-free glass for coating semiconductor elements that has a small environmental impact, is highly acid-resistant, and can be fired at a low temperature.
• the present inventors have found that the above technical problems can be solved by using a SiO 2 -B 2 O 3 -Al 2 O 3 based glass having a specific glass composition, and propose this as the present invention. That is, the glass for covering semiconductor elements of the present invention contains, in mole percent, SiO 2 35-65%, ZnO 0-8%, B 2 O 3 5-30%, Al 2 O 3 5-15%, MgO+CaO+SrO+BaO 8-35% as a glass composition, ZnO/SiO 2 is 0-0.2 in mole ratio, and is substantially free of lead components.
• substantially free of means that the relevant components are not intentionally added as glass components, and does not mean that even impurities that are inevitably mixed in are completely excluded. Specifically, it means that the content of the relevant components including impurities is less than 0.1 mass%.
• MgO+CaO+SrO+BaO is the total content of MgO, CaO, SrO and BaO.
• ZnO/SiO 2 is the value obtained by dividing the ZnO content by the SiO 2 content.
• the glass for covering semiconductor elements of the present invention has the content range of each component regulated, which reduces the environmental load, improves acid resistance, and makes it easier to lower the firing temperature. As a result, it is suitable for covering semiconductor elements.
• the semiconductor element coating material of the present invention preferably contains 75 to 100 mass % of glass powder made of the above-mentioned semiconductor element coating glass, and 0 to 25 mass % of ceramic powder.
• the semiconductor element covering material of the present invention preferably has a thermal expansion coefficient of 20 ⁇ 10 ⁇ 7 /° C. to 55 ⁇ 10 ⁇ 7 /° C. or less in the temperature range of 30 to 300° C.
• the "thermal expansion coefficient in the temperature range of 30 to 300° C.” refers to a value measured using a push rod type thermal expansion coefficient measuring device.
• the present invention provides lead-free glass for coating semiconductor elements that has a small environmental impact, excellent acid resistance, and a low firing temperature.
• the glass for covering semiconductor elements of the present invention contains, in mole percent, SiO 2 35-65%, ZnO 0-8%, B 2 O 3 5-30%, Al 2 O 3 5-15%, and MgO+CaO+SrO+BaO 8-35% as a glass composition, and is characterized in that the molar ratio of ZnO/SiO 2 is 0-0.2 and the glass is substantially free of lead.
• the reasons for limiting the content of each component as described above are explained below. In the following explanation of the content of each component, the percentage indicates mole percent unless otherwise specified.
• the numerical range indicated by "to” means a range including the numerical values before and after "to" as the minimum and maximum values, respectively.
• SiO2 is a glass network forming component and a component that enhances acid resistance. Its content is 35-65%, preferably 36-62%, 37-60%, 38-58%, 39-56%, and particularly 40-55%. If the SiO2 content is too low, the acid resistance is easily reduced and vitrification is difficult. On the other hand, if the SiO2 content is too high, the glass firing temperature becomes high, which easily deteriorates the characteristics of the semiconductor element in the coating process.
• ZnO is a component that stabilizes glass.
• the ZnO content is preferably 0-8%, 0-6%, and especially 0.1-5%. If the ZnO content is too low, the glass will be more prone to devitrification when melted, making it difficult to obtain homogeneous glass. On the other hand, if the ZnO content is too high, the glass will be more prone to phase separation when melted, crystals will be more likely to precipitate during firing, and acid resistance will be reduced.
• ZnO/ SiO2 is 0 to 0.2, preferably 0 to 0.18, 0 to 0.16, and particularly preferably 0 to 0.14.
• B 2 O 3 is a glass network forming component and a component that enhances softening fluidity.
• the content of B 2 O 3 is 5-30%, preferably 8-27%, particularly 10-25%. If the content of B 2 O 3 is too low, the crystallinity becomes strong, so that the softening fluidity is impaired during coating, making it difficult to uniformly coat the surface of the semiconductor element. On the other hand, if the content of B 2 O 3 is too high, the acid resistance tends to decrease.
• Al 2 O 3 is a component that stabilizes glass.
• the content of Al 2 O 3 is 5 to 15%, preferably 7 to 13%, and particularly preferably 9 to 12%. If the content of Al 2 O 3 is too low, vitrification becomes difficult. On the other hand, if the content of Al 2 O 3 is too high, there is a risk that the firing temperature will be too high.
• MgO, CaO, SrO, and BaO are components that lower the viscosity of glass.
• MgO + CaO + SrO + BaO is 8-35%, preferably 9-33%, and especially 11-31%. If there is too little MgO + CaO + SrO + BaO, the softening temperature of the glass tends to rise. On the other hand, if there is too much MgO + CaO + SrO + BaO, the thermal expansion coefficient tends to become too high, and acid resistance and insulation properties tend to decrease.
• MgO, CaO, SrO, and BaO are as follows:
• the MgO content is preferably 0-22%, 4-22%, 8-22%, 9-21%, and particularly preferably 10-20%.
• the CaO content is preferably 0-15%, 1-14%, 2-13%, 3-12%, and particularly preferably 4-11%.
• the SrO content is preferably 0-10%, 0-8%, 0-6%, 0-4%, and especially 0.1-2%.
• the BaO content is preferably 0-10%, 0-8%, 0-6%, 0-4%, and especially 0.1-2%.
• other components e.g., MnO2 , Bi2O3 , Ta2O5 , Nb2O5 , CeO2 , Sb2O3 , etc.
• MnO2 , Bi2O3 , Ta2O5 , Nb2O5 , CeO2 , Sb2O3 , etc. may be contained up to 7% (preferably up to 3%).
• the material contains substantially no lead components (e.g., PbO, etc.) and substantially no F or Cl. It is also preferable that the material contains substantially no alkaline components (Li 2 O, Na 2 O, and K 2 O) that adversely affect the surface of semiconductor elements.
• lead components e.g., PbO, etc.
• alkaline components Li 2 O, Na 2 O, and K 2 O
• the glass for coating semiconductor elements of the present invention is preferably in powder form, that is, glass powder. If it is processed into glass powder, it can be easily used to coat the surface of a semiconductor element, for example, by using a paste method, electrophoretic coating method, etc.
• the average particle diameter D50 of the glass powder is preferably 25 ⁇ m or less, particularly 15 ⁇ m or less. If the average particle diameter D50 of the glass powder is too large, it becomes difficult to make a paste. In addition, it becomes difficult to apply the paste by electrophoresis.
• the lower limit of the average particle diameter D50 of the glass powder is not particularly limited, but in reality, it is 0.1 ⁇ m or more.
• the "average particle diameter D50" is a value measured on a volume basis, and refers to a value measured by a laser diffraction method.
• the glass for coating semiconductor elements of the present invention can be obtained, for example, by mixing raw powders of each oxide component into a batch, melting it at about 1500°C for about 1 hour to vitrify it, and then molding it (and then crushing and classifying it as necessary).
• the semiconductor element coating material of the present invention contains glass powder made of the semiconductor element coating glass, which may be mixed with ceramic powder to form a composite powder if necessary.
• the addition of ceramic powder makes it easier to adjust the thermal expansion coefficient.
• the ceramic powder is preferably cordierite powder.
• the ceramic powder is preferably 25% or less, less than 25%, and especially less than 20% relative to 100% by mass of the composite powder.
• the average particle diameter D50 of the ceramic powder is preferably 30 ⁇ m or less, particularly 20 ⁇ m or less. If the average particle diameter D50 of the ceramic powder is too large, the surface smoothness of the coating layer is likely to decrease.
• the lower limit of the average particle diameter D50 of the ceramic powder is not particularly limited, but is practically 0.1 ⁇ m or more.
• the thermal expansion coefficient in the temperature range of 30 to 300° C. is preferably 20 ⁇ 10 ⁇ 7 /° C. to 55 ⁇ 10 ⁇ 7 /° C., particularly 30 ⁇ 10 ⁇ 7 /° C. to 50 ⁇ 10 ⁇ 7 /° C. If the thermal expansion coefficient is outside the above range, cracks, warping, etc. are likely to occur due to the difference in thermal expansion coefficient with the semiconductor element.
• the material for coating semiconductor elements of the present invention is preferably fired at a temperature of 900°C or less, and particularly 880°C or less. If the firing temperature is too high, there is a risk that the characteristics of the semiconductor elements will be impaired during the coating process.
• Table 1 shows examples of the present invention (samples No. 1 to 4) and comparative examples (samples No. 5 to 9).
• Each sample was prepared as follows. First, raw material powders were mixed to obtain the glass composition shown in the table, and then the raw material powders were melted at 1500°C for 1 hour to be vitrified. The molten glass was then formed into a film, pulverized in a ball mill, and classified using a 350 mesh sieve to obtain glass powder with an average particle size D50 of 12 ⁇ m. In addition, in sample No. 3, cordierite powder (average particle size D50 : 12 ⁇ m) was added to the obtained glass powder in the amount shown in the table to obtain a composite powder.
• the softening point was measured using a macro-type differential thermal analyzer. Specifically, the value of the fourth inflection point in the chart obtained by measuring each glass powder sample using the macro-type differential thermal analyzer was taken as the softening point.
• the firing temperature was set to a temperature 20°C higher than the softening point.
• the thermal expansion coefficient was measured using a push rod type thermal expansion coefficient measuring device in the temperature range of 30 to 300°C.
• Acid resistance was evaluated as follows: Each sample was press molded to a size of about 20 mm in diameter and 4 mm in thickness, then sintered at softening point +20°C to produce a sintered body, and the mass change per unit area was calculated from the mass loss after immersing the sintered body in 30% nitric acid at 25°C for 1 minute. Note that a mass change per unit area of less than 1.0 mg/ cm2 was marked as " ⁇ ", and a mass change of 1.0 mg/ cm2 or more was marked as " ⁇ ".
• Samples No. 1 to 4 had a thermal expansion coefficient of 44 ⁇ 10 -7 /°C to 48 ⁇ 10 -7 /°C, were fired at temperatures below 900°C, and were also evaluated as having good acid resistance. Therefore, Samples No. 1 to 4 are considered to be suitable as semiconductor element coating materials.
• Sample No. 5 was fired at a high temperature.
• Sample No. 6 underwent phase separation when melted.
• Sample No. 7 had low acid resistance.
• Sample No. 8 had low acid resistance.
• Sample No. 9 was fired at a high temperature.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
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• General Chemical & Material Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Glass Compositions (AREA)
• Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)

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Citations (4)

• 2024
  • 2024-07-08 TW TW113125488A patent/TW202517596A/zh unknown
  • 2024-07-09 CN CN202480043969.9A patent/CN121532363A/zh active Pending
  • 2024-07-09 JP JP2025533998A patent/JPWO2025018225A1/ja active Pending
  • 2024-07-09 WO PCT/JP2024/024780 patent/WO2025018225A1/ja active Pending

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