Preparation And Properties Of Encapsulated Glass Slurry For Copper

Electronic pastes is the basic raw materials in the electronic information industry. Base metal pastes has always been getting wide attention and research due to its very low cost, good performance.Especially, the copper is very cheap, easy to obtain, and has excellent high-frequency characteristics, good electrical conductivity more than gold, nice weldability and welding resistance that can be comparable to precious metals. So people carried out extensive research and development work on copper pastes. There have been goods of copper electronic pastes in the market. However, there is no the overlazing glass pastes matching copper pastes that must be sintered in nitrogen in the market, which will slow down the development and application of cooper pastes. So, it’s very necessary and urgent to research and prepare a overlazing glass pastes sintered in nitrogen with a good practical value and significance.We prepared a low melting point lead-free Bi2O3-B2O3-ZnO-SiO2 glass by the traditional melt quenched methods and a kind of organic vehicle that can volatilize completely and has no ash residue when sintered in nitrogen, and finally got a overlazing glass pastes and a overlazing glass layer coated on the copper thick film. The glass structure, characteristic temperature, softening temperature, the volatile performance of organic vehicle, the performance of the overlazing layer were characterized through infrared spectrometer(IR), X-ray diffraction(XRD), scanning electron microscopy (SEM), differential thermal analyzer and digital ohmmeter test methods.The results showed that with the increase of CuO content (0-7%), the structure of the Bi2O3-B2O3-ZnO-SiO2 glass becomes loose, the glass characteristic temperature and soften temperature gradually decrease, chemical stability gradually declines, and the wettability with copper film is improved at first then turns worse. When CuO content is 2% the wettability of glass with copper thick film is best, when CuO content is greater than 3%, glass chemical stability abruptly turns worse. At the same time, Bi2O3-B2O3-ZnO-SiO2 glass system has a good glass forming ability and stability, and even under the condition of adding 3.0wt% CuO and 690℃ heat preservation with 1 Omin there is no crystallization.Poly alpha methyl styrene can volatilize completely when heated at 450℃ for 30min. The organic vehicle that consists of poly alpha methyl styrene meets the process requirement that the overlazing glass pastes must be sintered at low temperature and in nitrogen. In addition, with the increase of poly alpha methyl styrene content, the organic vehicle viscosity increases gradually, when the poly alpha methyl styrene content in organic vehicle is 18%, organic vehicle has an appropriate viscosity, that can satisfy the demand of silk screen printing.The addition of cupric oxide in the glass phase causes that the protecting effect of the overlazing glass layer becomes poor, copper thick film resistance change rate decreases, coating layer has the defects of shrinkage and pores. Sintering peak temperature is an important process parameters. The overlazing glass layer with a good performance can be obtained under suitable sintering peak temperature.