Influence Of Sol-gel Glass On The Property Of Copper Paste For Low Temperature Cofired Ceramic

In this paper,SiO₂-B₂O₃-Zn O-BaO?SBZB?glass was prepared or coated on copper powder by sol-gel route,respectively.As-prepared copper paste was printed on the LTCC substrate,followed by burning out in wet N2 and sintering in N2.After sintering,a well-dense copper film with good electrical conductivity and good bonding behavior on LTCC substrate was obtained.The microstructure and elements distribution were studied by SEM and EDS.Effects of glass content,sintering temperature and holding time on the properties of densification and conductivity were analyzed.TEOS,boric acid,barium acetate and zinc acetate was added to solution to form sol.A uniform and stable sol could be obtained by controlling the amount of water and glacial acetic acid.Effects of pH and H2O/Si molar ratio on the gel time were studied.In addition,the dispersity of glass powder was improved by addition of PEG1500 and glycol.SBZB?20:30:30:20?glass could be softened and wet the LTCC substrate under 900?.The copper paste was prepared by mixing B1-B3 glass with copper powder.The glass composition had little influence on the conductivity of the copper film with little glass after sintering at 910? for 60 min.The glass coated copper powder was prepared by controlling the amount of sol.The 1wt% glass-coated copper powder with regular shape and good dispersion had a relatively smooth surface.The copper paste was prepared from glass coated copper powder.Influence of sintering temperature and holding time on the microstructure and property of copper film was studied.When sintering at 910? for 60 min,a well-dense structure with good conductivity of copper film on LTCC substrate could be obtained.Influence of glass ratio on copper film was also studied.When pastes with 1wt% glass were sintered at 910°C,a dense copper film was obtained.At this condition,the film had a sheet resistance of 1.9m?/?,and a good bonding behavior between copper film and LTCC substrate was also observed.The different ways of glass added to copper paste were compared.The film prepared from glass-coated copper powder had a cleaner surface and stronger conductivity than the film prepared with glass mixing.