银粉和触变剂对低温银浆挥发速率影响的研究

Study on silver powder and thixotropic agent affecting the volatilization rate of low-temperature silver paste

采用不同密度的银粉,改变触变剂类型及含量,以线路复烤前后的电阻值变化率表征银浆的溶剂挥发速率,研究不同条件对银浆溶剂挥发速率的影响。结果表明,低振实密度粉体、有机膨润土、改性聚脲化合物和气相二氧化硅均能快速提高银浆溶剂挥发速率。由振实密度1.6~1.8 g/cm^(3)的片状银粉、0.25%有机膨润土、0.5%改性聚脲化合物搭配热塑性聚氨酯制备银浆,在150℃×1 min条件下,银浆快速干燥固化,附着力为5B,复烤后电阻变化率<3%。

The effects of silver powder densities,the type and content of thixotropic agents on volatilization rate of silver paste had been studied.The volatilization rate of solvents in silver paste was characterized by the change ratio of resistivity before and after recurring.Experiment results showed that the silver paste prepared with low tap density silver powder,organobentonite,modified polyurea and fumed silica significantly improved the evaporation rate of silver paste.Silver paste prepared by using flake silver powder with a tap density of 1.6~1.8 g/cm^(3),0.25%organobentonite,0.5%modified polyurea and thermoplastic polyurethane cured at 150℃in 1 min,showed adherence of 5B and resistivity change was less than 3%after re-curing.