Influence of Packing Density and Binder Contents of the Green Sheet on the Dimensional Stability and Warping of the Sintered Alumina Substrates

Abstract

The relations among packing density in Al₂O₃ green sheet and shrinkage, demensional stability and warping were discussed theoretically and experimentally. Dimensional stability in Al₂O₃ substrate strongly depended on packing density of particles in the green sheet and was experimentally varied by 0.5% when the packing density was changed around 1 vol%. These experimental values were fairly agreed with those obtained by theoretical considerations. Moreover, it was found that the warping observed in the sintered substrate was caused by the difference of shrinkage in thickness direction, which was due to the variations of packing density and binder content in thickness direction. This variation could be controlled around zero using the green sheet with a packing density of above 60 vol%. We could get the Al₂O₃ substrate with high dimensional stability.