Alumina based low permittivity substrate utilizing superplastically foaming method

Abstract

Alumina based closed pore dominated substrates have been fabricated by using superplastically foaming method developed by our group. Co-dispersing of magnesium aluminate spinel (Spinel) and zirconia without dopant (0YZ) provided adequate superplastisity to alumina matrix, while individual dispersion of spinel or zirconia resulted in only small deformation. The dielectric constant of superplastically foamed alumina decreased monotonically with porosity. Introduced pores were all closed nature at least up to 30%of porosity, at that porosity the permittivity became half as that of full dense one. Effect of the sweating water or ambient humidity has been proved to be identical to those of full dense one, which is favorable for semiconductor substrate. © 2010 The Ceramic Society of Japan. All rights reserved.