Li2O-Al2O3-SiO2 glass-ceramics used as anodic bonding materials

The glass-ceramics, whose coefficient of thermal expansion approximately matched to that of silicon, were studied to replace conventional heat-resistant glass as substrate material for anodic bonding. The basic glasses of the Li2O-Al2O3-SiO2 system with TiO2 and ZrO2 as nucleation agents were prepared by melting technology, and the temperatures of nucleation and crystallization were determined. The glass-ceramics were obtained by two-step heat-treatment method. The oriented crystallization of glasses in gradient temperature field was studied. The crystal phases and microstructures of glass-ceramics were analyzed. Effect of heat-treatment schedule on the coefficient of thermal expansion was discussed. The results showed that the most of the main crystal phases of the samples were beta-spodumene. The coefficient of thermal expansion of sample was about 32.5 x 10(-7)/degrees C, which was approach to that of silicon.