Property revealing for silicon chip-bonding glass

A low temperature glass solder of the ternary system with a stoichiometric composition of PbO:ZnO:B₂O₃=58:18:24(wt%) has been developed for bonding silicon chip onto a glass substrate. When bonding at 510°C, the quenched state from its molten (900°C) was used. After bonding, it turned into a crystalline state, whose thermal behaviour was obviously different from the quenched state. In order to illuminate the relationship between properties and behaviours, DSC infrared absorption spectroscopy and X-ray diffraction were carried out for two powders of the quenched and recondensed states. It can be confirmed that for the quenched one, the softening point (450°C) was lower and it was melted thoroughly at 500∼510°C for chip-bonding, and there was no X-ray diffraction peak, which is a typical spectrum for the glass phase. However, for the recondensed glass, the melting point was raised to 631∼644°C. There were the same X-ray diffraction peaks as the standard spectrum of Pb₂ZnB₂O₆. These results indicate that the recondensed glass solder possess a crystalline structure to benefit the usage for devices at higher temperature.