THE EFFECT OF PLASMA CURE TEMPERATURE ON SPIN-ON GLASS

The quality of spin-on glass (SOG) films, which are widely used as interlevel planarization dielectrics, can be improved by curing in gas plasma. The etch rate of SOG films plasma-cured in oxygen ambient is lower than that of films nitrogen-cured in a furnace, which is the commonly used SOG curing method. The etch rate decreases with increasing plasma cure temperature. Furthermore, a high-temperature plasma cure reduces the number of the silanols, which act as adsorption sites of water. However, plasma curing at 400-degrees-C promotes hot carrier degradation. There is an optimum plasma curing temperature that can improve film quality with a minimum of hot carrier degradation. That temperature is thought to be around 300-degrees-C. The plasma curing process at 300-degrees-C can also produce crack-free SOG films.