Some results on chemical etching of AT-cut quartz wafers in ammonium bifluoride solutions

Abstract

The kinetics of etching of AT-cut quartz plates are studied as a function of the etchant composition. Since etch rates are more rapid on a lapped surface, this investigation is essentially concerned with plates whose surfaces are free of a disturbed layer. Values of dissolution rates and a value of the activation energy determined for saturated ammonium bifluoride solution agrees quite well with published results. The dissolution rates are found to depend linearly on the concentration of etchant for concentrated solutions. A typical value of the activation energy of about 41.85 kJ mol-1 is deduced from an Arrhenius plot of etch rate against concentration of ammonium bifluoride. This value is consistent with previously published values for fluoride solutions. Some progress in the design of an etch system for high-frequency quartz resonators can thus be made by using some of the information provided in this paper. © 1982 Chapman and Hall Ltd.