Chemical Polishing in Etching Solutions That Contain Surfactants

The feasibility of chemical polishing a wide variety of quartz cuts has been demonstrated PreviOUSly. Chemical polishing etchants have been identified for AT-, BT-, IT-, sc-, ST-, Z-cuts and others. It has also been found that, in order to attain a uniform polish with the various etchants, the surfaces must be extremely clean. Surface contaminants can act as etch resists. The etching of contaminated surfaces can result in a "blotchy" appearance. Elaborate and time-consuming cleaning procedures have been developed in order to ensure that the surfaces are uniformly polished. SC-cuts and Z-cuts are especially sensitive to surface contamination. It has been found that adding certain surfactants to the etching solution can make the chemical polishing process virtually foolproof. The cleaning action and increased wettability produced by the surfactants minimize the need for precleaning. A short and simple cleaning procedure is all that is needed to ensure a uniform polish. A commercially available premixed etching solution that contains a p r o p r i e t a r y surfactant has been found to consistently produce a uniform chemical polish on SCand AT-cut crystals after only a minimum of precleaning. Commercially available fluorochemical surfactants which the user can add to a variety of fluoride-type etchants, have also been found to produce uniformly polished surfaces on both AT-cut and SC-cut crystals. The results of the evaluation of various surfactants will be reported.