CHEMICAL ETCHING OF Y-ROTATED QUARTZ PLATES - EXPERIMENTS AND THEORETICAL APPROACH

A study has been made on the effect of the orientation of quartz plate s on etching shapes resulting from a prolonged etching in an isotherma l concentrated solution of ammonium bifluoride. Surface texture, as we ll as lateral underetching and concave corner undercutting characteriz ing the anisotropy of micromachining have been studied. The cuts inves tigated here are doubly rotated cuts with various angles of cut, such as phi(0)=90 degrees and theta(0) varies. Emphasis has been placed on surface features such as textures and flatness of surfaces studied by means of scanning electron microscopy and atomic force microscopy. The se features are partly used to estimate the dissolution constants invo lved in the general equation of the dissolution slowness surface. The analysis of lateral underetching and corner undercutting gives importa nt information in order to realize mechanical devices such as resonato rs with high performance on non-conventional cuts. In addition, numeri cal simulations of 2D and 3D etching shapes are given. A systematic co mparison of theoretical predictions whith experiments allows us to dis cuss the suitability of the dissolution slowness surface.