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Micro-indentation and HF etching were explored as micro-fabrication techniques applied to glass surfaces. The effects of the aluminosilicate glass composition and of the etching conditions on the etching rate were investigated. It was found that the etching rate increased with increasing the ratio of Al2O3 to SiO2 in the aluminosilicate glass. Etching parameters, such as pH, concentration and temperature of HF acid, had effects on etching rate. However, the effects of these parameters were much smaller at indented area than at non-indented area. The results indicated that the etching rate difference between the two areas, which is one of the key factors in the micro-fabrication technique, could be controlled with these parameters. And the phenomena can be well explained in terms of etching and leaching mechanism of aluminosilicate glass.

The etching rate of some kind of glass decreases with micro-indentation. This paper is concerned chiefly with the mechanism for aluminosilicate glass. The change of glass surface condition arising from the indentation and the etching has been examined with X-ray photoelectron spectroscopy (XPS). It was found that the leaching reaction observed through the HF acid etching at non-indented area was restricted at the indented area. The etching rate change should be attributed to the leaching mechanism.

A negative-pion capture process for several kinds of hydrocarbons was studied by the simultaneous observation of low-energy pionic x rays and ${\mathrm{\ensuremath{\pi}}}^{0}$ decays following the nuclear capture of pions by hydrogen. We measured the pionic x-ray intensity pattern and the pion-capture probabilities of constituent carbon and hydrogen. The x-ray intensity pattern depends on the chemical environment; a cascade calculation showed that this can be qualitatively attributed to the effects of a pion transfer from hydrogen. The pion-capture probabilities on hydrogen could be explained by a combined model involving a modified large mesomolecular model and an external transfer process. The external transfer parameter of the pion from a pionic hydrogen atom to carbon atoms was deduced to be ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{C}}$=1.7\ifmmode\pm\else\textpm\fi{}0.2 based on the results for a series of alkanes in the condensed phase. The large difference between the pion-capture probabilities on hydrogen observed in alkanes and that in benzene can be well understood based on the proposed model. \textcopyright{} 1996 The American Physical Society.