Anisotropic etching for forming isolation slots in silicon beam leaded integrated circuits

Anisotropic silicon etches which preferentially attack the {100} and {110} crystal planes have been used to form narrow well-controlled isolation slots in silicon beam-leaded integrated circuits. The etches of interest are characterized by etching rates, R, on the low order crystal planes in the order R{100} > R{110} > R{111}, and for which R{111} is effectively zero.