Etching a substrate: processes – Nongaseous phase etching of substrate – Etching inorganic substrate
Reexamination Certificate
2005-05-17
2005-05-17
Norton, Nadine G. (Department: 1765)
Etching a substrate: processes
Nongaseous phase etching of substrate
Etching inorganic substrate
C216S102000, C216S106000, C216S107000, C216S108000, C216S109000
Reexamination Certificate
active
06893578
ABSTRACT:
An etching composition and method is disclosed for removing an oxide sacrificial material during manufacture of semiconductor devices including micromechanical, microelectromechanical or microfluidic devices. The etching composition and method are based on the combination of hydrofluoric acid (HF) and sulfuric acid (H2SO4). These acids can be used in the ratio of 1:3 to 3:1 HF:H2SO4to remove all or part of the oxide sacrificial material while providing a high etch selectivity for non-oxide materials including polysilicon, silicon nitride and metals comprising aluminum. Both the HF and H2SO4can be provided as “semiconductor grade” acids in concentrations of generally 40-50% by weight HF, and at least 90% by weight H2SO4.
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Clews Peggy J.
Mani Seethambal S.
Hohimer John P.
Norton Nadine G.
Sandia Corporation
Tran Binh X.
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