Formation of microstructures with removal of liquid by freezing

Details Formation of microstructures with removal of liquid by freezing Formation of microstructures with removal of liquid by freezing

1989-02-16

1991-05-07

Chaudhuri, Olik

Fishing, trapping, and vermin destroying

437901, 296211, H01L 2164

Patent

active

050136933

ABSTRACT:
Micromechanical structures having surfaces closely spaced from surfaces of a substrate are formed using normal wet etching techniques but are not dried in a conventional manner. While the substrate with the microstructures formed thereon is still wet, the substrate is covered with a liquid that can be frozen, such as deionized water. The liquid on the flooded structure is then frozen in a well controlled manner such that freezing is completed before the microstructure is uncovered. The microstructures are therefore undeflected and are covered by a solid on all surfaces. This solid is then sublimated at a predetermined temperature. Because the frozen liquid (e.g., ice) supports its own surface tension, the microstructures are not drawn toward the substrate, as occurs with the drying of liquids. The sublimation of all the frozen liquid leaves undeflected microstructures with no permanent bonding of the facing surfaces of the microstructure and the substrate.

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