US 6,187,216 B1 · Method for etching a dielectric layer over a semiconductor substrate

Abstract

A wet etch bath (61) holds a wet etchant (52) for etching a dielectric over a semiconductor substrate. The wet etch bath (61) has a tub (63) separated from a reservoir (64) by a wall (65). The tub (63) is filled with the wet etchant (52) to a height of the wall (65). The reservoir (64) is filled with the wet etchant (52) to a height less than the height of the wall. A pump (66) coupled to the reservoir (64) pumps the wet etchant (52) through an osmotic membrane degasifier (69) to the tub (63). Adding the wet etchant (52) to the tub (63) causes the wet etchant (52) to cascade over the wall (65) back to the reservoir (64). The osmotic membrane degasifier (69) reduces a concentration of a reactive agent in the wet etchant (52).

Claims13

Dependent claims

A method for etching a sacrificial silicon dioxide layer over a semiconductor substrate, comprising:

purging a buffered oxide etchant with a hydrophobic osmotic membrane degasifier that is corrosion resistant to said buffered oxide etchant, wherein said degasifier has a plurality of microporous hollow fibers knitted into an array that is wound around a distribution tube with a baffle, said purging said buffered oxide etchant with said hydrophobic osmotic membrane degasifier producing a purged etchant;
and
submerging a portion of said semiconductor substrate in said purged etchant to etch the sacrificial silicon dioxide layer over the semiconductor substrate.

Dependencies are inferred from the claim text.

Method for etching a dielectric layer over a semiconductor substrate

Life of this patent

Method for etching a dielectric layer over a semiconductor substrate

Life of this patent

Abstract

Claims13