Trench etch process for a single-wafer RIE dry etch reactor
AssigneeTexas Instruments Incorporated
InventorMonte A. Douglas
Life of this patent
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Abstract
A plasma dry etch process for trench etching in single slice RIE etch reactors wherein a selective sidewall passivation is accomplished to control the profile of the trench being etched. The process comprises methods of passivating the sidewall by passivation on a molecular scale and by passivation by a veneer type passivation comprising buildup of a macroscopic residue over the surface of the sidewall. Several methods are disclosed for forming and shaping the passivating layers (both mono-atomic and bulk). By carefully controlling the composition and shape of the sidewall passivating veneer in conjunction with other etch factors, the desired trench profiles can be achieved.
Claims35
A method of etching a trench in a silicon body, said method comprising:
- (a) etching a trench in said silicon body by a plasma source of ions and an etchant in an etcher;
- (b) introducing, for at least a preselected period during step (a), a silicon passivating agent in said plasma;
- and
- (c) selectively, for at least a predetermined period during step (a), depositing materials on the sidewalls of the trench.
A method of etching a trench in a silicon body, said method comprising:
- (a) etching a trench in said silicon body by a plasma source of ions and an etchant in an etcher;
- (b) introducing, for at least a preselected period during step (a), a silicon passivating agent in said plasma;
- (c) introducing, for at least a preselected period during step (a), a precipitating agent in said plasma;
- and
- (d) selectively, for at least a predetermined period during step (a), depositing materials on the sidewalls of the trench.
A method of etching a trench in a silicon body, said method comprising:
- etching an uppermost portion of said trench in a first etch step to provide a sidewall in said uppermost portion of said trench having a first predetermined profile angle;
- etching a lower portion of said trench in a second etch step to provide a sidewall in said lower portion of said trench having a second predetermined profile angle;
- and
- wherein said second predetermined profile angle is greater than said first predetermined profile angle.
A method of adjusting the sidewall profile of a trench being etched in a silicon body by a plasma etch process using at least one silicon etchant, the method comprising:
- including in the plasma an etchant which includes species which react with silicon compounds to form etch products which deposit on the sidewall of the trench being etched.
Dependencies are inferred from the claim text.