Back to results
US 8,187,486 B1Granted
Modulating etch selectivity and etch rate of silicon nitride thin films
AssigneeNovellus Systems, Inc.
InventorsXinye Liu, Chiukin Steven Lai
Life of this patent
Estimating the term…
Abstract
Etching of nitride and oxide layers with reactant gases is modulated by etching in different process regimes. High etch selectivity to silicon nitride is achieved in an adsorption regime where the partial pressure of the etchant is lower than its vapor pressure. Low etch selectivity to silicon nitride is achieved in a condensation regime where the partial pressure of the etchant is higher than its vapor pressure. By controlling partial pressure of the etchant, very high etch selectivity to silicon nitride may be achieved.
Claims26
A method comprising:
- (a) depositing an etchant on a feature of a surface of a work piece under conditions that thermodynamically provide for condensation of the etchant, wherein an oxide and a liner are on the feature;
- (b) etching the oxide on the feature;
- (c) depositing the etchant on the feature under conditions that thermodynamically provide for adsorption of the etchant;
- and
- (d) selectively etching the oxide on the feature without substantially etching the liner.
2 more elements
A method comprising:
- (a) condensing a layer of an ammonium halide etchant on a feature of a surface of a work piece, wherein an oxide and a nitride are on the feature;
- (b) etching the oxide on the feature;
- (c) depositing a partially saturated layer of the ammonium halide etchant on the feature of the surface of the work piece under conditions that thermodynamically provide for deposition of the partially saturated layer;
- and
- (d) selectively etching the oxide on the feature without substantially etching the nitride, wherein an etch selectivity for the oxide over the nitride is at least about 50:1.
2 more elements
A method comprising:
- (a) depositing an etchant on a feature of a surface of a work piece under conditions that thermodynamically provide for condensation of the etchant, wherein an oxide and a liner are on the feature;
- (b) etching the oxide on the feature with the etchant deposited under conditions that thermodynamically provide for condensation of the etchant;
- (c) removing the etchant from the feature to stop the etching of the oxide on the feature with the etchant deposited under conditions that thermodynamically provide for condensation of the etchant;
- (d) removing solid reaction product from the etching of the oxide on the feature with the etchant deposited under conditions that thermodynamically provide for condensation of the etchant;
- (e) depositing the etchant on the feature under conditions that thermodynamically provide for adsorption of the etchant;
- and
- (f) selectively etching the oxide on the feature with the etchant deposited under conditions that thermodynamically provide for adsorption of the etchant without substantially etching the liner.
4 more elements
A method comprising:
- (a) depositing an etchant on a feature of a surface of a work piece under conditions that thermodynamically provide for condensation of the etchant, wherein an oxide and a liner are on the feature;
- (b) etching the oxide on the feature with the etchant deposited under conditions that thermodynamically provide for condensation of the etchant;
- (c) removing the etchant from the feature to stop the etching of the oxide on the feature with the etchant deposited under conditions that thermodynamically provide for condensation of the etchant;
- (d) depositing the etchant on the feature under conditions that thermodynamically provide for adsorption of the etchant;
- and
- (e) selectively etching the oxide on the feature with the etchant deposited under conditions that thermodynamically provide for adsorption of the etchant without substantially etching the liner.
3 more elements
Dependencies are inferred from the claim text.