Selective thermal dry etch of memory devices using phosphoric acid derivatives
AssigneeApplied Materials, Inc.
InventorsAndrea Leoncini, Doreen Wei Ying Yong
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Abstract
Provided are methods of manufacturing memory devices. The methods include exposing a film stack to an etching gas to remove alternating sacrificial layers of silicon nitride in the film stack. The memory devices have alternating layers of silicon oxide and silicon nitride and an opening formed therein. The etching gas comprises derivatives of phosphoric acid, phosphonic acid, and phosphonic acid. The silicon nitride layers are selectively etched relative to the silicon oxide layers with improved isotropicity and without compromising the integrity of the film stack.
Claims20
A method of forming a memory device, the method comprising:
- exposing a film stack comprising a plurality of alternating layers of a first material layer and a second material layer to an etching gas to selectively remove at least a portion of the second material layer relative to the first material layer, the etching gas comprising one or more of a composition of formula (i), formula (ii), or formula (iii)
- wherein R and R′ are independently selected from hydrogen (H), aliphatic group, substituted or unsubstituted homocyclic group, substituted or unsubstituted heterocyclic group, or ester.
A method of forming a memory device, the method comprising:
- in a processing chamber, selectively etching a film stack comprising a plurality of alternating layers of a first material layer and a second material layer to selectively remove at least a portion of the second material layer relative to the first material layer in a process cycle comprising:
- exposing the film stack to an etching gas comprising one or more of a composition of formula (i), formula (ii), or formula (iii)
- wherein R and R′ are independently selected from hydrogen (H), aliphatic group, substituted or unsubstituted homocyclic group, substituted or unsubstituted heterocyclic group, or ester;
- and
- purging the processing chamber of the etching gas.
Dependencies are inferred from the claim text.