Directional chemical oxide etch technique
AssigneeInternational Business Machines Corporation
InventorsEmre Alptekin, Sivananda K. Kanakasabapathy, Ahmet S. Ozcan, Viraj Y. Sardesai, Cung D. Tran
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Abstract
A method of forming a trench in an oxide layer; where the oxide layer is formed on top of a nitride layer. The trench is formed using an iterative etching technique until the nitride layer is exposed, each iterative etching step includes; using an isotropic etching technique to remove a portion of the oxide layer, the isotropic etching technique produces a byproduct that remains along a sidewall and a bottom of the trench, then using an anisotropic etching technique to remove the salt from the bottom of the trench, leaving salt on the sidewalls of the trench.
Claims20
A method comprising:
- forming a semiconductor structure including a source-drain region in a substrate and adjacent to a gate structure and a nitride layer on the source-drain region, wherein the gate structure includes a gate, a gate cap on a top surface of the gate, and a gate spacer on a sidewall surface of the gate;
- forming a dielectric layer on the nitride layer and on the gate structure;
- and
- forming a contact trench in the dielectric layer by iteratively etching until the nitride layer is exposed, each iterative etching step comprising:
- removing a portion of the dielectric layer using an isotropic etching technique, the isotropic etching technique produces a byproduct that remains along a sidewall and a bottom of the contact trench;
- and
- removing the byproduct from the bottom of the contact trench using an anisotropic etching technique.
A method comprising:
- forming a contact trench in a dielectric layer of a semiconductor structure, wherein the dielectric layer is above a nitride layer, the contact trench is a result of a collection of iterative etching steps performed until the nitride layer is exposed, each iterative etching step comprising:
- removing a portion of the dielectric layer using an isotropic etching technique, the isotropic etching technique produces a byproduct that remains along a sidewall and a bottom of the contact trench;
- and
- removing the byproduct from the bottom of the contact trench using an anisotropic etching technique.
A method comprising:
- forming a nitride layer on a structure;
- forming a nitride trench in the nitride layer by iteratively etching until the structure is exposed, each iterative etching step comprising:
- oxidizing a portion of the nitride layer;
- and
- removing the portion of the nitride layer that has been oxidized by using an isotropic etching technique.
Dependencies are inferred from the claim text.