SILICON DIOXIDE-POLYSILICON MULTI-LAYERED STACK ETCHING WITH PLASMA ETCH CHAMBER EMPLOYING NON-CORROSIVE ETCHANTS
First Claim
1. A plasma etch apparatus, comprising:
- a process chamber;
a chuck disposed in the process chamber to support a substrate while being etched;
a plurality of source gases plumbed to the chamber, the plurality of source gases including SF6, NF3, CH4, O2, N2, and COS;
a plurality of RF generators to energize the process gases into a plasma with a plurality of RF frequencies; and
a pulse controller coupled to the plurality of RF generators, the pulse controller to pulse each of the plurality of RF generators over time between an RF on state and an RF off state synchronously to have all generators in the RF off state concurrently for at least some period of time.
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Abstract
Multilayered stacks having layers of silicon interleaved with layers of a dielectric, such as silicon dioxide, are plasma etched with non-corrosive process gas chemistries. Etching plasmas of fluorine source gases, such as SF6 and/or NF3 typically only suitable for dielectric layers, are energized by pulsed RF to achieve high aspect ratio etching of silicon/silicon dioxide bi-layers stacks without the addition of corrosive gases, such as HBr or Cl2. In embodiments, a mask open etch and the multi-layered stack etch are performed in a same plasma processing chamber enabling a single chamber, single recipe solution for patterning such multi-layered stacks. In embodiments, 3D NAND memory cells are fabricated with memory plug and/or word line separation etches employing a fluorine-based, pulsed-RF plasma etch.
7 Citations
7 Claims
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1. A plasma etch apparatus, comprising:
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a process chamber; a chuck disposed in the process chamber to support a substrate while being etched; a plurality of source gases plumbed to the chamber, the plurality of source gases including SF6, NF3, CH4, O2, N2, and COS; a plurality of RF generators to energize the process gases into a plasma with a plurality of RF frequencies; and a pulse controller coupled to the plurality of RF generators, the pulse controller to pulse each of the plurality of RF generators over time between an RF on state and an RF off state synchronously to have all generators in the RF off state concurrently for at least some period of time. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification