Cyclic Etch/Passivation-Deposition as an All-Spatial Concept toward High-Rate Room Temperature Atomic Layer Etching

Cyclic Etch/Passivation-Deposition as an All-Spatial Concept toward High-Rate Room Temperature Atomic Layer Etching

Roozeboom, F.
van den Bruele, F.
Creyghton, Y.
Poodst, P.
Kessels, W.M.M.

2015

Conventional (3D) etching in silicon is often based on the ‘Bosch’ plasma etch with alternating half-cycles of a directional Sietch and a fluorocarbon polymer passivation. Also shallow feature etching is often based on cycled processing. Likewise, ALD is time-multiplexed, with the extra benefit of half-reactions being self-limiting, thus enabling layer-by-layer growth in a cyclic process. To speed up growth rate, spatial ALD has been successfully commercialized for large-scale and high-rate deposition at atmospheric pressure. We conceived a similar spatially-divided etch concept for (high-rate) Atomic Layer Etching (ALEt). The process is converted from time-divided into spatially-divided by inserting inert gas-bearing ‘curtains’ that confine the reactive gases to individual injection slots in a gas injector head. By reciprocating substrates back and forth under such head one can realize the alternate etching/passivation-deposition cycles at optimized local pressures, without idle times needed for switching pressure or purging. Another improvement toward an all-spatial approach is the use of ALD-based oxide (Al2O3, SiO2, etc.) as passivation during, or gap-fill after etching. This approach, called spatial ALD-enabled RIE, has industrial potential in cost-effective back-endof-line and front-end-of-line processing, especially in patterning structures requiring minimum interface, line edge and fin sidewall roughness (i.e., atomic-scale fidelity with selective removal of atoms and retention of sharp corners).

Nano Technology
TFT - Thin Film Technology
TS - Technical Sciences
Energy Materials Industry Electronics
Industrial Innovation
Atomic layer etching
Atomic layer deposition

http://resolver.tudelft.nl/uuid:37fffc84-7dee-40ae-a82f-6e08b1d6a370

https://doi.org/10.1149/2.0111506jss

523912

Electrochemical Society Inc.

2162-8777

ECS Journal of Solid State Science and Technology, 4 (6), N5067-N5076

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