US 11,152,223 B2 · Fluorocarbon molecules for high aspect ratio oxide etch

Abstract

Etching gases are disclosed for plasma etching channel holes, gate trenches, staircase contacts, capacitor holes, contact holes, etc., in Si-containing layers on a substrate and plasma etching methods of using the same. The etching gases are trans-1,1,1,4,4,4-hexafluoro-2-butene; cis-1,1,1,4,4,4-hexafluoro-2-butene; hexafluoroisobutene; hexafluorocyclobutane (trans-1,1,2,2,3,4); pentafluorocyclobutane (1,1,2,2,3-); tetrafluorocyclobutane (1,1,2,2-); or hexafluorocyclobutane (cis-1,1,2,2,3,4). The etching gases may provide improved selectivity between the Si-containing layers and mask material, less damage to channel region, a straight vertical profile, and reduced bowing in pattern high aspect ratio structures.

Claims18

Dependent claims

A method for fabricating a 3D NAND flash memory having alternating layers of a first etching layer and a second etching layer on a substrate and a hardmask layer on the alternating layers, the method comprising the steps of:

forming a hardmask pattern on the hardmask layer;
and
using the hardmask pattern to form apertures in the alternating layers by selectively plasma etching the alternating layers of the first etching layer and the second etching layer versus the hardmask layer in a plasma reaction chamber using a hydrofluorocarbon etching gas selected from the group consisting of hexafluoroisobutene (CAS No. 382-10-5);
pentafluorocyclobutane (1,1,2,2,3-);
and tetrafluorocyclobutane (1,1,2,2);
wherein the first etching layer comprises a material different from that of the second etching layer.

3 more elements

Dependencies are inferred from the claim text.

Fluorocarbon molecules for high aspect ratio oxide etch

Life of this patent

Fluorocarbon molecules for high aspect ratio oxide etch

Life of this patent

Abstract

Claims18