Methods for wet atomic layer etching of silicon dioxide
AssigneeTokyo Electron Limited
InventorsBeronika Levtchin, Kate Abel
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Abstract
The present disclosure provides a new wet atomic layer etch (ALE) process for etching silicon dioxide (SiO2) materials. More specifically, the present disclosure provides various embodiments of methods that utilize new etch chemistries for etching a SiO2 layer in a cyclic wet ALE process. The new etch chemistries disclosed herein use an anhydrous basic surface modification solution to create self-limiting reactions on exposed surfaces of the SiO2 layer and form a silicate passivation layer, which is insoluble in the surface modification solution, but readily soluble in a dissolution solution.
Claims22
A method of etching a silicon dioxide (SiO2) layer, the method comprising:
- receiving a substrate having the silicon dioxide (SiO2) layer formed thereon, wherein a surface of the silicon dioxide (SiO2) layer is exposed on a surface of the substrate;
- exposing the surface of the substrate to a surface modification solution comprising a base dissolved in a non-aqueous solvent, wherein the base reacts with the surface of the silicon dioxide (SiO2) layer to form a silicate passivation layer, which is self-limited and insoluble in the surface modification solution;
- removing the surface modification solution from the surface of the substrate subsequent to forming the silicate passivation layer;
- exposing the surface of the substrate to a dissolution solution that selectively dissolves the silicate passivation layer;
- and
- removing the dissolution solution from the substrate to etch the silicon dioxide (SiO2) layer.
A method of etching a silicon dioxide (SiO2) layer using a wet atomic layer etching (ALE) process, the method comprising:
- a) receiving a substrate, the substrate having the silicon dioxide (SiO2) layer formed thereon;
- b) exposing the silicon dioxide (SiO2) layer to a surface modification solution containing a base dissolved in a non-aqueous solvent, wherein the base reacts with an exposed surface of the silicon dioxide (SiO2) layer to form a modified surface layer containing a silicate;
- c) rinsing the substrate with a first purge solution to remove the surface modification solution from a surface of the substrate;
- d) exposing the modified surface layer to a dissolution solution to dissolve the modified surface layer and uncover an unmodified surface of the silicon dioxide (SiO2) layer underlying the modified surface layer;
- e) rinsing the substrate with a second purge solution to remove the dissolution solution from the surface of the substrate;
- and
- f) repeating steps b)-e) for one or more cycles until an amount of the silicon dioxide (SiO2) layer is removed from the substrate.
Dependencies are inferred from the claim text.