US 2026/0282780 A1Published application

Cyclic process and method to provide uniform etching of material formed within features having different critical dimension (cd)

AssigneeTokyo Electron Limited

InventorsShan Hu, Sangita Kumari, Karthikeyan Pillai, Osamu Miyahara

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Abstract

Embodiments of processes and methods are disclosed to provide uniform etching of material within features (such as, e.g., trenches, holes, slits, etc.) having different critical dimension (CD). In the present disclosure, a cyclic process is used to provide uniform etching of the material within the features, regardless of CD. The cyclic process generally includes: (a) a surface modification step to chemically modify an exposed surface of the material and form a modified surface layer on the material, and (b) a removal step to selectively remove the modified surface layer without etching an underlying unmodified surface of the material. By using such a process, the embodiments disclosed herein provide “CD-independent etching” of material formed within features of different CD and enable an even thickness of the material to be removed from the features, regardless of CD.

Claims20

Dependent claims

A method of etching, comprising:

providing a substrate having a target material and a wall material formed adjacent to the target material on at least two sides of the target material, wherein the target material and the wall material comprise two different materials, wherein the target material and the wall material form a plurality of features, and wherein a critical dimension (CD) of the plurality of features is different for one or more of the features, such that the plurality of features comprise at least a first feature having a smaller CD and a second feature having a larger CD;
and
selectively etching the target material within the plurality of features, the selectively etching including exposing the substrate to a plurality of different reactants in series to:
(a) chemically modify an exposed surface of the target material by exposing the exposed surface of the target material to a gas-phase or liquid-phase reactant to form a modified surface layer having a self-limiting thickness, and (b) selectively remove the modified surface layer by exposing the modified surface layer to a chemical solution comprising a reactant, which differs from the gas-phase or liquid-phase reactant;
wherein the chemical modification of the exposed surface of the target material and the selective removal of the modified surface layer provides uniform etching of the target material within the plurality of features, regardless of CD;
and
wherein the chemical modification of the exposed surface of the target material and the selective removal of the modified surface layer are sequentially and alternatingly performed a plurality of times to selectively etch a desired amount of the target material.

4 more elements

A method of etching, the method comprising:

providing a substrate having a target material and a wall material formed adjacent to the target material on at least two sides of the target material, wherein the target material and the wall material comprise two different materials, wherein the target material and the wall material form a plurality of features, and wherein a critical dimension (CD) of the plurality of features is different for one or more of the features, such that the plurality of features comprise at least a first feature having a smaller CD and a second feature having a larger CD;
and
performing a cyclic process to selectively etch the target material without etching the wall material, wherein the cyclic process includes multiple cycles, each cycle including:
(a) a surface modification step that includes exposing the substrate to a gas-phase or liquid-phase reactant to chemically modify an exposed surface of the target material and form a modified surface layer on the target material, wherein the gas-phase or liquid-phase reactant does not etch the target material or the wall material;
and
(b) a removal step that includes exposing the substrate to a liquid-phase reactant to selectively remove the modified surface layer of the target material without etching the wall material or an unmodified surface of the target material underlying the modified surface layer, wherein the liquid-phase reactant used during the removal step is different from the gas-phase or liquid-phase reactant used during the surface modification step;
and
wherein said performing the cyclic process provides uniform etching of the target material within the plurality of features, regardless of CD.

5 more elements

Dependencies are inferred from the claim text.