KR-20260066766-A - Selective etching by removal of volatile terminal functional groups

Abstract

Examples relating to the selective etching of materials having similar chemical compositions are disclosed. One example provides a method for selectively etching a feature on a substrate. The substrate comprises a first silicon-containing material and a second silicon-containing material having volatile terminal functional groups at different concentrations. The method comprises the steps of exposing the substrate to energy sufficient to dissociate at least some of the terminal functional groups, and exposing the substrate to a halogen-containing etchant to form volatile silicon halide molecules to remove silicon from the substrate and thereby etch the substrate. The first silicon-containing material is etched at a higher rate than the second silicon-containing material.

Inventors

• 양, 웬빙
• 바헤디, 바히드
• 웡, 메렛
• 람나니, 판카지 간샴
• 발란, 아루니마 데야
• 리, 바이창
• 차울라, 아심
• 판, 이웬
• 탄, 사만다 시암화
• 카마르티, 고우리 찬나
• 싱, 하르미트

Assignees

• 램 리써치 코포레이션

Dates

Publication Date

20260512

Application Date

20240905

Priority Date

20230908

Claims (20)

1. A method for selectively etching a feature on a substrate comprising a first silicon-containing material and a second silicon-based material having volatile terminal functional groups of different concentrations, A step of exposing a substrate to energy sufficient to dissociate at least some terminal functional groups; and The method includes the step of exposing the substrate to a halogen-containing etchant to form volatile silicon halide molecules in order to remove silicon from the substrate and thereby etch the substrate, and A method for selectively etching features on a substrate, wherein the first silicon-containing material is etched at a higher rate than the second silicon-containing material.
2. In Article 1, A method for selectively etching features on a substrate, wherein the first silicon-containing material is a low dielectric constant (low k) material, and the functional groups include organic functional groups.
3. In Article 2, A method for selectively etching features on a substrate, wherein the above-mentioned low-k dielectric material comprises carbon-doped silicon oxide (SiOCH) and the organic functional groups comprise methyl groups.
4. In Article 2, A method for selectively etching features on a substrate, wherein the second silicon-containing material comprises an etching stop layer.
5. In Article 4, A method for selectively etching features on a substrate, wherein the etching stop layer comprises oxygen-doped silicon carbide.
6. In Article 1, A method for selectively etching features on a substrate, wherein the step of exposing the substrate to energy includes the step of exposing it to plasma.
7. In Article 1, A method for selectively etching features on a substrate, wherein the step of exposing the substrate to energy includes exposing the substrate to one or more of particle beam energy or photon energy.
8. In Article 1, A method for selectively etching features on a substrate, wherein the above-mentioned halogen-containing etchant comprises a fluorine-containing etchant.
9. In Article 1, A method for selectively etching a feature on a substrate, wherein the step of exposing the substrate to the energy and the step of exposing the substrate to the halogen-containing etchant are performed within an etching cycle, and the etching cycle further comprises the step of depositing a film layer within the feature using a deposition step during the etching cycle.
10. In Article 9, A method for selectively etching features on a substrate, wherein the above film layer is deposited after exposing the substrate to the halogen-containing etchant and before performing the next etching cycle.
11. In Article 9, A method for selectively etching features on a substrate, wherein the film layer is deposited after the substrate is exposed to the energy, before the substrate is exposed to the halogen-containing etchant, and before the next etching cycle is performed.
12. In Article 9, A method for selectively etching features on a substrate, wherein the step of depositing the film layer comprises the step of depositing the film layer using plasma.
13. In Article 9, A method for selectively etching features on a substrate, wherein the step of depositing the above film layer comprises the step of depositing one or more of an aminosilane precursor or a siloxane precursor without using plasma.
14. A method for selectively etching features on a substrate, The above substrate comprises a low dielectric constant material (low k dielectric material) and an etching stop layer, and the method comprises: A step of performing a plurality of etching cycles to etch the trench of the above k-layer, wherein the etching cycles of the plurality of etching cycles are, A step of exposing a low k dielectric material to a directional plasma to remove a large amount of terminal functional groups from the low k dielectric material, wherein an etching stop layer within a via formed in the low k dielectric material is also exposed to the directional plasma, and the etching stop layer has a lower concentration of volatile terminal functional groups than that of the low k dielectric material, and a step of exposing the low k dielectric material to a directional plasma. The method comprises the step of performing the plurality of etching cycles, wherein the substrate is exposed to a halogen-containing etchant to form volatile silicon halide molecules at the locations of the removed terminal functional groups in order to remove silicon from the low k dielectric material; A method for selectively etching features on a substrate, wherein the above etching stop layer is etched at an etching rate lower than the etching rate of the low k dielectric material.
15. In Article 14, A method for selectively etching features on a substrate, wherein the above-mentioned low-k dielectric material comprises a carbon-doped silicon oxide material, and the above-mentioned etching stop layer comprises an oxygen-doped silicon carbide.
16. In Article 14, A method for selectively etching features on a substrate, wherein the above etching cycle further includes the step of depositing a film layer.
17. In Article 14, A method for selectively etching features on a substrate, wherein the above-mentioned volatile terminal functional groups include methyl groups.
18. Processing chamber; A substrate holder disposed within the processing chamber above (dispose); Flow control hardware for controlling the flows of processing chemicals into the processing chamber; An energy source for exposing a substrate positioned within the substrate holder to energy; and A controller configured to control the processing tool to perform an etching process including a plurality of etching cycles, wherein for each of the etching cycles of the plurality of etching cycles, the controller Control the energy source to expose the substrate to energy sufficient to dissociate at least some terminal functional groups of the first silicon-containing material from the silicon atoms, and A processing tool comprising a controller configured to control the flow control hardware to expose the substrate to a halogen-containing etchant to form volatile silicon halide molecules in order to remove silicon from the substrate and thereby etch the substrate.
19. In Article 18, The above energy source is a processing tool including a plasma source.
20. In Article 18, The above energy source is a processing tool comprising one or more of a particle beam energy source or a photon energy source.

Description

Selective etching by removal of volatile terminal functional groups Semiconductor device manufacturing processes can involve many steps of material deposition, patterning, and removal to form integrated circuits on substrates. Various methods can be used to selectively remove material from a substrate. For example, Reactive Ion Etching (RIE) uses a chemically reactive plasma to remove material from the substrate surface. As another example, Atomic Layer Etching (ALE) can be used to remove substrate material layer by layer using etching cycles. In an ALE cycle, a modification step is used to chemically modify a layer of material on the substrate surface. Subsequently, a removal step volatilizes and removes the chemically modified layer. The content of this invention is provided to introduce a selection of simplified forms of concepts further described in the specific details for carrying out the invention below. The content of this invention is not intended to identify the main features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to embodiments that address any or all disadvantages mentioned in any part of this disclosure. Examples are disclosed regarding the selective etching of materials having similar chemical compositions by the removal of volatile terminal functional groups from the material to be etched. One example provides a method for selectively etching features on a substrate. The substrate comprises a first silicon-containing material and a second silicon-containing material having volatile terminal functional groups at different concentrations. The method comprises the steps of exposing the substrate to energy sufficient to dissociate at least some of the terminal functional groups, and exposing the substrate to a halogen-containing etchant to form volatile silicon halide molecules to remove silicon from the substrate and thereby etch the substrate. The first silicon-containing material is etched at a higher rate than the second silicon-containing material. In some of these examples, the first silicon-containing material is a low dielectric constant (low k) material, and the functional groups include organic functional groups. Alternatively or additionally, in some of these examples, the k dielectric material comprises carbon-doped silicon oxide (SiOCH), and the organic functional groups comprise methyl groups. Alternatively or additionally, in some of these examples, the second silicon-containing material includes an etching stop layer. Alternatively or additionally, in some of these examples, the etching stop layer comprises oxygen-doped silicon carbide. Alternatively or additionally, in some of these examples, the step of exposing the substrate to energy includes the step of exposing it to plasma. Alternatively or additionally, in some of these examples, the step of exposing the substrate to energy includes the step of exposing the substrate to one or more of particle beam energy or photon energy. Alternatively or additionally, in some of these examples, the halogen-containing etchant includes the fluorine-containing etchant. Alternatively or additionally, in some of these examples, the etching cycle further includes a step of depositing a film layer during the etching cycle. Alternatively or additionally, in some of these examples, a film layer is deposited after the substrate is exposed to a halogen-containing etchant and before the next etching cycle is performed. Alternatively or additionally, in some of these examples, the film layer is deposited after the substrate is exposed to energy and before the substrate is exposed to a halogen-containing etchant and before the next etching cycle is performed. Alternatively or additionally, in some of these examples, the step of depositing a film layer includes the step of depositing a film layer using plasma. Alternatively or additionally, in some of these examples, the step of depositing a film layer includes the step of depositing a film layer without using plasma. Another example provides a method for selectively etching features of a substrate. The substrate comprises a low dielectric constant material (low k dielectric material) and an etching stop layer. The method comprises the step of performing a plurality of etching cycles to etch trenches of the low k layer. The etching cycle of the plurality of etching cycles includes the step of exposing the low k dielectric material to a directional plasma to remove a large amount of terminal functional groups from the low k dielectric material, wherein the etching stop layer within vias formed in the low k dielectric material is also exposed to the directional plasma, and the etching stop layer has a lower concentration of volatile terminal functional groups than the low k dielectric material. The method further comprises the step of exposing the substrate