Method for recessing a fill material within openings formed on a patterned substrate

Patent metadata

Field	Value
Publication number	US-11848236-B2
Application number	US-202117479072-A
Country	US
Kind code	B2
Filing date	Sep 20, 2021
Priority date	Dec 2, 2020
Publication date	Dec 19, 2023
Grant date	Dec 19, 2023

Abstract

Process flows and methods are provided for recessing a fill material within openings formed within a patterned substrate. The openings are formed within a multilayer stack comprising a target material layer and one or more additional material layers, which overly and differ from the target material layer. After the openings are formed within the multilayer stack, a grafting material comprising a solubility-shifting agent is selectively deposited within the openings, such that the grafting material adheres to the target material layer without adhering to the additional material layer(s) overlying the target material layer. Next, a fill material is deposited within the openings and the solubility-shifting agent is activated to change the solubility of a portion of the fill material adjacent to and surrounding the grafting material. Then, a wet development process is used to remove the soluble/insoluble portions of fill material to the recess the fill material within the openings.

First claim

What is claimed is:

1. A method for recessing a fill material within openings formed within a patterned substrate, the method comprising:
receiving the patterned substrate comprising the openings, wherein the openings are formed within a multilayer stack comprising a target material layer and one or more additional material layers overlying the target material layer, wherein the one or more additional material layers differ from the target material layer;
selectively depositing a grafting material within the openings, such that the grafting material adheres to the target material layer without adhering to the one or more additional material layers overlying the target material layer, and wherein the grafting material includes a solubility-shifting agent;
depositing the fill material within the openings;
causing the solubility-shifting agent to diffuse into a portion of the fill material surrounding the grafting material, wherein diffusion of the solubility-shifting agent causes the portion of the fill material to become insoluble to a predetermined solvent; and
recessing the fill material within the openings by using the predetermined solvent to remove soluble portions of the fill material, while leaving the portion of the fill material that is insoluble to the predetermined solvent within the openings.

2. The method of claim 1 , wherein the predetermined solvent removes the soluble portions of the fill material to a depth within the openings defined by the solubility-shifting agent and physical characteristics of the target material layer.

3. The method of claim 1 , wherein the grafting material is selectively deposited onto opposing sidewalls of the openings at a depth defined by the target material layer, and wherein the solubility-shifting agent causes solubility changing reactions to occur within a region, which extends radially from the grafting material deposited onto the opposing sidewalls into the portion of the fill material to form a complete layer of insoluble material at the depth of the target material layer.

4. The method of claim 1 , wherein the grafting material is selectively deposited within the openings by forming self-assembled monolayers (SAMs) on opposing sidewall surfaces of the target material layer, and wherein the fill material is an acid protected resin.

5. The method of claim 4 , wherein the SAMs are functionalized with a photo-acid generator (PAG) or a thermal-acid generator (TAG).

6. The method of claim 4 , wherein the SAMs are functionalized with a photo-acid generator (PAG), and wherein said causing the solubility-shifting agent to diffuse into the portion of the fill material surrounding the grafting material comprises:
irradiating the PAG to generate an acid; and
performing a bake process to diffuse the acid into the portion of the fill material,
wherein diffusing the acid converts the acid protected resin within the portion of the fill material into an acid deprotected resin.

7. The method of claim 4 , wherein the SAMs are functionalized with a thermal-acid generator (TAG), and wherein said causing the solubility-shifting agent to diffuse into the portion of the fill material surrounding the grafting material comprises:
performing a bake process to generate an acid and diffuse the acid into the portion of the fill material; and
wherein diffusing the acid converts the acid protected resin within the portion of the fill material into an acid deprotected resin.

8. The method of claim 1 , wherein the predetermined solvent is an organic solvent.

9. The method of claim 1 , wherein after using the predetermined solvent to remove soluble portions of the fill material, said recessing the fill material further comprises:
using an aqueous solvent to remove the portion of the fill material that is insoluble to the predetermined solvent from the openings.

10. A method for recessing a fill material within openings formed within a patterned substrate, the method comprising:
receiving the patterned substrate comprising the openings, wherein the openings are formed within a multilayer stack comprising a target material layer and one or more additional material layers overlying the target material layer, wherein the one or more additional material layers differ from the target material layer;
selectively depositing a grafting material within the openings, such that the grafting material adheres to the target material layer without adhering to the one or more additional material layers overlying the target material layer, and wherein the grafting material comprises an acid generator;
depositing the fill material within the openings, wherein the fill material is an acid protected material;
activating the acid generator within the grafting material to generate and diffuse an acid into a portion of the fill material surrounding the grafting material, wherein diffusing the acid converts the portion of the fill material into an acid deprotected material; and
recessing the fill material within the openings by using a first solvent to remove portions of the acid protected material overlying the portion of the fill material containing the acid deprotected material.

11. The method of claim 10 , wherein the grafting material is selectively deposited onto opposing sidewalls of the openings at a depth defined by the target material layer, and wherein the acid diffuses radially from the grafting material deposited onto the opposing sidewalls into the portion of the fill material to form a complete layer of acid deprotected material at the depth of the target material layer.

12. The method of claim 10 , wherein the grafting material is selectively deposited within the openings by forming self-assembled monolayers (SAMs) on opposing sidewall surfaces of the target material layer.

13. The method of claim 12 , wherein a head group of the SAMs comprise a thiol, a carboxylic acid, a phosphinic acid or a silane.

14. The method of claim 10 , wherein the acid generator is a photo-acid generator (PAG), and wherein said activating the acid generator comprises:
irradiating the PAG to generate the acid; and
performing a bake process to diffuse the acid into the portion of the fill material.

15. The method of claim 10 , wherein the acid generator is a thermal-acid generator (TAG), and wherein said activating the acid generator comprises performing a bake process to generate the acid and diffuse the acid into the portion of the fill material.

16. The method of claim 10 , wherein diffusing the acid is localized to a region encompassing the grafting material.

17. The method of claim 10 , wherein said activating the acid generator comprises a bake process, and wherein a diffusion length and profile of diffusing the acid is dependent on a composition of the acid generator, a composition of the fill material, a bake temperature, a bake time and/or a molecular weight of the acid.

18. The method of claim 10 , wherein the first solvent is an organic solvent.

19. The method of claim 10 , wherein after using the first solvent to remove portions of the acid protected material overlying the portion of the fill material containing the acid deprotected material, said recessing the fill material further comprises using a second solvent to remove the portion of the fill material containing the acid deprotected material.

20. The method of claim 19 , wherein the second solvent is an aqueous solvent.

Assignees

• Tokyo Electron Ltd

Inventors

• Devilliers Anton
• Murphy Michael

Classifications

• H10W20/057 Primary

  by selectively depositing, e.g. by using selective CVD or plating · CPC title

• H10W20/056

  by filling conductive material into holes, grooves or trenches · CPC title

• H10W20/023 Primary

  the interconnections being through-semiconductor vias · CPC title

• H10P95/08

  Planarisation of organic insulating materials · CPC title

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title