CN-115516604-B - Selective deposition of carbon on photoresist layers for lithographic applications

Abstract

A method of etching a hard mask layer includes forming a photoresist layer comprising an organometallic material over a hard mask layer comprising a metal-containing material, exposing the photoresist layer to ultraviolet radiation through a mask having a selected pattern, removing non-irradiated regions of the photoresist layer to pattern the photoresist layer, selectively forming a passivation layer comprising a carbon-containing material over a top surface of the patterned photoresist layer, and etching the hard mask layer exposed by the patterned photoresist layer having the passivation layer formed thereon.

Inventors

• Larry Gao
• Nan Xi.feng

Assignees

• 应用材料公司

Dates

Publication Date

20260508

Application Date

20210317

Priority Date

20210315

Claims (20)

1. 1. A method of etching a hard mask layer, comprising the steps of: forming a photoresist layer comprising an organometallic material on the hard mask layer comprising a metal-containing material; Exposing the photoresist layer to ultraviolet radiation through a mask having a selected pattern, creating irradiated and non-irradiated areas of the photoresist layer; removing the irradiated or non-irradiated areas of the photoresist layer to pattern the photoresist layer; selectively forming a passivation layer comprising a carbon-containing material on a top surface of the patterned photoresist layer, and Etching the hard mask layer exposed by the removed irradiated or non-irradiated regions of the patterned photoresist layer having the passivation layer formed thereon.
2. 2. The method of claim 1, wherein the organometallic material comprises one or more metallic elements and an organic ligand.
3. 3. The method of claim 2, wherein the one or more metallic elements comprise tin (Sn).
4. 4. The method of claim 2, wherein the organic ligand is selected from the group consisting of alkyl, alkenyl, and carboxylate.
5. 5. The method of claim 1, wherein the step of forming the passivation layer comprises the steps of: A deposition gas comprising a gas selected from the group consisting of CO and CH 4 is supplied onto the patterned photoresist layer.
6. 6. A method for etching a film stack, comprising the steps of: forming a bottom antireflective coating over the film stack; Forming a hard mask layer comprising a metal-containing material over the bottom antireflective coating; Forming a photoresist layer containing an organic metal material on the hard mask layer; Exposing the photoresist layer to ultraviolet radiation through a mask having a selected pattern, creating irradiated and non-irradiated areas of the photoresist layer; removing the irradiated or non-irradiated areas of the photoresist layer to pattern the photoresist layer; Selectively forming a passivation layer comprising a carbon-containing material on a top surface of the patterned photoresist layer; etching the hard mask layer exposed by the removed irradiated or non-irradiated regions of the patterned photoresist layer having the passivation layer formed thereon to pattern the hard mask layer; Etching the bottom anti-reflective coating exposed by the patterned hard mask layer to pattern the bottom anti-reflective coating, and Etching the film stack exposed by the patterned bottom antireflective coating.
7. 7. The method of claim 6, wherein the organometallic material comprises one or more metallic elements and an organic ligand.
8. 8. The method of claim 7, wherein the one or more metallic elements comprise tin (Sn).
9. 9. The method of claim 7, wherein the organic ligand is selected from the group consisting of alkyl, alkenyl, and carboxylate.
10. 10. The method of claim 6, wherein the step of forming the passivation layer comprises the steps of: a deposition gas comprising a gas selected from the group consisting of CO and CH 4 is supplied to the patterned photoresist layer.
11. 11. The method of claim 6, wherein the metal-containing material of the hard mask layer comprises tin (Sn).
12. 12. The method of claim 11, wherein the metal-containing material of the hard mask layer is selected from the group consisting of tin oxide (SnO), tin silicon oxide (SnSiO), indium tin oxide (InSnO), and any combination thereof.
13. 13. The method of claim 6, wherein the bottom antireflective coating comprises a carbon-containing material.
14. 14. A method for selectively forming a passivation layer on a patterned photoresist layer, comprising the steps of: Exposing a photoresist layer comprising an organometallic material to ultraviolet radiation through a mask creating irradiated and non-irradiated regions of the photoresist layer; Removing the irradiated or non-irradiated areas of the photoresist layer, and A passivation layer comprising a carbon-containing material is selectively formed on a top surface of the photoresist layer.
15. 15. The method of claim 14, wherein the organometallic material comprises one or more metallic elements and an organic ligand.
16. 16. The method of claim 15, wherein the one or more metallic elements comprise tin (Sn).
17. 17. The method of claim 15, wherein the one or more metallic elements are selected from the group consisting of tin (Sn), antimony (Sb), and indium (In), and any combination of the foregoing.
18. 18. The method of claim 15, wherein the organic ligand is selected from the group consisting of alkyl, alkenyl, and carboxylate.
19. 19. The method of claim 14, further comprising the step of: Heating the patterned photoresist layer.
20. 20. The method of claim 14, wherein the step of forming the passivation layer comprises the steps of: a deposition gas comprising a gas selected from the group consisting of CO and CH 4 is supplied onto the patterned photoresist layer.

Description

Selective deposition of carbon on photoresist layers for lithographic applications Technical Field Embodiments herein relate generally to a film stack and an etching process for etching the film stack with high selectivity and good profile control for extreme ultraviolet (extreme ultraviolet; EUV) lithography exposure and patterning processes. Background The reliable generation of submicron and smaller features is one of the key requirements for large scale integration (VERY LARGE SCALE integration; VLSI) and Ultra LARGE SCALE Integration (ULSI) of semiconductor devices. However, with continued miniaturization of circuit technology, additional demands are placed on processing power, such as the size and spacing of interconnected circuit features. The heart of this technology is a multilevel interconnect that requires precise imaging and placement of high aspect ratio features such as vias and other interconnects. Reliable formation of these interconnects is critical to further increase device and interconnect density. In addition, it is desirable to reduce waste of intermediate materials (e.g., resist and hard mask materials) while forming sub-micron sized features and interconnects. As feature sizes become smaller, the demand for higher aspect ratios (defined as the ratio of feature depth to feature width) steadily increases to 20:1 and even higher. It is a significant challenge to develop a film stack and etch process that can reliably form features with such high aspect ratios. However, inaccurate control or low resolution of the photolithographic exposure and development process may result in inaccurate dimensions of the photoresist layer used to transfer features in the film stack, resulting in unacceptable line width roughness (LINE WIDTH roughess; LWR). The large linewidth roughness (LARGE LINE WIDTH roughess; LWR) and the undesirable swing profile of the photoresist layer resulting from the photolithographic exposure and development process can lead to inaccurate transfer of features to the film stack, thus ultimately leading to device failure and yield loss. Furthermore, during etching of the film stack, redeposition or accumulation of byproducts or other materials generated in the etching process may accumulate on the top and/or sidewalls of the etched features, undesirably blocking the openings of the features formed in the material layer. Different materials selected for the film stack may result in different amounts or distributions of byproducts redeposited in the film stack. Furthermore, since the openings of the etched features are narrowed and/or sealed by the cumulative redeposition of material, the reactive etchant is prevented from reaching the lower surface of the features, thus limiting the available aspect ratio. Furthermore, because the accumulation of redeposited material or byproducts may randomly and/or irregularly adhere to the top surfaces and/or sidewalls of the etched features, the resulting irregular profile and growth of the redeposited material may alter the flow path of the reactive etchant, resulting in a curved or distorted profile of the features formed in the material layer. Inaccurate topography or structural dimensions can lead to breakdown of the device structure, ultimately leading to device failure and low product yields. Poor etch selectivity to materials contained in the film stack may lead to inaccurate profile control, ultimately leading to device failure. Accordingly, there is a need in the art for a suitable film stack and an etching method for etching features having a desired profile and small dimensions in such a film stack. Disclosure of Invention Methods for forming and etching a film stack to form high aspect ratio features in the film stack are provided. The methods described herein facilitate profile and dimension control of features with high aspect ratios with appropriate sidewall and bottom management schemes utilizing desired materials selected for film stacks. In one or more embodiments, a method for etching a hard mask layer includes forming a photoresist layer comprising an organic metal material over a hard mask layer comprising a metal-containing material, exposing the photoresist layer to ultraviolet radiation through a mask having a selected pattern, removing non-irradiated regions of the photoresist layer to pattern the photoresist layer, selectively forming a passivation layer comprising a carbon-containing material over a top surface of the patterned photoresist layer, and etching the hard mask layer exposed by the patterned photoresist layer having the passivation layer formed thereon. In other embodiments, a method for etching a film stack includes forming a bottom antireflective coating over the film stack, forming a hard mask layer comprising a metal-containing material over the bottom antireflective coating, forming a photoresist layer comprising an organometallic material over the hard mask layer, exposing the photoresist layer to