CN-121995698-A - Expandable negative photoresist with suspended material and method for reducing flare in spacer oxide using the same

Abstract

The present invention provides an expandable negative photoresist and a method for adjusting the profile of a spacer oxide by using the expandable negative photoresist. The expandable negative photoresist comprises a polymer material, a suspension material and a photoacid generator. The suspension material comprises a plurality of expandable molecules.

Inventors

• ZHOU ZIYU
• CAI ZHIYING

Assignees

• 南亚科技股份有限公司

Dates

Publication Date

20260508

Application Date

20250617

Priority Date

20241101

Claims (20)

1. 1. An expandable negative tone photoresist comprising: A polymer material; A suspension material comprising a plurality of expandable molecules, and A photoacid generator.
2. 2. The negative-tone photoresist of claim 1, wherein the suspending material has a coefficient of expansion greater than a coefficient of expansion of the polymer material.
3. 3. The negative-tone photoresist of claim 2, wherein the suspension material has a density less than a density of the polymer material.
4. 4. The negative-tone photoresist of claim 1, wherein the swellable molecules are chemically bonded to the polymeric material by a chemical bond.
5. 5. The negative-tone photoresist of claim 4, wherein the chemical bond is cleaved using a photolytic bond cleavage process.
6. 6. The negative-working photoresist of claim 1, wherein the polymeric material comprises poly (t-butoxycarboxystyrene).
7. 7. The expandable negative-tone photoresist of claim 1, wherein the photoacid generator comprises triphenylsulfonium hexafluoroantimonate.
8. 8. A method of adjusting a cross-sectional profile of a spacer oxide, comprising: Providing a substrate; Applying a bottom layer on the substrate; forming a first photoresist layer over the underlayer, wherein the first photoresist layer comprises a first suspended material, wherein the first suspended material comprises a plurality of first expandable molecules; performing an exposure process on the first photoresist layer to create a second photoresist layer in the first photoresist layer, wherein the second photoresist layer comprises a second suspending material, wherein the second suspending material comprises a plurality of second expandable molecules; performing a developing process on both the first photoresist layer and the second photoresist layer to form a third photoresist layer and an expandable layer on the third photoresist layer, wherein the expandable layer comprises a plurality of second expandable molecules; Depositing a spacer oxide layer to cover the third photoresist layer and the expandable layer, and A thermal process is performed on the expandable layer to adjust the cross-sectional profile of the spacer oxide.
9. 9. The method of claim 8, wherein the first photoresist layer is a negative photoresist.
10. 10. The method of claim 9, wherein the first suspended material is uniformly distributed throughout the first photoresist layer.
11. 11. The method of claim 10, wherein each of the plurality of first expandable molecules is chemically bonded to a first polymeric material in the first photoresist layer by a chemical bond.
12. 12. The method of claim 11, wherein a coefficient of expansion of the first suspension material is greater than a coefficient of expansion of the first polymeric material.
13. 13. The method of claim 12, wherein a density of the first suspending material is less than a density of the first polymeric material.
14. 14. The method of claim 13, wherein the first polymeric material of the first photoresist layer comprises poly (t-butoxycarboxystyrene).
15. 15. The method of claim 8, wherein each of the plurality of second expandable molecules is separated from a second polymeric material in the second photoresist layer.
16. 16. The method of claim 15, wherein a coefficient of expansion of the second suspension material is greater than a coefficient of expansion of the second polymeric material.
17. 17. The method of claim 16, wherein a density of the second suspending material is less than a density of the second polymeric material.
18. 18. The method of claim 17, wherein the second polymer material of the second photoresist layer comprises poly (4-hydroxystyrene).
19. 19. The method of claim 15, wherein the third photoresist layer does not comprise the plurality of second expandable molecules and the expandable layer comprises the plurality of second expandable molecules.
20. 20. The method of claim 15, further comprising: A mask is disposed over the first photoresist layer, wherein the mask includes an unmasked portion defining a region in the first photoresist layer that is to be subsequently exposed.

Description

Expandable negative photoresist with suspended material and method for reducing flare in spacer oxide using the same The present application claims priority to U.S. patent application Ser. No. 18/934,430 (i.e., priority date "2024, 11, 1"), the contents of which are incorporated herein by reference in their entirety. Technical Field The present invention relates to a negative photoresist and a method for adjusting the profile of a spacer oxide, and more particularly, to an expandable negative photoresist with suspended material and a method for reducing flare in a spacer oxide using the same. Background Semiconductor devices are used in a variety of electronic applications including personal computers, mobile phones, digital cameras, and other electronic devices. The size of semiconductor devices is continually shrinking to meet the increasing demands for computing power. However, challenges with such downsizing are becoming more and more frequent and influential. Thus, challenges remain in terms of improving quality, yield, performance, and reliability while reducing complexity. Spacers and spacer oxides are commonly used in the fabrication of semiconductor devices to ensure proper distance and function between components. Due to the demands for smaller linewidths and spacings, e.g., critical dimensions (critical dimensions, CD) less than 50nm, and more complex manufacturing processes, including pitch doubling and multiple patterning, ensuring the functional integrity of the spacers while avoiding the horn shape, remains a continuing challenge. The discussion of the prior art paragraphs merely provides background information. The statements in the discussion of the prior art paragraphs do not constitute an admission that the disclosure in this paragraph constitutes prior art with respect to the present invention and any part of the discussion of the prior art paragraphs is not used as an admission that any part of the present invention, including the part of the discussion of the prior art paragraphs, constitutes prior art with respect to the present invention. Disclosure of Invention An aspect of the present invention is to provide an expandable negative photoresist comprising a polymer material, a suspending material, and a photoacid generator (PAG). The suspension material comprises a plurality of expandable molecules. In some embodiments, the suspension material has a coefficient of expansion greater than a coefficient of expansion of the polymeric material. In some embodiments, a density of the suspension material is less than a density of the polymer material. In some embodiments, the swellable molecule is chemically bonded to the polymeric material by a chemical bond. In some embodiments, the chemical bond is cleaved using a photolytic bond cleavage process. In some embodiments, the polymeric material comprises poly (t-butoxycarboxystyrene) (PBOCSt)。 In some embodiments, the photoacid generator comprises triphenylsulfonium hexafluoroantimonate (Ph 3SSbF6). Another aspect of the present invention is to provide a method of adjusting a cross-sectional profile of a spacer oxide, comprising providing a substrate, applying a bottom layer on the substrate, forming a first photoresist layer on the bottom layer, performing an exposure process on the first photoresist layer to create a second photoresist layer in the first photoresist layer, performing a development process on the first photoresist layer and the second photoresist layer to form a third photoresist layer and an expandable layer on the third photoresist layer, depositing a spacer oxide layer to cover the third photoresist layer and the expandable layer, and performing a thermal process on the expandable layer to adjust the cross-sectional profile of the spacer oxide. The first photoresist layer includes a first suspending material including a plurality of first expandable molecules, and the second photoresist layer includes a second suspending material including a plurality of second expandable molecules. The expandable layer includes the plurality of second expandable molecules. The heat treatment is performed by activating the plurality of second expandable molecules in the expandable layer. In some embodiments, the first photoresist layer is a negative photoresist. In some embodiments, the first suspended material is uniformly distributed throughout the first photoresist layer. In some embodiments, each of the plurality of first expandable molecules is chemically bonded to a first polymeric material in the first photoresist layer by a chemical bond. In some embodiments, the first suspending material has a coefficient of expansion greater than a coefficient of expansion of the first polymeric material. In some embodiments, a density of the first suspending material is less than a density of the first polymeric material. In some embodiments, the first polymeric material of the first photoresist layer comprises poly (t-butoxycarboxystyrene) (PB