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Proceedings Paper

New approach for pattern collapse problem by increasing contact area at sub-100-nm patterning
Author(s): Sung-Koo Lee; Jae Chang Jung; Min Suk Lee; Sung Kwon Lee; Sam Young Kim; Young-Sun Hwang; Cheol Kyu Bok; Seung-Chan Moon; Ki Soo Shin; Sang-Jung Kim
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Paper Abstract

To accomplish minimizing feature size to sub 100nm, new light sources for photolithography are emerging, such as ArF(193nm), F2(157nm), and EUV(13nm). However as the pattern size decreases to sub 100nm, a new obstacle, that is pattern collapse problem, becomes most serious bottleneck to the road for the sub 100 nm lithography. The main reason for this pattern collapse problem is capillary force that is increased as the pattern size decreases. As a result there were some trials to decrease this capillary force by changing developer or rinse materials that had low surface tension. On the other hands, there were other efforts to increase adhesion between resists and sub materials (organic BARC). In this study, we will propose a novel approach to solve pattern collapse problems by increasing contact area between sub material (organic BARC) and resist pattern. The basic concept of this approach is that if nano-scale topology is made at the sub material, the contact area between sub materials and resist will be increased. The process scheme was like this. First after coating and baking of organic BARC material, the nano-scale topology (3~10nm) was made by etching at this organic BARC material. On this nano-scale topology, resist was coated and exposed. Finally after develop, the contact area between organic BARC and resist could be increased. Though nano-scale topology was made by etching technology, this 20nm topology variation induced large substrate reflectivity of 4.2% and as a result the pattern fidelity was not so good at 100nm 1:1 island pattern. So we needed a new method to improve pattern fidelity problem. This pattern fidelity problem could be solved by introducing a sacrificial BARC layer. The process scheme was like this. First organic BARC was coated of which k value was about 0.64 and then sacrificial BARC layers was coated of which k value was about 0.18 on the organic BARC. The nano-scale topology (1~4nm) was made by etching of this sacrificial BARC layer and then as the same method mentioned above, the contact area between sacrificial layer and resist could be increased. With this introduction of sacrificial layer, the substrate reflectivity of sacrificial BARC layer was decreased enormously to 0.2% though there is 20nm topology variation of sacrificial BARC layer. With this sacrificial BARC layer, we could get 100nm 1:1 L/S pattern. With conventional process, the minimum CD where no collapse occurred, was 96.5nm. By applying this sacrificial BARC layer, the minimum CD where no collapse occurred, was 65.7nm. In conclusion, with nano-scale topology and sacrificial BARC layer, we could get very small pattern that was strong to pattern collapse issue.

Paper Details

Date Published: 12 June 2003
PDF: 9 pages
Proc. SPIE 5039, Advances in Resist Technology and Processing XX, (12 June 2003); doi: 10.1117/12.485052
Show Author Affiliations
Sung-Koo Lee, Hynix Semiconductor, Inc. (South Korea)
Jae Chang Jung, Hynix Semiconductor, Inc. (South Korea)
Min Suk Lee, Hynix Semiconductor, Inc. (South Korea)
Sung Kwon Lee, Hynix Semiconductor, Inc. (South Korea)
Sam Young Kim, Hynix Semiconductor, Inc. (South Korea)
Young-Sun Hwang, Hynix Semiconductor, Inc. (South Korea)
Cheol Kyu Bok, Hynix Semiconductor, Inc. (South Korea)
Seung-Chan Moon, Hynix Semiconductor, Inc. (South Korea)
Ki Soo Shin, Hynix Semiconductor, Inc. (South Korea)
Sang-Jung Kim, Dongjin Semichem Co. (South Korea)


Published in SPIE Proceedings Vol. 5039:
Advances in Resist Technology and Processing XX
Theodore H. Fedynyshyn, Editor(s)

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