| Autor: |
Ningqi Zhu, Jason Pei, Erik Xiao, Haydn Zhou, Miao Bing, Seddy Chu, Xin Li, Jin Zhu, Bob Dong, Leeming Tu, Cynthia Li, Kevin Huang |
| Rok vydání: |
2021 |
| Předmět: |
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| Zdroj: |
Metrology, Inspection, and Process Control for Semiconductor Manufacturing XXXV. |
| DOI: |
10.1117/12.2583760 |
| Popis: |
In recent years, the pursuit of high storage capacity in 3D-NAND flash devices has driven the addition of more layers to increase the stack height. Challenges arise when etching high aspect ratio memory holes. Due to the existence of a thick and opaque hard mask layer, overlay control faces significant lot-to-lot variation and difficulty of run-to-run feedback control. In this paper, a fundamental study on channel hole overlay variation is revealed by collecting and analyzing step-by step overlay, etch tilt and stress data. The strong correlation between overlay/tilt/stress identifies the main contributor of overlay lot-to-lot variation to be from etch tilt, which also strongly correlates to etch chamber RF hour (accumulated hours the chamber has run since its last PM event) without chamber dependency. In addition, overlay simulations showed lots grouped by RF hour can effectively reduce lot-to-lot overlay variation. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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