Paper
20 March 2020 New improving metrology for advanced memory devices with high transmission attenuated phase shift mask
Chia-Hung Chen, Sheng-Tsung Tsao, CongCong Fan, Jie Du, Richer Yang, Asei Chou, Kunyuan Chen, Jimmy Chang, JunJun Zhang, Wallace He, Leslie Zhang, YunSheng Xia
Author Affiliations +
Abstract
In order to achieve better resolution and improve lithography process window, device manufacturers are looking into or adopting high transmission attenuated phase shift mask (HTM). The critical dimension uniformity (CDU) of the device pattern can be quite a bit better with high transmission mask as compared to conventional attenuated phase shift mask, which makes it an attractive choice for advanced memory devices. However, it poses challenges on metrology targets such as alignment marks or micro diffraction-based overlay (uDBO) marks, which has different dimensions as device patterns as required by the metrology sensors. The challenges include printability, detectability, accuracy, process compatibility and defectively on the same device layer. In this paper we demonstrate solutions to address these challenges and thereby improve metrology for advanced memory devices with HTM. Without sacrificing mark contrast on wafer, the wafer quality of alignment mark is improved up to 10 times with respect to array like alignment marks and the stack sensitivity of uDBO mark can also increase more than 7 times as array like marks. Through a holistic target approach involving target design, target OPC, and recipe setup, we are able to achieve accurate metrology for optimal on-product overlay and device yield.
© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Chia-Hung Chen, Sheng-Tsung Tsao, CongCong Fan, Jie Du, Richer Yang, Asei Chou, Kunyuan Chen, Jimmy Chang, JunJun Zhang, Wallace He, Leslie Zhang, and YunSheng Xia "New improving metrology for advanced memory devices with high transmission attenuated phase shift mask", Proc. SPIE 11325, Metrology, Inspection, and Process Control for Microlithography XXXIV, 113252U (20 March 2020); https://doi.org/10.1117/12.2552025
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Optical alignment

Photomasks

Semiconducting wafers

Metrology

Phase shifts

Overlay metrology

Optical proximity correction

Back to Top