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20 May 2006 Quartz etch challenges for 45 nm phase-shift masks
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Proceedings Volume 6283, Photomask and Next-Generation Lithography Mask Technology XIII; 62831X (2006)
Event: Photomask and Next Generation Lithography Mask Technology XIII, 2006, Yokohama, Japan
One means of extending the limits and lifetime of current lithography platforms for 45nm and beyond is the development of resolution enhancement techniques (RET) in the form of optical phase-shifting masks (PSM). By employing optical interference from 180° shifted lithography emission, PSM masks are able to enhance feature resolution at the wafer. This is particularly important for sub-wavelength features (i.e., features with critical dimensions less than the lithography wavelength) where line resolution can be severely degraded without such techniques. For these PSMs, the challenge is to provide highly uniform quartz etch performance across the entire active area of the mask for various feature sizes and local loads. Micro-loading (a.k.a. RIE lag or reactive ion etch lag) and phase angle range are key performance parameters to control. As the demands for these parameters tighten and mask costs rise, strict performance control is required for all PSM mask varieties utilized in the mask shop. In this paper we will discuss process improvements for the Applied Materials Tetra IITM chromeless phase lithography (CPL) etch application. In particular, the discussion will focus on recent process improvements in phase uniformity and RIE lag for our chrome hard mask CPL etch process. Results from modifications to the etch process are presented. Feature profiles are also discussed with examples showing near vertical sidewalls and no micro-trenching.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Scott A. Anderson, Madhavi Chandrachood, Michael Grimbergen, Toi Yue Becky Leung, Ibrahim M. Ibrahim, Sheeba Panayil, and Ajay Kumar "Quartz etch challenges for 45 nm phase-shift masks", Proc. SPIE 6283, Photomask and Next-Generation Lithography Mask Technology XIII, 62831X (20 May 2006);

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