Multiple patterning: Difference between revisions

Revision as of 00:52, 17 April 2024

Revision as of 08:41, 11 May 2024

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==EUV multiple patterning possibilities==

[[File:2D_Layout_Decomposition.png|thumb|left|200px|'''EUV layout splitting due to different illuminations.''' This layout consists of vertical and horizontal lines requiring two different illuminations optimized for each, since the horizontal layout includes wider lines and spaces. Consequently, the layout needs to be split, even for EUV lithography. Furthermore, additional cut exposures are preferred for the gaps between line tips (circled).]]

Although [[Extreme ultraviolet lithography|EUV]] has been projected to be the [[next-generation lithography]] of choice, it could still require more than one lithographic exposure, due to the foreseen need to first print a series of lines and then cut them; a single EUV exposure pattern has difficulty with line end-to-end spacing control.<ref name=setten/> In addition, the line end placement is significantly impacted by photon shot noise.<ref>[https://www.linkedin.com/pulse/photon-shot-noise-impact-line-end-placement-frederick-chen Photon Shot Noise Impact on Line End Placement]</ref>

The existing 0.33 NA EUV tools are challenged below 16&nbsp;nm half-pitch resolution.<ref name=asmlbeol>T-B. Chiou ''et al.'', Proc. SPIE 9781, 978107 (2016).</ref> Tip-to-tip gaps are problematic for 16&nbsp;nm dimensions.<ref>T. H-Bao ''et al.'', Proc. SPIE 9781, 978102 (2016).</ref> Consequently, EUV 2D patterning is limited to >32&nbsp;nm pitch.<ref name=asmlbeol /> Recent studies of optimizing the EUV mask features and the illumination shape simultaneously have indicated that different patterns in the same metal layer could require different illuminations.<ref name=ychen>Y. Chen et al., J. Vac. Sci. Tech. B35, 06G601 (2017).</ref><ref>M. Crouse ''et al.'', Proc. SPIE 10148, 101480H (2017).</ref><ref>W. Gillijns ''et al.'', Proc. SPIE 10143, 1014314 (2017).</ref><ref>T. Last ''et al.'', Proc. SPIE 10143, 1014311 (2017).</ref><ref>S. Hsu ''et al.'', Proc. SPIE 9422, 94221I (2015).</ref> On the other hand, a single exposure only offers a single illumination.