Paper
28 July 2014 Two new design methods for lithography mask: phase-shifting scattering bar and interlaced phase-shifting mask
Kwei-Tin Yeh, Chao-Yi Huang
Author Affiliations +
Abstract
For 193 nm immersion lithography, it is hard to print clear 4X nm dense images (ex. contact holes) on wafer without any modifications due to lower light intensity. In the past, the most common method is to add the scattering bars, which can enhance the light intensity of contact holes. However, with tinier pattern, the distance between scattering bars and contact holes will get quite close. Hence, the error tolerance for mask making was reduced. On the other hand, this method may also cause the pattern twist which will induce pattern crosslink. To solve this issue, a new design method for lithography mask was proposed, which is named “Phase-shifting Scattering Bar”, and it shows better performance in 1D chain array patterns than those with traditional scattering bars. However, for even tinier patterns, it is quite difficult to put these scattering bars on mask. Hence, another special design named “Interlaced Phase-shifting Mask” was proposed to handle such tiny dense patterns. In this design, main patterns are also the scattering bars for adjacent patterns. Hence, there is no need for additional tiny scattering bars, and the mask making requirement can be also relaxed. Both of these two mask design are useful tools to trim and modify light intensity profile on wafer. The image contrast was largely enhanced which means a better resolution and a larger process window can be gained without the cost of new illumination equipments.
© (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kwei-Tin Yeh and Chao-Yi Huang "Two new design methods for lithography mask: phase-shifting scattering bar and interlaced phase-shifting mask", Proc. SPIE 9256, Photomask and Next-Generation Lithography Mask Technology XXI, 92560W (28 July 2014); https://doi.org/10.1117/12.2065207
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Scattering

Light scattering

Photomasks

Phase shifts

Mask making

Lithography

Immersion lithography

Back to Top