Exploration of linear and non-linear double exposure techniques by simulation

Abstract

In this work, a framework for the assessment of different double exposure techniques is laid out. Both the simulation environment and the utilized models, derived from well-established resist models, are discussed. Numerous simulation results are evaluated to investigate strengths and weaknesses of different double exposure approaches. Non-linear superposition techniques are examined in respect of their process performance for both standard and sub 0.25 ktief1 values. In addition to a study of these effects in the scope of basic layouts, an application to interference-assisted lithography (IAL) is proposed and discussed

Revisiting the linear programming framework for leakage power vs. performance optimization

“…To mitigate the impact of this tapering effect on device performance, we can increase the poly line-end extension in the SRAM bitcell design, which may result in a somewhat larger bitcell size. Another way to reduce this line-end tapering effect is to implement IAL in a double pattern process, which is the subject of another paper at SPIE Advanced Lithography 2009 [17]. …”

Optimizing lithographic techniques with predictive modeling

“…To enhance this process, we designed a development and research lithography simulator (Dr.Litho). 4 We have also used lithography simulation to evaluate new patterning strategies and materials. Our simulation of different double-exposure and double-patterning strategies supported material development in the European MD3 project.…”

“…We compared different lithography options, including a standard single exposure, and interference assisted lithography in combination with various double-exposure and patterning options. 4 We also used simulation to explore the capabilities and limitations of extreme UV lithography.…”

Higher-Order Lithography: Double-Deprotected Chemically Amplified Photoresists (DD-CAMP)

“…Robert Bristol [3], among others [4,5], has proposed that higher-order responses to light by a photoresist system could provide a number of lithographic benefits by essentially squaring the information provided by the aerial image and thereby enabling double-exposure produced at relaxed pitches [3]. Fabrication of a CAMP photoresist exhibiting a higher-order mechanism would result in the distribution of carboxylic acid resembling a sine squared wave (Fig.…”