Implementation of KrF DBARCs for implant applications on advanced lithography nodes

Lowes, Joyce; Guerrero, Alice; Weigand, Michael; Washburn, Carlton; Stroud, Charlyn; Sharma, Shalini; Torres, David; Slezak, Mark; Dabbagh, G.; Tang, Cherry

doi:10.1117/12.879464

Cited by 1 publication

(1 citation statement)

References 10 publications

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“…The studies of CD variation of pre-gate implant layers have been experimentally demonstrated [5,6,8] and simulated [7,9,10].The control and optimization of PR profile of post-gate LDD layers, especially in the SRAM area, are demonstrated. Several factors of the implant lithography process that could impact the photoresist profile and the optimization of full-map CD uniformity are studied.…”

Section: Introductionmentioning

confidence: 99%

Studies of Photo Resist Profile Improvement in 28 nm Implanting Layer’s Lithography Process without BARC

Liu

et al. 2014

ECS Trans.

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For 28 nm node and below, implant layer patterning is becoming challenging with node shrinkage, due to decreasing critical dimension and usage of non-uniform reflective substrates without bottom anti-reflection coating (BARC). The ADI CD uniformity of a test feature is dramatically improved by adding BARC to reduce substrate reflection, nevertheless a prevalent LDD loop will not introduce BARC for the concern of cost and process complication reduction. The considerable bottom substrate reflectivity not only causes standing wave in photo resist but also introduces slight footing between the photo resist line and the substrate poly head if the substrate topography is rough (especially in the SRAM region). It is necessary to optimize the photo resist profile even under a very high bottom reflectivity. In this paper, several factors of the implant litho process that could impact the photo resist profile and line width roughness (LWR) are studied, and a comprehensive optimization based on these factors' splits test are defined and adopted in the 28 nm LDD loop litho process. Firstly we changed the mask CD to wafer CD bias and simultaneously modified the exposure dosage to meet the ADI target, which is based on our previous study that larger mask bias and over-dosage exposure will result in better photo resist profile. Secondly we studied the PR profile dependence on temperature of post exposure baking (PEB), we tried out the best temperature setting to improve photoresist footing. Thirdly we slightly shifted the focus offset during exposure away from the best focus defined by process FEM results, so that the photoresist profile is improved and meanwhile maintaining a large enough depth of focus for the process.

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Section: Introductionmentioning

confidence: 99%

Studies of Photo Resist Profile Improvement in 28 nm Implanting Layer’s Lithography Process without BARC

Liu

et al. 2014

ECS Trans.

View full text Add to dashboard Cite

show abstract

Implementation of KrF DBARCs for implant applications on advanced lithography nodes

Cited by 1 publication

References 10 publications

Studies of Photo Resist Profile Improvement in 28 nm Implanting Layer’s Lithography Process without BARC

Studies of Photo Resist Profile Improvement in 28 nm Implanting Layer’s Lithography Process without BARC

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