Numerical Investigations on Requirements for BARC Materials for Hyper NA Immersion Lithography

Matsuzawa, Nobuyuki; Watanabe, Yoko; Thuunakart, Boontarika; Ozawa, Ken; Yamaguchi, Yuko; Ikeda, Rikio; Kawahira, Hiroichi

doi:10.2494/photopolymer.18.587

Cited by 2 publications

(4 citation statements)

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“…For the optimizations of BARC parameters, we have already shown that there is essentially no dependence of optimized values on the presence or absence of top-coat layer and the thickness of photoresist layer 11 . For example, for the case of optimizations of BARC parameters on silicon substrate, variation of optimized complex index of refraction and thickness at various photoresist thicknesses (10 -300 nm) was less than 1.5 % and 3 %, respectively, meaning that the optimizations of BARC parameters can be done independently from the thickness of photoresist layer.…”

Section: Calculationsmentioning

confidence: 97%

“…Figure 1 and 2 show some selected results of this optimizations, where only the results with the thickness of the silicon oxide and nitride layer being 50 nm, 100 nm, 150 nm and 200 nm are shown. For the purpose of comparison, we also show in Figure 1 and 2 the results of the optimizations on a silicon substrate that we reported previously 11 .…”

Section: Optimizations Of Dual-barc Parametersmentioning

confidence: 98%

“…Thickness of top-coat layer was shown to affect the optimizations even less; variation of optimized complex index of refraction and thickness of BARC layer was less than 0.5 % and 0.6 %, respectively. 11 Thus, all optimizations described below are performed at a fixed thickness of photoresist layer (100 nm) without the presence of top-coat layer. The refractive index of the photoresist layer is set to be 1.70.…”

Section: Calculationsmentioning

confidence: 99%

“…We have also performed an estimation of the requirement on substrate reflectance for the contact-hole fabrication for the 45-nm technology node. The results of the dual-BARC optimizations were analyzed in line with the requirement on substrate reflectance, from which we obtained margins of dual-BARC parameters, such as allowed variation of thickness and refractive index, which assure the substrate reflectance to become lower than the required value 11 . This work showed that in case if NA < 1.2, organic dual-BARC structures will work, whereas if NA > 1.2, novel materials whose refractive index exceeds 2.0 may become required.…”

Section: Introductionmentioning

confidence: 99%

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Optimization of dual BARC structures for hyper-NA immersion lithography

et al. 2006

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For the purpose of finding feasible dual-BARC (Bottom Anti-Reflective Coating) parameters for immersion lithography that do not depend on the polarization of light, illumination conditions and pattern sizes and pitches, comprehensive optimizations of the dual-BARC parameters were performed. A computational code was developed that performs automatic and comprehensive optimizations of dual-BARC parameters under any kind of conditions. Margins of dual-BARC parameters, which assure the substrate reflectance to be lower than a desired value, were also estimated by using the code. Dual-BARC parameters to minimize the substrate reflectance were successfully obtained for the BARC formed on a silicon oxide and nitride layer for cases of NA being 1.0, 1.1, 1.2 and 1.3 to 1.4. The thickness of the silicon oxide and nitride layer was varied from 10 to 200 nm. It was found that the dual-BARC concept works up to NA = 1.1 and 1.4 for the BARC on a silicon oxide and a silicon nitride layer, respectively, although for the case of the dual BARC on a silicon oxide layer, the range of the thickness of the oxide layer where the dual-BARC concept works is limited. In addition, for both of the cases of the dual BARC on silicon oxide and nitride, it was calculated that the top-layer of the dual BARC has to be extremely thin. Feasibility of using a layer structure consisting of a planarization and hardmask layer as a reflection-control structure was also examined. This showed that this concept can work up to NA = 1.2 and 1.4 for the case on silicon oxide and nitride, respectively. Finally, a routine to optimize graded-BARC structure was successfully implemented into our computational code. By using the routine, advantages of the graded-BARC concept over the dual-BARC concept in terms of suppressing substrate reflectance were demonstrated.

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Section: Calculationsmentioning

confidence: 97%

Section: Optimizations Of Dual-barc Parametersmentioning

confidence: 98%

Section: Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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