Patterning 80-nm gates using 248-nm lithography: an approach for 0.13-μm VLSI manufacturing

Etch rate control in a 27 MHz reactive ion etching system for ultralarge scale integrated circuit processing Current semiconductor technology requires optical lithography to image feature sizes smaller than the exposure tool wavelength. In order to achieve this subwavelength imaging, some form of optical resolution-enhancement technology is required, with phase-shift methods offering the greatest potential enhancement. Major impediments to the wide-scale adoption of this technology have included mask cost, inspectability/repair, and turnaround time. The correction of optical proximity effects, which are typically large in phase-shift techniques, have also been an important issue. In this work, we propose a new type of phase-shift approach utilizing gratings of regular arrays and trim exposures. This method makes use of multiple-exposure phase-shift imaging of dense-only features. Proximity effects can be nearly eliminated along with the complex optical proximity corrections typically required on the mask. The simple phase-shift masters can also be reused for multiple designs, thereby addressing cost and turnaround time issues.

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Optical imaging properties of dense phase shift feature patterns

Fritze

Tyrrell

Mallen

et al. 2002

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Articles you may be interested inSpatial shaping for generating arbitrary optical dipole traps for ultracold degenerate gases Rev. Sci. Instrum. 85, 103106 (2014); 10.1063/1.4895676 Reducing the pattern redundancy in optical proximity correction modeling by analyzing the pattern linearity Optical lithography resolution enhancement methods are continuing to develop, driven by the semiconductor industry's requirements for imaging subwavelength feature sizes. In the phase shift area, pattern decomposition into multiple exposures has been found to be useful and is finding its way into production. Recently, layout construction based on dense fine-pattern imaging has received increasing interest. This type of approach can minimize the proximity and other spatial frequency effects that otherwise limit strong phase shift technologies. Simple fine-feature template masks are easier and cheaper to fabricate and inspect as well as offering the potential to be reused for multiple designs. In this article, imaging and process issues specific to dense phase shift patterns are explored both experimentally and through simulation. Progress is reported in applying our gratings of regular arrays and trim exposures for ultralarge scale integrated circuit lithography ͑GRATEFUL͒ imaging method to fine features in both x and y orientations. The use of a graytone trim mask to vary fine-feature dimensions in a dual-exposure, strong phase shift process has been explored. We have also studied multiple-exposure lithography using one mask and varying illumination between exposures.

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Patterning 80-nm gates using 248-nm lithography: an approach for 0.13-μm VLSI manufacturing

Cited by 5 publications

References 6 publications

Enhanced resolution for future fabrication

Enhanced resolution for future fabrication

Gratings of regular arrays and trim exposures for ultralarge scale integrated circuit phase-shift lithography

Optical imaging properties of dense phase shift feature patterns

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