Paper
1 April 2008 Integration of high-speed surface-channel charge coupled devices into an SOI CMOS process using strong phase shift lithography
Jeffrey Knecht, Vladimir Bolkhovsky, Jay Sage, Brian Tyrrell, Bruce Wheeler, Charles Wynn
Author Affiliations +
Abstract
To enable development of novel signal processing circuits, a high-speed surface-channel charge coupled device (CCD) process has been co-integrated with the Lincoln Laboratory 180-nm RF fully depleted silicon-on-insulator (FDSOI) CMOS technology. The CCDs support charge transfer clock speeds in excess of 1 GHz while maintaining high charge transfer efficiency (CTE). Both the CCD and CMOS gates are formed using a single-poly process, with CCD gates isolated by a narrow phase-shift-defined gap. CTE is strongly dependent on tight control of the gap critical dimension (CD). In this paper we review the tradeoffs encountered in the co-integration of the CCD and CMOS technologies. The effect of partial coherence on gap resolution and pattern fidelity is discussed. The impact of asymmetric bias due to phase error and phase shift mask (PSM) sidewall effects is presented, along with adopted mitigation strategies. Issues relating to CMOS pattern fidelity and CD control in the double patterning process are also discussed. Since some signal processing CCD structures involve two-dimensional transfer paths, many required geometries present phase compliance and trim engineering challenges. Approaches for implementing non-compliant geometries, such as T shapes, are described, and the impact of various techniques on electrical performance is discussed.
© (2008) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jeffrey Knecht, Vladimir Bolkhovsky, Jay Sage, Brian Tyrrell, Bruce Wheeler, and Charles Wynn "Integration of high-speed surface-channel charge coupled devices into an SOI CMOS process using strong phase shift lithography", Proc. SPIE 6924, Optical Microlithography XXI, 69244R (1 April 2008); https://doi.org/10.1117/12.777133
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KEYWORDS
Charge-coupled devices

Photomasks

Phase shifts

Lithography

Signal processing

Etching

CMOS technology

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