Devon Kinkead

Real-time methodologies for monitoring airborne molecular contamination in modern DUV photolithography facilities

In this paper, the authors discuss the critical airborne molecular contaminants found in DUV photolithography facilities. They present an overview of real-time monitoring methodologies that can detect and measure these contaminants at low concentrations, enabling users to anticipate and resolve AMC challenges before production problems can result. Citing actual examples of how real-time monitoring is being employe din production fabs, the authors examine single point investigate and multi-point process monitoring strategies, compare the different monitoring strategies, compare the different monitoring technologies now is use, and describe critical points to monitor in tracks, steppers, clean rooms, and air filtration systems. As a separate item, the authors describe an innovative, practical approach to quantifying resist environment sensitivity. It is anticipated this work will result in a standard methodology that can be used at individual process sites to determine the resist sensitivity to airborne molecular contamination under local operating conditions.

Prevention of optics and resist contamination in 300-mm lithography: improvements in chemical air filtration

Atmospheric pressure deep UV lithography using fast chemically amplified photoresists will be the mainstay of semiconductor production into the foreseeable future. Airborne molecular contamination (AMC) in the form of bases and condensable organic and inorganic materials however, threaten both sensitive optics and modern resists thereby creating a host of yield limiting contamination issues. Past work by Kunz at MIT has described photo-induced organic contamination of lithographic optics as a significant concern in leading-edge lithography. Moreover, Kinkead and Ercken, and Kishkovich and Dean have published work on the impact of base contamination on CD uniformity in modern photoresists. Herein, the authors discuss solutions to control both optics and resist contamination in a single compact filter system for advanced lithography. The results of this work suggest that resist and optics contamination can be controlled as we enter the era of low K1 factor <150nm/300mm-device production.

Real-time amine monitoring and its correlation to critical dimension control of chemically amplified resists for sub-0.25-μm geometries

One such issue is the quantitative control of critical dimension (CD) and how to calibrate fab contamination levels to linewidth control. Since most fabs build several generations of devices, contamination levels for older generations may not be suitable for new generations. Therefore, studies to control CD for each generation are required to determine the effectiveness of filtration schemes. In this paper the authors have investigated CD control for imaging dimensions from 0.25 micrometers to 0.15 micrometers . We have also correlated this data back to chemical monitoring levels to determine CD vs. PED stability for these geometrys to determine the contamination level tolerance. Additionally, the authors have generated process windows to determine the effect such delays have on process windows.