Phase shifting and optical proximity corrections to improve CD control on logic devices in manufacturing for sub 0.35 mu m I-Line

The use of I-Line Exposure Wavelength for manufacturing at and beyond 0.35 mu m presents many challenges in manufacturing. The lack of Resolution, Depth of Focus, Exposure latitude, and Iso/Dense offsets have caused some to switch from I-Line to DUV. With our installed I-Line base we felt it necessary to implement techniques to extend our tool life, reduce manufacturing costs while improving manufacturing margins. The results of the differential modification techniques were used to reduce the effects of topography, density, and low k lens issues. The differences seen between the binary and phase shift plates show the advantage of Phase shifting below 0.35 mu manufacturing. We have been able to demonstrate better Critical Dimension (CD) control using Phase Shift Mask with Dense Iso Compensation (PSMDIC) over a standard binary reticle. The data shows improved CD control across the stepper field, wafer, and overall lot distribution. The impact of this work was improved speed performance. It also allowed us to move the CD's to smaller dimension because of the better control without increasing fallout due to electrical parametric roll-off.