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Product Briefing Outline: Litel Instruments, has released of two new products designed to increase silicon chip performance and yield in leading edge semiconductor factories. The new products, dubbed ‘Distortion Mapper' (DMAP) and ‘Transmission Mapper' (TMAP), are used for analyzing and optimizing lens and illumination performance of photolithography tools.

Problem: As feature sizes get smaller, aberration caused malfunction is getting more important and should be considered for correct use of lens. Accurate lens aberration measurements are needed to predict patterning characteristics of critical layer of a device at given lens and to decide whether the lens is usable for the IC device. Unlike other techniques in the market, DMAP allows the customer to independently measure lens distortion and scan sync errors and provide customers with the necessary corrections which will attribute to overlay improvement programs demanded by chip manufacturers. TMAP has the ability to measure and correct unbalanced N.A. values among multiple scanners in manufacturing, thus reducing CD impacts, as well as measuring and monitoring lens transmission over time.


Solution: DMAP provides lithography engineers with the ability to analysis and correct photolithography tool subsystems, including the precision mechanics responsible for maintaining position control of the silicon wafer. Unlike other techniques in the market, DMAP allows the customer to independently measure lens distortion and scan sync errors, and provide customers with the necessary corrections which will attribute to overlay improvement programs demanded by chip manufacturers. TMAP will allow customers to measure the accuracy of the Numerical Aperture of the lens, and the ability to measure the lens to uniformly transmit light from the light source to the silicon wafer. This information is essential measuring error sources in 65 nm and smaller semiconductor devices. TMAP has the ability to measure and correct unbalanced N.A. values among multiple scanners in manufacturing, thus reducing CD impacts, as well as measuring and monitoring lens transmission over time.


Applications: All lithography tools (ASML,Canon, Nikon)

Platform: All Litel products operate with standard resist coated wafers. The wafer is exposed with the Litel interferometer on the lithography tool to be evaluated. The interferometer is handled by the reticle handling system in the same way as a standard reticle. Exposure time is typically just a few minutes, and only one wafer is needed. No special photoresist or developing processes are required for the wafer. Litel software provides a full analysis of the lithography tool's optical properties. Analysis time is a few minutes only

Availability: July 2006 onwards.