Precision OEM Sensors for High Resolution Measurement Applications - MTI Instruments - #1

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MTI Instruments, Inc. 325 Washington Avenue Extension Albany, NY 12205 PH: +1-518-218-2550 OR USA TOLL FREE: 1-800-342-2203 FX: +1-518-218-2506 sales@mtiinstruments.com www.mtiinstruments.com APPLICATION NOTE Precision OEM Sensors for High Resolution Measurement Applications Introduction Capacitance based measurement probes have long been employed for high precision non-contact measurement. The ability to customize the probe/amplifi er confi guration makes them a popular choice for measurement applications demanding maximum accuracy and repeatability. One specifi c area where capacitance systems excel is high resolution focusing of complex lens systems, such as those found in atomic force microscopes, vision inspection machines and photolithography tools. The Problem In a multi-million dollar photolithography tool, high accuracy, nanometer resolution and maximum thermal stability are absolutely critical to maintain proper focus and obtain integrated circuit line widths as small as 45 nanometers. Additionally, most systems demand low power consumption and maximum heat dissipation to eliminate any adverse affects from temperature gradients. The Solution A leading supplier of photolithography equipment contracted MTII to develop a custom OEM measurement sensor for active feedback control in the lens systems for their latest generation tools. Working closely with our customer’s engineers, MTII’s Application and Design team developed a multi-channel, capacitance based solution featuring a measurement accuracy of 3 nanometers and astonishing resolution of less than 1 nanometer. MTII designed the probe amplifi er for direct integration into the customer’s control system utilizing the existing power supply and system bus. Special design consideration was given to thermal stability and long term electronic drift to provide years of fault free operation in a production environment. The Results After extensive laboratory testing, prototype units were provided within 3 months of product concept for additional testing in an actual production environment. The results were immediate. Based on customer feedback, the sensors were not only integrated into new tools, but were also incorporated as part of a fi eld-wide upgrade program to increase the capabilities of existing tools. Building on the experience gained in supplying measurement solutions for next generation photolithography equipment, MTII has expanded its presence in similar applications involving complex lens focusing systems. MTII appnote: oemcapacitance.pdf - Page 1 of 1