In-Line Optical Measurement of MicroElectroMechanical Systems (MEMS) Devices During Production

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

This grant provides for the development of a metrology tool to enhance quality assurance of micro-electro-mechanical systems (MEMS). The micro-interferometers developed will enable the high-speed geometric measurement of micro-geometries providing feedback as to the conformance of the micro-part geometry to target specifications. The sensors to be developed in this research are based on diffraction grating interferometry making them extremely accurate, reliable and fast. As the sensors are fabricated using MEMS technology, they can be inexpensively fabricated in the form of an array. Furthermore, electrostatic drives will be integrated into the sensor arrays along with electronics and logic for tuning individual sensors in the array. This will permit the generation of self-tuning, parallel sensors increasing the speed at which a group of MEMS parts can be measured with sub-nanometer resolution. Inspection results will be generated for several known geometries to validate the sensors. The micro-interferometer arrays, which provide three-dimensional information, will also be compared to current two-dimensional metrology systems used in IC fabrication as another means of determining their capabilities. If successful, the proposed work will enable the measurement of micro-components that are critical in micro-electro-mechanical systems (MEMS). To date, measurement of such devices has been slow and inaccurate at best. The new metrology capabilities will enable both an increased understanding of the quality level of such systems that will, in turn, permit the monitoring and enhancement of the processes that are used in fabricating such systems. Furthermore, the speed at which measurement can be taken with the proposed sensors will enable dynamic measurement of moving MEMS devices. This will permit the validation of not only the static geometry of the devices, but also the validation of the dynamic behavior of these devices.