New packaging concept for ultra high precision 3D tactile probes for CMM applications

True three dimensional (3D) measurements of micro and nano structures are becoming vital due to the increase in micro mechanical and optical devices used in today´s technologies. Measurements with resolutions less than 100 nm in industry and less than 20 nm in national metrology institutes are desired today. In order to achieve this goal we have developed an ultra high precision tactile probe for micro/nano-coordinate measuring machines (CMMs) [1]. The first stage of the development of the silicon based CMM micro probe has been reported earlier [2, 3]. The probe consists of a compliant silicon micro structure with piezo-resistive elements as readout technique. This paper reports on the optimization of the packaging of the silicon sensing element. Starting with the initial design of the packaging where the chip was contacted and mounted directly through probing pins a first optimization is presented where the chip is mounted to a printed circuit board (PCB) carrier and contacted electrically through wire bonding. By replacing the PCB with a ceramic substrate the performance of the micro probe could be enhanced further. Measuring results are presented demonstrating the progress of this optimization process.