458 JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 21, NO. 2, APRIL 2012 Interchangeable Stage and Probe Mechanisms for Microscale Universal Mechanical Tester Joseph J. Brown, Member, IEEE, Dmitriy A. Dikin, Rodney S. Ruoff, and Victor M. Bright, Senior Member, IEEE, Fellow, ASME Abstract—A microfabricated mechanical test platform has been designed, fabricated, and operated. This system consists of a reusable chip capable of large-displacement actuation, which in- terfaces to a test coupon chip compatible with synthesis conditions for many nanomaterials. Because only normal forces are used for mechanical interfacing, the two chips are not permanently connected, allowing exchange of the test coupon chips. The ac- tuated test platform chip contains a thermal actuator driving a compliant displacement amplification transmission, and a bulk- micromachined well in which the test coupon chips may be placed and removed. The displacement amplification structure provides 40 μm of output displacement, extending a probe over the well and into contact with the test coupon. The test coupon contains compliant structures that are actuated by the probe from the test platform. [2011-0279] Index Terms—Assembly, compliant structure, interchangeable, microactuator, micromanipulator, universal mechanical tester. I. I NTRODUCTION T HIS PAPER reports the development and operation of a new micromechanical probe and stage system consisting of a reusable actuated test platform chip in combination with in- terchangeable test coupon chips capable of withstanding high- temperature nanomaterial synthesis conditions (Fig. 1). This design is intended as the basis for a microfabricated universal mechanical tester compatible with electron microscopes and other analytical tools for mechanical property cross-correlation experiments. Universal mechanical testers, also known as uni- versal testing machines, are commonly used for mechanical characterization of material specimens. These machines per- form tensile, compressive, and bending tests, depending on the Manuscript received September 19, 2011; revised October 20, 2011; accepted November 8, 2011. Date of publication December 27, 2011; date of current version April 4, 2012. This work was supported by the DARPA Center on Nanoscale Science and Technology for Integrated Micro/Nano- Electromechanical Transducers (iMINT) through the DARPA N/MEMS S&T Fundamentals Program (Award #HR0011-06-1-0048). The work of J. J. Brown was supported by a National Science Foundation Graduate Research Fellow- ship. Subject Editor R. T. Howe. J. J. Brown and V. M. Bright are with the Department of Mechanical Engineering and the DARPA Center on Nanoscale Science and Technology for Integrated Micro/Nano-Electromechanical Transducers (iMINT), Univer- sity of Colorado, Boulder, CO 80309-0427 USA (e-mail: joseph.j.brown@ colorado.edu; victor.bright@colorado.edu). D. A. Dikin is with the Department of Mechanical Engineering, Northwest- ern University, Evanston, IL 60208 USA (e-mail: d-dikin@northwestern.edu). R. S. Ruoff is with the Department of Mechanical Engineering, Univer- sity of Texas at Austin, Austin, TX 78712-0292 USA (e-mail: r.ruoff@mail. utexas.edu). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/JMEMS.2011.2177071 Fig. 1. UTP and test coupon dual-chip system. Interfacing between coupon and UTP was designed as a loose fit with 10 μm in-plane fit allowance. setup of test specimens. Such test machines generally consist of mechanisms for supporting and applying load to material specimens, and means of detecting the force and strain expe- rienced by the specimen. In order to serve as a component of a microscale universal mechanical tester, a micromechanical test stage, suspended from compliant flexures, was defined on a “test coupon” microchip. Actuation was achieved with a surface-micromachined probe on an additional chip that con- tacted the removable test coupon. The central motivation of this work was the development of microdevices for tensile testing, but this derived from a broader goal to demonstrate a flexible adaptable platform for miniatur- ization of laboratory instrumentation for experimentation with solid structures. The systems presented here were designed to be adapted and repurposed to additional applications. Mi- crosystems and nanosystems for analysis and manipulation of solid materials have produced many scientific and engineering advances [1]–[3], but more work is needed for these systems to develop impacts and uses comparable to those achieved by the 1057-7157/$26.00 © 2011 IEEE