BSAC MEMS Testing
BSAC MEMS Testing
Advanced testing methods for the dynamics of microdevices are necessary to develop reliable, marketable microelectromechanical systems (MEMS). The main purpose for MEMS testing is to provide feedback to the design-and-simulation process in an engineering development effort. This feedback should include device behavior, system parameters, and material properties. An essential part of a more effective microdevice development is high-speed visualization of the dynamics of MEMS structures. BSAC Professor Richard S. Muller and his team consisting of Christian Rembe and Rishi Kant have a forefront project to install a laboratory for measurements and observations of dynamic behavior of microstructures in MEMS. Ultimately, we will connect the measuring equipment to a new high-speed Internet (SuperNet), which will make our test facilities accessible remote from Berkeley. The SuperNet testbed is supported by DARPA’s Next-Generation-Internet program. The goals of this program (Matisse) are: (1) The development of advanced technologies that enable up to 10Gigabit-per-second streams between end systems over a shared, wide-area infrastructure; (2) the development of automated-network monitoring and a network management and planning tool. The Matisse project will extend the capabilities of the BSAC-optical-characterization facilities for dynamic and static behavior of MEMS to users across the country through their use of the new Gbit/s SuperNet in a "Virtual-Laboratory" environment with SuperNet connection to advanced MEMS CAD and Simulation tools (see Figure 1).
BSAC has three optical test facilities available for MEMS characterization.
The first system, developed at BSAC, is a computer-controlled, phase-shifting, microscopic, stroboscopic interferometer for high-resolution deflection measurements with very precise spatial resolution. This system can measure full three-dimensional motions and deflections of microdevice surfaces with nm accuracy. Periodic or repeated transient processes can be studied at frequencies as high as 1MHz.
In addition a commercial Laser Doppler Vibrometer (Polytec PI) is available to measure motions at one point on a micro device. On this one point the Vibrometer is able to measure either single transient motions or frequency responses of the samples. Therefore, synchronization between the input signal and Vibrometer is not necessary and broad-bandwidth (0.5Hz-1.5MHz) noise characteristics in mechanical devices can be investigated.
A third measurement tool is the Micro-Computer-Vision System developed at MIT. The MIT system is especially designed to extract in-plane motions with subpixel resolution. Through an out-of-focus measurement technique it is also possible to extract out-of-plane motions. The MIT system can measure periodic events and can extract frequency responses.
A
commercial white-light interferometer (Veeco
Instruments) for accurate static profiling is also available. Click here
to see the different features of the BSAC MEMS testing systems.
The connection of the BSAC MEMS test facilities to the SuperNet is a major goal of present work. Thus far, we have developed a Java-based network client and a network protocol to use as the interface to the new global high-speed network (SuperNet). In the next six months we plan to develop a C++ network-server program to automate the interferometer system. When these two programs are in operation, we will make our setup accessible from outside (see Figure 2). In addition we will use the SuperNet to save interferometer images on the Distributed, Parallel-Storage System (DPSS) developed and placed at LBNL (Berkeley). We will use the ftp protocol to transfer the images. The structure of the planned networked interferometer is shown in Figure 2. Our image-evaluation software has been developed in MATLABŪ. We plan to develop a C++-based, networked, stand-alone application of this software. The evaluation will be performed on the computational engines at Sarnoff (Princeton). We plan to demonstrate a "Virtual Laboratory" environment for the stroboscopic interferometer within a year.
Figure 1: Logic Arrangement of MEMS Facilities connected through the SuperNet.
Figure 2: Schematic of networked Microscopic Stroboscopic Interferometer System.