Digital Platform for Wafer-Level MEMS Testing and Characterization Using Electrical Response

Abstract

The uniqueness of microelectromechanical system (MEMS) devices, with their multiphysics characteristics, presents some limitations to the borrowed test methods from traditional integrated circuits (IC) manufacturing. Although some improvements have been performed, this specific area still lags behind when compared to the design and manufacturing competencies developed over the last decades by the IC industry. A complete digital solution for fast testing and characterization of inertial sensors with built-in actuation mechanisms is presented in this paper, with a fast, full-wafer test as a leading ambition. The full electrical approach and flexibility of modern hardware design technologies allow a fast adaptation for other physical domains with minimum effort. The digital system encloses a processor and the tailored signal acquisition, processing, control, and actuation hardware control modules, capable of the structure position and response analysis when subjected to controlled actuation signals in real time. The hardware performance, together with the simplicity of the sequential programming on a processor, results in a flexible and powerful tool to evaluate the newest and fastest control algorithms. The system enables measurement of resonant frequency (Fr), quality factor (Q), and pull-in voltage (Vpi) within 1.5 s with repeatability better than 5 ppt (parts per thousand). A full-wafer with 420 devices under test (DUTs) has been evaluated detecting the faulty devices and providing important design specification feedback to the designers.

A New Non-Invasive Air-Based Actuator for Characterizing and Testing MEMS Devices

“…In previous studies [15][16][17][18][19][20][21][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41], the focus was on developing a specific handler for a specific domain for ATE parallel testing. However, in a situation of existing different domains such as electrostatic, piezoelectric, and piezoresistive, a methodology capable of handling all the domains are required.…”

“…By applying this equation to the abovementioned equations, the equation of motion will be derived. The outcome of such mathematical efforts is seen in Equations (20) and (21).…”

“…A sophisticated testing line has been established in Sandia National Laboratories (SHiMMeR-Sandia High-Volume Measurement of Micro-Machine Reliability), which is capable of simultaneous control and test of up to 256 MEMS devices, which is a lab test scale [19]. X-Ray Diffraction (XRD) has been adopted to test the creep of MEMS accelerometers, but is very slow in mass production [19,20]. These inefficient methods have motivated more studies in this imperative industry.…”

Mechanical Characterization of Polysilicon MEMS: A Hybrid TMCMC/POD-Kriging Approach

“…Such effect was shown in [ 23 , 30 ] to give rise to variations of the measured (effective) Young’s modulus of the microcantilever, on the order of ±5% with respect to the reference isotropic value [ 14 ]. Another uncertainty source is related to the patterning/etching stages of the production process, which do not provide a uniform geometry of the moving structure over the whole wafer (see, e.g., [ 12 ]). Accordingly, the overetch defect [ 32 ], which modifies the in-plane dimensions of the device components with respect to the target ones, needs to be considered too.…”

“…Geometrical uncertainties, namely variations of the fabricated device geometry away from the designed layout, strongly depend at this length-scale on the fabrication process tolerances (see e.g., [ 10 ]). For instance, in [ 11 , 12 ], flexure width variations up to 0.4 m and 0.7 m were respectively reported. Fabrication inaccuracies can then result in a 10% variation of the geometry of conventional MEMS [ 10 ], and can consequently spoil or compromise the target performance.…”