Bosch Drie Shaping Mems - History, Applications and Future Directions

Abstract

Deep Reactive Ion Etching (DRIE) is virtually shaping the MEMS-field. The basic technology originally developed at Bosch is free from the design restrictions and compatibility problems related to the old wet-etching technology which was based on potassium hydroxide (KOH-) solution. The technology has enabled a wide range of new devices like the inertial sensors for acceleration and yaw rate detection, pressure sensors for mid-to high-pressure applications, MEMS microphones, micro-mirrors and quite recently also timing devices fabricated in silicon. These products conquered both the automotive application area, and later on also the consumer field. From the surface-near micromachining of the early development stages, DRIE is nowadays heading towards a true 3D-microstructuring. Pressure sensors, microphones and micromirrors represent first examples of this trend, but also packaging applications like DRIE-structured silicon caps, functionalized silicon carrier substrates for intelligent systems-inpackage, and through-silicon vias (TSV's) for chip-stacking and new chip-integration concepts are receiving increasing attention.This paper leads from the early development phase targeting first high-volume products, to the development of advanced highrate etching solutions targeting today's new and challenging product families.

Mechanics of Out-of-Plane MEMS via Postbuckling: Model-Experiment Demonstration Using CMOS

“…In this paper, the material properties were provided by the foundry, while high-resolution profilometry (Zygo, [31]) and scanning electron micrograph (SEM) imaging were used to characterize the elements' geometry (see hereinafter and the Appendix). Equation (8) is plotted in Fig. 3, where we show a two-parameter (σ mean and K) stress-deflection curve for a polysilicon/dielectric layered bridge (L = 400 μm × b = 40 μm × h = 2.91 μm, E = 169 GPa, and σ grad = +40 MPa).…”

“…As a consequence, most MEMS devices are still composed of planar 2-D structures and are therefore intrinsically limited in their ability to provide 3-D sensing and actuation capabilities. This has resulted in highly tailored solutions where multiple MEMS units with different detection modes and sensitivity axis are combined (e.g., via packaging) to allow multiaxial functionalities [8], [9], hence increasing device complexity and overall cost. In an effort to overcome these limitations, some fabrication techniques have been recently developed that allow to achieve nontrivial height in MEMS.…”

Characterization and Production Control for Drie of Mems Accelerometers Using Optical Displacement Transducer Measurements

“…The invention and widespread use of Bosch DRIE processing has facilitated a dramatic increase in the number, type and success of MEMS devices being fabricated [1]. The very deep, high aspect ratio features created using this etch process allow the manufacture of the various sensors, actuators and resonators critical to the MEMS industry.…”