11-Megapixel CMOS-Integrated SiGe Micromirror Arrays for High-End Applications

• Published in: Journal of microelectromechanical systems Vol. 19; no. 1; pp. 202 - 214
• Main Authors: Witvrouw, A., Haspeslagh, L., Pedreira, O.V., De Coster, J., De Wolf, I., Tilmans, H.A.C., Bearda, T., Schlatmann, B., van Bommel, M., de Nooijer, M.-C., Magnee, P.H.C., Lous, E.J., Hagting, M., Lauria, J., Vanneer, R., van Drieenhuizen, B.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Arrays; Circuit properties; Cleaning; CMOS integration; Dies; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Flatness; Germanium silicon alloys; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Integrated optics. Optical fibers and wave guides; Mechanical instruments, equipment and techniques; Microelectronic fabrication (materials and surfaces technology); Micromechanical devices and systems; micromirror; Micromirrors; Optical and optoelectronic circuits; Optical arrays; Optical device fabrication; Optical interferometry; Optical modulation; Packaging; Physics; reliable; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; SiGe; Silicon carbide; Silicon germanides; Silicon germanium; Testing; White light; Encapsulation; Integrated optics; Spatial modulator; Metal; Surface metrology; micromirror; Cutting; reliable; SiGe; Complementary MOS technology; Microelectromechanical device; Micromirrors; Mirror antenna; Optical modulator; Cleaning; Experimental study; Tilt angle; Light interferometers; Silicon carbide; Maskless lithography; Particle transport; CMOS integration; Nanotechnology; Pixel; Flatness
• ISSN: 1057-7157; 1941-0158
• DOI: 10.1109/JMEMS.2009.2036271

In this paper, we report on the design, fabrication, packaging, and testing of very reliable CMOS-integrated 10-cm 2 11-megapixel SiGe-based micromirror arrays on top of planarized six-level metal 0.18-¿m CMOS wafers. The array, which is to be used as a spatial light modulator (SLM) for optical maskless lithography, consists of 8 ¿m × 8 ¿m pixels, which can be individually addressed by an analog voltage to enable accurate tilt angle modulation. Due to very stringent requirements on mounted-die flatness (< 0.01 mrad), the first level packaging of SLM die is done using specially designed SiC holders. To avoid trapped particles between the die and holder, which would jeopardize the flatness spec, special backside cleaning of the dies (less than or equal to one 0.8-¿m particle/cm 2 ) is needed before mounting the SLM die on the holder. To enable this backside cleaning and to avoid front-side particles during dicing, handling, and wire bonding, a temporary waferor zero-level packaging cap, which can be placed and removed at room temperature, was developed. The dynamic white light interferometer measurements of packaged dies showed that 99.5% of the 123 648 mirrors tested are within the spec. In addition, a stable average cupping of below 7 nm, an rms roughness of below 1 nm, and a stable actuation of over 2.5 teracycles are demonstrated.