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The manufacturing process of planar microsprings by the UV-LIGA process was introduced; the mechanism of fabrication error was analyzed from three process stages of exposure, SU-8 swelling, and corrosion; and the corresponding improvement measures were proposed. The line width of two groups of microsprings after the exposure, SU-8 swelling, and debonding was measured, and the elastic coefficients in three coordinate directions were accurately measured. The results show that the factors that affect the line width error are stable. The effects of the exposure diffraction, swelling of SU-8 glue, and debonding corrosion process on the line width size follow the order: corrosion error > swelling error > exposure error. When the line width is small, the aspect ratio of the microspring is large, and the direction of machining error is generally negative. The relative error of the elastic coefficient of microsprings in three coordinate directions is larger. The influence rule of the line width error on the elastic coefficient follows the order: kerrory > kerrorx > kerrorz.

In this paper, a platform based on the composite-IC concept that is optimized for high-frequency (HF) applications will be presented. Surface-micromachined microsprings are used for temporary connection and testing. This provides the system with an individual compensation of different contact heights due to production tolerances. In addition, self-alignment structures have been added to compensate lateral tolerances. The presented self-alignment structures were designed to compensate rising precision requirements in contrary to commonly used placing machines. Key elements of the HF platform are coplanar waveguides and microsprings that are processed using microelectromechanical-system technologies on alumina ceramic. Microsprings with outer dimensions between 2000 and 125 μm with different beamwidths, beam thicknesses, and beam lengths were designed, simulated, and fabricated. All structures were tested mechanically and electrically. As a further development, spiral microsprings are presented. These combine minimal space requirement with no preferred orientation. Positioning in an individual array is possible. Due to the design and the integration of the spiral microsprings as part of the flip-chip connection, the scattering parameters show excellent HF performance up to frequencies of 9 GHz. The same microsprings could also be used for onboard testing on multichip modules (MCMs). This provides the MCM with cheap and powerful testability and reworkability. This paper covers the mechanical and electrical design, simulation, optimization, production, and characterization of suitable microsprings. [ABSTRACT FROM AUTHOR]