Optimisation of industrial production of low-force sensors - adhesive bonding of force-centring ball

39th International Microelectronics and Packaging IMAPS Poland 2015 Conference

无线电电子学

Maeder, T.^1 ; Jacq, C.^1 ; Blot, M.^1 ; Ryser, P.^1

Laboratoire de Production Microtechnique (LPM), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne

CH-1015, Switzerland^1

关键词: Adhesive bonding;    Adhesive materials;    Capillary force;    Cleaning process;    Industrial production;    Piezo-resistive;    Soldering process;    Wheatstone bridges;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/104/1/012006/pdf
DOI  :  10.1088/1757-899X/104/1/012006

来源: IOP

【 摘 要 】

This work addresses the issue of attaching the force-centring part (a round ball) to the load cell of a force sensor, a piezoresistive thick-film Wheatstone bridge deposited onto a ceramic cantilever. As the current soldering process requires expensive metallisation steps for both the ball and the cantilever, and subjects the solder pads used for mounting the cantilever to an additional reflow cycle, an alternative adhesive bonding process was developed, allowing both simpler production and the use of other ball materials such as ceramic and glass. The selfcentring action of solder capillary forces was ensured by structuring the adhesive so as to form a mechanical cuvette allowing centring of the ball by gravity. The selected adhesive materials exhibited good printability and bonding, as well as surviving the subsequent soldering and cleaning process steps.