Abstract
An original packaging method suitable for integrated thermal mass flow sensors is presented. The method is based on a polymethyl-methacrylate (PMMA) adapter, used to convey the fluid flow to the chip areas where the sensing structures are located. Sealing of the adapter was obtained by heating the chip itself to the PMMA glass transition temperature, in order to soften the adapter front surface and improve adhesion. The proposed approach was applied to the packaging of thermal flow meters obtained by post-processing standard integrated circuits. The resulting compact devices have been characterized by measuring the response to a nitrogen flow. Fabrication and testing of a very compact flow sensor is described.
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Acknowledgments
This work was financed by the Fondazione Cassa di Risparmio di Pisa (Italy) and by the company Laben, Florence. The authors thank the STMicroelectronics of Cornaredo (Italy) for fabricating the chips.
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Bruschi, P., Nurra, V. & Piotto, M. A compact package for integrated silicon thermal gas flow meters. Microsyst Technol 14, 943–949 (2008). https://doi.org/10.1007/s00542-007-0490-2
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DOI: https://doi.org/10.1007/s00542-007-0490-2