Raymond Ka Hui

59456051, Aug 31, 1999

Nov 19, 1997

8/974005

Francis S. Julian - San Jose CA
Raymond P. Hui - San Jose CA
James H. Hoffman - Santa Clara CA
Christos D. Cartsonas - Menlo Park CA

SenSym, Inc. - Milpitas CA

G01L 904
G01L 906

73727

A non-invasive sensor assembly device includes a pedestal mounted sensor die for stress isolation of the sensor die from external stresses, a substrate and die porting configuration to limit exposure of the sensor assembly to only the interior of the sensor die and a connecting tube to provide significant isolation of the sensor assembly and its constituent parts from the fluid stream, and an inert coating conformally deposited on the inside surfaces of the die, pedestal, and connecting tube that are in contact with the fluid media to thereby provide complete isolation of the sensor assembly from the media. The pedestal is fabricated on the substrate by screening multiple layers of conductive ink on the substrate, flashing off the solvents, and firing the substrate to burn off the binders to provide a boss of sufficient height such that the sensor die, once mounted on the boss, is substantially isolated from the substrate and, therefore, from included stresses that might otherwise have been transferred to the die from the substrate. The contact area of the boss with the die is optimally selected to provide maximum stress isolation and sufficient mounting strength. A through hole in the substrate and through the longitudinal center of the boss is in cooperative coaxial alignment with a fluid entry port in the die to permit measurement of the physical characteristic of interest within the interior of the die.