Characterization of Thin-Film Temperature Sensors and Ultra-Thin Chips for HySiF Integration

Hybrid System-in-Foil (HySiF) complements the merits of the very-large scale integration of silicon ICs with the largerarea electronics [1] , [2] . Both worlds/concepts are integrated on mechanically flexible substrates using, in our case, ChipFilm Patch technology (CFP) [3] . In this work, two CFP-compatible components, namely a temperature sensor and an ultra-thin microcontroller IC, are electrically and thermally characterized. The thin-film temperature sensor is fabricated using platinum metal resistor. The extracted temperature coefficient ranges from 2 m to 3 m (Ω/Ω)/°C depending on the substrate composition. In addition, the CMOS microcontroller IC is back-thinned to 30 μm using the dicing-before-grinding process sequence (DBG) [4] . The on-chip temperature sensor, 10-bit analog-to-digital converter (ADC) and RC oscillators are then characterized and compared to a reference design. The extracted ADC performance in terms of linearity remained within the datasheet specifications. A slight drop in the on-chip temperature sensor sensitivity from 3.6 to 3.5 mV/°C is observed. Finally a shift in the absolute frequency of the lowfrequency oscillator is detected, and the period jitter of the high-frequency oscillator degraded significantly.