Mechanical and Electrical Characterization of FOWLP-Based Flexible Hybrid Electronics (FHE) for Biomedical Sensor Application

Susumago, Yuki; Zhou, Qian; Jacquemond, Achille; Takahashi, Noriyuki; Kino, Hisashi; Tanaka, Tetsu; Fukushima, T.

doi:10.1109/ectc.2019.00046

Cited by 7 publications

(1 citation statement)

References 14 publications

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“…We have previously suggested the SBL contributes to high bendability because the SBL can mitigate wire stresses derived from the thermal and mechanical rapid/large deformation of the PDMS elastomer. Therefore, SBLs having a relatively hard Young's modulus ranging from 2 to 3 GPa exhibit higher toughness than that having a lower Young's modulus below 1 GPa [20]. Here, the spin-on hard polyurethane NPR-90/305B (2.3 GPa) is employed as a planarization layer to compensate the die protrusion of within 5 μm in addition to the Parylene-C (2.9 GPa) SBL layer.…”

Section: B Bendabilitymentioning

confidence: 99%

Significant Die-Shift Reduction and μLED Integration Based on Die-First Fan-Out Wafer-Level Packaging for Flexible Hybrid Electronics

Fukushima

Susumago

Zhou

et al. 2020

IEEE Trans. Compon., Packag. Manufact. Technol.

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Typical die shift is beyond several tens micrometers or more, which is a serious problem on advanced fan-out wafer-level packaging (FOWLP), to give inevitable misalignment errors in the subsequent photolithography processes for fine-pitch redistributed wiring layer (RDL) formation. In particular, this problem is expected to grow all the more serious in chiplets and tiny dies less than 1 mm in a side. In this work, the use of an anchoring layer is proposed to fix these dies/chiplets on a double-side laminate thermo release tape and drastically reduce the die shift. In addition, an on-nail photoplethysmogram (PPG) sensor system as a flexible hybrid electronics (FHE) is integrated with μLED (270 μm by 270 μm) based on a die-first FOWLP methodology using a biocompatible polydimethylsiloxane (PDMS) mold resin for real-time monitoring pulse wave and percutaneous oxygen saturation (SpO2). The repeated bendability of fan-out Au wirings formed on the PDMS and the current-voltage (I-V) behavior of the μLED before and after die embedment in the PDMS is characterized.

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Section: B Bendabilitymentioning

confidence: 99%