Heterogenous Integration of MEMS Gas Sensor using FOWLP : Personal Environment Monitors

• Main Authors: Benedict, Samatha, Nagarajan, Ashvin, K, Thejas, Alam, Arsalan, Illango, Murugaiya Sridar, Ezhilarasu, Goutham, Prajapati, Chandra Shekhar, Bhat, Navakanta, Iyer, Subramanian
• Format: Conference Proceeding
• Language: English
• Subjects: FlexTrate; FOWLP; Gas detectors; Heating systems; MEMS sensor; Metals; Micromechanical devices; Monitoring; Temperature sensors
• ISSN: 2377-5726
• DOI: 10.1109/ECTC32862.2020.00134

The exponentially increasing global population has led to environmental pollution which drastically affects human health; emphasizing the need for personal environmental monitoring. This demands the development of wearable devices capable of sensing the local environment and wirelessly transmitting data to cloud for spatial pollution tracking.In this paper, we have demonstrated the integration of MEMS gas sensors on flexible PDMS substrate using the fan out wafer packaging technique called FlexTrate™. One of the main issues in FOWLP involving the integration of MEMS sensors with a released membrane is the stability of the membrane during the molding process which results in poor yield. We have optimized the process for integrating released MEMS devices by protecting the membrane prior to the molding process and thus improving the stability of the released membranes and improving the yield by >80%. If the membrane is not protected, during curing the cavity which is filled by PDMS leads to membrane cracking due to generation of stresses. Simulation studies on the temperature profile of the microheater after protecting the membrane shows that the power consumption for 300 o C of heater temperature is 0.1W as compared to 0.091W where the PDMS fills the cavity of the membrane, which is