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

Takafumi Fukushima, Yuki Susumago, Zhengyang Qian, Chidai Shima, Bang Du, Noriyuki Takahashi, Shuta Nagata, Tomo Odashima, Hisashi Kino, Tetsu Tanaka

Research output: Contribution to journalArticlepeer-review

Abstract

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 module as a part of flexible hybrid electronics (FHE) is integrated with \mu LED ( 270\,\,\mu \text{m}\,\,\times 270\,\,\mu \text{m} ) 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 \mu LED before and after die embedment in the PDMS is characterized.

Original languageEnglish
Article number9143172
Pages (from-to)1419-1422
Number of pages4
JournalIEEE Transactions on Components, Packaging and Manufacturing Technology
Volume10
Issue number8
DOIs
Publication statusPublished - 2020 Aug

Keywords

  • Biosensor
  • die shift
  • fan-out wafer-level packaging (FOWLP)
  • flexible hybrid electronics (FHE)
  • micro-LED
  • polydimethylsiloxane (PDMS)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

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