Next-generation flexible systems have attracted much attention where vast amounts of data such as visual, auditory, behavioral, and emotional information are being collected in real-time. Silicon-based semiconductors have played significant roles of signal processing, nerve stimulation, memory storage, and wireless communication in implantable electronics. However, the rigid and bulky LSI chips have limited its uses in in vivo and flexible devices.
Human electronics systems realized by flexible memory devices enable data extraction, processing and analysis with low power consumption. We have developed silicon-based flexible large-scale integrated circuits (LSI) for bio-medical applications. We fabricated flexible LSI interconnected with thousand nano-transistors on silicon wafer by state-of-the-art 0.18 CMOS process, and then the entire bottom substrate except top 100 nm active circuit layer was removed by wet chemical etching. This work could provide an approach to flexible LSI for an ideal artificial retina system and other bio-medical devices. Also, the result represents an exciting technology with the strong potential to realize fully flexible consumer electronics such as application processor (AP) for mobile operating system, high-capacity memory, wireless communication in the near future.
The high performance inorganic electronics for human augmentation should be developed into form-factor free devices, which can be conformally attached on arbitrary 3D surfaces such as human skins, clothes, and curved regions. However, in contrast to the outstanding achievement in active device performance, there still remains some critical bottlenecks to develop the flexible packaging technologies with reliable electrical interconnections, mechanical stabilities, and uniform power distribution under bent state. Our group developed innovative flexible packaging method using anisotropic conductive film (ACF) as an elastic and resilient packaging medium, which formed a vertical current path between the active device and electrodes through a thermo-compressive bonding process. We introduced flexible GaAs micro light-emitting diodes (µLEDs) interconnected by ACF bonding process on a plastic substrate. Additionally, we demonstrated Si-based flexible NAND flash memory via roll-based ACF packaging technology, presented in International Electron Device Meetings (IEDM, 2015), which showed reliable interconnection characteristics in various stress conditions.
[Related References]
"ACF Packaged Flexible NAND Flash Memory" IEDM, Washington DC, 19.3, 1, 2015
"Simultaneous Roll Transfer and Interconnection of Flexible silicon NAND Flash Memory" Adv. Mater., 28, 8371, 2016
"Optogenetic Control of Body Movements via Flexible Vertical Light-Emitting Diodes on Brain Surface", Nano Energy, 44, 447, 2018
“A Flash-Induced Robust Cu Electrode on Glass Substrates and Its Application for Thin-Film μLEDs” Adv. Mater., 33, 2007186, 2021
Next-generation flexible systems have attracted much attention where vast amounts of data such as visual, auditory, behavioral, and emotional information are being collected in real-time. Silicon-based semiconductors have played significant roles of signal processing, nerve stimulation, memory storage, and wireless communication in implantable electronics. However, the rigid and bulky LSI chips have limited its uses in in vivo and flexible devices.
Human electronics systems realized by flexible memory devices enable data extraction, processing and analysis with low power consumption. We have developed silicon-based flexible large-scale integrated circuits (LSI) for bio-medical applications. We fabricated flexible LSI interconnected with thousand nano-transistors on silicon wafer by state-of-the-art 0.18 CMOS process, and then the entire bottom substrate except top 100 nm active circuit layer was removed by wet chemical etching. This work could provide an approach to flexible LSI for an ideal artificial retina system and other bio-medical devices. Also, the result represents an exciting technology with the strong potential to realize fully flexible consumer electronics such as application processor (AP) for mobile operating system, high-capacity memory, wireless communication in the near future.
The high performance inorganic electronics for human augmentation should be developed into form-factor free devices, which can be conformally attached on arbitrary 3D surfaces such as human skins, clothes, and curved regions. However, in contrast to the outstanding achievement in active device performance, there still remains some critical bottlenecks to develop the flexible packaging technologies with reliable electrical interconnections, mechanical stabilities, and uniform power distribution under bent state. Our group developed innovative flexible packaging method using anisotropic conductive film (ACF) as an elastic and resilient packaging medium, which formed a vertical current path between the active device and electrodes through a thermo-compressive bonding process. We introduced flexible GaAs micro light-emitting diodes (µLEDs) interconnected by ACF bonding process on a plastic substrate. Additionally, we demonstrated Si-based flexible NAND flash memory via roll-based ACF packaging technology, presented in International Electron Device Meetings (IEDM, 2015), which showed reliable interconnection characteristics in various stress conditions.
[Related References]
"ACF Packaged Flexible NAND Flash Memory" IEDM, Washington DC, 19.3, 1, 2015
"Simultaneous Roll Transfer and Interconnection of Flexible silicon NAND Flash Memory" Adv. Mater., 28, 8371, 2016
"Optogenetic Control of Body Movements via Flexible Vertical Light-Emitting Diodes on Brain Surface", Nano Energy, 44, 447, 2018
“A Flash-Induced Robust Cu Electrode on Glass Substrates and Its Application for Thin-Film μLEDs” Adv. Mater., 33, 2007186, 2021