Fast, flexible microprocessor adds computation to thin-film technology
At the 2022 International Solid-State Circuits Conference (2022 ISSCC), imec, KU Leuven, and PragmatIC Semiconductor unveiled an 0.8 micron metal oxide flexible technology, claiming it is the fastest 8-bit microprocessor capable of running real-time complex assembly code. The microprocessor was implemented with a digital design flow that allowed the creation of a new standard cell library for metal-oxide thin film technologies for designing a range of loT applications. PragmatIC Semiconductor is imec’s foundry partner and its thin-film technology was used to integrate the approximately 16,000 metal-oxide thin film transistors on a 24.9mm2 flexible chip.
Flexible electronics based on thin-film transistor technology is already being used in healthcare patch sensors, RFID labels and panel displays. This flexible microprocessor can perform more complex signal processing calculations, adding compute functionality to a range of IoT applications, explained imec.
The research centre has designed the flexible 8-bit microprocessor in 0.8 micron indium-gallium-zinc-oxide (IGZO) transistor technology. Kris Myny, principal scientist at imec, said: “Our flexible microprocessor shows excellent characteristics for IoT applications, including high speed (71.4kHz max operating speed), low power consumption (11.6mW when running at 10kHz, 134.9mW at max operating speed), and high transistor integration density.
“Metal-oxide thin-film transistors based on IGZO are inherently n-type. This results in circuits with a higher (static) power consumption compared to complementary technologies. To address this, we created our own design flow starting from the open-source file of the MOS6502 microprocessor . . . . We engineered the number of cells and logic gates to obtain the most optimal design for our flexible 6502 microprocessor in terms of area, power, and speed – using pseudo-CMOS as our logic family,” he explained.
The design flow allowed imec to create a new standard cell library for metal-oxide thin-film technology that can be used to innovate applications based on metal-oxide thin-film technology.
Foundry partner, PragmatIC’s FlexLogIC fab was used to integrate the large number of thin-film transistors with sufficient yield.