Producing high quality full colour polymer OLED displays by inkjet printing requires accurate placement of ink droplets into predefined pixel well structures. Recent improvements in inkjet printer design have significantly increased the drop landing accuracy, making it possible to inkjet print higher resolution displays

Stainless steel substrates enable a combination of low cost, flexibility, durability, high processing temperatures, and sub-100 um thickness making it well suited for sheet based and roll-to-roll processing. NFC (13.56 MHz) based circuits using high performance polysilicon TFTs on steel sheets have been manufactured using a hybrid printed process in a production environment. The process scheme utilizes a hybrid, additive materials approach encompassing low cost manufacturing steps such as slot die coating and screen printing of silicon and dopant inks to enable a high throughput, low cost, manufacturing flow. This paper describes the approach for migrating from a sheet-based hybrid process flow to a R2R-based process. A comparison of substrate choices and considerations for R2R process integration is presented. A sensitive electrical method for evaluating the feasibility of R2R-based process integration schemes and materials selection is presented. MIM capacitor leakage, TFT device characteristics, NFC circuit performance, and defect density considerations are shown as a function of steel substrate bending, down to a diameter of 0.75 inches. Electrical characteristics and optical inspections show no measurable change to insulator characteristics, demonstrating a high degree of flexibility and overall device and process capability for R2R processing.

Roll-to-roll (R2R) production of polysilicon CMOS TFTs on steel substrates for electronic devices allows for low-cost and highvolume manufacturing, enabling the Internet of Things (IOT). R2R process capabilities are demonstrated along with key equipment considerations and de-risking approaches for scaling from a sheet-based to roll-based process.