Flexible Electronics Production Deployment on FPD Standards: Plastic Displays & Integrated Circuits Stanislav Loboda R&D engineer
The world-first small-volume contract manufacturing for plastic TFT-arrays and ICs Gen 2 (370*470 mm MG) 3,600 sqm CR (incl. 1,700 sqm ISO5) Capacity 10,000 sqm TFT p.a. Location Troitsk, Moscow area, Russia Production ready Q1 2019 Invested by RUSNANO (Russian biggest technology investment group) Managing by TechnoSpark (professional venture-building company) Products Technologies IGZO TFT world s most powerful plastic ICs Plastic RFID/NFC-chip (0,2 scm) Organic Photo-detector (4 inch) Large-area backplane for sensors and displays (10 inch) Flexible EPD (4 inch) Organic TFT enables truly flexible TFT arrays
Performance: Charge carrier mobility (cm 2 /Vs) Semiconductors for flexible electronics rigid on flex transfer to foil direct on high T foil (~300 C) direct on low T foil (plastic: PEN ~180 C) 10 3 10 2 10 1 10-1 10-2 10-3 Poly Si a:si Oxide Poly Si Oxide a: Si Oxide Organic IoT Surfaces
Organic TFT backplanes brings the best value in terms of price per sq meter Wearables Organics on PI Sensors Displays Automotive
IGZO TFT the best value in terms of price per function Wireless tags RFID, NFC 13.5MHz clock generators 12-128bit code generators Rectifiers, modulators Standard cell libraries (building blocks in IGZO TFT) e.g., AND, OR, XOR, XNOR, inverters o Maximum performance o Minimum power o High Yield Signage control 7-segment driver IC Pixel array driver IC Memory LPROM, P2ROM Array architectures Read-write controls Microprocessors X-bit core chips ALUs P 2 ROM integration Sensor interfaces ADC (up to 6-bit) Comps, Opamps C2C-SAR VCO Integrated
Applications of IGZO TFT and organic TFT IGZO TFT otft Thickness <20 µm, flexible, lightweight, transparent, low cost Advantages: high mobility / productivity Advantages: Truly flexible, lowest cost R&D Prototype Product Temperature, pressure, X- ray, image sensors Microprocessor, Memory, NFC-tags Logic Glass LCD-displays Light-emitting transistors for displays Roll-to-Roll printing LCD, OLED Displays Sensors X-Ray& Fingerprint Plastic EPD-displays In future it is planned to combine organic and IGZO technologies in hybrid CMOS structures for number of applications such as logic circuits.
370 From wafers to panels optimization of coating process Spin coating Widely used in Labs VS. Slit coating Industry applicable technology The non-round shape makes it hard to use all of coated material: offrectangle material gets lost G2.5 470 Slot coated area Spin coated area + Coating area perfectly fits rectangular glass: less material loss Spin-coated material at periphery is almost 2.5 thicker than slotcoated and 3 times thicker comparing to the center point Source: SID-2017 Reid Chesterfield et al. + Slot-die coating method yields more uniformity
Patterning techniques photolithography & wet/dry etching Technologies of photolithography View of mask frame, optics path and substrate chuck Wet etching Source: Young Hee Byun et al., IEEE, 1996 Stepper Scanner Accuracy More Less Combination of resist coating, exposure and developer working together Throughput Less More Cost More Less Scanner as an exposure tool provides accuracy of 3 μm which is enough for TEN FLECS OTFT design patterning
Optical inspection critical dimension measurements Automatic optical inspection (AOI), array test & repair connected at one SPC to ensure maximum yield Optical inspection is carried out across the entire mother glass active area to detect defects and to carry out CD-measurements: Classification of defects repairable not-repairable source-drain develop source-drain etch gate develop gate etch screen develop screen etch top pixel develop top pixel etch The effect of a large fibre that has caused problems for patterning the gate layer and resulting in shorts Selective AOI provides more productivity vs individual; No need for +1 tool Laser ablation by array repair tool No further actions (utilized) The defect caused problems for patterning the top pixel layer. 15 pixels shorted together as a result
Via interconnections between source electrode & lines, drain & pixel electrodes Dry etched Vias Relief diameter ~40µm Gate line width ~80µm Annular construction of TFTs provides: cheaper masks cost Source Laser drilling + + more stable & qualitative photolithography + better reproducibility Gate (green) OSC and dielectric layers patterned earlier (blue circle) Drain TFT channel
Scalability of flexible TFT manufacturing FETs Logic circuits Electronic industry Silicon wafers-based process Arrays (display backplanes, sensor arrays) Flat-panel display industry Glass-based process 300 mm Flat-panel display industry enables almost unlimited scalability of transistor-based device fabrication comparing to electronics industry It enables much lower production costs of electronic devices.
Challenge of getting technology from lab to fab Advanced R&D findings can t be efficiently implemented on large-scale manufacturing lines Overcapacity of FPD industry = opportunities to adapt existing lines for flexible electronics manufacturing. When technology is ready Intermediate step of technology transfer is needed to establish efficient step-by-step scaling up R&D Development of technologies, products, systems Prototyping/small scale Industrialization of technology Mass production Small scale manufacturing facility is a key to organic & oxide electronics industrial implementation and commercialization
Conclusions Industrial implementation stage of organic electronics Organic TFT electronics together with IGZO TFT completes a platform for FPD manufacturing of flexible electronics FPD process for TFT technology allows better scalability comparing to wafer process Efficient scaling up of flexible electronics manufacturing process flow through small scale stage
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