43.2: Low‐Temperature Polycrystalline‐Silicon TFT Color LCD Panel Made of Plastic Substrates

Abstract

An all-plastic, full-color LTPS TFT LCD has been fabricated with practical image quality. The diagonal size is 1.5 inch with a panel thickness of only 0.4mm. The TFT layer on a plastic substrate was prepared with a newly developed transfer process, which does not cause any significant damage to the device layer. This technology will lead to a lightweight, shock-resistant LCD panel suitable to mobile applications.

OLED Displays on Plastic

“…Alternative inorganic TFT technologies with suitably low processing temperatures are being explored as well (Carcia et al 2003). In addition, TFT transfer technologies, in which the TFTs are fabricated on a substrate that can withstand high processing temperatures and then transferred to the plastic substrate, offer another avenue for circumventing the hightemperature issues of Si processing; not only can traditional LTPS techniques be used (Asano and Kinoshita 2002;Utsunomiya et al 2003), but so can those for single-crystal silicon, which has even higher mobilities (Shi et al 2002).…”

Polysilicon thin-film transistors on polymer substrates

“…Different thin film transistor (TFT) technologies have been demonstrated on polymeric substrates, including hydrogenated amorphous silicon [1], organic materials [1], oxide semiconductors [1] and low-temperature polycrystalline silicon [2][3][4][5][6][7][8]. Among the different TFT technologies, LTPS offers best device performance as well as the possibility to provide CMOS circuits.…”

“…Different applications of the SUFTLA technology were demonstrated, including a backplane for liquid crystal displays (LCDs) with integrated drivers [2] or a fingerprint sensor and an electrophoretic display [3]. Transfer processes similar to SUFTLA and based on the substrate removal were proposed by Asano and Kinoshita [4] and by Wang et al [5,6]. In the Asano and Kinoshita process, the glass substrate was removed by etching in HF and an etch stopper was introduced between the glass and the TFT layers, also removed prior the final bonding on the polymer substrate [4].…”

“…Transfer processes similar to SUFTLA and based on the substrate removal were proposed by Asano and Kinoshita [4] and by Wang et al [5,6]. In the Asano and Kinoshita process, the glass substrate was removed by etching in HF and an etch stopper was introduced between the glass and the TFT layers, also removed prior the final bonding on the polymer substrate [4]. Instead, Wang et al used Si-wafers as substrate, which was removed either by chemicalmechanical polishing (CMP) and wet chemical etching [5] or by spin-etching [6].…”

“…Instead, Wang et al used Si-wafers as substrate, which was removed either by chemicalmechanical polishing (CMP) and wet chemical etching [5] or by spin-etching [6]. It should be noted that in substrate removal processes [4][5][6] the either glass or Si-wafer substrate is wasted, in contrast to SUFTLA process where the glass substrate can be re-used, thus leading to a higher cost. Another form of the transfer process was proposed by Lee et al [7], who demonstrated a separation process based on a nanostructured high surface-tovolume ratio film which serves as sacrificial release layer.…”