Investigation on the Improvement of ESD Protection Circuits for Low Temperature Polycrystalline Silicon Thin Film Transistor Panels
|關鍵字:||低溫多晶矽;靜電保護電路;LTPS;ESD protection circuit|
迄今，廣泛被LCD業界使用的MOS-Diode 靜電保護電路，因其直接與面板Power line 電路連接，所以即使在沒動作狀態時也為一漏電流途徑，而其經ESD stress後，又有著高漏電流和特性變異的隱憂，影響著後續製程的生產良率，更甚危害到LCD產品運用在車載及航太上的使用安全。
本論文基於LTPS製程所特有NMOS、PMOS 特性及PIN-Diode 的高導通電流現象，探討PIN-Diode、Single MOS-diode、Multi MOS-diode 三種靜電保護電路，預期研究出較佳的靜電保護電路設計；實驗結果指出靜電保護電路漏電流表現在ESD stress 之前，PIN-Diode靜電保護電路為最佳，但在ESD stress 後，則是Multi MOS-Diode 靜電保護電路為最佳；而在靜電保護能力方面，以PIN-Diode 靜電保護電路為最佳，Single MOS-Diode為次之，Multi MOS-Diode則是最差；三種靜電保護電路設計都有其優缺點，這些實驗數據可作為日後LCD面板在靜電保護電路設計上的參考依據。|
In the information developed time, LCD in addition to enhance the resolution to cope with the purposes of access information and documents processing, but also need to take into account the design of energy saving and the use of safety; High-resolution LCD panel resulted in the internal metal traces and the circuit operation becomes narrower and complex, not only panel current consumption increased, but also increase the probability of LCD internal circuit electrostatic hazards from the production process. Up to today, MOS-Diode ESD protection circuit used in the LCD industry widely, Because of its connect directly to the panel Power line circuit, therefore even it is not in the operating mode, it still to be a pathway of leakage current, and its through ESD stress, but also has a high leakage currents and characteristics variation worries, affecting subsequent production processes yield rate , even more endanger to the safety of LCD products what used in the automotive and aerospace. Based on the particular NMOS and PMOS character of LTPS process and the higher turn-on current of PIN diode, this paper was researched the PIN diode , the Single MOS-diode ,and the Multi MOS-diode of ESD protection circuit for finding out the best one of them. According to experimental result for comparing the leakage current condition of ESD protection circuit, the PIN diode circuit would be the lowest of them before ESD stress , but the Multi MOS-diode circuit would be the lowest after ESD stress. And for the ability of ESD protection, the PIN-diode circuit would be the best one, the second was the Single MOS-diode circuit, and the Multi MOS-diode was the worst. The three types of ESD protection circuit have advantage and weakness respectively, our experimental data can be referred in ESD protection of LCD panel future.