The Electrostatics Susceptibility Mode of FPD Array Fabrication

Key words of glossary

FPD: Flat Panel Display, nowdays mainly including display technologies of TFT-LCD and LTPS drived AMOLED (both Rigid & Flexible types)

TFT: Thin Film Transistor, the most and important fundamental microelectronic devices within FPD displays of TFT-LCD and AMOLED. Nowadays TFT technologies mainly includes a-Si, LTPS and IGZO types.

TFT Array Glass: the key electronic part of FPD displays of TFT-LCD and AMOLED to realize electronic drived display, the finished semi-product of FPD front-end manufacturing (ie. TFT Array Fabrications) of TFT-LCD and AMOLED.

The Susceptibility / Sensitivity of FPD TFT Array Fabrications

Note: the technical contents of this part was firstly released officially by LEAN ESD Technology (Guangzhou) Co., Ltd. at ESDA EOS/ESD Manufacturing Symposium in China on May 21st of 2019 in Shanghai. And the copyright has been covered by the authorized China Innovation Patent of No. ZL201910196277.9 by LEAN ESD Technology (Guangzhou) Co., Ltd.

TFT Array fabrications of nowadays FPD manufacturing take almost the same / similar processing technologies with traditional wafer fabrications of semiconductors (such as CVD, PVD for thin film formations, photo lithography and wet/dry etching to form the microelectronic patterns), however, due to the unique designs (adopting the insulating glasses as substates and large amount of long metal line patterns) of FPD products. As the result, the electrostatics induced product failures (electrical failures of mal-functions or degraded reliabilities) throughout productions of TFT array fabrications exhibit quite different mode from traditional microelectronics (MR heads assembly, Chip assembly and SMT assembly of ICs and wafer fabciations of semiconductors). The mode of electrostatics induced TFT array failures at array fabrications could be described as "over-higher electronic charges induced Zap (or called ESD) damage". this could be demonstrated as below illustrations,

Figure 1. The mode of electrostatics induced TFT array failures at array fabrication manufacturing

The very common seen electrostatics induced TFT electrical failures (or damages) is the event of TFT glasses lifted up from vacuum stages (automation equipment of Exposure, PR coater, TFT array testing or inspections, etc)

Figure 2. The typical event type of electrostatics induced TFT array failures at vacuum stages

Brief Technical Remarks of the electrostatics controls of FPD TFT Array Fabrications

So, the truely effective technical approaches to manage electrostatics induced failures of FPD TFT array fabrications cannot take same or similar ways of traditional microelectronics of ICs. The amount of Electrostatic Charges or Electrostatics induced Electric Fields shall be always the Top Consideration in electrostatics mananagement in FPD TFT Array Fabrications.