The obvious changing trends in display technology are products getting thinner and lighter and flexible display devices. There is a common trend for higher resolution and pixels per inch (PPI) and increasing screen sizes for new display devices. Also, there are continuous developments for brighter, lower reflectance displays for better visibility under high ambient light conditions. Future display trends will continue to be introduced at industry trade shows including Internationale Funkausstellung (IFA) and International Consumer Electronics Show (CES). Some of the newer technologies and finished products are Quantum Dots, curved and flexible displays with higher resolution and higher pixels per inch, Low-temperature polycrystalline silicon (LTPS) and Indium gallium zinc oxide (IGZO) technology, OLED, and transparent display technologies.
What are the FPD manufacturing details that can be a potential problem for ESD (like defects, glass material properties, etc.)?
During FPD fabrication processes, a variety of charge generation elements can cause static related issues. For example, friction from photoresist coated glass substrate and deionized water spray rinses in the cleaning process causes change generation. There is also charge generation when glass substrates transfer through conveyor rollers between processes. Most ESD damage on glass substrates resembles CDM damage after semiconductor device testing. A major difference between legacy CDM and ESD discharge on glass substrates is the discharge energy path to ground. ESD phenomena on glass substrates have no ground path and limited current flowing; thus breakdown events occur between metal structures or between thin films that are at different potentials.
How is ESD in the FPD production process controlled? Are there any gaps between ESDA standards?
The FPD manufacturers control their processes based on their own failure and control experiences, not published standard documents. There is no published standard document to describe how to test FPD panels or completed display panel modules that have repeatable results. There is no published standard for requirements for the fabrication process. There are technical gaps and communication issues between FPD manufacturers and OEMs about correct control methods.
What challenges remain?
To create these documents and make them technically correct, the EOS/ESD Association, Inc. invites volunteers and experts who are working in FPD manufacturing organizations and interested in ESD damage on FPD devices.
- ESD TR21.0-01-18 for Challenges in Controlling ESD in the Manufacturing of Flat Panel Display
- J. Yoo, D.S Kim, A. Steinman, “Comparing Room Ionization Technologies in FPD Manufacturing,” EOS/ESD Symposium 2012
- D.S Kim, J. Yoo, “Electrostatic Control and its Analysis of Roller Transferring Processes in FPD Manufacturing,” EOS/ESD Symposium in 2013
- J. Yoo, E. Choi, E. Koo, “ESD Risk from Pulsed AC Ionizer,” EOS/ESD Manufacturing Symposium in Germany 2018
- J. Yoo, E. Choi, E. Koo, “CPM Test Limitation Study for AC, Pulsed AC and High-Frequency AC Ionizers vs. DC Based Ionizers,” EOS/ESD Symposium 2019