The E-Panel measures electrostatic charges to flat-panel-displays under production. By locating where electrostatic charges affect or damage the substrates within the production process it helps to minimize the amount of yield-loss.
The glass backside of the flat-panel-displays is the most likely area to become electrostatically charged due to friction within the production process. The electric fields pass through the dielectric glass panel, inducing potential differences in the front-side patterns - resulting in ESD damages. Even well engineered electrostatic protection concepts cannot foresee or eliminate all points where electrostatic charges can form on the substrates. Especially, since the measuring of all areas of the production process with conventional fieldmeters or electrostatic voltmeters is nearly impossible even while production is at a standstill and the results obtained here can differ greatly from the actual charges that build up when all parts (including the glass itself) are moving.
Electrostatic charges on the glass substrates can cause ESD events, non-uniform surface conditions or increased particle deposition. The continuous control of electrostatic potentials on the surface of the substrate is therefore a necessary quality assurance measure. The E-Panel provides this control.
The E-Panel is a flexible polyimid board (size: 178mm by 1000mm, maximum thickness: 1.65mm, weight: 80g) that is applied to a bare glass panel via removable adhesive film on site. It contains eight different sensing areas, distributed linear with equal distance over the 1m length. Electronics and battery as well as the contact points for the computer interface are housed within the controller-box. A manually handled interface is responsible for battery charging, communications and data transfer, neutralizing and zeroing. It is connected to the controller-box via spring-contacts and fixed by magnetic force. The battery allows for up to two hours of measuring time. The entire system is hermetically closed and covered with a highly chemical resistant polyimid layer. Therefore, it can be immersed in wet processes and handled in vacuum. The real-time clock allows for the processed logfiles to be synchronized. Of course the E-Panel is delivered with specific analysis software.
