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European consortium active matrix iii

Exploitable results

The project concerns the reduction of manufacturing yield loss caused by electro static discharge (ESD). By a series of steps, such as introduction of suitable ioniser equipment and a careful analysis of the manufacturing and place handling ESD yield loss could be reduced below the 5 % level. An advanced anisotropic conductive film chip on glass (ACF-COG) interconnect technology has been introduced. The program included improvements for the ACF-COG bond process, optimization of the repair process. The program resulted in higher yield, improved reliability and a better controlled, more stable interconnect process. A new procedure to detect defective integrated circuits (IC) before bonding has been installed. Thus reducing yield loss at video testing. Quality description sheets have been agreed upon with IC suppliers and a new column driver introduced successfully. Cleaning of incoming glass substrates and cell cleaning have been improved with respect to the impact on product reliability. Particle monitors and out of control procedures have been installed in several steps of the production process. Yield loss due to products being out of specification, the so-called parametric yield loss, has been reduced significantly. By various improvements, product performance with respect to burn-in, image retention, contrast, viewing angle, cross-talk and flicker is well under control. In its facility in Moirans, Thomson LCD has upgraded glass plate capability to 320x352 mm {2}, while at the same time improving process performance with respect to ESD and cleaning. Ciba Geigy Chemicals has developed latent pigments for use in colour filters. These materials are easier to handle and process, thus reducing manufacturing costs and giving colours with greater brightness.