Ion beam alignment for liquid crystal display fabrication

Abstract

The ability to align liquid crystals to a substrate is a critical step in the liquid crystal display (LCD) manufacturing process with the industry standard technique employing a mechanical rubbing technique to accomplish this function. However, mechanical rubbing can result in debris generation contaminating not only the substrate being processed but also the clean room housing the equipment. As such, post-cleaning of the display panels is required to remove the debris from the surface in addition to the physical isolation of the mechanical rubbing equipment within the clean room environment introducing considerable time and expense. In addition, uneven wear of the mechanical roller during the rubbing process may result in localized defects that will not be observed until final inspection of a completely assembled display. We have developed and introduced into LCD manufacturing a non-contact alignment technique utilizing both diamond-like carbon (DLC) and a low energy ion beam (IB). The replacement of the polyimide alignment layer with DLC results in a completely dry processing technique for both the thin film deposition and alignment steps.