Assembly of a prototype flip-chip-on-glass liquid crystal display

The authors discuss the stages of development and assembly of a prototype Flip-Chip-On-Glass (FCOG) liquid crystal display. The driver IC's were mechanically bonded and electrically interconnected using anisotropically conductive adhesive (ACA). In the first phase, test panels were assembled using an ultraviolet (UV) curable ACA. Without the benefit of the self-alignment properties of solder, a high precision pick-and-place machine was used. A modified MCM/Hybrid die attach system was successfully used. Properties of the material are given along with the necessary process steps and conditions. The panels were subject to reliability tests, the results of which are given. In the second phase, glass panels for the a prototype display and bumped driver ICs were prepared. Design considerations are discussed. The assembly of the prototype display required a machine capable of handling a large area panel and capable of radiation processing. A new flip chip bonder was designed and built to the necessary specifications. Other key requirements for the bonder were placement accuracy and force. In the assembly of the displays, process difficulties were encountered and overcome. Some of these experiences are shared. Suggestions for future enhancement to materials, equipment, and process are offered.