Development of micro-assembling technology for fabrication of large size liquid crystal displays

A liquid crystal display (LCD) has two substrates sandwiching a liquid crystal layer. One is a pixel-controlling substrate (PCS or thin-film-transistor-array substrate), and the other is a color filter substrate. This paper is to study the feasibility of a new technology for making PCS. In the technology, many small crystalline silicon ultra large scale integrated circuits (ULSI) chips with a size of a few hundred pm are used for pixel control instead of using the conventional amorphous-silicon thin-film transistor. A new assembling technology for treating pm-size chips, micro-assembling technology (MAT), is particularly investigated as a technology for depositing almost a million of ULSI chips onto proper positions on the substrate. Processes to fabricate PCS by MAT are also investigated. It is found that when the diagonal size of an LCD exceeds 50-100 in., the present technology becomes realistic technically and economically.