This excerpt taken from the HIMX 6-K filed Aug 15, 2006.
Special Assembly and Testing Requirements
Manufacturing display drivers requires certain assembly and testing technologies and equipment that are not standard for other semiconductors and are offered by a limited number of providers. The assembly of display drivers typically uses either tape automated bonding, also known as TAB, or chip-on-glass, also known as COG, technologies. Display drivers also require gold bumping, which is a process in which gold bumps are plated onto each wafer to connect the die and the processed tape, in the case of TAB packages, and the glass, in the case of COG packages. TAB may utilize tape carrier package, also known as TCP, or chip on film, also
known as COF. The type of assembly used depends on the panel manufacturers design which is influenced by panel size and application and is typically determined by the panel manufacturers. Display drivers for large-sized applications typically require TAB package types and, to a lesser extent COG package types, whereas display drivers for mobile handsets and consumer electronics products typically require COG packages. The testing of display drivers also requires special testers that can support high-channel and high-voltage output semiconductors. Such testers are not standard in the semiconductor industry.