In the field of flat panel displays, packaging technology has asignificant influence on display performance. The electricalinterconnect between the LCD and the LCD driver circuit is an area thatneeds improvement to achieve finer pitch, easier assembly and greaterconnection reliability. For LCD driver packaging, the ideal assemblyprocess would possess the following characteristics: low processingcost; reliability suitable to the final application; high-density, finepitch capability; low product profile; acceptable joint resistance; easeof inspection; and reworkability. The overall trend in LCD driver ICpackaging has been to move the driver IC closer to the LCD itself. Atpresent, TAB is the predominant packaging approach for large area LCDs.In most cases, the TAB is directly connected to the ITO traces on theglass using anisotropic conductive adhesive (ACA). In chip-on-glass(COG) technology, the driver LSI chips have moved all the way on to theLCD glass itself. COG is typically done by flip chip, also often withthe use of conductive adhesives. ITO traces fan out from the IC to thedisplay area, as well as to the point where a polyimide flexible circuitis connected to the glass substrate to supply power and pictureinformation. COG mounting is currently being used in a number ofproducts, in particular when the pixel density is high
展开▼
