The Study Of Picking-Route Algorithm On The Wafer Of Thick-Film LED Bonder

The thick-film LED bonder is a kind of advanced micro-electronic packaging equipment which bonds the thick-film LED chip. It utilizes interdisciplinary technologies such as auto-control, fine mechanics, computer-control, visual position and optical design. The key parts of thick-film LED bonder system are control system and visual position system. The control system manages each part of thick-film LED bonder to work in phase. The visual position system can distinguish, filter and locate the chip automatically.This paper introduces the work principle and structure of thick-film LED bonder. And based on the analysis of control system and visual position system, this paper mainly studies picking-route algorithm, which has been overlooked for a time by researcher, and presents some efficient improving algorithms directing the LED bonder picking all chips on the wafer according to some special picking-route algorithm. Also, this paper discusses the way to improve the precision of chip-picking, the methods of visual position and full closed loop control are presented, guaranteeing the veracity and reliability of thick-film LED bonder.Because a new packaging technique has been carried out, there is a bump on the chip which used in the thick-film LED bonder and the size of chip is smaller to 0.25*0.25mm~2, and the shape of wafer's brim is special too. The usual die bonder can not deal with it swimmingly. This paper analyzes all kinds of problems when picking chips from the wafer, studies some picking-route algorithms such as right-angle cross algorithms, assurgent preferential algorithms, picking with direction algorithms, alterable eyeshot algorithms and recording track algorithms, then discusses them contrastively. Then using the ideas of these algorithms synthetically, this paper presents the standard improving algorithm to deal with the standard wafer and the special improving algorithm to deal with the special wafer used in the thick-film LED bonder. The special improving algorithms use particular methods such as symbol direction, history track tracing, alterable size of view, jumping pick. It overcomes the practical problem of chip emerging on the wafer , and is able to deal with all complicated situation of chips alignment such as corner missing, hole, bad chip, making the picking-route reasonable and efficient. The improving algorithms are remarkably ameliorated in picking intelligence, working reliability and bonding...