There are two options for post-mapping yield improvement. The first is to improve the TFT and/or CF plate yield. This approach requires improvement in the manufacturing processes, technology, tooling, etc., and may be costly and have technological constraints. The second option is to use a judicious mapping policy to optimize yield mapping. The yield mapping problem can be a significant loss contributor. A judicious matching policy is very cost effective because it does not require a significant investment to produce yield improvement. This study uses the second approach to improve the yield. We first propose a linear programming formulation to optimally solve the problem. The results were compared with two heuristics utilized in practice and showed superior solution quality.
Next, we consider a mapping problem by using a sorter. We use LP formulation to compare the various ports in the yield mapping problem and a reduction algorithm to reduce the number of ways for choosing different matched objects when the number of matched cassettes is large. This LP method provides an optimal solution and offers LCD manufacturers important yield information. The proposed reduction algorithm avoids computer over-load and produces very good results on the large scale cassettes matching problem. This avoids a great quantity of LCD display scrap, reduces production costs and improves the production yield. The LTPS focuses on manufacturing small and medium size LCD panels, scribing glass prior to the cell process leads to a much lower economy of scale. The proposed reduction algorithm can provide a better choice.
Implementation results revealed that proposed approaches are effective in solving a practical problem.
For the large scale cassettes matching problem, future research can consider developing a better classification method to reduce the number of ways for choosing different matched objects. In addition, the mapping costs should be investigated to obtain an overall optimal solution.
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