Study on Correction Method for Die Position Deviation Caused by Adhesive Tape Puncture

Accurate peeling off and transferring of microchips play a critical role in LED die sorting technology. Generally, sorting efficiency of more than 36 KUPH, and an alignment deviation less than 1 mil ( $25.4~\mu \text{m}$ ) is required. High precision position control and cooperation of multifactors should be implemented precisely. Among all the factors, the film deformation is an important one. As the sorting proceeds, dies are peeled off from substrates one by one, and the adhesive substrate is penetrated through a hole each time. As the number of stripped chips increases, viscoelastic deformation of tape surface takes place and tiny position shift of die adhered on tape arises. This shift may cause a negative impact on the peeling process. In this paper, linear viscoelastic deformation impact is tested with well-designed experiments. To evaluate the effect of tape deformation accurately for sorting the performance, stochastic Petri net model of the transferring system with dual-independent arms is formulated to analyze the influence of factors. On this basis, strategy on coordinating motion control and scheduling is proposed, rational velocity section is planned, and the active position compensation of supply platform is set, so that the die can be peeled off correctly and efficiently. Finally, to improve sorting performance, methods on active compensation of aligning platform are proposed and proven effective by an experimental validation.