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A Dual Vacuum Wafer Prealigner and a Multiple Level Structure  

Kim, H.T. (한국생산기술연구원 스마트시스템연구부)
Choi, M.S. ((주)나인벨)
Publication Information
Transactions of The Korea Fluid Power Systems Society / v.8, no.3, 2011 , pp. 14-20 More about this Journal
Abstract
This study aims at aligning multiple wafers to reduce wafer handling time in wafer processes. We designed a multilevel structure for a prealigner which can handle multiple wafer simultaneously in a system. The system consists of gripping parts, kinematic parts, vacuum chucks, pneumatic units, hall sensors and a DSP controller. Aligning procedure has two steps: mechanical gripping and notch finding. In the first step, a wafer is aligned in XY directions using 4-point mechanical contact. The rotational error can be found by detecting a signal in a notch using hall sensors. A dual prealigner was designed for 300mm wafers and constructed for a performance test. The accuracy was monitored by checking the movement of a notch in a machine vision. The result shows that the dual prealigner has enough performance as commercial products.
Keywords
Prealigner; Wafer Alignment; Dual Structure; Vacuum Type Fixture; Notch Finding;
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