Measure and control for IC mask alignment based on quadrant detectors

Abstract

A measure and control system for Integrated circuit (IC) mask alignment based on Programmable Controller (PLC) and quadrant detectors is presented. The measure device consists of two quadrant detectors, which measure alignment errors in real-time. The alignment errors and the motions of IC mask can be decoupled via reasonably choosing the position and orientation of the measure device. Programmable controller is employed to adjust the manipulator's position and orientation in order to align the IC mask according to the alignment errors. Furthermore, a stepwise approach with varying step lengths, and a compensation strategy following the manipulator's rotation are introduced in the IC mask alignment. The experimental results verified the effectiviness of proposed system and methods. Show more