Position analysis of a hybrid serial-parallel manipulator in immersion lithography

Abstract

This paper proposes a novel hybrid serial-parallel mechanism with 6 degrees of freedom. The new mechanism combines two different parallel modules in a serial form. 3-P and UnderBar; (P H) parallel module is architecture of 3 degrees of freedom based on higher joints and specializes in describing two planes' relative pose. 3-P and UnderBar; SP parallel module is typical architecture which has been widely investigated in recent researches. In this paper, the direct-inverse position problems of the 3-P and UnderBar; SP parallel module in the couple mixed-type mode are analyzed in detail, and the solutions are obtained in an analytical form. Furthermore, the solutions for the direct and inverse position problems of the novel hybrid serial-parallel mechanism are also derived and obtained in the analytical form. The proposed hybrid serial-parallel mechanism is applied to regulate the immersion hood's pose in an immersion lithography system. Through measuring and regulating the pose of the immersion hood with respect to the wafer surface simultaneously, the immersion hood can track the wafer surface's pose in real-time and the gap status is stabilized. This is another exploration to hybrid serial-parallel mechanism's application.