Abstract

To produce microchips modern optical lithography systems are used. In an attempt to follow Moore?s law ASML is using extreme ultraviolet (EUV) light in their machines, which has a wavelength of only 13.5 nanometers. In EUV systems the wafer is rapidly moving inside a vacuum chamber where a blueprint of the chip is projected onto a silicon wafer with nanometer accuracy. To ensure that the wafer is at the right position at the right time, a position module is used. It?s connected to the base frame of the machine by means of a flexible connection called cable slab, which consists of cables for power and data, and hoses for transport of fluids and gasses. Because of high accelerations of the position module the cable slab behaves very dynamically. As a result, large deformations occur which might cause the cable slab to hit other parts inside the machine. Insufficient clamping force may also lead to slip between cables and brackets. This could result in damage or wear of the cable slab. Additionally, due to this dynamical behavior disturbance forces occur on the position module which negatively influence the positioning of the wafer. This article focuses on the prediction of the dynamic behavior of wafer stage cable slab in order to overcome existing issues and potentially minimize disturbance forces acting on the position module. To simulate complex non-linear dynamic behavior of cable slab at high operational speeds Altair RADIOSS explicit solver was used. For the propose of correct representation of cable slab?s behavior during different dynamic load cases, pre-loading of a system was performed by application of folding motion and gravity acceleration. Dynamic effects in these quasi-static load cases were minimized by using slow dynamic computation and energy discrete relaxation approaches to converge simulation towards static equilibrium. Following pre-loading steps, dynamic analysis of cable slab under various operating conditions was conducted. Proposed model allows fully describe the stress-stain state of cable slab at any given time and track its volume consumption during simultaneous movement of position module in two perpendicular directions, thus predict potential volume conflicts with surrounding parts. Knowledge about magnitude of contact forces at the interfaces allows to predict a wear of contacting parts. Disturbance forces on position module due to dynamic motion of cable slab also were investigated. Simulation shows a good level of correlation with experimental results obtained on test rig.