Design Of The Vertical Scanner For The Large Tilt Angle Ion Implanter

Vertical scanner is a significant part of the large tilt ion implanter, which transfers high speed movement outside of the high vacuum chamber to the inside, so that the target which the wafer installed on is able to carry out reciprocating movement and forms the required high speed mechanical scanning in the vertical orientation.As the development of device art, today ion implant tools employ"single wafer process"instead of traditional"batch wafer process", it is required that the scanning speed of the target should be as high as several hundreds millimetre per second to prevent the wafer from local overheating. The vacuum and the number of particles in the chamber are the significant factors to achieve high quality final wafers, if the vacuum isn't high enough, it will result in getting larger of ion beam's emittance, more losses of ion beam, appearance of neutral beam, impurity of ion beam and so on; if the number of particles is too large, it will cause too much defect of the wafer, even make devices invalidation when the density of defect reach critical value.Based on the structural diagram and some concerning data of the large tilt ion implanter, this thesis deals with a design and performance calculation of the gas bearings and differential vacuum seal part. Mainly provides basic theory research of gas-lubrication, introduction of modelling and computation method, process of choosing the structural data, performance analysis and accuracy validation of the method. Combined with general fluid analysis software, the very popular practical finite volume method is used in this thesis to directly solve the governing equations on the solution domain instead of traditional methods that solve the Reynolds Equations. On the other hand, based on theory of vacuum technology. This thesis also deals with a design and performance calculation of the differential vacuum seal. The results show that the vertical scanner has the feature of low friction and low gas leakage rate, which can meet the high vacuum and low particle contamination requirement for the chamber in the wafer process.