Papers by Author: Xiao Zhu Xie

Abstract: For MHT is an integrated system for different domains, namely fluids, structures, piezoelectrics and circuitry, a component library consisting of inlets, outlets, chambers and piezoelectric blocks is developed with Modelica. The governing equations of inlet and outlet channels, chamber and piezoelectric block are proposed and parameter models are created based on object-oriented method with Modelica. Then the model of MHT is established by connecting different components’ pins of equivalent type. Simulation results on Dymola show accordance with that on Simulink, which indicates that this method can achieve high efficiency and precision.

Abstract: Chemical mechanical polishing (hereinafter referred to as CMP) which is to provide the best global planarization technology has been researched and applied in the field of ultra-precision surface finish. This article outlines the principles of the CMP process, focusing on the development of the major theoretical models such as phenomenological model, contact mechanics model, fluid dynamics model and hybrid model based contact mechanics and fluid dynamics in chemical mechanical polishing process. The hybrid model based contact mechanics and fluid dynamics has been a good developed in recent years. The model based on the molecular / atomic scale is proposed the further research methods of CMP's theoretical model.

Abstract: In this paper, micro-nano scratching experiments were conducted on mono-crystalline silicon wafer to investigate the material removal mechanism of silicon. Two loading methods (increasing-loading and constant-loading) were used. The characteristics of the scratching grooves, and the relationship between the groove size and the load were analyzed by observing the surface torography and measuring the groove. The results show that there are four distinct regimes existed with an increasing scratching load: elastic regime, ductile regime, ductile-brittle regime and brittle regime. The critical load of the transition from ductile to ductile-brittle regime can be considered as 120mN, within which smooth scratching surfaces have been obtained by ductile removal. The scratching load has very significant effects on the groove sizes of the mono-crystal silicon.

Abstract: The three dimensional (3D) coupling model is set up for analyzing the energy reflection and absorption on the kerf using ray tracing method after the laser beam cutting nonmetallic materials with high absorptance through multiple reflections. The laser beam characterized by focused gauss beam and fresnel absorption on the kerf are taken into account. The influences of the polarization on the absorbed intensity both in the front and the two walls are also discussed. Results indicate the differences of absorptive intensity among the three polarized lights are relatively small compared to metal. Thus, the polarization has little effects on the kerf of nonmetallic materials with high absorptance. The experimental results also agree well with the theoretical analysis.

Abstract: This paper studied the effects of the off-process conditioning parameters on the pad performances. The pad conditioning was evaluated based on the measurement of pad removal rate, the observation of the conditioned pad surface. The performances of conditioned pads were evaluated also by the material removal rate (MRR) and the surface roughness of polished wafers in the CMP experiments of LiTaO3 crystal wafers.