Materials Science Forum Vols. 505-507

Abstract: The effects of abrasive particle size on polishing phenomena during wafer planarization are investigated using a high precision polishing process test bench with in-situ measurement technology. The present experimental results are found to be comported with the experimental and theoretical data published previously. The current experimental outcomes can help to understand the polishing mechanism and develop the relating theoretical model.

Abstract: Nano-imprinting Lithography (NIL) has been considered as the most promising technique for nano-scaled fabrication and patterning. Recently, a new approach known as Laser-Assisted Direct Imprinting(LADI) has been proposed and demonstrated as an even more efficient way for direct nanofabrication and nanopatterning. In this study, we focused on silicon materials and utilized a single KrF excimer laser pulse (248 nm wavelength and 30 ns pulse duration) as the heating source. Molds of micro-scaled size have been prepared using conventional photolithography techniques. A working platform based on an Excimer Laser Micro-Machining system is constructed for LADI process. The influence of laser fluence and the imprinted pressure on the resulting structures was verifying by varying the laser fluence (1.0 ~ 1.2 J/cm2) and the imprinted load (3 ~ 9kg). The results have shown that the morphology and the imprinted depth were directly related to the laser fluence and the imprinted pressure. Quantitative data are obtained and will be addressed.

Abstract: A membrane thickness process control expert system of chemical vapor deposition (CVD) based on neural network is presented. In general, there are many factors would influence the membrane quality. Most of them can be adjusted by changing the recipe, which are the process parameters of the working machines. Finding out a suitable and steady recipe and on-line real-time controlling the recipe is the target that process engineers devote to. Generally speaking, the recipe adjustment is based on the accumulation of experiences or learning from the try and error results. However, the process of thin film deposition is a very complicate and nonlinear system. It is very difficult to find out the relationships between the variation of process parameters and membrane quality. Therefore, a system was developed to simulate the CVD’s process using a technique of neural network. An expert system was then set up by extracting out the regular rule between process input and output from the trained neural network, which would provide references to engineers for the need of on-line recipe adjustment.

Abstract: This paper studies the elevated-temperature sweep characteristics of wire bond during transfer molding process for semiconductor package. A set of sweep experiments is also conducted to acquire the sweep stiffness of wire bond for several bond spans and bond heights. The results show the increase of the sweep deflections is more delicate to bond span than bond height. The main objectives of this research are to obtain elevated-temperature material properties of gold wire experimentally and to predict the wire sweep of various bond spans and bond heights subjected to drag force in the compound flow during transfer molding. Based on the analysis results of ANSYS, the effects of bond span and bond height on wire sweep in the elevated-temperature environment can be obtained. Then, the elevated-temperature deflections of wire sweep can be predicted.

Abstract: The radiometric temperature measurement is often applied to the in-situ and real-time monitor for rapid thermal processing of semiconductor wafer. To obtain good accuracy, the effective emissivity of measured spot is determined simultaneously as well. However, the effective emissivity strongly depends on the characteristics of wafer, processing chamber, and sensors. This paper presents a Monte Carlo model with bi-directional reflection distribution function to estimate the related effective emissivity of wafer. The ends of radiation thermometer considered are located either on the inner surface of processing chamber or at the proximity of wafer. The results are checked and compared with those of the previous work. Finally the primary effects on radiometric temperature measurement are analyzed and discussed.

Abstract: The design criteria and dynamic analysis of SCARA substrate transfer robot for cluster tools have been investigated in this paper. The design criteria for SCARA robot to meet the application of semiconductor and flat panel display processing have been verified. The dynamic equations of decomposed modules of SCARA substrate transfer robot, such as arm module, friction module, servomotor module, harmonic drive module and belt module are formulated by Lagrange’s method respectively. Then, the dynamic equations are all built and simulated with MATLAB software. In addition, the elasticity characteristics of belt and harmonic drive are further discussed in this paper. In the aspect of control, the PID controller and force control method are both used to suppress the vibration and improve the transient response.

Abstract: XeF excimer laser-induced melting and recrystallization of amorphous silicon was studied using in-situ online time-resolved reflection and transmission measurements with a nanosecond time resolution. The explosive crystallization was observed for 50nm thick amorphous silicon on SiO2 deposited on non-alkali glass substrate upon 25ns pulse duration of excimer laser. Three distinct regrowth regimes were found using various excimer laser fluences. Scanning electron microscopy, Raman spectroscopy and atomic force microscopy were used to evaluate the excimer laser- irradiated region of the sample. Grain size, surface roughness and melt duration as a function of different laser fluences are also determined.

Abstract: A self-built micro-particle image velocimetry (micro-PIV) with a diode laser is established to measure the micro-fluidic phenomenon in a 100 μm rectangular capillary. By scanning method, a 3-D flow image with a flowrate of 0.3 μL/min is presented. With this calibration method, the measurement ability for 3-D micro-fluidic dynamics could be achieved. This technique also reveals its benefit and potential in metrology. Hence, it provides a helpful tool for Bio-MEMS research. The experiment is proceeded under laminar flow, Re= 0.011. The measurement range is ranging from 0.05μm/s to 4.3mm/s. The vector grid resolution is optimized to 2.5 μm.

Abstract: A new optical encoder system is presented for displacement measurement by the curve fitting method. In this paper, another pondering model is based on the previous development. That is the new measurement method using a homemade periodical gray level code, which can be used to replace the traditional doublet grating. A high precision is achieved by a fitting method with one single-frequency harmonic function. The experiment result shows that the concept is feasible.

Abstract: For a present study, a cryogenic ball milling process was applied to reduce the Ibuprofen particles to submicron in order to enlarge their dissolution rate. The cryogenic ball milling was performed using 6 mm zirconia balls at a temperature of -180 °C or lower. The effects of milling time, the weight ratio of ball to Ibuprofen, and milling speed on the particle size were investigated. SEM and particle size analyzer were used to analyze the shape and size of particles before and after ball milling. The chemical changes before and after the cryogenic ball milling process were examined through XRD (x-ray diffraction) analysis. The results show that the size of Ibuprofen particles was reduced to about 1/20 of its initial size and the particle size showed negligible change after six hours of ball milling. The effect of weight ratio and the milling speed on the particle size was almost negligible. The results also show that cryogenic ball milling yielded no chemical changes in the particle.