Design And Research Of Cusp Magnetic Field In A Large Diameter Single Crystal Furnace

Information technology and green energy are supporting industries of modern world, silicon single crystal as the fundamental material is essentially important. With the rapid development of the solar PV industry and semiconductor industry, there is a larger and larger demand for silicon material. At present, most 3-8 inch silicon crystal for IC manufacture in China are pulled by imported CZ furnace. For 90nm-45nm line width IC fabrication, all the crystal growth technology, control system and equipments manufacture technique for 12 in crystal growth are monopolized by foreign companies..Cusp magnetic equipment-as one of the most important parts of large diameter furnace plays an important role in silicon quality control.The traditional Cusp magnetic field has the disadvantage of high power consumption, unworkableness and low reproducibility, particularly in the large diameter furnace. This paper puts forward a new coil type and cooling method to address this issue, On this basis, we finished the design, machining and test. Then based on the TDR130-single crystal furnace, the design parameters of Cusp magnetic field were simulated, analysed and optimized by using the finite element method, which include Magnetic-field distribution, coil turns, distance and so on,which can improve the excitation efficiency of magnet coil.The main research contents of this paper are as follows:In chapter l,the bacakground,significance and the development actuality are given.then the main research contents and key techniques are presented.In chapter 2, on the basis of the analysis of single-crystal furnace melt convection and oxygen transport,research how Cusp magnetic field affects the silicon quality,as the basis of technical requirements of Cusp magnetic field.In chapter 3, based on the TDR130-single crystal furnace, the design parameters of Cusp magnetic field were simulated, analysed and optimized by using the finite element method, which include Magnetic-field distribution coil turns, distance and so on,which provides a meathod for Cusp magnetic field design.In Chapter4, firstly we analysis the power dissipation of the Cusp mangnetic field. To address the issue of high power consumption,we put forward a new coil type and cooling method,also, we finished the design, machining and test work.In Chapter 5, the performance test and pulling test of Cusp magnetic field are carried on. The result through experimental verification indedicated that the pamameters of Cusp magnetic field can meet the requiement of the single crystal furnace, the finite element method is relable, and power power consumption is reduced by 20%.In Chapter 6, the paper'main research work and achievement are summarized,and the future investigations on Cusp magnetic field are pointed out.