Two dimensional simulation of electromagnetic field distribution in magnetron sputtering

     In this paper, the mathematical model of the magnetic field of the coil is established by using computer FORTRAN language, and the distribution of the magnetic field generated by the coil near the magnetron sputtering target is numerically simulated. The calculation results show that when the inner and outer loop are added with reverse current, the current in the inner or outer loop can be increased, which can increase the magnetic field unbalance degree of the coil. With the increase of inner and outer loop current, the magnetic field intensity distribution in the vacuum chamber is more uniform. By regulating the inner and outer coil current, the distribution of the magnetic field can be controlled, thereby controlling the distribution of the plasma density and the energy distribution. In addition, the electromagnetic field of the magnetic field can increase the magnetic field of the magnetic control device, so the plasma produced by the magnetron sputtering is enhanced. This result provides an important reference for the magnetic field configuration of the magnetron sputtering device.

Magnetron sputtering coating machine technology as a way to effectively thin film deposition, has become now industrial coating process in the main production, generally applied to microelectronics, optical film, and surface treatment and other fields. The key technology of magnetron sputtering system is the design of magnetron sputtering target, such as the magnetic field of the magnetron target, the column shaped magnetic control target and the moving rectangular magnetic control target. Abroad, the advantages of magnetron sputtering technology analysis and design, has achieved the industrialization of professional technology, many domestic magnetron sputtering equipment manufacturers to design a more random field.

Based on this, many researchers in China began to simulate the magnetic field distribution and optimization of the rectangular flat, circular and cylindrical targets. Zhao Zhuo et al. Calculation of the closed non equilibrium magnetic field shows that the magnetic field can be closed to a certain degree with the magnetic field opposite to the bottom of the target, so that the magnetic field has a certain degree of spatial distribution. Planar magnetron target, change the magnetic dipole and pole shoe size and shape, with guide disk, control the radial magnetic field distribution, increase the level of magnetic induction intensity, so that the target surface etching runway becomes wider. That increased rotating cylindrical targets the magnetic size and magnetic sub angle, with twin cylindrical targets and other means, improve the column target tangential direction of the surface of the magnetic sense of strength, increase the target surface to be sputtered area.

It is worth noting that, Chinese Academy of Sciences; Shenyang Metal the magnetron sputtering and cathodic arc ion plating, in the vicinity of the magnetic field of the applied magnetic field simulation calculation and experiment show that magnetic field can influence of a magnetic field on the degree of non-equilibrium, which changes the distribution characteristics of glow discharge plasma and plasma. In addition, the numerical simulation results show that the control of the magnetic field distribution is the best way to improve the etching condition of the target surface. Therefore, the results of simulation can be used to guide the design of the magnetic control device.

In the design of magnetron target, the permanent magnetic material is limited, and the increase of the strength of the permanent magnetic field is limited. Vacuum technology network (http://www.chvacuum.com/) that the coil produces a magnetic field and to enhance the magnetron device of magnetic field intensity and magnetic field changes in the distribution of the magnetic field magnetron sputtering adjustable, adjustable field intensity distribution, will enable the target of controlling the sputtering rate, plasma particle density and energy increase.

1, the research object and the establishment of physical model

The vacuum chamber of the magnetron sputtering system is a cylindrical cavity. The target placed under the plate location in the vicinity of the rectangular circular coil winding, and plugged into negative potential electrode sputtering. The upper electrode plate can be connected with the power supply, the ground or the suspension, and the upper polar plate is higher than the lower electrode plate. After the system is filled with argon, the voltage between the two electrodes and the internal pressure of the system is adjusted, and the gas discharge is generated between the two electrodes, and the plasma is formed. The space magnetic field generated by the coil in the system is used to bind the partial plasma to the substrate, and the other part is more evenly distributed in the vacuum chamber between the upper and lower electrodes. The system height is 0.5 m, and the ionization region of the sputtering system is 0.28 m. When the cylindrical coordinate system is used to simulate the system along the central axis of the section of physical properties, it is assumed that coil around in on the periphery of the sputtering device, and the section size of the rectangular coil is 5 cm x 5C m and the distance between coil and plate for 1 cm. According to the boundary condition of the magnetic field, the magnetic field in the region of 2 times of the ionization region of the sputtering system and 3 times of the system height can be selected. The specific system structure is shown in figure 1.

2, conclusion

Based on the drift diffusion theory, the mathematical model of the magnetic field in the magnetron sputtering device is established. The magnetic field distribution in the device is obtained by solving Maxwell's equations. The results show that the distribution of the magnetic field intensity is mainly influenced by the unbalance degree of the electric current of the conducting wire. The contribution of the coil to the magnetic field is mainly concentrated in the inner region of the coil, and the magnetic field strength increases with the increase of the current. Increase the external coil current, that is, to enhance the intensity of the N magnetic pole, the magnetic field can be distributed more evenly, stronger.