Modulation of the plasma uniformity in inductively coupled plasma by external magnetic field: a study by a two-dimensional fluid model

With the development of the semiconductor chip industry, higher requirements have been put forward for plasma etching technology, such as higher plasma uniformity, lower ion bombardment damage, and more flexible chemical composition modulation. Introducing an external static magnetic field into inductively coupled plasma may provide an effective way to solve the above technical problems. In this work, a two-dimensional fluid model is used to self-consistently study the influence of axial static magnetic field on plasma parameters such as plasma density, potential, and plasma uniformity in ICP. The results show that the axial static magnetic field can regulate the uniformity of the plasma. When the gas pressure is 20 mTorr and the power is 100 W, as the magnetic strength increases from 0 Gs to 10 Gs, the electron density distribution gradually changes from center-high/edge-low to edge-high/center-low. When the magnetic strength is about 5 Gs, the plasma uniformity reaches the best. This is because the magnetic field restricts the radial transport process of electrons, thereby restricting the convergence of electrons to the radial center. In addition, the simulation results also show that the plasma potential decreases with the increase of the magnetic strength, indicating that the ion bombardment energy can be reduced with the increase of the magnetic strength. The above results provide a reference for optimizing plasma uniformity and reducing ion bombardment energy.