Impedance monitoring of chamber by deposited material properties on the wafer

When performing a continuous process, such as an oxide/nitride stack (ON stack) in 3D NAND flash manufacturing, the impedance of the wafer can change. Changes in the impedance of the wafer can lead to changes in the impedance of the chamber. This may change the characteristics of the plasma (reactance and ignition time, etc.), which in turn may change the process results. Therefore, we measured the impedance of the chamber according to the characteristics of the material deposited on the wafer. Four measurements were performed: no wafer loaded, wafer loaded, wafer with oxide deposited loaded, wafer with nitride deposited loaded. In addition, the thickness of oxide deposition was varied. The higher the dielectric constant, the higher the reactance was measured when loading the chamber (Nitride > Oxide > Wafer > w/o wafer). Also, the higher the reactance was measured as the thickness of the deposited oxide increased. We expect to be able to indirectly check the deposition thickness through this.