A wafer processing system is provided for use with a driver and a material supply source. The driver is operable to generate a driving signal. The material supply source is operable to provide a material. The wafer processing system includes an upper confinement chamber portion, a lower confinement chamber portion, a confinement ring, and an electro-static chuck. The upper confinement chamber portion has an upper confinement chamber portion inner surface. The lower confinement chamber portion is detachably disposed in contact with the upper confinement chamber portion. The lower confinement chamber portion has a lower confinement chamber portion inner surface. The confinement ring is removably disposed in contact with the upper confinement chamber portion inner surface and the lower confinement chamber portion inner surface. The confinement ring has a confinement ring inner surface. The electro-static chuck has an electro-static chuck upper surface and is arranged to receive the driving signal. The upper confinement chamber portion, the lower confinement chamber portion, the confinement ring and the electro-static chuck are arranged such that the upper confinement chamber portion inner surface, the lower confinement chamber portion inner surface, the confinement ring inner surface and the electro-static chuck upper surface surround a plasma-forming space that is capable of receiving the material. The upper confinement chamber portion, the lower confinement chamber portion, the confinement ring and the electro-static chuck are operable to transform the material into a plasma when the electro-static chuck receives the driving signal. The confinement ring has a non-rectangular cross section.