Patent ID: 9567668
Date: 2017-02-14
CPC Classifications: C23C,H01J

Claim:
1. A plasma apparatus, comprising: a plasma chamber; a wafer chuck disposed in the plasma chamber; a target element located over the wafer chuck; a retaining element located above the target element, the retaining element comprising a circular shape and a circular receiving groove disposed in the retaining element; and an electromagnet array, located over the target element, comprising a plurality of electromagnets that are arranged in the receiving groove, wherein some of the electromagnets in a first magnetic-field zone of the electromagnet array are enabled to generate a first magnetic field adjacent to the target element, wherein the some of the electromagnets are arranged in an approximately circular pattern, and the some of the electromagnets comprises a first group of electromagnets and a central electromagnet surrounded by the first group of electromagnets, wherein the first group of electromagnets each comprise a pole that is opposite a pole of the central electromagnet, wherein a location of the first magnetic-field zone is adjusted by switching the electromagnets during a semiconductor manufacturing process, wherein some of the electromagnets in a second magnetic-field zone of the electromagnet array are enabled to generate a second magnetic field adjacent to the target element, and at least one of the electromagnets between the first magnetic-field zone and the second magnetic-field zone is disabled.