FIELD

The present disclosure relates generally to plasma processing of workpieces, such as semiconductor workpieces.

BACKGROUND

Plasma processing is widely used in the semiconductor industry for deposition, etching, resist removal, and related processing of semiconductor wafers and other workpieces. Plasma sources (e.g., microwave, ECR, inductive, etc.) are often used for plasma processing to produce high density plasma and reactive species for processing workpieces. RF plasma sources can be used in plasma etch applications because of the ability of the RF plasma source to generate a process chemistry out of feed gases, and to provide an isotropic or highly anisotropic etch at high or low etch rates. Plasma processing tools can be able to sustain a stable plasma in very different gases and under very different conditions (gas flow, gas pressure, etc.) and can provide for independent control of plasma density, plasma profile and ion energy.

SUMMARY

Aspects and advantages of embodiments of the present disclosure will be set forth in part in the following description, or may be learned from the description, or may be learned through practice of the embodiments.

One example aspect of the present disclosure is directed to a workpiece processing apparatus. The apparatus includes a plasma source configured to generate a plasma. The workpiece processing apparatus includes a chamber configured to receive a workpiece. The workpiece processing apparatus includes a workpiece support contained in the chamber and configured to support the workpiece. The workpiece processing apparatus includes a focus ring assembly. The focus ring assembly includes a focus ring having an upper tier and a lower tier. An inner edge of the upper tier can be separated a lateral distance of at least about 3 mm from an outer edge of the workpiece located on the workpiece support.

These and other features, aspects and advantages of various embodiments will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the related principles.

