Patent ID: 11887808
Assignee: AXCELIS TECHNOLOGIES, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 17:
18. A thermal electrostatic clamp apparatus, comprising:
a central electrostatic portion defining a central clamping surface, wherein the central electrostatic portion is associated with a central region of a workpiece and wherein the central electrostatic portion comprises:
a central body having a clamping surface defined thereon;
one or more electrodes associated with the central body, wherein the one or more electrodes are configured to selectively electrostatically clamp at least the central region of the workpiece to the clamping surface based, at least in part, on an electrical current selectively passed through the one or more electrodes; and
one or more first heaters associated with the central body and configured to selectively heat the central electrostatic portion to a first temperature; and

a non-electrostatic peripheral portion, wherein the non-electrostatic peripheral portion is associated with a peripheral region of the workpiece, wherein the non-electrostatic peripheral portion comprises:
a peripheral body generally encircling the central body and separated from the central body by a gap, wherein the peripheral body is positioned beneath the peripheral region of the workpiece when the central region of the workpiece is electrostatically clamped to the clamping surface, wherein a top-most surface of the peripheral body faces the workpiece and is contiguous and planar about the peripheral region of the workpiece, and wherein the peripheral body is not configured to electrostatically clamp the peripheral region of the workpiece thereto; and
one or more second heaters associated with the peripheral body and configured to selectively heat the non-electrostatic peripheral portion to a second temperature.