Method and apparatus for chuck thermal calibration

摘要

A chuck includes a first material layer having an upper surface upon which a wafer is supported. The upper surface includes portions that physically contact the wafer and portions that form gaps between the upper surface and the wafer. The chuck also includes a second material layer defined to support the first material layer. The second material layer is formed of a thermally conductive material and includes a first number of channels. The chuck also includes a second number of channels defined to direct a gas to portions of the upper surface that form gaps between the upper surface and the wafer. The chuck is characterized by a thermal calibration curve that represents a thermal interface between the upper surface and the wafer, heat transfer through the first material layer to the second material layer, and heat transfer through the second material layer to the first number of channels.

主权项

1. A thermally calibrated chuck for supporting a semiconductor wafer during a fabrication process, comprising:
a first material layer having an upper surface upon which a wafer is to be supported, wherein the upper surface includes portions that form gaps between the upper surface and the wafer when the wafer is present; a second material layer defined to support the first material layer, the second material layer formed of a thermally conductive material and including a first number of channels; and a second number of channels defined to direct a gas to portions of the upper surface that form the gaps between the upper surface and the wafer when the wafer is present, wherein the chuck is characterized by a thermal calibration curve generated by,
(a) holding a test object on the chuck in exposure to a heat source, wherein the test object is a test wafer representing the semiconductor wafer to be supported by the thermally calibrated chuck during the fabrication process,(b) applying a gas at a substantially constant pressure within the gaps between the upper surface and the test object,(c) removing the heat source,(d) measuring a temperature of the test object as a function of time following removal of the heat source while maintaining the substantially constant pressure of the gas within the gaps between the upper surface and the test object,(e) determining a chuck thermal characterization parameter value for the substantially constant pressure of the gas applied in operation (b) based on the temperature of the test object as a function of time as measured in operation (d),(f) repeating operations (a) through (e) for a number of different gas pressures applied in operation (b), and(g) establishing a correlation between the chuck thermal characterization parameter values determined in operation (e) and the corresponding gas pressures applied in operation (b) to generate the thermal calibration curve.