Patent ID: 8918303
Filing Date: 2014-12-23
Classification: G01J,H01L

Abstract:
1. A process for determining a temperature dependent optical characteristic of a wafer, comprising: placing a wafer made of semiconductor material within a thermal processing chamber, the thermal processing chamber comprising a heating source and at least one calibrating light source; emitting first light energy from the at least one calibrating light source on the wafer when the wafer is in a first temperature range, detecting, with at least one light detector, the amount of first light energy emitted from the at least one calibrating light source that is transmitted through or reflected from the wafer during at least one rotation of the wafer; averaging the amount of detected first light energy transmitted through or reflected from the wafer during the at least one rotation of the wafer over a time period to obtain an averaged first light energy measurement, wherein averaging the amount of detected light energy transmitted through or reflected from the wafer during the at least one rotation of the wafer over a time period reduces an effect of interference caused by a varying thickness of the wafer; after emitting first light energy, emitting second light energy from the at least one calibrating light source on the wafer when the wafer is in a second temperature range; detecting, with at least one light detector, the amount of second light energy emitted from the at least one calibrating light source that is transmitted through or reflected from the wafer to obtain a second light energy measurement; and determining a temperature dependent optical characteristic of the wafer based on the averaged first light energy measurement and the second light energy measurement.