Pyrometer apparatus for use in rapid thermal processing of semiconductor wafers

摘要

Pyrometer apparatus measures the temperature of a semiconductor wafer which when heated by radiation from a bank of lamps emits thermal radiation which includes radiation contained in a selected spectral band. The apparatus includes a reaction chamber supporting the wafer and disposed above the bank of lamps. A hollow envelope reflecting incident radiation and thermal radiation from the wafer surrounds and is spaced from the chamber and the bank of lamps. A portion of the reflected radiation and the thermal radiation passes upwardly through a first opening. A source of said incident radiation disposed adjacent a second opening produces radiation within said spectral band which enters said envelope and is reflected inside the envelope to illuminate a selected spot on the wafer hemispherically. The spot reflects a portion of the incident radiation upwardly through the first opening. A device disposed outside of said envelope adjacent and above the first opening in the path of the reflected portion of incident radiation and said upward portion of wafer thermal radiation and responds within said spectral band to both of said portions to produce a first electrical signal proportional to the said reflected portion of incident radiation and a second electrical signal proportional to said upward portion of wafer thermal radiation. Another device responds to the first and second electrical signals to calculate the temperature of the wafer.