ANNEALING APPARATUS USING TWO WAVELENGTHS OF RADIATION

摘要

A thermal processing apparatus and method in which a first laser source, for example, a CO2 emitting at 10.6 μm is focused onto a silicon wafer as a line beam and a second laser source, for example, a GaAs laser bar emitting at 808 nm is focused onto the wafer as a larger beam surrounding the line beam. The two beams are scanned in synchronism in the direction of the narrow dimension of the line beam to create a narrow heating pulse from the line beam when activated by the larger beam. The energy of GaAs radiation is greater than the silicon bandgap energy and creates free carriers. The energy of the CO2 radiation is less than the silicon bandgap energy so silicon is otherwise transparent to it, but the long wavelength radiation is absorbed by the free carriers.

主权项

1. A thermal processing system, comprising:
a stage; a first source of a first radiation having a wavelength of at least about 1.2 μm; a first optical assembly to shape the first radiation into a first beam onto a first area of the stage having a first dimension extending along a first axis and a second dimension longer than the first dimension extending along a second axis transverse to the first axis; a second source of a second radiation having a wavelength less than about 1 μm; and a second optical assembly to shape the second radiation into a second beam onto a second area of the stage that surrounds the first area.