Method of thermal processing a substrate with direct and redirected reflected radiation
View Patent ↗Apparatus and methods for thermally processing a substrate with scanned laser radiation are disclosed. The apparatus includes a continuous radiation source and an optical system that forms an image on a substrate. The image is scanned relative to the substrate surface so that each point in the process region receives a pulse of radiation sufficient to thermally process the region.
1. A method of thermally processing one or more regions of a substrate, comprising the steps of:
a. generating a continuous beam of radiation having a wavelength capable of heating the one or more regions;
b. irradiating the substrate with the continuous beam of radiation as a first beam of radiation to form an irradiated image on the substrate at the one or more regions;
c. capturing reflected continuous radiation from the one or more regions of the substrate and directing the reflected radiation back to each of the one or more regions as a recycled radiation beam that approaches each of the one or more regions of the substrate at a non-normal incident angle selected according to the one or more regions of the substrate to a form a reflected image having, point by point, the same orientation as the irradiated image formed at the same of each of the one or more regions; and
d. scanning the first beam of radiation and the recycled radiation over the one or more regions so that the one or more regions receives an amount of thermal energy capable of processing the one or more regions;
wherein directing the reflected radiation back to the one or more regions includes reflecting the reflected radiation from a roof mirror and a cylindrical mirror.
2. The method of claim 1 , wherein the recycled radiation beam is formed to have an incident angle corresponding to the minimum substrate reflectivity at the select wavelength.
3. The method of claim 1 wherein the recycled radiation beam is formed from parallel rays.
4. A method of thermally processing one or more regions of a substrate, comprising the steps of:
a. generating a continuous beam of radiation having a wavelength capable of heating the one or more regions;
b. irradiating the substrate with the continuous beam of radiation as a first beam of radiation to form an irradiated image on the substrate at the one or more regions;
c. capturing reflected continuous radiation from the one or more regions of the substrate and directing the reflected radiation back to each of the one or more regions as a recycled radiation beam that approaches each of the one or more regions of the substrate at a non-normal incident angle selected according to the one or more regions of the substrate to a form a reflected image having, point by point, the same orientation as the irradiated image formed at the same of each of the one or more regions; and
d. scanning the first beam of radiation and the recycled radiation over the one or more regions so that the one or more regions receives an amount of thermal energy capable of processing the one or more regions;
wherein directing the reflected radiation back to the one or more regions includes:
directing the reflected light to a polarization-preserving roof mirror via a cylindrical mirror and a unit-magnification ( 1 X) relay, wherein the roof mirror is adapted to reflect the reflected radiation back through the unit-magnification relay in order to form a focused image at the substrate portion.
5. The method of claim 4 , wherein the recycled radiation beam is formed to have an incident angle corresponding to the minimum substrate reflectivity at the select wavelength.
6. The method of claim 4 wherein the recycled radiation beam is formed from parallel rays.