Minimization of Surface Reflectivity

A method for processing a surface of a substrate having a surface normal and a surface pattern, comprising:

• a. producing a photonic beam;
• b. directing the photonic beam toward the substrate surface at an incidence angle with respect the surface normal and at an orientation angle of the beam relative to the surface pattern;
• and
• c. scanning the beam across the substrate while maintaining the orientation angle and incidence angle at values selected to minimize substantially substrate surface reflectivity variations and/or minimize the substrate surface reflectivity during scanning.

A method for processing a surface of a substrate, wherein the surface has a surface normal and a surface pattern that exhibits directionally and/or orientationally different reflectivities relative to radiation of a selected wavelength and polarization, comprising:

• a. producing a photonic beam of the selected wavelength and polarization;
• b. directing the beam toward the substrate;
• and
• c. providing relative scanning movement between the stage and the beam while maintaining the substrate at a orientation angle value relative to the beam and the beam at incidence angle value relative to the substrate surface normal during scanning to minimize substantially substrate surface reflectivity variations and/or minimize the substrate surface reflectivity during scanning.

A method for selecting an optimal orientation angle and/or incidence angle for processing a surface of a substrate with a photonic beam of a selected wavelength and polarization, wherein the surface has a surface normal and a surface pattern that exhibits directionally and/or orientationally different reflectivities relative to radiation of the selected wavelength and polarization, comprising:

• a. directing the photonic beam toward the substrate surface at an incidence angle;
• b. scanning the photonic beam with respect to the substrate surface;
• c. measuring radiation reflected from the substrate during step b.;
• and
• d. repeating steps a. through c. while rotating the substrate about the normal and/or changing the incidence angle to find the optimal orientation and/or incidence angles that correspond to a minimum in substrate surface reflectivity variations and/or minimize the substrate surface reflectivity.