METHODS TO SELECTIVELY TREAT PORTIONS OF A SURFACE USING A SELF-REGISTERING MASK

摘要

Processes increase light absorption into silicon wafers by selectively changing the reflective properties of the bottom portions of light trapping cavity features. Modification of light trapping features includes: deepening the bottom portion, increasing the curvature of the bottom portion, and roughening the bottom portion, all accomplished through etching. Modification may also be by the selective addition of material at the bottom of cavity features. Different types of features in the same wafers may be treated differently. Some may receive a treatment that improves light trapping while another is deliberately excluded from such treatment. Some may be deepened, some roughened, some both. No alignment is needed to achieve this selectively. The masking step achieves self-alignment to previously created light trapping features due to softening and deformation in place.

主权项

1. A method for providing a texture to a semiconductor surface, the method comprising the steps of:
a. providing a mask of material on the surface, which mask material is patterned so that some regions of the surface are covered with resist material, and a plurality of region are exposed; b. providing an etchant to the surface; c. allowing the etchant to etch away semiconductor material at the exposed regions, thereby producing a plurality of cavities in the surface, which cavities undercut the mask material, leaving overhanging portions of mask material; d. deforming the overhanging mask portions into covering proximity with a portion of the surface of the plurality of cavities, wherein at least a region of each cavity surface remains exposed; and e. providing, to the semiconductor surface a treating agent, of a type and under conditions such that, cavity surface portions covered by the mask resist treatment and the exposed regions of the cavities become treated.