Patent ID: 8591716
Filing Date: 2013-11-26
Classification: B29D

Abstract:
1. A process of fabricating a semiconductor optical lens, said process comprising the steps of: preparing a semiconductor substrate having a flat top surface and a flat bottom surface opposed to each other; forming an anode on said bottom surface, placing said semiconductor substrate in an electrolyte solution; flowing a current between said anode and a cathode within said solution to anodize the top surface of said substrate to a varying depth from portions to portions, leaving a porous layer in said top surface; and removing said porous layer from said substrate to leave a curved surface on said top surface, thereby providing the lens having said curved surface on top of said substrate, said process being characterized by said anode which is deposited and on said bottom surface to give a consolidated structure and is configured to give a predetermined distribution of an electric field intensity which varies from portion to portions of said substrate across said top and bottom surfaces of said substrate, thereby providing said porous layer having the varying depth in match with the distribution of said electric field intensity, and also by including a smoothing step of smoothening out minute projections remaining on said curved surface, wherein said smoothing step follows the step of removing said porous layer and comprises: immersing said semiconductor substrate in an etching solution to etch out said minute projections, wherein said anode has an anode pattern, said anode pattern has an opening, whereby the top surface of said semiconductor substrate has a portion corresponding to said opening, said electrical current is flown between said anode and said cathode so as to anodize the top surface of said semiconductor substrate selectively in correspondence to the anode pattern, whereby the portion corresponding to said opening, of the top surface of said semiconductor substrate, is anodized to the varying depth and the portion forms the optical lens.