Patent ID: 8574951

Claim:
A process of manufacturing an interdigitated back-contact solar cell, comprising at least the following steps: (F) providing a semiconductor substrate having a micro-structure surface, forming a heavily doped N ++ semiconductor layer on a front side and a back side of said semiconductor substrate, wherein a chemical-resistant mask layer is coated on the back side of said semiconductor substrate by screen printing or spraying to form a first mask layer; said semiconductor substrate is placed into a chemical etching solution to remove a certain thickness of said heavily doped N ++ semiconductor layer on a front side of said semiconductor substrate so that the heavily doped N ++ semiconductor layer on the front side of said semiconductor substrate becomes a lightly doped first N-type semiconductor layer; and said first mask layer is removed; (G) performing a screen printing or spraying process to form, respectively, a second mask layer on the front side of said semiconductor substrate to cover said first N-type semiconductor layer, and to form a patterned third mask layer on the back side of said semiconductor substrate, so that the N ++ semiconductor layer on the back side of said semiconductor substrate is partially exposed while the unexposed part of the N++ semiconductor layer is protected by said third mask layer; (H) etching the interior of the semiconductor substrate by using a chemical etching solution to form a plurality of trenches in the exposed part of the N ++ semiconductor layer, and the unexposed part of the N ++ semiconductor layer protected by said third mask layer is less susceptible to etching, or is completely un-etched, maintaining the function of back surface field, wherein the unexposed part of the N ++ semiconductor layer protected by said third mask layer forms a second N-type semiconductor layer, meanwhile said first N-type semiconductor layer on the front side of said semiconductor substrate is protected by said second mask layer, maintaining the function of front surface field; (I) removing said second and third mask layers, and then coating an antireflection layer on the front side of said semiconductor substrate; and (J) forming a P-type metal electrode and an N-type metal electrode by printing, respectively, in the trench and at a part of the area of said second N-type semiconductor layer, and then forming a P-type semiconductor layer at a part of the bottom or at the whole bottom of each trench through co-firing so that said P-type metal electrode and said N-type metal electrode both form good electrical contact with said semiconductor substrate in the fabrication of the interdigitated back-contact solar cell.