Photovoltaic devices with fine-line metallization and methods for manufacture

Abstract

A method for use in forming a photovoltaic device includes forming a doped semiconductor layer on a surface of a semiconductor substrate and forming a metal film on the doped semiconductor layer. A patterned etched resist is formed on the metal film and a dielectric layer is formed on the doped semiconductor layer and the etched resist. A laser having a wavelength absorbable by the patterned etch resist is applied through the dielectric layer to the patterned etch resist to remove the patterned etch resist.

1 . A method for use in forming a photovoltaic device, comprising:
 forming a metal film on the doped semiconductor;   forming a patterned etch resist on the metal film;   etching the metal film to form a metal grid pattern;   forming a dielectric layer on the doped semiconductor and the etch resist such that a first portion of the dielectric layer is directly on the etch resist and a second portion of the dielectric layer is directly on the doped semiconductor; and   applying a laser to the patterned etch resist through the dielectric layer to remove the patterned etch resist and the first portion of the dielectric layer.   
     
     
         2 . The method of  claim 1  wherein the etching the metal film to form the grid pattern comprises etching the metal film to form the metal grid pattern for a plurality of bus bars and a plurality of conductive fingers for the photovoltaic device. 
     
     
         3 . The method of  claim 1  wherein the forming the dielectric layer comprises forming the dielectric layer while retaining a texture pattern of the doped semiconductor. 
     
     
         4 . The method of  claim 1  wherein the applying the laser comprises applying the laser using full-area patterning. 
     
     
         5 . The method of  claim 1  further comprising pretreating the metal film prior to the forming of the patterned etch resist to make the metal film hydrophobic. 
     
     
         6 . The method of  claim 1  wherein the forming the etch resist further comprises curing the etch resist to pin the etch resist in a position on the seed metal layer. 
     
     
         7 . The method of  claim 1 , further comprising annealing the metal film after the patterned etch resist and the portion of the layer are removed. 
     
     
         8 . The method of  claim 7 , wherein the anneal is conducted at a temperature less than 500° C. 
     
     
         9 . The method of  claim 8 , wherein the anneal is conducted at a temperature in the range of about 250° C. to about 500° C. 
     
     
         10 . The method of  claim 7 , wherein the anneal is conducted for about 5 minutes. 
     
     
         11 . The method of  claim 1 , further comprising forming a conductor on the metal film to form a plurality of bus bars and a plurality of conductive fingers by electroplating. 
     
     
         12 . The method of  claim 11  wherein the forming the conductor comprises repairing an undercut in the seed metal layer. 
     
     
         13 . The method of  claim 11 , wherein the conductor is formed by electroless deposition. 
     
     
         14 . The method of  claim 11 , wherein the conductor is formed by an electroplated sequential deposition of nickel, copper and silver. 
     
     
         15 . The method of  claim 1 , wherein the laser has a wavelength of about 1064 nm absorbable by the patterned etch resist. 
     
     
         16 . The method of  claim 1 , wherein the laser beam comprises a plurality of non-overlapping laser spots. 
     
     
         17 . The method of  claim 1 , wherein the laser spots are spaced from each other by up to 50 micrometers. 
     
     
         18 . The method of  claim 1 , wherein the forming the dielectric layer comprises forming an antireflection layer or a passivation layer.