Photovoltaic devices with fine-line metallization and methods for manufacture
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 a doped semiconductor;
forming a patterned etch resist on the metal film;
etching the metal film;
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 first portion and the second portion, the laser having a wavelength absorbable by the patterned etch resist through the dielectric layer to the patterned etch resist, the laser removing the patterned etch resist and the first portion of the dielectric layer, the laser heating the etch resist to cause the etch resist to expand and crumble and the first portion of the dielectric layer breaking apart in response to the expanding and crumbling of the etch resist.
2. 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.
3. 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 metal film.
4. The method of claim 1 , further comprising annealing the metal film after the patterned etch resist and the first portion of the dielectric of the layer are removed.
5. The method of claim 4 , wherein the anneal is conducted at a temperature less than 500° C.
6. The method of claim 5 , wherein the anneal is conducted at a temperature in the range of about 250° C. to about 500° C.
7. The method of claim 4 , wherein the anneal is conducted for about 5 minutes.
8. The method of claim 1 , further comprising forming a conductor on the metal film by electroplating.
9. The method of claim 8 wherein the forming the conductor comprises repairing an undercut in the metal film.
10. The method of claim 8 , wherein the conductor is formed by electroless deposition.
11. The method of claim 8 , wherein the conductor is formed by an electroplated sequential deposition of nickel, copper and silver.
12. The method of claim 1 , wherein the wavelength comprises a wavelength of about 1064 nm.
13. The method of claim 1 , wherein the laser beam comprises a plurality of non-overlapping laser spots.
14. The method of claim 1 , wherein the laser spots are spaced from each other by up to 50 micrometers.
15. The method of claim 1 , wherein the forming the dielectric layer comprises forming an antireflection layer or a passivation layer.