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US 8,148,191 B2Granted
Combined etching and doping media
AssigneeMerck Patent GmbH
InventorsSylke Klein, Armin Kübelbeck, Werner Stockum, Wilfried Schmidt, Berthold Schum
Life of this patent
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Abstract
The present invention relates firstly to HF/fluoride-free etching and doping media which are suitable both for the etching of inorganic layers and also for the doping of underlying layers. The present invention secondly also relates to a process in which these media are employed.
Claims10
A process for the etching of passivation and antireflection layers of silicon nitride on solar cells, comprising
- (a) applying a printable paste-form etching medium comprising phosphoric acid or a salt thereof in a single process step, over the entire surface of said solar cell or selectively to the surface regions of said solar cell to be etched, and
- (b) heating the entire surface or the surface regions to be etched to 250 to 350° C. for from 30 to 120 seconds.
A process for the etching of passivation and antireflection layers of silicon nitride on solar cells, comprising
- (a) applying a printable paste etching medium in a single process step, over the entire surface or selectively to the surface regions to be etched, and
- (b) heating the entire surface or the surface regions to be etched to 250 to 350° C. for from 30 to 120 seconds,
- wherein said printable paste etching medium comprises an etchant component consisting essentially of phosphoric acid or a salt thereof and 1-20% by weight of a thickener, based on the total weight of the etching paste.
Dependencies are inferred from the claim text.