Process for reducing series resistance of solar cell metal contact systems with a soldering flux etchant

Claim 2

A process for substantially reducing the series resistance of a solar cell having a thick film metal contact assembly thereon while simultaneously removing metal oxides from the surface of said contact assembly prior to applying solder thereon without a need to etch said oxides with a hydrofluoric acid, said process comprising the steps of: (a) applying a flux to said solar cell contact assembly; (b) removing said series resistance associated with said thick film contact assembly without using said hydrofluoric acid to etch said metal oxides by heating said cell for a period of time sufficient to cause said flux to substantially etch away said metal oxides from said surface of said assembly during said heating.

Claim 3

A process as recited in claim 1, wherein said flux is an organic soldering flux.

Claim 4

A process as recited in claim 1, wherein said flux is an inorganic soldering flux.

Claim 5

A process as recited in claim 1, wherein said cell is heated to a first temperature substantially equal to a second temperature used to apply said solder to said assembly.

Claim 6

A process as recited in claim 1, wherein a range of said period of time in which said flux is heated is from about 1 second to about 1000 seconds.

Claim 7

A process as recited in claim 4, wherein a range of said first temperature for heating said flux is from about 25° C. to about 300° C.

Claim 8

A thick film metallization process for solar cells, said process comprising the steps of: (a) depositing a thick film material onto a semiconductor substrate to form a conductor assembly thereon, said thick film material including metal oxides and a frit-like material; (b) heating said substrate and said thick film material sufficient to form a glaze-like film between said substrate and said thick film material, said film causing said metal oxides to be bonded to said substrate; (c) applying a flux to said conductor assembly defined by said thick film material deposited on said substrate; (d) substantially removing a series resistance associated with said thick film material defined by said conductor assembly while substantially removing said oxides from said surface of said thick film material without a need to etch said metal oxides with a hydrofluoric etchant by heating said conductor assembly to a first temperature for a period of time sufficient to cause said flux to substantially etch away said metal oxides during said heating; and (e) soldering said conductor assembly to an electrical assembly to form a functional solar cell, said first temperature being substantially equal to a solder-melt temperature for a desired solder subsequently applied to said assembly.

Claim 9

A thick film metallization process for solar cells, said process comprising the steps of: (a) depositing a thick film material onto a semiconductor substrate to form a conductor assembly thereon, said thick film material including metal oxides and a frit-like material; (b) heating said substrate and said thick film material sufficient to form a glaze-like film between said substrate and said thick film material, said film causing said metal oxides to be bonded to said substrate; (c) applying a flux to said conductor assembly defined by said thick film material deposited on said substrate; (d) substantially removing a series resistance associated with said thick film material defined by said conductor assembly while substantially removing said oxides from said surface of said thick film material without a need to etch said metal oxides with a hydrofluoric etchant by heating said conductor assembly to a first temperature for a period of time sufficient to cause said flux to substantially etch away said metal oxides during said heating; and (e) soldering said conductor assembly to an electrical assembly to form a functional solar cell, said first temperature being substantially equal to a solder-melt temperature for a desired solder subsequently applied to said assembly.

Claim 10

A thick film metallization process as recited in claim 7, wherein said flux is an organic flux.

Claim 11

A thick film metallization process as recited in claim 7, wherein said flux is an inorganic flux.

Claim 12

A thick film metallization process as recited in claim 9, wherein a range of first period of time in which said conductor assembly is heated is from about 1 second to about 1000 seconds.

Claim 13

A thick film metallization process as recited in claim 10, wherein a range of said first temperature for heating said flux is from about 25° C. to about 300° C.