Tin/tin-lead stripping solutions

Claim 2

An improved tin/tin-lead stripping solution comprising: about 280 grams of ammonium bifluoride; about 100 milliliters of 35% by weight hydrogen peroxide; and about 1.0 gram of the amino acid glycine.

Claim 3

An improved tin/tin-lead stripping solution comprising: about 280 grams of ammonium bifluoride; about 100 milliliters of 35% by weight hydrogen peroxide; about 1.0 grams of the amino acid glycine; and about 0.4 gram of the aromatic carboxylic acid known as salicylic acid.

Claim 4

An improved tin/tin-lead stripping solution comprising: about 280 grams of ammonium bifluoride; about 100 milliliters of 35% by weight hydrogen peroxide; about 1.0 grams of the amino acid glycine; and about 0.4 gram of the aromatic carboxylic acid known as salicylic acid.

Claim 9

An acidic aqueous solution for selectively stripping tin or tin-lead solder alloy from a copper substrate comprising: a fluoride concentration of about 70-330 grams/liter in which the fluoride is supplied by hydrofluoric acid and/or one or more of its water/acid soluble salts, fluoboric acid and/or one or more of its water/acid soluble salts, or mixtures thereof; a hydrogen peroxide concentration of about 20-100 grams/liter actual hydrogen peroxide; and about 0.05-100 grams/liter of an amino acid compound, containing at least one amino group (NH 2 ), one carboxylic acid group (--COOH), and/or about 0.01 gram up to the limit of solubility of an aromatic carboxylic acid having the general formula: ##STR2## where R 1 , R 2 , R 3 , =H, OH, NH 2 , COOH R 4' =H, SO 3 H

Claim 10

An acidic aqueous solution for selectively stripping tin or tin-lead solder alloy from a copper substrate comprising: a fluoride concentration of about 70-330 grams/liter in which the fluoride is supplied by hydrofluoric acid and/or one or more of its water/acid soluble salts, fluoboric acid and/or one or more of its water/acid soluble salts, or mixtures thereof; a hydrogen peroxide concentration of about 20-100 grams/liter actual hydrogen peroxide; and about 0.05-100 grams/liter of an amino acid compound, containing at least one amino group (NH 2 ), one carboxylic acid group (--COOH), and/or about 0.01 gram up to the limit of solubility of an aromatic carboxylic acid having the general formula: ##STR2## where R 1 , R 2 , R 3 , =H, OH, NH 2 , COOH R 4' =H, SO 3 H

Claim 11

An acidic aqueous solution as recited in claim 5 wherein the amino acid compound contains only one amino (NH 2 ) group and one carboxylic acid group.

Claim 12

An acidic aqueous solution as recited in claim 6 wherein the selected amino acid is glycine.

Claim 13

An acidic aqueous solution as recited in claim 5 wherein the amino acid contains at least one amino group (NH 2 ), one carboxylic acid group, and a divalent sulfur group.

Claim 14

An acidic aqueous solution as recited in claim 8 wherein the selected amino acid is cysteine.

Claim 15

An acidic aqueous solution as recited in claim 5 wherein the aromatic carboxylic acid is ether benzoic acid, salicylic acid, or a mixture thereof.

Claim 16

An acidic aqueous solution as recited in claim 5 wherein the aromatic carboxylic acid contains a sulfonic acid group.

Claim 17

An acidic aqueous solution as recited in claim 11 wherein the aromatic carboxylic acid is 5-sulfosalicylic acid.

Claim 18

An acidic aqueous solution as recited in claim 5 wherein the solution is operated within a temperature range of 55° F.-145° F.

Claim 19

An acidic aqueous solution as recited in claim 13 wherein the solution contains a compatible hydrogen peroxide stabilizer.

Claim 20

An acidic aqueous solution as recited in claim 14 wherein the solution contains about 0.01-60 grams/liter of the hydrogen peroxide stabilizer having the general formula: CH.sub.3 --(CH.sub.2).sub.n --COOH where n=0-4.

Claim 21

An acidic aqueous solution as recited in claim 14 wherein the solution contains about 0.01-60 grams/liter of a hydrogen peroxide stabilizer which is selected from the group known as polyethylene glycols having the general formula: HO--(C.sub.2 H.sub.O).sub.n --C.sub.2 H.sub.2 --OH where n≧o.

Claim 22

An acidic aqueous solution as recited in claim 14 wherein the solution contains about 0.01-60 grams/liter of a hydrogen peroxide stabilizer which is selected from the group of compounds known as polypropylene glycols having the general formula: HO--(C.sub.3 H.sub.6 O).sub.n --C.sub.3 H.sub.6 OH where n≧o.