Lead-free electroless tin plating solution

A tin plating solution and lead-free chemical technology, applied in the field of lead-free electroless tin plating solution, can solve the problems of inability to realize continuous autocatalytic deposition of tin, inability to process deep hole parts, blind hole parts, and inability to meet industrial requirements, etc. Few types, low cost, easy to control effect

CN102994994AInactive Publication Date: 2013-03-27NANTONG HUIFENG ELECTRONICS TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2013-03-27
Estimated Expiration
Not applicable · inactive patent
Patent Text Reader

Abstract

The invention relates to a lead-free electroless tin plating solution. The lead-free electroless tin plating solution is characterized by comprising the following components: 20 to 30g / L of stannous mono-sulphate, 60 to 120g / L of thiourea, 15 to 25g / L of citric acid, 20 to 50g / L of sulfur dioxide, 3 to 5g / L of ethylene diamine tetraacetic acid, 0.01 to 0.05g / L of polyethylene glycol, 20 to 55m / L of 98% of concentrated sulfuric acid, 0.5 to 1.0g / L of gelatin, and the balance of regulator. The lead-free electroless tin plating solution has the advantages that few categories of chemical materials are used and cost is low; the tin can be continuously deposited at a high speed on copper and a copper alloy substrate, thus semi-bright chemical coatings with different thicknesses can be produced, and the flatness of the chemical coatings can be improved; and the lead-free electroless tin plating solution is remarkable in grain refinement, low in porosity, simple in formula of plating solution, easy to control, stable in plating solution, long in service life and high in stability in batch production; and polyethylene glycol is a nontoxic and nonirritating substance with high water solubility, and can be combined with other materials without producing harmful substances.
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Description

technical field

[0001] The invention relates to a lead-free chemical tin plating solution. Background technique

[0002] With the miniaturization of electronic products, since the tin-plated layer is a coating with good solderability and certain corrosion resistance, it is widely used in electronic wires and printed circuit boards. The tin-plated layer can be electroplated, dipped and chemically Plating method is prepared, immersion tin is easy to operate and low in cost, but the thickness of the coating is limited, generally only 0.5 μm, the plating solution is easily poisoned, and cannot meet industrial requirements. Electrolytic tin plating cannot process deep hole parts and blind hole parts. Electroless tin plating The thickness of the coating is uniform, the dispersion ability of the plating solution is good, the production efficiency is high, and the operation is easy to control. Electroless plating technology for electronic wires, but because tin has high hydrogen ev...

Examples

Embodiment 1

[0019] A lead-free chemical tin plating solution, the lead-free chemical tin plating solution is composed of the following components: 20g / L of stannous sulfate; 60g / L of thiourea; 15g / L of citric acid; 20g / L of sulfur dioxide; 3g / L; polyethylene glycol 0.01g / L; 98% concentrated sulfuric acid 20m / L; gelatin 0.5g / L; the rest is sulfuric acid.

Embodiment 2

[0021] A lead-free chemical tin plating solution, the lead-free chemical tin plating solution is composed of the following components: tin protochloride 25g / L; thiourea 90g / L; citric acid 20g / L; sulfur dioxide 30g / L; Acetic acid 4g / L; polyethylene glycol 0.03g / L; 98% concentrated sulfuric acid 35m / L; gelatin 0.7g / L; the rest is a combination of sulfuric acid and ammonia water.

Embodiment 3

[0023] A lead-free chemical tin plating solution, which is composed of the following components: tin tetrachloride pentahydrate 30g / L; thiourea 120g / L; citric acid 25g / L; sulfur dioxide 50g / L; Diamine tetraacetic acid 5g / L; polyethylene glycol 0.05 g / L; 98% concentrated sulfuric acid 55m / L; gelatin 1.0g / L; the rest is ammonia water.

[0024] The tin plating solution has few types of chemical materials and low cost. Continuous self-catalytic deposition of tin is realized on copper and copper alloy substrates. The deposition speed is fast, and semi-bright chemical coatings of different thicknesses can be obtained, which improves the flatness of the chemical coating and the grain size. Obvious refinement, low porosity, simple plating solution formula, easy to control, stable plating solution, long service life, high batch production stability, polyethylene glycol is a non-toxic, non-irritating substance with good Water-soluble, so no harmful substances will be produced when combi...