Tin stripping liquid

A technology of tin stripping and nitric acid, which is applied in the field of tin stripping liquid, can solve the problems of unstable tin stripping rate, high copper corrosion rate, and low amount of tin dissolution, and achieve stable and stable tin stripping rate, suppressed copper corrosion rate, and low tin stripping rate. The effect of high speed

Inactive Publication Date: 2010-06-30
广东奥美特集团有限公司
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  • Summary
  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

The deficiencies of these common nitric acid types are: the rate of tin removal is unstable, the amount of dissolved tin is low, the rate of copper corrosion is high, and the glos

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0012] 30% of industrial-grade nitric acid with a concentration of 65%, 9% of iron nitrate nonahydrate with a purity of 99% of industrial-grade ferric nitrate, 0.8% of sulfamic acid as a corrosion inhibitor, 0.6% of ethylenediamine as a surfactant, and 0.6% of soluble tin The agent is sodium chloride 0.8%, the brightener is thiourea 0.8%, and water 58%. Preparation method: Add water and ferric nitrate into the stirring tank and stir until the ferric nitrate is completely dissolved, then add nitric acid, and then stir to make the liquid uniform; cool the solution to below 40°C; finally add various additives such as corrosion inhibitors, surfactants, Tin dissolving agent, brightener, just stir to dissolve. The most important feature of this embodiment is the large tin stripping capacity, high and stable tin stripping rate.

Embodiment 2

[0014] Nitric acid with a concentration of 68% is 36.7%, iron nitrate is 11% iron nitrate nonahydrate with a purity of 99%, corrosion inhibitor is 0.5% benzotriazole, surfactant is 90% alcohol 0.8%, tin-dissolving agent is potassium chloride 0.5%, brightener is thiourea 0.5%, soft water 50%. The preparation method is the same as in Example 1. The most important feature of this embodiment is that the copper corrosion rate is significantly suppressed.

Embodiment 3

[0016] Concentration of 68% nitric acid 38%, ferric nitrate is 9.8% ferric nitrate nonahydrate with a purity of 99%, corrosion inhibitor is sulfamic acid 0.5%, surfactant is 96% alcohol 0.7%, tin dissolving agent sodium chloride 0.5% %, brightener is thiourea 0.5%, deionized water 50%. The preparation method is the same as in Example 1. The most important feature of this embodiment is that the treated copper surface has good gloss.

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Abstract

The invention relates to tin stripping liquid used for a process for stripping tin from a printed wiring board. The tin stripping liquid comprises the following ingredients: 30 to 38 percent of nitric acid, 9 to 11 percent of ferric nitrate, 0.5 to 0.8 percent of inhibitors, 0.6 to 0.8 percent of surface active agents, 0.5 to 0.8 percent of tin dissolving agents, 0.5 to 0.8 percent of brightening agents and 50 to 58 percent of water. The invention has the advantages that the tin stripping capacity is large and stable, the copper etching efficiency is obviously inhibited, and the processed copper surface has good laser and no agglomerated precipitates.

Description

technical field [0001] The invention relates to a tin stripping liquid used in the tin stripping process of a printed circuit board. Background technique [0002] At present, the main components of the tin stripping solution used for stripping tin from printed circuit boards are nitric acid and iron ions, or hydrogen peroxide and fluorine compounds, and there are also tin stripping solutions with inorganic acids and nitro-substituted aromatic compounds as the main components. liquid. Among them, the tin stripping solution with nitric acid and iron ions as the main components is more commonly used. The deficiencies of these common nitric acid types are: the rate of tin removal is unstable, the amount of dissolved tin is low, the rate of copper corrosion is high, and the gloss of the copper surface after treatment is not good; there is precipitation and coagulation, which blocks the nozzle of the machine; corrosion of the substrate and copper surfaces. Contents of the inve...

Claims

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Application Information

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IPC IPC(8): C23F1/30C23F3/06
Inventor 林春涛
Owner 广东奥美特集团有限公司
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