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Alkaline micro-etching liquid for copper surface treatment and preparation method of alkaline micro-etching liquid

A micro-etching solution and alkaline technology, which is applied in the field of alkaline micro-etching solution for copper surface treatment and its preparation, can solve the problems affecting the qualified rate of finished products, the area of ​​copper pads becomes smaller, and the open circuit becomes thinner.

Active Publication Date: 2022-04-15
SOUTH CHINA UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, under acidic conditions, two metals connected and different in activity, copper and gold, are in contact with the acidic microetching solution to undergo a galvanic reaction. The more active copper loses electrons and is oxidized (corroded). The essence is that the active metal is oxidized. Therefore, the biting amount of the acidic micro-etching solution on the copper pad is much larger than normal, resulting in a smaller area of ​​the copper pad, or a thinner open circuit of the copper hole, which affects the subsequent component mounting and reliability, and seriously affects the quality of the finished product. Pass rate

Method used

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  • Alkaline micro-etching liquid for copper surface treatment and preparation method of alkaline micro-etching liquid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] (1) Under continuous stirring conditions, add ferric chloride 60g, copper sulfate 51g, sulfamic acid 10g, sodium potassium tartrate 5g, urea 2.5g, formamide 2g, triethylamine 15g to pure water successively, mix uniformly, to obtain a mixed solution;

[0042] (2) Adjust the pH value of the mixed solution obtained in step (1) to 9.5 with ethanolamine, and finally dilute it to 1 L with pure water to obtain an alkaline microetching solution.

[0043] The alkaline micro-etching solution prepared by the foregoing embodiment has no corrosion to the nickel plate (according to the measurement method of the micro-etching rate, the micro-corrosion rate of the nickel-plated steel sheet is 0, and the nickel surface has no discoloration), and the copper layer is micro-etched. After that, the copper surface is uniform and shiny, and the measured microetching rate is 0.63 μm / min (25°C); 0.87 μm / min (30°C); 1.26 μm / min (40°C).

Embodiment 2

[0045] (1) Under continuous stirring conditions, 58g of ferric chloride, 47g of copper sulfate, 8g of sulfamic acid, 4g of sodium potassium tartrate, 2g of urea, 1g of formamide, and 10g of triethylamine were successively added to pure water, and mixed uniformly to obtain mixture;

[0046] (2) Adjust the pH value of the mixed solution obtained in step (1) to 9.0 with ethanolamine, and finally dilute it to 1 L with pure water to obtain an alkaline microetching solution.

[0047] The alkaline micro-etching solution prepared by the foregoing embodiment has no corrosion to the nickel plate (according to the measurement method of the micro-etching rate, the micro-corrosion rate of the nickel-plated steel sheet is 0, and the nickel surface has no discoloration), and the copper layer is micro-etched. After that, the copper surface is uniform and shiny, and the measured microetch rate is 0.61 μm / min (25°C); 0.84 μm / min (30°C); 1.18 μm / min (40°C).

Embodiment 3

[0049](1) Under continuous stirring conditions, add ferric chloride 62g, copper sulfate 55g, sulfamic acid 12g, sodium potassium tartrate 6g, urea 3g, formamide 3g, triethylamine 20g successively to pure water, mix uniformly, obtain mixture;

[0050] (2) Adjust the pH value of the mixed solution obtained in step (1) to 10.0 with ethanolamine, and finally dilute it to 1 L with pure water to obtain an alkaline microetching solution.

[0051] The alkaline micro-etching solution prepared by the foregoing embodiment has no corrosion to the nickel plate (according to the measurement method of the micro-etching rate, the micro-corrosion rate of the nickel-plated steel sheet is 0, and the nickel surface has no discoloration), and the copper layer is micro-etched. After that, the copper surface is uniform and shiny, and the measured microetching rate is 0.66 μm / min (25°C); 0.91 μm / min (30°C); 1.29 μm / min (40°C).

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Abstract

The invention discloses alkaline micro-etching liquid for copper surface treatment and a preparation method of the alkaline micro-etching liquid. The preparation method comprises the following steps: adding ferric chloride, copper sulfate, sulfamic acid, potassium sodium tartrate, urea, formamide and triethylamine into pure water under a continuous stirring condition, uniformly mixing, and finally adjusting the pH value to 9.5 by using ethanolamine to obtain the alkaline micro-etching liquid. According to the invention, the problem of corrosion discoloration generated when the nickel-plated steel sheet of the printed circuit board passes through an organic solderability preservative (OSP) process can be solved, the defect that a sulfuric acid-hydrogen peroxide micro-etching system is easily polluted by chloride ions is overcome, and the micro-etching rate is stable. The micro-etching liquid can also be used for chemical nickel gold and OSP micro-etching pretreatment, and can inhibit the galvanic effect, thereby improving the quality of the printed circuit board.

Description

technical field [0001] The invention belongs to the technical field of printed circuit board processing, and in particular relates to an alkaline microetching solution for copper surface treatment and a preparation method thereof. Background technique [0002] During the processing and production of flexible printed boards, nickel-plated steel sheets need to be pressed at certain positions to enhance the mechanical properties of the circuit board. During the processing process, the acidic microetching solution will corrode the nickel-plated steel sheet, and uneven discoloration may appear on the surface. This problem can be solved by increasing the thickness of the nickel layer, but this will lead to a substantial increase in cost. [0003] In the processing of some high-end circuit boards, the chemical nickel gold + OSP process is often used as the final surface treatment. However, this process is prone to produce Giavanni effect, which will cause quality defects. The Gia...

Claims

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Application Information

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IPC IPC(8): C23F1/34C23F1/44
CPCC23F1/34C23F1/44
Inventor 郭文杰
Owner SOUTH CHINA UNIV OF TECH