Method for manufacturing flexible circuit board

A technology for flexible circuit boards and manufacturing methods, which is applied to the reinforcement of conductive patterns and the secondary treatment of printed circuits, etc., can solve the problems of long soldering time, difficult process control, and high difficulty, and achieve the reduction of tin whiskers. Easy to operate and prevent mutual diffusion effect

Inactive Publication Date: 2011-01-12
XIAMEN DIAL ELECTRONICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this process is difficult to control, the difficulty is large, the operable range is small, and the copper content in the coating is difficult to control
2. A layer of tin is chemically plated on the bare copper of the flexible circuit board (called: chemical immersio

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example Embodiment

[0016] Example one:

[0017] A method for manufacturing a flexible circuit board includes the following steps:

[0018] 1. Degreasing: Put the flexible circuit board into a container containing an acid degreasing agent with a concentration of 15% (V / V). The temperature of the solution is 30°C and soak for 5 minutes;

[0019] 2. Water washing: clean the dirt and liquid medicine on the surface of the flexible circuit board;

[0020] 3. Micro-etching: Put the flexible circuit board into a tank containing a micro-etching solution formed by mixing sodium persulfate, sulfuric acid and water. The sodium persulfate is 80 g / l and the sulfuric acid is 3% (V / V) , The temperature of the microetching solution is 20℃, and the immersion time is 30 seconds;

[0021] 4. Pickling in acid: Put the flexible circuit board into a container with a concentration of 5% methanesulfonic acid solution and soak for 1 minute;

[0022] 5. Chemical tin deposition: Put the flexible circuit board into a container contai...

Example Embodiment

[0031] Embodiment two:

[0032] A method for manufacturing a flexible circuit board includes the following steps:

[0033] 1. Degreasing: Put the flexible circuit board into a container containing an acid degreasing agent with a concentration of 10% (V / V). The temperature of the solution is 40°C and soak for 5 minutes;

[0034] 2. Water washing: clean the dirt and liquid medicine on the surface of the flexible circuit board;

[0035] 3. Micro-etching: Put the flexible circuit board into a tank containing a micro-etching solution formed by mixing sodium persulfate, sulfuric acid and water. Sodium persulfate is 50 g / L and sulfuric acid is 2% (V / V) , The temperature of the micro-etching solution is 30℃, and the immersion time is 90 seconds;

[0036] 4. Acid pickling: the flexible circuit board is soaked in a container with a concentration of 10% methanesulfonic acid solution for 2 minutes;

[0037] 5. Chemical tin deposition: Put the flexible circuit board into a container containing tin t...

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PUM

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Abstract

The invention discloses a method for manufacturing a flexible circuit board, which comprises processes of oil removal, washing, micro etching, acid dipping, tinning and drying of the flexible circuit board. The method is characterized in that: after the acid dipping of the flexible circuit board and before tinning, chemical tin deposition is performed. Because the chemical tin deposition is performed before tinning, a chemical tin deposition layer serving as a barrier layer is increased between the copper of the flexible circuit board and the tin of the plating layer so as to effectively prevent mutual diffusion of the copper of the flexible circuit board and the tin of the tinning layer and reduce the generation of tin whiskers without changing the properties and purposes of the flexible circuit board; and the method is convenient in process operation, simple, reliable and easy to control.

Description

technical field [0001] The invention relates to a method for manufacturing a flexible circuit board, in particular to a method for manufacturing a flexible circuit board capable of reducing tin whiskers. Background technique [0002] Flexible circuit boards are widely used. Usually, a layer of tin is plated on the exposed copper surface of the flexible circuit board with a thickness of 5-15 microns to protect the copper surface from oxidation and improve solderability. The tin plating process is simple, easy to control, low in price, good in solderability, in line with environmental protection requirements, and widely used in circuit boards. However, after tin plating, tin and copper diffuse each other to form intermetallic compounds, and the internal compressive stress of the tin layer increases rapidly, causing tin atoms to diffuse along the crystal boundaries, forming tin whiskers, and causing short circuits. With the increase of circuit board density, the distance betw...

Claims

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Application Information

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IPC IPC(8): H05K3/22H05K3/24
Inventor 张利
Owner XIAMEN DIAL ELECTRONICS
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