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Flexible circuit plating surface whisker inhibition technology

A surface suppression and flexible circuit technology, applied in the field of whisker suppression on the surface of flexible circuit electroplating, can solve problems such as hidden dangers of fine line spacing circuits, lack of competitiveness of products, deterioration of solder wettability, etc., and achieve low cost and electroplating workability. Good effect of eliminating whisker growth

Active Publication Date: 2010-10-27
厦门华天华电子有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

There are several ways to use lead-free treatment: one is to use tin-copper (Sn / Cu) alloy. In a well-managed enterprise, if the basic process and the ratio of metal ions are well controlled, it will be effective in inhibiting the growth of whiskers. Obvious effect, but not ideal, and it is difficult to completely eliminate it, especially for fine-pitch circuits. The second is to use Ni / Au electroplating. Although this method can prevent whisker growth, the cost is Sn / Cu It is not economically suitable and the product lacks competitiveness; the third is to use pure tin electroplating (Sn), but the disadvantages of pure tin electroplating are prominent. The biggest problem is that the wettability of solder deteriorates over time, so it is not easy to promote

Method used

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  • Flexible circuit plating surface whisker inhibition technology
  • Flexible circuit plating surface whisker inhibition technology
  • Flexible circuit plating surface whisker inhibition technology

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] The pickling steps include: spraying in a 1% sulfuric acid solution tank at a temperature of 25° C. and a speed of 2 m / min; washing with clear water.

[0015] The mechanical brushing step is as follows: brushing is carried out on a 1000-mesh alumina brush roller with a transmission speed of 1.5 m / min and a rotating speed of 1200 rpm.

[0016] The aging treatment step is as follows: put the product in layers in an oven to ensure a uniform heating temperature, and then heat it for 120 minutes at a temperature of 145° C. to perform post-aging treatment.

Embodiment 2

[0018] The pickling steps include: spraying in a 2% sulfuric acid solution tank at a temperature of 35° C. and a speed of 2.5 m / min; washing with clear water.

[0019] The mechanical brushing step is as follows: brushing is carried out on a 1200-mesh alumina brush roller with a transmission speed of 2.0 m / min and a rotating speed of 1400 rpm.

[0020] The aging treatment step is as follows: put the product in layers in an oven to ensure uniform heating temperature, and heat for 150 minutes at a temperature of 155° C. to perform post-aging treatment.

[0021] In addition, the present invention requires the following key points for process control of electroplated tin-copper (Sn / Cu) alloy products:

[0022] 1) Quantitative analysis must be carried out on the ratio of copper ions precipitated from the electroplating layer. When the content of copper ions in the electrolyte increases, the content of copper ions in the plating layer also increases almost proportionally, and the al...

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Abstract

The invention discloses a flexible circuit plating surface whisker inhibition technology. The technique adds acid cleaning, mechanical brushing and ageing treatment besides plating in the traditional technology. The adopted mechanical brushing can effectively mechanically damage the original plating metal structure, thereby damaging whisker growth condition and stopping the whisker growth, thus the flexible circuit product meets the requirement of long term reliability. The technology of the invention is implemented to eliminate the problem that the whisker growth is difficult to overcome in previous lead-free plating, find out a method with less investment, simple technology control and obvious whisker growth inhibiting effect, thus being a new technology with good plating workability andlow cost in the industry and providing basic assurance for long term reliability of the plating products of fine circuit processing.

Description

technical field [0001] The invention relates to a method for manufacturing a circuit board, in particular to a process for suppressing whiskers on the electroplating surface of a flexible circuit. Background technique [0002] Metal whiskers have always been an invisible killer of electronic devices and equipment failures. Due to the long time characteristic of whiskers growth, there is no problem in short-term equipment operation, so it is easy for people to ignore its harm. With the technological advancement of electronic circuits, the density is getting higher and higher, and the conductor spacing of flexible circuits is getting finer. In the design and processing of flexible circuits, the contradictions are becoming more and more prominent, which has restricted the healthy development of flexible circuits in various fields. [0003] The current status of the flexible circuit processing industry is that although the application of tin-lead alloys can effectively inhibit t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23G1/02C25D5/48C25D5/50
Inventor 李敏
Owner 厦门华天华电子有限公司