Method for electroplating silver on surface of printed circuit board through pulse current

A printed circuit board, pulse current technology, applied in the direction of circuits, semiconductor devices, etc., can solve the problems of PC power supply and power supply price that cannot provide high power, high cost of electroless nickel plating, and limit industrialization process, etc., to reduce the porosity of the plating layer The effect of reducing the plating time and improving the purity of the coating

Inactive Publication Date: 2015-11-18
ZHUHAI YUANSHENG ELECTRONICS SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main reason is due to the high cost of electroless nickel plating and the limited assembly of organic solder resist protective agent, and the poor compatibility with flux
[0003] Pulse electroplating technology started in our country in the late 1970s. It has achieved remarkable results in precious metal electroplating. Although it has many advantages, its industrialization process is limited because it cannot provide high-power PC power supply and the power supply is expensive.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Polish the copper plate of the cathode with 320-mesh and 600-mesh sandpaper, and degrease with an alkaline degreasing agent. Use about 15% hydrochloric acid solution to remove the oxide layer on the surface of steel parts. Then activate by immersing in 10% hydrochloric acid solution for 30 seconds to 1 minute at room temperature; the main purpose of activation is to expose the new matrix structure, so as to increase the epitaxiality of the coating metal grain growth and improve the bonding between the coating and the substrate force. The same below.

[0019] Electroplating is carried out at a temperature of 50-60°C, using reverse pulse plating, pulse parameters: forward current 5A, reverse current 15A, forward pulse time 18ms, reverse pulse time 2ms, plating time 60min.

[0020] In this embodiment, the uniformity and compactness of the silver on the electrodeposited through hole are good, and the bonding force with the copper substrate is good.

Embodiment 2

[0022] Polish the copper plate of the cathode with 320-mesh and 600-mesh sandpaper, and degrease with an alkaline degreasing agent. Use about 15% hydrochloric acid solution to remove the oxide layer on the surface of steel parts. Then soak in 10% hydrochloric acid solution at room temperature for 30 seconds to 1 minute to activate.

[0023] Electroplating is carried out at a temperature of 50-60°C, using reverse pulse electroplating, pulse parameters: forward current 5A, reverse current 15A, forward pulse time 36ms, 72ms, 108ms, reverse pulse time 2ms, electroplating The time is 60 minutes.

[0024] In this embodiment, the uniformity and compactness of the silver on the electrodeposited through hole are good, and the bonding force with the copper substrate is good. As the forward pulse time increases, the uniformity performance of the via increases.

Embodiment 3

[0026] Polish the copper plate of the cathode with 320-mesh and 600-mesh sandpaper, and degrease with an alkaline degreasing agent. Use about 15% hydrochloric acid solution to remove the oxide layer on the surface of steel parts. Then soak in 10% hydrochloric acid solution at room temperature for 30 seconds to 1 minute to activate.

[0027] Electroplating is carried out at a temperature of 50-60°C, using reverse pulse electroplating, pulse parameters: forward current 5A, reverse current 15A, forward pulse time 18ms, reverse pulse time 2ms, 4ms, 8ms, plating time for 60min.

[0028] In this embodiment, the uniformity and compactness of the silver on the electrodeposited through hole are good, and the bonding force with the copper substrate is good. With the increase of the reverse pulse time, the through-hole uniformity of all apertures first increases and then decreases, and the extreme value is obtained when the reverse pulse time is 4ms.

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PUM

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Abstract

The invention discloses a method for electroplating silver on the surface of a printed circuit board through pulse current. The method is low in cost, simple in process and controllable. The method comprises the steps of (1) preparing electroplate liquid containing silver salt and (2) carrying out the silver plating process. In the step (1), silver cyanide, sodium cyanide and sodium hydroxide are used as main salt, dimethylamine-borane and thiourea serve as supporting electrolytes, and an inorganic molten salt plating solution system is prepared. In the step (2), the silver plating process comprises the steps of grinding of the surface of the printed circuit board, chemical oil removal, water flushing, brush polishing, etching activation, pulse silver plating, washing and drying, wherein the pulse silver plating process is that electroplating is carried out at the temperature of 50-60 DEG C, and reverse pulse electroplating is adopted; pulse parameters are that forward current is 5-15 A, reverse current is 15 A, forward pulse time is 18-108 ms, reverse pulse time is 2 ms, and electroplating time is 60 min. The method can be applied to the field of metal materials.

Description

technical field [0001] The object of the present invention is to provide a method for electroplating silver on the surface of a printed board with pulse current with low cost and simple and controllable process. It specifically relates to electroplating silver on the surface of a printed board with a pulse current, and belongs to the technical field of metal materials. Background technique [0002] The electroless silver plating process has been applied to printed circuit boards for a long time, but due to its susceptibility to air oxidation, it forms a black oxide film layer, which not only has poor surface quality, but more importantly, the surface resistance changes greatly, which directly affects the carrier. electrical properties. However, after improvement, electroless silver plating can be used for both soldering and pressure welding, so it is generally valued. The main reason is due to the high cost of the electroless nickel plating used and the limited assembly of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D5/18C25D3/46C25D7/12
Inventor 徐景浩何波胡文成
Owner ZHUHAI YUANSHENG ELECTRONICS SCI & TECH
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