Goldplating solution unsubstituted with nickel

A technology of solution and gold plating layer, which is applied in the field of gold plating solution that is not replaced by nickel, and can solve problems such as poor bonding force of the gold plating layer

Inactive Publication Date: 2003-02-05
INST OF ELECTRONICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The commonly used sulfite gold plating solution and citrate gold plating solution will have part of the displaced gold mixed in the gold plating during the electroplating process, resulting in poor bonding of the gold plating layer.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Take an integrated circuit T0-8 lead shell, its substrate and leads are made of Kovar 4J29 material (Fe, Ni, Co alloy). It was previously chemically polished and pre-plated with 4-6 micron dark nickel and a layer of 1-1.5 micron thick electroless nickel. It is electroplated using a water-based electroplating solution with the following composition:

[0024] Potassium aurous cyanide 12 g / L

[0025] Potassium oxalate 80 g / L

[0026] Dipotassium hydrogen phosphate 25 g / L

[0027] Potassium dihydrogen phosphate 15 g / L

[0028] Potassium sulfite 4 g / L

[0029] Thiourea 0.08 g / L

[0030] Dipotassium EDTA 6 g / L

[0031] Potassium cyanide 1.5 g / L

[0032] The electroplating conditions are: the DC current density (barrel plating) used is 0.04A / dm 2 , the temperature of the electroplating solution is 55° C., the pH value is 8.0, and the electroplating time is 80 minutes.

[0033] The gold plating layer is 1.6 microns, and the bonding is 2.51mm 2 For silicon chips, its b...

Embodiment 2

[0035] Take a pressure sensor housing with an outer diameter of 18mm stainless steel substrate and an inner lead wire of ф0.45mm Kovar (4J29 Ni, Fe, Co, alloy). , lead wire energization in this shell, in the water base gold-plating solution of the present invention composition as follows:

[0036] Potassium aurous cyanide 16 g / L

[0037] Potassium dihydrogen phosphate 10 g / L

[0038] Dipotassium hydrogen phosphate 20 g / L

[0039] Potassium oxalate 100 g / L

[0040] Potassium sulfite 6 g / L

[0041] Dipotassium EDTA 8 g / L

[0042] Potassium metabisulfite 0.02 g / L

[0043] The electroplating conditions are: the temperature of the electroplating solution is 60°C, the pH value is 8.0; the DC current density (rack plating) is 0.2A / dm 2 , the plating time is 15 minutes.

[0044] The thickness of the gold layer is 1.40 microns, and the bonding strength can reach 8.25 grams with ф38 microns silicon-aluminum wire bonding wire, and the standard value is 2.5 grams (microelectronic d...

Embodiment 3

[0046] Take a thickness of 2.2mm and an area of ​​30×30mm 2 Kovar material base (4J29, Ni, Fe, Co alloy), lead wire is ф0.50mm Kovar wire (same base material) 28-lead hybrid circuit shell, the shell is pre-plated with 6 micron sulfamate nickel and 1.5 micron thick chemical nickel, Then, under lead wire energization, base not energization condition, in the water-based gold-plating solution of the present invention composition as follows:

[0047] Potassium aurous cyanide 16 g / L

[0048] Potassium dihydrogen phosphate 12 g / L

[0049] Dipotassium hydrogen phosphate 25 g / L

[0050] Potassium oxalate 120 g / L

[0051] Potassium sulfite 3 g / L

[0052] Potassium cyanide 6 g / L

[0053] Thiourea 0.08 g / L

[0054] Dipotassium EDTA 12 g / L

[0055] Gold plating conditions are: bath temperature is 55°C, pH value is 8.5; average current density is 0.2A / dm 2 , The electroplating time is 25 minutes, the current waveform is square wave DC, and the working ratio is 0.1:0.9ms.

[0056] The...

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Abstract

The present invention provides a gold-plating solution which can not be substituted by nickel. When the matrix for plating chemical nickel is not powdered with direct current, the matrix can not be substituted in the gold-plating solution to form layer with poor adhesive force, so that it can raise boding force of gold-plated layer on the matrix. Said invention water base gold-plating solution contains potassium dicyanoaurate, EDTA salt, pyrophosphite and thiourea. The use condition of gold-plating solution includes: temp. of plating solution is 55-60 deg.C, pH value is 7.5-10, current intensity is 0.04-0.5 A/sq.dm, and its power supply can be D.C. power supply or pulse square-wave power supply.

Description

technical field [0001] The invention relates to a gold-plating solution, more specifically, a gold-plating solution that is not replaced by nickel, and its application in gold-plating processes for microelectronics, semiconductor devices and certain electronic components. Background technique [0002] In the packaging production of semiconductor devices, the problem of failure of the bonding strength between the chip and the casing substrate often occurs, especially when the casing substrate is produced by barrel gold plating. When people use this method to plate gold, they often cannot detect the phenomenon that the nickel plating layer of the substrate is replaced by gold. When the nickel-plated shell is put into the gold-plating solution without electricity, it will be found that the surface of the shell substrate is quickly replaced by a layer of gold. The substituted or partially substituted gold layer has weak bonding force with the substrate. Reflected in the die bo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/48
Inventor 许维源马金娣
Owner INST OF ELECTRONICS CHINESE ACAD OF SCI
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