Electroplating solution for gold-tin eutectic alloy

A technology of tin alloy and alloy, applied in the field of electrolyte

Inactive Publication Date: 2008-03-26
B F TECHNOLOGY INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] As mentioned above, the electrolytes of the prior art are not always stable and have also been found to be useful in providing eutectic gold-tin, especially for the electroplating of small moldings for electronic components or composite substrates. alloy is ineffective

Method used

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  • Electroplating solution for gold-tin eutectic alloy
  • Electroplating solution for gold-tin eutectic alloy
  • Electroplating solution for gold-tin eutectic alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Eutectic gold-tin alloy electrodeposits were obtained from the following electrolytes:

[0048] Citric acid 52g / l

[0049] Potassium citrate 67g / l

[0050] Tin (in the form of tin sulfate) 3g / l

[0051] Gold (in the form of potassium gold cyanide) 6g / l

[0052] Ethoxylated phenol esters 0.15ml / l

[0053] Catechol 1g / l

[0054] pH 4.0 adjusted with KOH

[0055] The citric acid electrolyte deposits 80-20 wt% gold-tin alloy with a semi-bright appearance. The current density was 10 ASF and the temperature was 140°F.

Embodiment 2

[0057] Ascorbic acid 100g / l

[0058] Tin (in the form of tin sulfate) 3g / l

[0059] Gold (in the form of potassium gold cyanide) 13g / l

[0060] Ethoxylated phenol esters 0.15ml / l

[0061] pH adjusted with KOH 4

[0062] The ascorbic acid electrolyte deposits 80-20 wt% gold-tin alloy with a semi-bright appearance. The current density was 10 ASF, and the temperature was 120°F.

Embodiment 3

[0064] Potassium Malonate 100g / l

[0065] Tin (in the form of tin sulfate) 1g / l

[0066] Gold (in the form of potassium gold cyanide) 6g / l

[0067] Ethoxylated phenol esters 0.35ml / l

[0068] Ascorbic acid 2g / l

[0069] pH adjusted with KOH 4

[0070] The potassium malonate electrolyte deposits 80-20 wt% gold-tin alloy with a semi-bright appearance. The current density was 10 ASF and the temperature was 130°F.

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Abstract

The invention relates to an electrolyte used in connection with the deposition of a gold-tin alloy on an electroplatable substrate. This solution generally includes water; stannous and / or stannic tin ions, a complexing agent to render the stannous and / or stannic tin ions soluble, complexed gold ions, and an alloy stabilizing agent that includes ethoxylated compounds with phosphate ester functional group, brightening additives based on ethoxylated phosphate esters and alkali metal fatty acids dipropionates. The brighteners may be used alone or in conjunction with each other to achieve beneficial synergistic effect. The alloy stabilizing agent is present in an amount sufficient to stabilize the composition of the gold-tin deposit over a usable current density range. The solution has a pH of between 2 and 10 and the gold ions and tin ions are present in relative amounts sufficient to provide a deposit having a gold content less than 90% by weight and a tin content greater than 10% by weight.

Description

field of invention [0001] The present invention describes an electrolyte for depositing eutectic gold-tin alloys that can be used in a variety of microelectronic applications, including die bonding and wafer strike plating. It is especially desirable to use an 80-20 weight percent (70-30 atomic %) eutectic gold-tin alloy solder. Vacuum coating or 80-20wt% AuSn alloy eutectic gold-tin alloy preformation is currently the current method for manufacturing electronic devices. However, electrodeposition, due to its low cost and versatility, is the preferred method for application. Background of the invention [0002] The present inventors have found that the electroplating baths used for gold-tin alloy deposition are not capable of depositing eutectic alloys over the entire range of available current densities. This has been confirmed in Djurfors and Ivey (GaAs MANTECH, 2001) "Film Growth Properties of Pulse Electrodeposited Au / Sn Tin Films", where they show that at about 1.5mA / ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25D3/62A61F2/06C25D5/00
CPCC25D3/62
Inventor H·赫拉迪尔G·赫拉迪尔E·赫拉迪尔
Owner B F TECHNOLOGY INC
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