Co-deposition electroplating method with cyanogen-free Au-Sn alloy electrolyte

An alloy electroplating solution and co-deposition technology are applied in the field of cyanide-free Au-Sn alloy electroplating solution, which can solve the problems of slow plating speed and unstable plating solution.

Inactive Publication Date: 2011-04-13
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] The purpose of the present invention is to provide a co-deposition electroplating process of the faster Au-Sn alloy electroplating solution of the plating speed, ...

Method used

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  • Co-deposition electroplating method with cyanogen-free Au-Sn alloy electrolyte
  • Co-deposition electroplating method with cyanogen-free Au-Sn alloy electrolyte
  • Co-deposition electroplating method with cyanogen-free Au-Sn alloy electrolyte

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Experimental program
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Effect test

Embodiment 1

[0060] Embodiment 1: Au-30at.% Sn eutectic coating is electroplated with positive variable amplitude pulse current and the composition of the plating solution of the present invention

[0061] (1) Preparation of Au-Sn alloy electroplating solution

[0062] 1. The composition and content of the plating solution are as follows:

[0063] Potassium chloroaurate (KAuCl 4 ) 10g / L (5.8g / L as Au)

[0064] Stannous chloride (SnCl 2 ) 5g / L (3.13g / L based on Sn)

[0065] Sodium sulfite (Na 2 SO 3 ) 60g / L

[0066] Ethylenediaminetetraacetic acid (EDTA) 5g / L

[0067] Potassium pyrophosphate 40g / L

[0068] L-Ascorbic Acid 15g / L

[0069] Catechol 5g / L

[0070] Nickel Chloride (NiCl 2 ) 1g / L

[0071] 2. The preparation steps are as follows:

[0072] 1) Take 3 / 4 of the volume of deionized water to prepare the plating solution in a beaker (the total volume of the plating solution is 40mL), and add potassium pyrophosphate, stannous chloride, catechol, L-ascorbic acid, chlorine Nick...

Embodiment 2

[0094] Embodiment 2: Au-30at.% Sn eutectic coating is electroplated with a positive variable amplitude pulse current and the plating solution of the present invention

[0095] Bath composition and parameters:

[0096] Sodium gold sulfite (Na 3 Au(SO 3 ) 2 ) 15g / L (7g / L as Au)

[0097] Stannous Sulfate (SnSO 4 ) 9g / L (5g / L based on Sn)

[0098] Sodium sulfite (Na 2 SO 3 ) 80g / L

[0099] Ethylenediaminetetraacetic acid (EDTA) 15g / L

[0100] Potassium pyrophosphate (K 4 P 2 o 7 ) 60g / L

[0101] L-Ascorbic acid 30g / L

[0102] Catechol 2g / L

[0103] Nickel Chloride (NiCl 2 ) 0.5g / L

[0104] pH 8

[0105] The preparation steps of the plating solution are the same as in Example 1. The Au-Sn electroplating solution can be stored at room temperature for about 2 months, and the plating solution does not decompose when heated to 50° C., and has good stability.

[0106] use as Figure 5 The positive-going periodic pulse shown (period 10ms, duty ratio 2:8, on-time 2ms) w...

Embodiment 3

[0113] Embodiment 3: Au-Sn alloy coatings (Au-30at.%Sn, Au-35at.%Sn) with different tin contents are prepared by electroplating with positive variable amplitude pulse current and plating solution of the present invention

[0114] Bath composition and parameters:

[0115] Ammonium Chloraurate (NH 4 AuCl 4 ) 7.2g / L (4g / L as Au)

[0116] Stannous methanesulfonate 7.76g / L (3g / L based on Sn)

[0117] Sodium sulfite (Na 2 SO 3 ) 40g / L

[0118] Ethylenediaminetetraacetic acid (EDTA) 3g / L

[0119] Potassium pyrophosphate 30g / L

[0120] L-Ascorbic acid 10g / L

[0121] Catechol 8g / L

[0122] Nickel Chloride (NiCl 2 ) 3g / L

[0123] pH 9

[0124] The preparation steps of the plating solution are the same as in Example 1. The Au-Sn plating solution can be placed at room temperature for about 2 months, and the plating solution does not decompose when heated to 50° C., and has good stability.

[0125] Using the same commutation cycle pulse and measurement steps as in Example 1, d...

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Abstract

The invention relates to a co-deposition electroplating method for preparing Au-Sn alloy on an electroplating substrate and a cyanogen-free Au-Sn alloy electrolyte. The wave forms of electroplating current pulses are forward variable-amplitude pulses, namely that two different forward square wave pulses exist in one period, and the peak values and the conducting time of the electroplating current pulses respectively correspond to peak value current density and time which are required for generating Au5Sn and an Au-Sn alloy phase in a plating layer. In the electrolyte, sodium sulfite is adopted as a main complexing agent and ethylene diamine tetraacetic acid is adopted as an auxiliary complexing agent for the gold ion complexing agent, potassium pyrophosphate is used as a tin ion complexing agent, hydroquinone is used as an antioxidant, and the pH value of the electrolyte is from 8 to 9. When the method is used for preparing Au-30at.%Sn eutectic plated layer through electroplating, the plating speed reaches 13 mum/hour, the electrolyte is stable, the operation is simple, and the gold and tin content in the plated layer is easy to control. The method can be applied in microelectronics and photoelectron industry for connecting and encapsulating LED chips, connecting flip chips, forming welding pads or patterns on the surface of semiconductor devices or similar devices, etc.

Description

technical field [0001] The invention relates to a co-deposition electroplating process for preparing Au-Sn alloy on an electroplating substrate and a cyanide-free Au-Sn alloy electroplating solution. Background technique [0002] The alloy of Au-30at.% Sn eutectic composition has good thermal conductivity, electrical conductivity, wettability, corrosion resistance, creep resistance, no flux is needed in welding, and it is used in microelectronic device packaging, chips and circuit substrates It is widely used in the connection of materials and in the hermetic packaging of high-reliability circuits. For example, in the high-power light-emitting diode (LED) flip-chip manufacturing technology, the alloy of Au-30at.%Sn eutectic composition can be used to make bumps on the chip, which can make the LED have better heat dissipation performance, Improved LED reliability. [0003] Au and Sn are co-deposited on the substrate by electroplating to form an alloy of Au-30at.%Sn eutectic...

Claims

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Application Information

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IPC IPC(8): C25D3/60C25D3/62C25D5/18
Inventor 黄明亮潘剑灵卿湘勇张福顺马海涛王来
Owner DALIAN UNIV OF TECH
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