Method for selectively preparing gold-tin eutectic solder on surface of ceramic substrate

A technology of ceramic substrate and eutectic solder, applied in the field of selective preparation of gold-tin eutectic solder on the surface of ceramic substrate, can solve the problems of reduced heat dissipation efficiency, poor stability of plating solution, influence of heat dissipation effect, etc., and achieves high stability and welding. The effect of good performance and high production efficiency

Inactive Publication Date: 2017-05-31
SYSU CMU SHUNDE INT JOINT RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the current production methods of gold-tin eutectic solder are generally physical methods, such as gold-tin solder preforms; there are also electrodeposition methods, but their formulas are mostly cyanide systems such as gold cyanide, which seriously pollutes the environment. The liquid has poor stability and is easy to decompose
[0003] When heat dissipation is realized on a high thermal conductivity substrate, the heat conduction effect of the solder seriously affects the heat dissipation effect of the entire component, thereby reducing the heat dissipation efficiency

Method used

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  • Method for selectively preparing gold-tin eutectic solder on surface of ceramic substrate

Examples

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Effect test

Embodiment 1

[0025] On an alumina ceramic substrate with a thickness of 0.5 μm, the first conductive layer with a thickness of 20 nm is sputtered, and copper is electroplated as the second conductive layer (50 nm in thickness), and the pattern layer is obtained by photolithography, and then etched copper gets as figure 1 Array graph shown. The gold-tin alloy solder is electroplated on the array pattern, and the gold-tin alloy electroplating solution is a cyanide-free electroplating solution with a pH of 3 to 7, including gold salt, tin salt, brightener, complexing agent and antioxidant, and finally a patterned Au-Sn eutectic solder.

Embodiment 2

[0027] A gold layer (thickness 1nm) is electrochemically plated on a highly thermally conductive aluminum nitride substrate with a thickness of 0.5 μm, and then a patterned gold layer is obtained through a positive resist lithography process and etching technology, and electroplating is realized on the gold layer Gold-tin alloy solder, the electroplating solution is a cyanide-free system, including gold salts, tin salts, brighteners, complexing agents, antioxidants, indium salts, and gallium salts. Finally, the patterned gold-tin eutectic solder is obtained (the enlarged picture of two gold-tin eutectic bumps is shown in figure 2 ).

Embodiment 3

[0029] On the alumina ceramic substrate with a thickness of 5 μm, a gold layer (thickness of

[0030] 100nm), then on the gold layer, obtain a graphic layer through negative resist etching, etch the gold layer with a gold etchant to obtain a patterned gold layer, and realize electroplating gold-tin alloy solder on the gold layer, and the electroplating solution is a cyanide-free system Electroplating solution, including gold salt, tin salt, brightener, complexing agent, antioxidant and indium salt, gallium salt. Finally, a patterned gold-tin eutectic solder is obtained.

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Abstract

The invention discloses a method for selectively preparing gold-tin eutectic solder on the surface of a ceramic substrate. The method comprises the following steps: (1) plating a metal layer on the ceramic substrate via a physical method or an electrochemistry method; (2) treating the metal layer via a photoetching technique to obtain a pattern layer; (3) etching the metal layer by using a metal etching solution to obtain a patterned metal layer; and (4) carrying out electroplating of a gold-tin alloy on the patterned metal layer to form solder, wherein a gold-tin electroplating solution used by electroplating is an electroplating solution of a cyanide-free system and comprises gold salt, tin salt, brighteners, complexing agents and antioxidants. The gold-tin eutectic solder is capable of carrying out electroplating in the specific position to obtain the gold-tin alloy plating layer with bright and dense surface; the gold-tin eutectic bumps are controllable in thickness and can meet different packaging requirements; the melting point of the formed eutectic alloy is 280+ / -0.2 DEG C; the eutectic alloy has high welding performance and oxidation resistance and is used as optimal solder in the field of optoelectronic packaging.

Description

technical field [0001] The invention relates to a method for preparing solder, in particular to a method for selectively preparing gold-tin eutectic solder on the surface of a ceramic substrate. Background technique [0002] Gold-tin alloy solder has the characteristics of high strength, good oxidation resistance, excellent thermal fatigue and creep resistance, low melting point, and good fluidity. It is the most ideal solder in the field of optoelectronic packaging. With the rapid development of optoelectronic devices, the demand for gold-tin alloy solder is also increasing. Since the current production methods of gold-tin eutectic solder are generally physical methods, such as gold-tin solder preforms; there are also electrodeposition methods, but their formulas are mostly cyanide systems such as gold cyanide, which seriously pollutes the environment. The liquid has poor stability and is easy to decompose. [0003] When the high thermal conductivity substrate realizes he...

Claims

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Application Information

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IPC IPC(8): C25D5/02C25D5/54C25D3/56
CPCC25D3/56C25D5/02C25D5/54
Inventor 崔国峰杨涵
Owner SYSU CMU SHUNDE INT JOINT RES INST
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