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High-temperature brazing filler metal preparing method based on foamed silver filled with metal tin

A technology of high-temperature solder and foamed silver, which is applied in metal processing equipment, welding equipment, manufacturing tools, etc., can solve problems such as inability to play a connection role, achieve excellent thermal cycle reliability, good compatibility, and reduce heat damage effect of possibility

Inactive Publication Date: 2016-12-14
HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The phase change metal thermal interface composite material obtained by this scheme is for the purpose of heat dissipation, and the heat is removed through the phase change heat absorption. When in service, the filling metal is converted between solid and liquid, and cannot play a connecting role.

Method used

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  • High-temperature brazing filler metal preparing method based on foamed silver filled with metal tin
  • High-temperature brazing filler metal preparing method based on foamed silver filled with metal tin
  • High-temperature brazing filler metal preparing method based on foamed silver filled with metal tin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Implementation example 1, refer to figure 1 and 2 :

[0040] A method for preparing high-temperature solder based on metal tin filling foam silver, the method specifically includes the following steps (making metal tin fill foam silver into a solder sheet by printing solder paste and then reflowing it, and finally making it High temperature solder joints as an example):

[0041] (1) Cut out a silver foam sheet with a length of 10mm*width of 10mm*thickness of 0.6mm, and its pore size is generally less than 20μm;

[0042] (2) Step (1) gained foam silver sheet is placed in the solution containing thiourea, citric acid, salt of wormwood (mass ratio, thiourea: citric acid: potassium carbonate: deionized water=1:3:1: 25), and finally wash the copper powder 3 times with deionized water, and dry it for later use;

[0043] (3) Print Sn1Ag0.5Cu solder with a length of 10mm*width of 10mm*thickness of 0.5mm on the silver foam sheet by screen printing, and reflow at 250°C for 30...

Embodiment 2

[0044] Implementation example 2, refer to figure 1 and 2 :

[0045] A method for preparing high-temperature solder based on metal tin filling foam silver, the method specifically includes the following steps (making metal tin fill foam silver into a solder sheet by printing solder paste and then reflowing it, and finally making it High temperature solder joints as an example):

[0046] (1) Cut out a silver foam sheet with a length of 10mm*width of 10mm*thickness of 0.6mm, and its pore size is generally less than 20μm;

[0047] (2) Step (1) gained foam silver sheet is placed in the solution containing thiourea, citric acid, salt of wormwood (mass ratio, thiourea: citric acid: potassium carbonate: deionized water=1:3:1: 25), and finally wash the copper powder 3 times with deionized water, and dry it for later use;

[0048] (3) The foamed silver sheet is first impregnated with flux (the flux is purchased from the market and conforms to the electronic industry standard SJ / T112...

Embodiment 3

[0049] Embodiment 3 metal welding

[0050] Use the high-temperature solder sheet obtained in the above steps of Example 1 to carry out welding, the welding temperature is selected as 250 ° C, and the heat preservation is 3 minutes. After testing, the weld seam finally formed is composed of remaining foamed silver and Ag 3 Composition of Sn. The welding seam can realize low-temperature (250°C) welding, and the obtained solder joints can withstand high-temperature (480°C) service.

[0051] The obtained weld structure is as image 3 Shown:

[0052] It has been verified by a large number of experiments that the resistivity of this weld is 5.18μΩ·cm, and its conductivity is far superior to that of traditional tin-based solder (11.5μΩ·cm) and the solder made entirely of silver-tin compounds made by the traditional TLP process. Pure IMC solder joints are in the same order of magnitude (2.5-10μΩ·cm) as the welds after nano-silver sintering.

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Abstract

The invention provides a high-temperature brazing filler metal preparing method based on foamed silver filled with metal tin. High-temperature brazing filler metal is a metal sheet formed by the foamed silver with micro and nanoscale pores filled with the metal tin, the foamed silver is filled with liquid metal tin through the capillary action, and preparing of the brazing filler metal is achieved. When the brazing filler metal is used for welding, a finally-formed welding line is composed of an intermetallic compound and remaining foamed silver, low-temperature welding can be achieved, an obtained welding point can be subject to high-temperature service, welding point reliability and welding line stability are greatly improved, and the method can be widely applied to various high-temperature welding fields.

Description

technical field [0001] The invention belongs to the interdisciplinary technical field of material physics and material processing, and relates to a method for preparing a high-temperature solder based on metal tin filling foamed silver. Background technique [0002] With the rapid development of the electronic industry, electronic products tend to be miniaturized and integrated, and the interconnection density and power density of integrated circuits continue to increase. In this regard, packaging researchers need to overcome two key problems. One is that the higher current density inside the chip will generate more heat, which requires corresponding high-temperature solder. High-temperature power devices in fields such as detection and nuclear reaction environments are particularly important. Second, in order to meet the increasing interconnection density, it is necessary to seek new interconnection technologies. The 3D packaging that makes full use of the three-dimensiona...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/26B23K35/14
CPCB23K35/262B23K35/0233
Inventor 陈宏涛李准
Owner HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL
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