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Binary leadless soldering plaster

A lead-free solder paste, solder paste technology, applied in the direction of welding medium, welding equipment, welding/cutting medium/material, etc., can solve the problems of lead poisoning

Inactive Publication Date: 2009-02-18
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, lead is a toxic metal, and the human body absorbs low doses of lead to cause lead poisoning

Method used

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  • Binary leadless soldering plaster
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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] The binary lead-free solder paste of this embodiment is composed of eutectic micron lead-free solder paste Sn-Bi and nano powder Sn-Ag-Cu, the size of nano powder is ≤100nm, the total weight is 25g, and its composition is calculated by weight fraction: :

[0016] Micron lead-free solder paste 97 parts

[0017] Nano powder 3 parts

[0018] a. The nanopowder stored in the paraffin liquid is separated, and chloroform is selected as the separation solvent.

[0019] b. Mix the separated nano-powder with micron lead-free solder paste evenly.

[0020] c. Screen print the prepared solder paste, and then reflow at 180°C for 6 minutes to form good solder joints.

[0021] d. If figure 1 As shown, the microhardness of the solder joint formed by the binary lead-free solder paste is higher than that of the pure eutectic micron lead-free solder paste Sn-Bi; as figure 2 As shown, the shear strength of the solder joints formed by the binary lead-free solder paste is higher than th...

Embodiment 2

[0023] The binary lead-free solder paste of this embodiment is composed of eutectic micron lead-free solder paste Sn-Bi and nano powder Sn-Ag-Cu, the size of nano powder is ≤100nm, the total weight is 25g, and its composition is calculated by weight fraction: :

[0024] Micron lead-free solder paste 99 parts

[0025] Nano powder 1 part

[0026] Mix the above evenly, then perform screen printing, and reflow at 180°C for 6 minutes to form good solder joints. Performance is improved, as in figure 1 , 2 shown.

Embodiment 3

[0028] The binary lead-free solder paste of this embodiment is composed of micron lead-free solder paste Sn-Bi and nano-powder Sn-Co-Cu, the size of the nano-powder is ≤100nm, the total weight is 25g, and its composition is calculated by weight fraction:

[0029] Micron lead-free solder paste 99 parts

[0030] Nano powder 1 part

[0031] Mix the above evenly, then perform screen printing, and reflow at 180°C for 6 minutes to form good solder joints.

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Abstract

The invention relates to binary lead-free solder paste for welding and surface mounting of electronic components. Nanopowder is added based on micron lead-free solder paste; and the solder paste comprises the following compositions in percentage by mass: 90 to 99 percent of micron lead-free solder paste and 0.1 to 10 percent of the nanopowder, wherein the nanopowder is nanopowder of ordinary lead-free solder paste or nanopowder of metal or nanopowder of SiC, SiN, BN, and AL2O3. The binary lead-free solder paste has the entire basic performances of the ordinary lead-free solder paste, and reduces the cost and the melting point. Compared with the prior tin lead solder paste, the binary lead-free solder paste does not contain toxic element lead, and is particularly suitable for electronic packaging technology in the microelectronic industry.

Description

technical field [0001] The invention relates to a lead-free solder paste used for soldering and surface packaging of electronic components, in particular to a binary lead-free solder paste. Background technique [0002] Soldering is a very old and practical technology, mainly based on tin-lead alloy system, the eutectic temperature of this tin-lead alloy is 183 ℃, it has good physical properties, mechanical properties and metallurgical properties, so it is widely used in the electronics industry. The use of tin-lead eutectic solder alloy has a long history, and a lot of practical application experience has been accumulated in production. At the same time, the cost of raw materials is low and the resources are extensive. However, lead is a toxic metal, and low doses of lead absorbed by the human body can cause lead poisoning. With the increase of electronic waste, a large number of waste electronic devices are discarded or buried, and the toxic component lead in electronic ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K35/20
Inventor 刘建影张利利陈思张燕翟启杰高玉来
Owner SHANGHAI UNIV
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