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A preparation method of mixed lead-free solder paste with size effect

A lead-free solder, hybrid technology, applied in the direction of welding/cutting media/materials, welding equipment, manufacturing tools, etc., can solve the problems of organic residue precipitation, difficulty in forming complete and full solder joints, and low metal content. Achieve the effects of increasing specific gravity, avoiding premature failure, and simple and feasible process

Active Publication Date: 2016-08-17
马鑫 +4
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the size of the nanoparticles is too small, the surfactant will occupy a relatively large proportion of the volume. If the flux is directly added to the nano-powder and stirred evenly, the content of metal components in the nano-solder paste will be too low, and it will be difficult to form a complete solder paste after soldering. Full solder joints, and there will be a lot of organic residues [Materials Science and Engineering B 177(2012)197-204]
It is also for this reason that there has not yet been a real nano-lead-free solder paste.

Method used

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  • A preparation method of mixed lead-free solder paste with size effect
  • A preparation method of mixed lead-free solder paste with size effect
  • A preparation method of mixed lead-free solder paste with size effect

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The nano / micron particle mixed type lead-free solder paste of the present embodiment is composed of Sn-3.0Ag-0.5Cu nano-solder powder (particle diameter is 5-15nm), Sn-3.0Ag-0.5Cu lead-free solder powder (particle diameter 25-45μm), composed of rosin flux, with a total mass of 5g, and its components are calculated by mass fraction as:

[0039] Nano lead-free solder Sn-3.0Ag-0.5Cu 30%

[0040] Micron lead-free solder Sn-3.0Ag-0.5Cu 60%

[0041] Rosin type solder paste 10%

[0042] Among them, the micron lead-free solder Sn-3.0Ag-0.5Cu used has a melting temperature range of 217-221°C, and the experimental steps are as follows:

[0043] First, separate the nano-lead-free solder stored in ethylene glycol liquid, and select stearic acid as the separation solution; slowly add the nano-lead-free solder to the solder paste / agent, and mechanically stir at a speed of 30r / min 30min, then introduce ultrasonic oscillation, continue stirring for 30min, then stop ultrasonic oscill...

Embodiment 2

[0046]The nano / micron particle mixed type lead-free solder paste of the present embodiment is composed of Sn nano-solder powder (particle diameter is 5-15nm), Sn-1.0Ag-0.5Cu-0.01Ni micron lead-free solder powder (particle diameter is 25nm) -38μm), composed of rosin flux, with a total mass of 5g, and its components are calculated by mass fraction as:

[0047] Nano lead-free solder Sn 35%

[0048] Micron lead-free solder Sn-1.0Ag-0.5Cu-0.01Ni 55%

[0049] Rosin type solder paste 10%

[0050] Among them, the micron lead-free solder Sn-1.0Ag-0.5Cu-0.01Ni used in this example has a melting temperature range of 217-225°C, and the experimental steps are:

[0051] First, separate the nano-lead-free solder stored in ethylene glycol liquid, and choose stearic acid as the separation solution; slowly add the nano-lead-free solder to the rosin-type solder paste, and mechanically stir at a speed of 30r / min 30min, then introduce ultrasonic oscillation, continue stirring for 30min, then st...

Embodiment 3

[0054] The nano / micron particle mixed type lead-free solder paste of the present embodiment is composed of Sn nano-solder powder (particle size is 5-15nm), Sn-3.5Cu lead-free solder powder (particle size is 25-45 μm), rosin Flux composition, the total mass is 5g, and its components are calculated by mass fraction as:

[0055] Nano lead-free solder Sn 45%

[0056] Micron lead-free solder Sn-3.5Cu 45%

[0057] Rosin type solder paste 10%

[0058] Among them, the micron lead-free solder Sn-3.5Ag used in this example has a melting temperature of 221°C, and the experimental steps are as follows:

[0059] First, separate the nano-lead-free solder stored in ethylene glycol liquid, and select stearic acid as the separation solution; slowly add the nano-lead-free solder to the solder paste / agent, and mechanically stir at a speed of 30r / min 30min, then introduce ultrasonic oscillation, continue stirring for 30min, then stop ultrasonic oscillation, slowly add micron-sized solder / paste...

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Abstract

The invention provides a method for preparing a mixed lead-free solder paste with size effect, which includes the following steps: slowly adding nano-scale solder into the solder paste / agent, introducing ultrasonic vibration after mechanical stirring, and continuing to stir, Then stop the ultrasonic oscillation, slowly add micron-sized solder / paste, and continue to stir to obtain a uniformly mixed mixed solder paste. Beneficial effects of the present invention: 1. The process of the method is simple and feasible. By adding large-size micron-scale solder to the nano-solder paste, the proportion of metal components in the solder paste is increased, and the low melting point characteristic of the nano-solder is retained. 2. It can form round and full solder joints at a lower reflow temperature. 3. The obtained solder joints are polycrystalline solder joints, and the grain size in the solder joints can be changed by adjusting the size distribution of the micron solder, which avoids premature failure of the solder joints.

Description

technical field [0001] The invention belongs to the technical field of lead-free solder alloys and electronic packaging, and relates to a preparation and application method of nano-scale / micron-scale particle mixed type lead-free solder paste with size effect. Background technique [0002] With the in-depth understanding of the toxicity of Pb in the society and the implementation of the EU WEEE / ROHS Act on July 1, 2006, it is the general trend to replace the traditional Sn-Pb solder with lead-free solder. At present, lead-free alloys such as Sn-Ag, Sn-Cu, and Sn-Ag-Cu have been widely used in the field of electronic packaging. The melting point of these lead-free solder alloys is generally 217-227°C, which is much higher than the melting point of the traditional Sn-Pb eutectic solder (183°C). Therefore, the use of lead-free solder has brought new problems after solving environmental problems. . First of all, the increased soldering temperature is not conducive to energy sa...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K35/26B23K35/14B22F1/052B22F1/054
CPCB23K35/0244B23K35/262B23K35/362B23K2101/36B22F1/052B22F1/054B23K35/26C22C9/02
Inventor 马鑫李明雨杨明
Owner 马鑫
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