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Core-shell Al-Sn-Bi lead-free solder and preparation method thereof

A lead-free solder, core-shell type technology, applied in the direction of coating, etc., can solve the problems of restricted powder application, difficult control, complicated process, etc., and achieve the effect of reducing bridging defects, simple preparation process and short process

Inactive Publication Date: 2010-10-27
SHANGHAI JIAO TONG UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, this prior art is difficult to control and complicated to ensure the composition uniformity and size uniformity of the multi-component coating.
Wang Cuiping proposed in the patent publication number CN101337274A a method for preparing core-shell aluminum tin indium powder by atomization method, but the price of indium is expensive, which greatly limits the application of the powder

Method used

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  • Core-shell Al-Sn-Bi lead-free solder and preparation method thereof
  • Core-shell Al-Sn-Bi lead-free solder and preparation method thereof
  • Core-shell Al-Sn-Bi lead-free solder and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Weigh 0.7441g pure aluminum (purity is 99.99wt.%), 1.4070g pure bismuth (purity is 99.99wt.%), 1.0237g pure tin (purity is 99.99wt.%), (by mass percentage, Al: Bi= 34.6:65.4, Bi:Sn=57.9:42.1), put it into a quartz crucible with a leak hole in the bottom with a diameter of 0.8mm, put the quartz crucible with metal into a vacuum induction furnace to evacuate to 6.7Pa, and fill it with After being protected by 0.06MPa pure argon gas, the metal is melted by induction. After the metal is melted and overheated to 1130°C, keep it warm for ten minutes, and then fill the top of the crucible with 0.02MPa argon gas to make the alloy melt flow out from the leak hole of the crucible. And drop it into the 200℃ methyl silicone oil 2cm below the crucible. After the alloy melt drops completely, use a sieve to screen out the alloy spheres with a diameter of 0.02-1.4mm, and then get the core-shell aluminum-tin-bismuth lead-free solder . .

[0023] The schematic diagram of the cross-sect...

Embodiment 2

[0026] Weigh 0.7444g pure aluminum (purity is 99.99wt.%), 1.3917g pure bismuth (purity is 99.99wt.%), 1.0553g pure tin (purity is 99.99wt.%), (by mass percentage, Al: Bi= 34.8:65.2, Bi:Sn=56.9:43.1), put it into a quartz crucible with a leak hole in the bottom with a diameter of 0.8mm, put the quartz crucible with metal into a vacuum induction furnace to evacuate to 5.9Pa, and fill it with After being protected by 0.06MPa pure argon gas, the metal is melted by induction. After the metal is melted and overheated to 1180°C, keep it warm for ten minutes, and then fill the top of the crucible with 0.04MPa argon gas to make the alloy melt flow out from the leak hole of the crucible. And drip into the methyl silicone oil at room temperature 3cm below the crucible, until the alloy liquid is completely dripped, and then use a sieve to screen out alloy spheres with a diameter of 0.02-1.4mm to obtain the core-shell aluminum-tin-bismuth lead-free solder.

[0027] The cross-sectional sche...

Embodiment 3

[0031] Weigh 0.8131g pure aluminum (purity is 99.99wt.%), 1.5671g pure bismuth (purity is 99.99wt.%), 1.1470g pure tin (purity is 99.99wt.%), (by mass percentage, Al: Bi= 34.2: 65.8, Bi: Sn=57.7: 42.3), put into a quartz crucible with a diameter of 0.8mm leakage hole at the bottom, other processes are similar to Example 2, the difference is that the temperature of methyl silicone oil is 200°C, and Schematic diagram of the cross-sectional structure of the core-shell Al-Sn-Bi lead-free solder and figure 1 Similar to the core-shell structure. Through the energy spectrum analysis of the shell layer composition of the solder with a diameter of 1.1mm, the weight ratio of tin and bismuth in the shell layer is: Sn:Bi=41.7:58.3. When the solder diameter is 0.6 mm, the composition ratio of tin and bismuth in the shell is: Sn: Bi = 42.3: 57.7.

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Abstract

The invention provides a core-shell Al-Sn-Bi lead-free solder and a preparation method thereof, belonging to the technical field of particle material preparation. The method comprises the following steps of: weighing Al-Sn-Bi metals, placing the Al-Sn-Bi metals into a quartz crucible with a leak at the inner bottom, placing the quartz crucible into a vacuum induction furnace, melting the Al-Sn-Bi metals by adopting an induction melting mode under the inert gas environment, overheating the Al-Sn-Bi metals for 100-300 DEG C and keeping the temperature of the Al-Sn-Bi metals for 10-30min to obtain alloy melt, introducing pressure gas to enable the alloy melt to flow out from the leak , and treating the alloy melt by protective cooling to obtain the core-shell Al-Sn-Bi lead-free solder. The prepared lead-free solder provides better electrical performance and better heat dissipation performance, reduces the bridging defects and has the advantages of simple preparation process, short flow and low production cost.

Description

technical field [0001] The invention relates to a solder in the technical field of granular material preparation and a preparation method thereof, in particular to a core-shell type aluminum-tin-bismuth lead-free solder and a preparation method thereof. Background technique [0002] With the development of integrated circuit packaging technology towards high density, miniaturization, and integration, the development of packaging technology after the 1990s has focused more on the improvement of miniaturization, narrow spacing, and heat dissipation. Traditional solders are generally tin-based materials. Under the condition of narrow spacing, solder balls are easily deformed during reflow soldering or subsequent processing and cause defects such as loss, bridging, and non-coplanarity. [0003] After searching the existing technology, it is found that US Patent No. US6,906,417 describes a solder with a core-shell structure. This technology uses a metal or conductive polymer sphe...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F1/02B22F9/08
Inventor 张曙光戴嫆嫆赵辰恺肖超杨鑫李建国胡庆周
Owner SHANGHAI JIAO TONG UNIV