Nano silver paste for chip mounting and method for preparing nano silver paste

A nano-silver paste, chip mounting technology, applied in nanotechnology, nanotechnology, nanotechnology and other directions for material and surface science, can solve problems such as large heat generation, affecting light output efficiency and service life, and achieve heat dissipation. problems, suitable for automated production, the effect of reducing the sintering time

Active Publication Date: 2013-02-20
深圳市先进连接科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

1W, 3W, 5W high-power LED chips and modules have entered the market one after another. Large power dissipation brings large heat generation, which seriously affects the light output efficiency and service life of LEDs.

Method used

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  • Nano silver paste for chip mounting and method for preparing nano silver paste

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] First, weigh 6mL, 2mol / L sodium citrate at a speed of 20mL / min, and add it dropwise to 2.5mL, 1mol / L silver nitrate solution, while applying 400r / min mechanical stirring. After the solution was added dropwise, the stirring was continued for 5 min.

[0027] The nano-silver solution obtained by the chemical reaction was centrifuged at a speed of 3500 r / min for 10 min. After the centrifugation is completed, pour off the mixed solution in the upper layer to obtain the silver nanoparticles precipitated in the lower layer. After the nano-silver particles were washed with deionized water, they were flocculated with 50 mL, 1 mol / L potassium nitrate solution and centrifuged again.

[0028] Repeat for three times to obtain the final nano silver paste. The nano-silver paste is applied to the surface of the interconnection between the chip and the substrate, heated with a hot-air workbench, the sintering temperature is set to 150°C, and the sintering time is 10 minutes to form a ...

Embodiment 2

[0030] First, mix 2.5mL, 1mol / L sodium citrate with 3.5mL, 2mol / L sodium borohydride solution, add dropwise to 3mL, 0.5mol / L silver nitrate solution at a speed of 10mL / min, At the same time, 1 mL of 0.3 mol / L polyvinylpyrrolidone solution was added dropwise, and mechanical stirring was applied at 500 r / min. After the solution was added dropwise, the stirring was continued for 5 min.

[0031] The obtained nano-silver solution was centrifuged at a speed of 5000r / min for 5min. After the centrifugation is completed, pour off the mixed solution in the upper layer to obtain the nano-silver slurry precipitated in the lower layer. After cleaning the nano-silver paste with deionized water, flocculate with 50 mL, 1 mol / L sodium citrate solution, and centrifuge again.

[0032] Repeat for three times to obtain the final nano silver paste. The nano-silver paste is applied to the surface of the interconnection between the chip and the substrate, heated with a hot air workbench, the sinte...

Embodiment 3

[0034] First, weigh 3.5mL, 1.5mol / L sodium citrate dihydrate and mix with 2.5mL, 1mol / L ferrous sulfate solution, and add dropwise to 2.5mL, 0.5mol / L silver nitrate solution at a speed of 20mL / min. In the solution, a mechanical stirring of 300r / min was applied. After the solution was added dropwise, the stirring was continued for 5 min.

[0035] The obtained nano-silver solution was centrifuged at a speed of 5000r / min for 5min. After the centrifugation is completed, pour off the mixed solution in the upper layer to obtain the nano-silver slurry precipitated in the lower layer. After cleaning the nano-silver paste with deionized water, flocculate with 50 mL, 1.5 mol / L sodium citrate solution, and centrifuge again.

[0036] Repeat for three times to obtain the final nano silver paste. The nano-silver paste is applied to the surface of the interconnection between the chip and the substrate, heated with a hot air workbench, the sintering temperature is 200°C, and the sintering ...

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Abstract

The invention provides a method for preparing a nano silver paste. The method includes step A, a reducing agent and a dispersing agent are dropwise added in a silver nitrate solution and stirred; step B, the solution obtained through the step A is subjected to centrifugation to obtain nano silver particles with upper layers as mixed solutions and lower layers as sedimentation; step C, the nano silver particles separated through the step B is cleaned by deionized water and subjected to flocculation by a electrolyte solution, and nano silver particles capable of being subjected to centrifugation are re-precipitated; step D, the nano silver particles are subjected to cleaning, flocculation and centrifugation for a plurality of times to obtain a water-soluble nano silver paste; and step E, the nano silver paste is applied to a chip and a substrate surface to be interconnected, and the interconnected chip and substrate surface is heated in a hot air work bench or a stove to form a sintering joint.

Description

technical field [0001] The invention is suitable for electronic packaging and interconnection applications, relates to a nano-silver paste for chip mounting and a preparation method thereof, in particular to a low-temperature rapid sintering nano-silver paste for chip mounting and a preparation method thereof. Background technique [0002] Due to the limitation of lead-free electronic products in the world, silver paste products as lead-free interconnect materials have emerged as the times require. Because the material has many advantages such as green environmental protection, no solid-state aging phenomenon, and strong corrosion resistance, it is used in chip mounting interconnection. [0003] The existing nano-silver paste or micro-silver paste used as interconnection materials for electronic packaging chips has a common disadvantage that sintering pressure needs to be applied during processing. This process is not conducive to the realization of chip mounting automation ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F9/24B22F1/00B82Y40/00B82Y30/00
Inventor 李明雨王帅计红军
Owner 深圳市先进连接科技有限公司
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