Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Method for preparing composite grain size nano silver paste

A technology of nano-silver and nano-silver particles, which is applied in metal processing equipment, transportation and packaging, etc., can solve problems such as temperature increase, time extension, and thermal conductivity reduction, so as to improve thermal conductivity, reduce mean free path, crystallization, etc. The effect of small particle size

Inactive Publication Date: 2017-03-15
SHANGHAI RADIO EQUIP RES INST
View PDF6 Cites 9 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to solve the problem that the thermal conductivity of the sample decreases after sintering of a single small-size nano-silver paste, and the nano-sintering size effect of a single large-size silver paste will decrease with the increase of the particle size of the nano-silver particles, resulting in sintering interconnection Defects such as the required temperature increase and time extension provide a composite particle size nano-silver paste, which uses the small-size particle size nano-silver particles contained therein as fillers to increase the initial packing density of the particles and keep the overall sintering temperature constant. change; using large-size nano-silver particles as a support to maintain the dimensional stability of the sintered interconnect

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0042] The preparation method of composite particle size nano-silver paste provided by the invention, the preparation method comprises:

[0043] Step 1, preparing the first-size nano-silver particles, specifically comprising:

[0044] Step 1.1, uniformly mix the sodium citrate dihydrate solution with the ferrous sulfate heptahydrate solution to make a reducing solution; preferably, the sodium citrate dihydrate solution has a concentration of 1-2.5mol / L, and its volume fraction is 20 -50 parts; the concentration of ferrous sulfate heptahydrate solution is 1-2mol / L, and its parts by volume are 20-50 parts;

[0045] Step 1.2, adding the above-mentioned reducing solution dropwise to the silver nitrate solution that is strongly mechanically stirred to carry out the reduction reaction; preferably, the concentration of the silver nitrate solution is 0.5-1mol / L, and its volume fraction is 20-50 parts;

[0046] In step 1.3, the reduced and precipitated nano-silver particles are separa...

Embodiment 1

[0062] Evenly mix 35mL, 1.5mol / L sodium citrate dihydrate solution with 25mL, 1mol / L ferrous sulfate heptahydrate solution to make a reducing solution, and add dropwise to 25mL, 0.5mol / L in the silver nitrate solution. After the reaction is completed, the reduced and precipitated silver nanoparticles are separated from the solution by centrifugation at a speed of 4000 rpm for 3 minutes, and then the upper layer solution is removed. The nano-silver particles at the bottom of the centrifuge tube were redissolved in 20mL of ultrapure water, and ultrasonication was applied to disperse them evenly, forming a nano-silver sol. Then add 10mL, 1.5mol / L sodium citrate dihydrate solution for flocculation. After the nano-silver sol is added to the electrolyte solution, the ionization balance is destroyed and becomes unstable, and the nano-silver particles are re-precipitated and centrifuged again. This process was repeated three times to remove impurity ions in the nano-silver paste. F...

Embodiment 2

[0067] Evenly mix 50mL, 2mol / L sodium citrate dihydrate solution with 50mL, 2.5mol / L ferrous sulfate heptahydrate solution to make a reducing solution, and add dropwise to 50mL, 1mol / L in silver nitrate solution. After the reaction is completed, the reduced and precipitated silver nanoparticles are separated from the solution by centrifugation at a speed of 4000 rpm for 3 minutes, and then the upper layer solution is removed. Re-dissolve the nano-silver particles at the bottom of the centrifuge tube in 50mL of ultrapure water, and apply ultrasound to make them uniformly dispersed and become a nano-silver sol. Then add 30mL, 2.5mol / L sodium citrate dihydrate solution for flocculation. After the nano-silver sol is added to the electrolyte solution, the ionization balance is destroyed and becomes unstable, and the nano-silver particles are re-precipitated and centrifuged again. This process was repeated twice to remove impurity ions in the nano-silver paste. Finally, a single ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
Particle sizeaaaaaaaaaa
Particle sizeaaaaaaaaaa
Concentrationaaaaaaaaaa
Login to View More

Abstract

The invention discloses a method for preparing composite grain size nano silver paste. The method comprises the steps that 1, silver nitrate is reduced with trisodium citrate dehydrate and ferrous sulfate, centrifugal separation is carried out, nano silver particles are dispersed in ultrapure water, trisodium citrate dehydrate is added for flocculation, centrifugal separation is carried out again, the steps of dispersing, flocculation and centrifugal separation are repeated more than three times, and nano silver particles of a first size are obtained; 2, silver nitrate is reduced with trisodium citrate dehydrate, wherein a trisodium citrate dehydrate solution is adopted for flocculation, and centrifugal separation is carried out to obtain nano silver particles of a second size; 3, the nano silver particles of the first size and the nano silver particles of the second size are mixed according to the mass ratio of 2:1 to 5:1 and dispersed in ultrapure water, the trisodium citrate dehydrate solution is added for flocculation, and centrifugal separation is carried out to obtain the composite grain size nano silver paste. The heat conductivity of the provided composite grain size nano silver paste is greatly improved, and the situation that the size of an interconnection joint of nano silver paste obtained under the low-temperature sintering interconnection conditions is unstable in the high-temperature service process is relieved.

Description

technical field [0001] The invention is applicable to the application range of electronic packaging and interconnection, and relates to a preparation method of nano-silver paste with composite particle size for chip-level or other micro-device mounting. Background technique [0002] As a new type of chip-level interconnection material, nano-silver paste has three advantages over traditional soldering materials: no remelting of interconnection solder joints, high thermal and electrical conductivity, and high reliability. [0003] However, silver pastes containing only smaller-sized silver nanoparticles have the problem of dimensional instability of sintered interconnects. After this type of nano-silver paste is sintered to form interconnection joints, the microstructure does not reach the final stable state in the process of high-temperature service. Macroscopically, the interconnection joints will shrink in size with the increase of service temperature, affecting Interconne...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): B22F9/24B22F1/00
CPCB22F9/24B22F1/054
Inventor 王帅陈思高源巫婕妤
Owner SHANGHAI RADIO EQUIP RES INST
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com