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CN-122000114-A - Solvent-assisted low-temperature sintering silver paste and preparation method and application thereof

CN122000114ACN 122000114 ACN122000114 ACN 122000114ACN-122000114-A

Abstract

The invention discloses solvent-assisted low-temperature sintering silver paste, a preparation method and application thereof, wherein the sintering silver paste comprises, by mass, 90-92 parts of conductive silver powder, 8-9 parts of low-volatility latent heat sintering-assisted ether solvent and 1-2 parts of long-chain fatty acid dispersing agent. The preparation method comprises the steps of mixing the low-volatile latent heat sintering aid ether solvent, the dispersing agent and the conductive silver powder to obtain conductive silver paste, drying the conductive silver paste, and sintering the conductive silver paste at 180-220 ℃ to obtain the solvent-assisted low-temperature sintering silver paste. The invention can realize the high-efficiency densification sintering at lower temperature and in shorter time under a resin-free/low resin system, and simultaneously obtain the interconnection joint with high density, high heat conduction, high electric conduction and high mechanical strength, and is particularly suitable for the low-temperature high-reliability packaging interconnection of third-generation semiconductor devices such as SiC power modules and the like.

Inventors

  • WANG FENGJIANG
  • REN ZHENYI
  • LIN KEXIN

Assignees

  • 江苏科技大学

Dates

Publication Date
20260508
Application Date
20260319

Claims (10)

  1. 1. The solvent-assisted low-temperature sintering silver paste is characterized by comprising, by mass, 90-92 parts of conductive silver powder, 8-9 parts of low-volatilization latent heat sintering-assisted ether solvent and 1-2 parts of long-chain fatty acid dispersing agent.
  2. 2. The solvent assisted low temperature sintered silver paste of claim 1 wherein the low latent heat of vaporization sintering aid ether solvent is tripropylene glycol monobutyl ether.
  3. 3. The solvent assisted low temperature sintered silver paste of claim 1, wherein the long chain fatty acid dispersant is oleic acid or stearic acid.
  4. 4. The solvent-assisted low temperature sintered silver paste of claim 1, wherein the conductive silver powder is a submicron spherical silver powder.
  5. 5. The solvent-assisted low temperature sintered silver paste of claim 1, wherein the conductive silver powder has an average particle size of 0.3 to 0.45um.
  6. 6. A method of preparing the solvent-assisted low temperature sintered silver paste according to any one of claims 1 to 5, comprising the steps of: (1) Mixing the sintering-assisting ether solvent with low volatilization latent heat, a dispersing agent and conductive silver powder to obtain conductive silver paste; (2) And drying the conductive silver paste, and sintering at 180-220 ℃ to obtain the solvent-assisted low-temperature sintered silver paste.
  7. 7. The method for preparing solvent-assisted low-temperature sintered silver paste according to claim 6, wherein in the step (2), the sintering time is 1 to 1.5 hours.
  8. 8. The method for preparing solvent-assisted low-temperature sintered silver paste according to claim 6, wherein in the step (2), the drying temperature is 110-130 ℃ for 0.3-0.5h.
  9. 9. The method for preparing the solvent-assisted low-temperature sintered silver paste according to claim 6, wherein in the step (1), the low-volatile latent heat sintering-assisted ether solvent, the dispersing agent and the conductive silver powder are subjected to high-speed centrifugal stirring, grinding, centrifuging, separating and defoaming to obtain the uniformly mixed conductive silver paste.
  10. 10. Use of the solvent-assisted low temperature sintered silver paste of claim 1 in semiconductor packaging materials, flexible electronics, printed electronics, aerospace and extreme environment electronics, sensors or biological monitoring.

Description

Solvent-assisted low-temperature sintering silver paste and preparation method and application thereof Technical Field The invention relates to silver paste for a semiconductor device, a preparation method and application thereof, in particular to solvent-assisted low-temperature sintering silver paste. Background Silver paste is used as a key electronic packaging and interconnection material, is widely applied to the fields of photovoltaic cells, printed electronics, semiconductor packaging, high-temperature power devices and the like, and directly determines the overall performance and service life of the device, wherein the electric conduction, heat conduction, mechanical strength and interface reliability of the silver paste are achieved. Particularly in the third generation of semiconductor silicon carbide (SiC) power module package, in order to adapt to the working characteristics of high frequency, high temperature and high power density, stringent requirements of lower sintering temperature, higher heat and electrical conductivity, higher interface bonding strength and lower void ratio are put forward for interconnection materials, and the packaging requirements of a new generation of SiC devices are difficult to meet by a traditional silver paste system. The traditional high-performance silver paste mostly uses high polymer resins such as epoxy resin, cellulose derivative and the like as organic binders, and can provide good initial adhesion and pattern shape retention before sintering. On the one hand, the thermal decomposition and complete ablation of the resin are required to be completed slowly in a wider temperature range (usually 200-400 ℃), the energy consumption is high, the process time is long, the peak temperature is required to be increased to realize full glue discharge, the method contradicts the packaging process targets of a SiC device, such as low temperature, short time and low stress, on the other hand, incomplete decomposition of the resin is easy to generate carbon residue, interface holes and inclusions, effective contact among silver powder particles and metallurgical sintering are prevented, the density of a silver layer, the electric conduction and heat conduction performance and the long-term reliability of a joint are obviously reduced, and the method is difficult to adapt to the service environment of the SiC power module, such as high temperature and high cyclic stress. In order to alleviate the problems of residue and densification brought by a resin system, the industry gradually develops resin-free or resin-less low-temperature sintering silver paste, and high-boiling-point organic solvents such as terpineol, butyl carbitol and the like are often adopted to replace part or all of organic binders. Although the system can reduce resin decomposition residues, the sintering driving force mainly depends on external heating, the surface diffusion and grain boundary migration activation energy of silver powder particles is higher, densification kinetics is insufficient, if good sintering is realized, the process temperature is usually higher than 300 ℃, and if sintering is performed at a lower temperature, the problems of loose silver layer, high porosity, low shear strength, poor electric conduction and heat conduction performance and the like are easy to occur. For SiC power module packaging, the thermal stress mismatch between a chip and a substrate, the warping of a bonding layer and the cracking of an interface are easily caused by the excessively high sintering temperature, so that the reliability of a device and the power cycle life are severely restricted. Therefore, how to realize high-efficiency densification sintering at lower temperature and in shorter time under a resin-free/low-resin system and obtain interconnection joints with high density, high heat conduction, high electric conduction and high mechanical strength at the same time has become a key technical bottleneck for restricting the low-temperature and high-reliability packaging of SiC power devices. Disclosure of Invention The invention aims to provide solvent-assisted low-temperature sintering silver paste which is free of resin and low in temperature and rapid in full sintering, and a second aim of the invention is to provide a preparation method of the solvent-assisted low-temperature sintering silver paste, and a third aim of the invention is to provide application of the solvent-assisted low-temperature sintering silver paste. The solvent-assisted low-temperature sintering silver paste comprises, by mass, 90-92 parts of conductive silver powder, 8-9 parts of low-volatile latent heat sintering-assisted ether solvent and 1-2 parts of long-chain fatty acid dispersing agent. Wherein the sintering-assisting ether solvent with low latent heat of volatilization is tripropylene glycol monobutyl ether. Wherein the long-chain fatty acid dispersing agent is oleic acid or stearic acid. Wherein the conductive