阅读说明：本技术 一种低温烧结的铟掺杂纳米银烧结膏的制备方法及烧结方法 (Preparation method and sintering method of low-temperature sintered indium-doped nano-silver sintering paste ) 是由 刘盼 张靖 叶怀宇 张国旗 于 2019-10-28 设计创作，主要内容包括：一种低温烧结的铟掺杂纳米银烧结膏的制备方法,包括：S1：配置纳米银溶液；S2：将纳米铟颗粒加入纳米银溶液,获得铟掺杂纳米银浆液,所述铟掺杂纳米银浆液内,铟占总质量比的范围为0.05％-2.5％；S3：采用混合器对铟掺杂纳米银浆液做均匀混合处理,获得铟掺杂纳米银烧结膏。本发明解决了现有的纳米银膏体烧结后裂纹较多,孔隙率较大,连接强度较低的的技术问题,有效提高银烧结膏热学,电学,力学性能可靠性。(A preparation method of indium-doped nano-silver sintering paste sintered at low temperature comprises the following steps: s1: preparing a nano silver solution; s2: adding nano indium particles into a nano silver solution to obtain indium-doped nano silver slurry, wherein the indium accounts for 0.05-2.5% of the total mass ratio in the indium-doped nano silver slurry; s3: and uniformly mixing the indium-doped nano silver slurry by adopting a mixer to obtain the indium-doped nano silver sintering paste. The invention solves the technical problems of more cracks, larger porosity and lower connection strength of the existing nano silver paste after sintering, and effectively improves the reliability of thermal, electrical and mechanical properties of the silver sintering paste.)

1. A preparation method of indium-doped nano-silver sintering paste sintered at low temperature is characterized by comprising the following steps:

s1: preparing a nano silver solution;

s2: adding nano indium particles into a nano silver solution to obtain indium-doped nano silver slurry, wherein the indium accounts for 0.05-2.5% of the total mass ratio in the indium-doped nano silver slurry;

s3: uniformly mixing the indium-doped nano-silver slurry by using a mixer to obtain indium-doped nano-silver sintering paste;

the mixer comprises a first rotating cylinder rotating anticlockwise and a second rotating cylinder rotating clockwise, or the first rotating cylinder rotating clockwise and the second rotating cylinder rotating anticlockwise;

and the uniform mixing treatment is to inject indium-doped nano silver slurry into the outer wall of the first rotating cylinder, rotate the first rotating cylinder and the second rotating cylinder at the same time, and strip off the coating which is moved from the surface of the first rotating cylinder to the surface of the second rotating cylinder during rotation to obtain the indium-doped nano silver sintering paste.

2. The method for preparing the low-temperature sintered indium-doped nano-silver sintering paste as claimed in claim 1, wherein the nano-silver particle size is less than 100nm, and the nano-indium particle size is less than 50 nm.

3. The method for preparing the low-temperature sintered indium-doped nano-silver sintering paste according to claim 1, wherein the S1 comprises:

s1.1: preparing a solvent, wherein the solvent comprises a dispersing agent, a diluent and a binder; the mass fraction ratio of the dispersing agent, the diluent and the adhesive is 2:2: 1;

s1.2: adding the nano silver particles into a solvent, mechanically oscillating for at least 15 minutes by adopting a spiral oscillator, and ultrasonically oscillating for at least 50 minutes by adopting an ultrasonic cleaner.

4. The method for preparing the low-temperature sintered indium-doped nano-silver sintering paste according to claim 1, wherein the S2 comprises: and adding the nano indium particles into the nano silver solution, mechanically oscillating for at least 15 minutes by adopting a spiral oscillator, and ultrasonically oscillating for at least 50 minutes by adopting an ultrasonic cleaner to obtain the indium-doped nano silver slurry.

5. The method for preparing the low-temperature sintered indium-doped nano-silver sintering paste according to claim 3, wherein the step S1 further comprises: s1.3, uniformly mixing the nano-silver solution subjected to ultrasonic oscillation by the ultrasonic cleaner by using a mixer;

and the uniform mixing treatment is to inject nano-silver solution into the outer wall of the first rotating cylinder, rotate the first rotating cylinder and the second rotating cylinder simultaneously, and strip off the coating which is moved from the surface of the first rotating cylinder to the surface of the second rotating cylinder during rotation to obtain the nano-silver solution.

6. The method for preparing the low-temperature sintered indium-doped nano-silver sintering paste as claimed in claim 3, wherein the dispersant is terpineol, the diluent is isobutanol, and the binder is polyvinyl alcohol.

7. The method for preparing the low-temperature sintered indium-doped nano-silver sintering paste according to claim 1, wherein the temperature range for uniformly mixing the indium-doped nano-silver slurry by using the mixer is as follows: 70-150 ℃.

8. A sintering method of a low-temperature sintered indium-doped nano-silver sintering paste prepared by the preparation method of a low-temperature sintered indium-doped nano-silver sintering paste according to claims 1 to 7, comprising:

s1: coating the indium-doped nano-silver sintering paste on a substrate;

s2: attaching the chip to the coated indium-doped nano-silver sintering paste;

s3: and controlling the pressure and the temperature to sinter the substrate, and cooling to obtain the sintered connecting device.

9. The sintering method of indium-doped nano-silver sintering paste according to claim 8, wherein in S3, the size is larger than 10x10cm ²The sintering pressure of the chip is 10-20MPa, the sintering time lasts for 1-2 minutes, the sintering temperature is 220-250 ℃, and the sintering temperature is raised in a step mode and lasts for 1-3 hours.

10. The sintering method of indium-doped nano-silver sintering paste according to claim 8, wherein in the S3, the size is less than 2x2cm ²The chip is not provided with sintering pressure, the sintering temperature is 220-250 ℃, the sintering temperature is increased in a step mode, and the sintering time is 1-3 hours.

Technical Field

The invention relates to the technical field of semiconductor chip packaging, in particular to paste for electrical interconnection

Background

Power electronic devices have been widely used in various fields of modern society, including power electronics, electric vehicles, automation systems, energy conversion, and the like. The demand for new interconnect materials and advanced packaging is also increasing. Among them, the stability of the interconnection material under high voltage and high current and high temperature is very important for reliability, and how to realize high electric conductivity, high thermal conductivity and high mechanical strength of the interconnection material and realize low temperature sintering is a problem which needs to be solved urgently.

The existing silver sintering technology is based on the diffusion principle of silver and welding plastic deformation, utilizes the free energy on the surface of silver ions as a driving force, and has the advantages of high electron migration rate, easy generation of cracks after sintering, high porosity and reduced connection strength.

Disclosure of Invention

In order to solve the technical problems of more cracks, larger porosity and lower connection strength of the existing nano-silver paste after sintering, the invention provides a preparation method of indium-doped nano-silver sintering paste sintered at low temperature, which comprises the following steps:

s1: preparing a nano silver solution;

s2: adding nano indium particles into a nano silver solution to obtain indium-doped nano silver slurry, wherein the indium accounts for 0.05-2.5% of the total mass ratio in the indium-doped nano silver slurry;

s3: uniformly mixing the indium-doped nano-silver slurry by using a mixer to obtain indium-doped nano-silver sintering paste;

the mixer comprises a first rotating cylinder rotating anticlockwise and a second rotating cylinder rotating clockwise, or the first rotating cylinder rotating clockwise and the second rotating cylinder rotating anticlockwise;

and the uniform mixing treatment is to inject indium-doped nano silver slurry into the outer wall of the first rotating cylinder, rotate the first rotating cylinder and the second rotating cylinder at the same time, and strip off the coating which is moved from the surface of the first rotating cylinder to the surface of the second rotating cylinder during rotation to obtain the indium-doped nano silver sintering paste.

Preferably, the particle size of the nano silver particles is less than 100nm, and the particle size of the nano indium particles is less than 50 nm.

Preferably, the S1 includes:

s1.1: preparing a solvent, wherein the solvent comprises a dispersing agent, a diluent and a binder; the mass fraction ratio of the dispersing agent, the diluent and the adhesive is 2:2: 1;

s1.2: adding the nano silver particles into a solvent, mechanically oscillating for at least 15 minutes by adopting a spiral oscillator, and ultrasonically oscillating for at least 50 minutes by adopting an ultrasonic cleaner.

Preferably, the S2 includes: and adding the nano indium particles into the nano silver solution, mechanically oscillating for at least 15 minutes by adopting a spiral oscillator, and ultrasonically oscillating for at least 50 minutes by adopting an ultrasonic cleaner to obtain the indium-doped nano silver slurry.

Preferably, the S1 further includes: s1.3, uniformly mixing the nano-silver solution subjected to ultrasonic oscillation by the ultrasonic cleaner by using a mixer;

and the uniform mixing treatment is to inject nano-silver solution into the outer wall of the first rotating cylinder, rotate the first rotating cylinder and the second rotating cylinder simultaneously, and strip off the coating which is moved from the surface of the first rotating cylinder to the surface of the second rotating cylinder during rotation to obtain the nano-silver solution.

Preferably, the dispersant is terpineol, the diluent is isobutanol, and the binder is polyvinyl alcohol.

Preferably, the temperature range for uniformly mixing the indium-doped nano-silver slurry by using the mixer is as follows: 70-150 ℃.

A sintering method of the low-temperature sintered indium-doped nano-silver sintering paste prepared by the preparation method of the low-temperature sintered indium-doped nano-silver sintering paste comprises the following steps:

s1: coating the indium-doped nano-silver sintering paste on a substrate;

s2: attaching the chip to the coated indium-doped nano-silver sintering paste;

s3: and controlling the pressure and the temperature to sinter the substrate, and cooling to obtain the sintered connecting device.

Preferably, in the S3, the size is larger than 10x10cm ²The sintering pressure of the chip is 10-20MPa, the sintering time lasts for 1-2 minutes, the sintering temperature is 220-250 ℃, and the sintering temperature is raised in a step mode and lasts for 1-3 hours.

Preferably, in the S3, the size is less than 2x2cm ²Without the chip being provided with a burn-inThe sintering pressure is 220-250 ℃, the sintering temperature is increased in a step mode, and the sintering time is 1-3 hours.

According to the invention, the nano indium particles are dispersedly added in the nano silver paste without agglomeration, so that the thermal property, the electrical property and the mechanical property reliability of the silver sintering paste can be effectively improved, the silver sintering paste can be applied to a high-temperature environment, the silver migration rate of the silver sintering paste is reduced, the connection strength is improved, and the technical effects of reducing crack initiation caused by silver migration and improving the connection strength are achieved. When the indium-doped nano silver paste provided by the invention is used for sintering connection, the sintering temperature is lower than that of the traditional silver sintering paste, and the process does not need pressurization and inert gas protection for small-size chips.

Drawings

FIG. 1 is a schematic diagram of a mixer for preparing a low-temperature sintered indium-doped nano-silver sintering paste according to an embodiment

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, the following examples of which are intended to be illustrative only and are not to be construed as limiting the scope of the invention.