CN102691055A

CN102691055A - Preparing method of novel silicon carbide nano-particle

Info

Publication number: CN102691055A
Application number: CN2012101444937A
Authority: CN
Inventors: 刘建影
Original assignee: SHANGHAI SHANG DA RUI HU MICROSYSTEM INTEGRATION TECHNOLOGY Co Ltd (SMIT LTD)
Current assignee: SHANGHAI SHANG DA RUI HU MICROSYSTEM INTEGRATION TECHNOLOGY Co Ltd (SMIT LTD)
Priority date: 2012-05-11
Filing date: 2012-05-11
Publication date: 2012-09-26

Abstract

The invention discloses a preparing method of a novel silicon carbide nano-particle which is used to strengthen composite leadless solders, aiming to synthesize a silicon carbide nano-particle for welding and surface packaging of electronic components. The method of the invention is characterized in that a chemical plating method is used for plating a layer of nano-silver particles with a thickness of about 2-5 nm on the surfaces of silicon carbide nano-particles, and the silver-plated silicon carbide nano-particles are added into a tin-base leadless solder to improve the strength of the solder without influences on the heat transfer property and the conductivity of the original solder. The method is simple in operation, requires no special conditions such as high temperature and high pressure, and has a single treating capacity far higher than that of electroplating methods, thereby being easier for industrial scale-up. Besides, the whole process is carried out in a solution system and the diffusion of nano-particles to environment is effectively reduced, so that harms on the health of the workers are reduced and the method is environment friendly.

Description

A kind of preparation method of novel silicon carbide nano particle

Technical field

The present invention relates to a kind of nanometer silicon carbide particle surface modification technology, particularly a kind of preparation method of novel silicon carbide nano particle is used to strengthen compound lead-free solder.

Background technology

Silit is a kind of structural ceramic material of excellent performance; Have the hardness height, characteristics such as hot strength is big, creep-resistant property good, resistance to chemical attack, antioxidant property is good, thermal expansivity is little, high thermoconductivity; Be widely applied to manufacturing, metallurgy, electronics, machinery, in the fields such as chemical industry and aviation.By the excellent properties of nano silicon carbide granulate self, through mixing, form matrix material with other materials, be one of major application field of nano ceramics with the performance that promotes material.In the interconnected field of microelectronics Packaging, as strengthening material, the research that improves Sn-Ag-Cu lead-free solder mechanical performance launches with nano silicon carbide granulate.

At present, lead-free solder has obtained using widely.But along with Electronic Packaging density constantly increases, size constantly reduces, the trend that chip power constantly increases, and lead-free solder also needs further to improve its mechanical property.In order to improve the mechanical property of lead-free solder, wherein a kind of effective means are to use molecule that lead-free solder is strengthened, and form composite solder.But composite solder is not widely used.Major cause be exactly between reinforcing particle and the matrix at calorifics, electricity, the mismatch of terms of mechanics causes solder joint failure or degradation very easily easily in application process.Typical example is the mismatch of thermal expansivity between reinforcing particle and matrix and the mismatch of hardness, in the equipment use, is prone to easily crack at the solder joint connecting zone, finally causes the hot machine fatigue failure of solder joint.Therefore the key point among the present invention is exactly how to solve nano silicon carbide granulate to combine relatively poor problem with the SAC alloy.

Summary of the invention

To the defective that prior art exists, the purpose of this invention is to provide a kind of preparation method of novel silicon carbide nano particle, prepare a kind of nano-ceramic particle that is used for electronic devices and components welding and surface encapsulation.Characteristics of the present invention are to adopt the method for electroless plating to plate the nano-Ag particles that a layer thickness is about 2-10nm on nanometer silicon carbide particulate surface; The nanometer silicon carbide particle of this electroplate is added tin-base lead-free solder; Be used to increase the intensity of scolder; Do not influence the thermal conduction and the electroconductibility of former scolder, improve its mechanical property, solve nano-ceramic particle simultaneously and combine relatively poor problem with the SAC alloy.

The objective of the invention is to realize through following technical proposals:

A kind of preparation method of novel silicon carbide nano particle; Be used to strengthen compound lead-free solder; This method has following technological process and step: under ultrasonic vibrations, be that the nanometer silicon carbide particle of 50-100nm joins in the dilute hydrochloric acid solution of tin protochloride that concentration is 0.05-0.5mol/L in 20-80 with diameter ^oC floods 0.5-3h, carries out surface active.Spinning on centrifuge separator after surface active is accomplished; Excessive stannous ion is separated with the activatory silicon-carbide particle, and the operating parameters of centrifuge separator is: rotating speed 3000-8000rpm, time 0.5-2h; De-ionized washing twice, absolute ethanol washing once.Particle after under ultrasonic agitation, will separating joins in the silver ammino solution that concentration is 0.01-0.1mol/L, and temperature of reaction is 20-80 ^oC, the reaction times is 0.5-3h, forms preliminary nano-Ag particles at the nanometer silicon carbide particle surface; The above-mentioned solution of spinning, the operating parameters of centrifuge separator is: rotating speed 3000-8000rpm, time 0.5-2h; Twice of de-ionized washing; Absolute ethanol washing once joins the nano particle after centrifugal and contains protectant silver nitrate solution, and this protective material can prevent the agglomeration of nano-Ag particles; Wherein said protective material is one or more in following: polyoxyethylene nonylphenol, Vinylpyrrolidone polymer, X 2073, this protectant massfraction in solution is 1%-60%.In this solution, adding a kind of reductive agent then, is silver-colored particle with silver ion reduction, and wherein said reductive agent is one or more in following: glucose, formaldehyde, ydrogen peroxide 50.Repeat to add above-mentioned silver nitrate solution and reductive agent; Make the silver-colored particle that originally loads on silicon carbide continue to grow up, form complete successive nanometer silver shell, the above-mentioned solution of spinning; The operating parameters of centrifuge separator is: rotating speed 3000-8000rpm; Time 0.5-2h, de-ionized washing twice, absolute ethanol washing is once.Obtain final silver-plated nanometer silicon carbide particle.

The present invention compared with prior art, have following conspicuous outstanding substantive distinguishing features and remarkable advantage: the present invention adopts chemical process that the nanometer silicon carbide particle is carried out surface-functionalized processing, compares with method non-chemically; It is easy and simple to handle, no high temperature, particular requirements such as high pressure; And the single treatment amount is far above electro-plating method; Thereby be easier to the industry amplification, because the entire treatment process is all carried out, effectively reduce the diffusion of nano particle in environment simultaneously in solution system; Thereby reduced healthy harm, accomplished environmental friendliness for the staff.

Description of drawings

Fig. 1 is the SEM image of the silver-plated front and rear surfaces form of nanometer silicon carbide particle, (a) is the pure carbon nano silicon particles, (b) is the nanometer silicon carbide particle of electroplate.

Fig. 2 is the TEM image of the silver-plated front and rear surfaces form of nanometer silicon carbide particle, (a) is the pure carbon nano silicon particles, (b) is the nanometer silicon carbide particle of electroplate.

Embodiment

The preferred embodiments of the present invention combine accompanying drawing to discuss as follows:

A kind of preparation method of novel silicon carbide nano particle; Be used to strengthen compound lead-free solder; This method has following technological process and step: under ultrasonic vibrations, the nanometer silicon carbide particle of 1g is joined in the dilute hydrochloric acid solution that 50mL concentration is the 0.1mol/L tin protochloride, with 35 ^oC floods 1h, carries out surface active.Spinning on centrifuge separator after surface active is accomplished separates excessive stannous ion with the activatory silicon-carbide particle, the operating parameters of centrifuge separator is: rotating speed 4000rpm, and time 0.5h, de-ionized washing twice, absolute ethanol washing is once.Particle after under ultrasonic agitation, will separating joins in the silver ammino solution that 50mL concentration is 0.04mol/L, and temperature of reaction is 30 ^oC, the reaction times is 1h, the above-mentioned solution of spinning, the operating parameters of centrifuge separator is: rotating speed 5000rpm; Time 0.5h, de-ionized washing twice, absolute ethanol washing is once; It is the silver nitrate solution that 0.3mmol/L contains 0.25 wt% polyoxyethylene nonylphenol that nano particle after centrifugal is joined 50mL concentration, in this solution, adds the ammonia soln of 1mL glucose and 1ml (28%) then respectively, is silver-colored particle with silver ion reduction; Triplicate adds above-mentioned silver nitrate solution and reductive agent, the above-mentioned solution of spinning, and the operating parameters of centrifuge separator is: rotating speed 5000rpm; Time 0.5h, de-ionized washing twice, absolute ethanol washing is once.Obtain final silver-plated nanometer silicon carbide particle.

As depicted in figs. 1 and 2, Fig. 1 is sem (SEM) image, and wherein a is the pure carbon nano silicon particles, and b is silver-plated nanometer silicon carbide particle.Fig. 2 is transmission electron microscope (TEM) image, and wherein a is the pure carbon nano silicon particles, and b is silver-plated nanometer silicon carbide particle.

Claims

1. the preparation method of a novel silicon carbide nano particle is used to strengthen compound lead-free solder, it is characterized in that this method has following technological process and step:

1) under ultrasonic vibrations, be that the nanometer silicon carbide particle of 50-100nm joins in the dilute hydrochloric acid solution of tin protochloride that concentration is 0.05-0.5mol/L in 20-80 with diameter ^oC floods 0.5-3h, carries out surface active;

2) use the whizzer separation solution, parameter of noncentricity is: rotating speed 3000-8000rpm, time 0.5-2h;

3) pour out centrifuge tube top liquid portion, use deionized water to bottom depositing silicon carbide nano particle washed twice, more once with absolute ethanol washing; Step 2 is used in each washing back) said parameter of noncentricity separation solution;

4) the nanometer silicon carbide particle after under ultrasonic agitation, will separating joins in the silver ammino solution that concentration is 0.01-0.1mol/L, and temperature of reaction is 20-80 ^oC, the reaction times is 0.5-3h;

5) repeating step 2) to 3) once;

6) the nanometer silicon carbide particle after centrifugal is joined contain protectant silver nitrate solution; Said protective material is one or more in following: polyoxyethylene nonylphenol, Vinylpyrrolidone polymer, X 2073, and this protectant massfraction in solution is 1%-60%;

7) in this solution, adding a kind of reductive agent then, is silver-colored particle with silver ion reduction, and wherein said reductive agent is one or more in following: glucose, formaldehyde, ydrogen peroxide 50;

8) repeating step 6) and 7) 2 to 5 times, make the silver nano-grain that originally loads on the nanometer silicon carbide particle surface continue to grow up, form complete successive nanometer silver shell;

9) repeating step 2) to 3) once, obtain final silver-plated nanometer silicon carbide particle.