[silver Conference] Industry Analysis of Photovoltaic Electronic Materials with Superfine Silver-coated Copper Powder

SMM10: at the 2020 China International Silver Industry chain Summit Forum and China Silver Market Application Symposium, Hu Xiaobin, doctoral supervisor of Shanghai Jiaotong University, introduced the industrialization of ultra-fine silver-coated copper powder photovoltaic electronic materials.

Hu Xiaobin said that silver is a commonly used electronic material with good electrical conductivity and thermal conductivity, but the price of silver is high, rigid and fluctuating; copper also has good electrical and thermal conductivity and low price, which has a huge price advantage compared with silver. However, the oxidation resistance of copper is poor, especially micron and submicron copper powder, which is chemically unstable, which is more obvious at wet and high temperature, which can not meet the requirements of electronic paste.

The purpose of developing silver-coated copper ultra-fine powder is to replace silver powder: it can not only meet the requirements of electronic paste, but also has a huge price competitive advantage.

The concept of silver-clad copper was put forward a long time ago, why is there no large-scale market application? Hu Xiaobin pointed out that the early silver-coated copper had the following problems: poor compactness of the coating, not resistant to high temperature, weak bonding of the coating, unable to pass the three-roller machine, poor compactness, not resistant to gas and liquid penetration (not weather-resistant), and the surface was not smooth. High oil absorption leads to low metal solid content.

At present, silver-clad copper has a huge market demand, such as photovoltaic positive silver / back silver, 5G, semiconductor packaging, electrical contact, low temperature touch screen, high thermal conductivity and high heat dissipation, silver-copper-carbon composites and so on.

Hu Xiaobin stressed the interaction between technology and the market. Technology is dynamic and must be tested by the market before it can be continuously improved. Any new technology just entered the market is not mature enough, the market should give new technology opportunities, enterprises should dare to try in order to courageously set the tide.

Ultra-fine Metal Powder-- Copper / Silver coated Copper / Nickel Powder

Display of four main products

Among them, spherical copper powder is suitable for high temperature sintering electronic paste; flake copper powder is suitable for low temperature curing electronic paste; spherical silver coated copper powder can replace high temperature sintered silver powder; flake silver coated copper powder can replace flake silver powder.

At present, the chemically synthesized micron single crystal copper powder has completed laboratory and pilot tests, and can be produced on a large scale. And the particle size of the powder can be controlled: 50nm, 100nm, 1.0um, 1.4um, 1.8um, 2.2um.

Analysis of Industry chain of Superfine Copper Powder

The data show that the global sales of ultra-fine copper powder in 2018 is about 4450 tons, and the average unit price is about 520000 yuan / ton. MLCC is an important electronic passive component, which is widely used in circuits. Widely used in 5G, mobile phones, Internet of things, electric vehicles and so on.

Covering thought

The morphology of copper particles has an important effect on the coating. The more nanocrystalline and atomized the coated particles are, the denser the coating is, which can provide higher temperature resistance. The finer the coating layer is, the closer the particles are to the color of copper, which can be used to judge the coating quality. And the higher the sintering temperature, the thicker the coating.

Comparison of silver-coated copper powder with silver powder and copper powder

Technical parameters of silver-coated copper powder

Product characteristics: the coating is compact and complete, the range of particle size distribution is narrow, the dispersion is good, and it is not easy to oxidize.

Application: suitable for silver conductive paste, EMI formula products, thick film paste and conductive adhesive, etc.

Key technology and technology

The key technology is to control the particle size and morphology of metal powder through the design of formula and the adjustment of process parameters.