Copper wire remains a key conductor, semicon interconnection alternative

Copper wire has been around for so long that some may consider it outdated, but it is not retiring anytime soon. While copper cannot be compared to gold, as a conductor it is second to silver but is not as expensive as either of those two precious metals - and it has the highest electrical conductivity among base or nonprecious metals. It is still extensively used in telecommunications and electric power systems today.

In electronics, copper wire is employed in cables, connectors, coils and transformers, and as structured wiring that connects computers, taking some of the burden off wireless networks, and computers with other devices such as printers. It is easier and less costly to install and maintain than the much lighter and faster fiber-optic cable, its rival and likely successor. It is recyclable and has a high resale value, while fiber-optic cables require time-consuming and costly methods to separate parts that can be recycled.

Copper wire is also important where Power over Ethernet (PoE) is used because it can deliver data and power simultaneously. And despite the popularity of wireless technology, PoE cannot be deposed just yet because it is needed in applications such as IP cameras, network routers, digital signage on buildings and in-building networks. Advances over the years mean that this technology can also provide a reliable and inexpensive power source for IoT devices and smart buildings.

In interconnections in semiconductors, including LEDs, where the current gold standard is, literally, gold bonding wire, copper is a cost-effective substitute. Introduced by IBM in 1997 in its ICs, the use of copper bonding wire in lieu of aluminum was a breakthrough at the time. Years of advancements and new technologies such as flip chip aside, this has remained a viable option, especially in applications where silver or gold is an unnecessary cost.

In China, manufacturers of copper wires are developing new techniques to boost tensile strength and overall reliability without impacting prices. Huzhou Nanxun Jueshengbo achieved a breakthrough in antioxidation treatment by extending immersion to 75 days compared to the conventional period of about 30 days.

Many Chinese copper wire manufacturers have introduced fully automatic equipment as well, not only to streamline production but also to improve the quality of output.

For wire bonding applications, suppliers build on the copper category's inherent high conductivity and low parasitic capacitance. Compared to gold, copper wire bonds deliver better reliability at elevated temperatures and possess greater mechanical stability while reducing cost by up to 90 percent. Yunnan Copper Science & Technology uses a self-developed material formula, combining pure copper and minerals to realize high tensile strength and elongation for ICs, discrete devices and LEDs.

Production expansion

One of the world's major manufacturing bases for copper wires, China continues to benefit from a steady rise in demand. Sales value grew by 5 to 10 percent in 2020 despite the COVID-19 pandemic, according to companies contacted by Global Sources Electronic Components. This will most likely be maintained in 2021, buoyed by the ongoing need for copper wire bonding.

The global wire bonding industry had a market scale of $5 billion in 2019, with China accounting for $1.07 billion, according to Newsijie.cn, and rose by 10 to 15 percent the following year. The copper category accounted for more than 70 percent.

In spite of the manufacturing shutdown in the early part of 2020, most Chinese suppliers were not impacted, according to suppliers. They therefore have a generally positive outlook for the rest of 2021, with many expecting to keep increasing production to meet domestic and overseas orders even through 2022.

There are hundreds of manufacturers of copper wires in China, most of which export 30 to 70 percent of their output, mainly to Europe, North America and the Asia-Pacific region.

These companies are located in the coastal and central provinces of Guangdong, Zhejiang, Jiangsu, Shandong, Hebei and Henan. The western regions have also attracted investment in recent years.

Amer International Group, a high-technology industrial enterprise, invested in a New Materials Industry Park in Xinjiang and set up a refined copper wires factory in late 2019 with an annual capacity of 100,000 tons. The company is said to be the world's leading new metallic materials producer and ranked 91st inForbes' Global 500 in 2020.

Copper wire types

China's range of copper wires, which is categorized by copper ratio, consists of brass, pure copper and phosphor copper.

Pure copper wires, which are at least 99.8 percent copper, dominate production. Brass wires have 65 percent copper and 35 percent zinc, and phosphor copper wires between 85 and 90 percent copper and 5 and 15 percent tin.

In terms of diameter, commonly available are 0.2, 0.25, 0.3, 1.2, 1.5, 1.75 and 2mm for single wires. Typical choices based on tensile strength are 450, 500, 900 and 1,000N/sqmm.

Key raw materials of copper and other types of metal are sourced domestically. The cost of these inputs fluctuated in the past year and caused a similar fluctuation in product prices. Most companies interviewed anticipate these will stabilize in the next six months.

Upping the recycling ante

China is one of the largest production bases for copper scraps. However, at a 40 to 50 percent recycling ratio, it falls behind developed countries, which are in the 60 to 70 percent range. In the next two years, China is targeting up to 60 percent.

By volume, China will churn out a total of 3.8 million tons of copper scrap in 2025, according to SOHU News.

Copper scraps come mainly from waste during copper production, as well as old wires and cables, household appliances, coils and pipes. It is estimated that one-third returns to the market as refined copper and two-thirds are as pure copper and copper alloy.

In China, the main recycling and production bases are in the Pearl River Delta, the Yangtze River Delta and the Bohai Bay Rim Economic Region. The key city locations include Taizhou and Ningbo in Zhejiang province, Foshan and Qingyuan in Guangdong, Linyi in Shandong, Baoding in Hebei, Changge in Henan, Jinghai in Tianjin and Miluo in Hunan.

99.9% pure copper wire

Available in 0.2, 0.25 and 0.3mm diameters, Hebei Hongju Metal Products Co. Ltd's HJ-Copperwire has 450, 500, 900 or 1,000N/sqmm tensile strength and 99.9 percent purity.

Order quantity is negotiable. Lead time is five days.

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Class 130 enameled copper wire

This Anhan-229 model from Hefei Anhan Metal Fty is a Class 130 enameled copper wire in sizes ranging from 22 to 24AWG. It meets IEC 60317-34 standards.

The minimum order is 1,000kg. Lead time is five days.

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Insulated 99.99% pure copper wires

These C1100, C10100, C10200 from Xiamen Yuxiang Magnetic Materials Technology Co. Ltd are insulated solid round copper wires with 99.99 percent purity.

An order of at least 1kg is required for delivery within 15 days.

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Enameled stranded copper wire

Yangzhou Positioning Tech Co. Ltd's QA-H is a stranded copper wire with an enameled insulation layer.

The minimum order quantity is 10kg. Delivery takes 15 days.

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