When I recently visited Kunming (Yunnan Province, China), I noticed the huge copper smelting operations which let me to ponder where the rising price of copper will take our industry. This was not the first time that rising copper prices made me think. It was in the 1970s when I added a bathroom to our modest ranch home in Wilmington, DE, and since copper had become very expensive, I used aluminum wiring. That was not a good idea, although acceptable at the time.

The reason we use copper in electronics is because it is a good conductor, it is reasonably resistant to oxidation, and although not a precious metal, it has good ductility and elongation which contributes to the reliability of electronic packages, making it a good value for the money, considering the alternatives. What alternatives? Well, silver is a better conductor than copper, but more expensive. It would be even more expensive had it not been for the rapid growth of digital photography. Gold is a little less conductive than copper and much more expensive. So it is not a good alternative, and we use it only where we need its low contact resistance and resistance to oxidation; e.g., on touch pads in cell phones, in wire bonding, and for connectors. Aluminum might be an alternative since it has respectable conductivity (but less than copper), however there is no well behaved plating process, comparable to acid copper plating baths. The price remained fairly stable over the years despite rising energy costs, mainly due to the fact that aluminum is the most widely recycled metal. An improved copper recycling technology and infrastructure may hold the answer to rising copper prices in the future!