In the rush to build an AI future, semiconductors are the silicon rock stars that soak up all the applause. Yet behind the curtain, an unglamorous stagehand is doing much of the heavy lifting. Printed circuit boards (PCBs) are the copper-laced panels inside every mobile phone, car key fob, digital camera and data-centre server rack on Earth. Without them, even the most advanced AI chip would be useless, unable to process even a single line of code. This year alone, more than 1 million square...