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30 PCB007 MAGAZINE I JANUARY 2023 to double every two years because of increases in the number of transistors a microchip can contain. It was a shocking statement when Moore announced that a single IC would some- day hold 65,000 transistors. e size of IC nodes is now being mass-produced at 5 nm, which was commercially released in the Apple A14 Bionic chip. e transistor count now sits at a stagger- ing 11.8 billion, a 38.8% increase from the A13's transistor count of 8.5 billion. By 2024, the expectation is to be even smaller at 2 nm. For perspective, that is smaller than human DNA and could hold over 50 billion transistors on a chip the size of a fingernail. But before we pop the cork on the champagne, I believe we have reached or are very close to reaching the limits of our capability to produce chips reasonably and reliably. As things shrink, simply controlling the current flow in such a small area is very difficult. In other words, we are now getting so small that we can no longer control the electrons. We are simply running out of room. Many believe that Moore's Law is dead, particularly NVIDIA CEO Jensen Huang, who proudly announced his belief in this idea last year. I am not at that point yet, but it does feel like Moore's Law is on life support. Although we call it a law, even Moore agreed it was more of an observation. In his 1965 publication, Cramming More Components onto Integrated Circuits, he admits "including micro-assembly techniques for individual components, thin film struc- tures, and semiconductor integrated circuits. Each approached evolved and rapidly and con- verged." In an interview in April 2005 2 , Gordon Moore stated that the projection could not be sustained indefinitely: "It can't continue for- ever. e nature of exponentials is that you push them out, and eventually disaster happens." He also noted that transistors eventually would reach the limits of miniaturization at atomic levels: In terms of size [of transistors], you can see that we're approaching the size of atoms which is a fundamental barrier, but it'll be two or three generations before we get that far—but that's as far out as we've ever been able to see. We have another 10 to 20 years before we reach a fun- damental limit. By then, they'll be able to make bigger chips and have transistor budgets in the billions. Another major problem we face is making all the interconnects to a high-density device so that it's a functional item on a PCB design. Con- ventionally it's done through wire bonds, which have not scaled down at the same pace as the transistor. With 11.8 billion transistors in a sin- gle chip, that is more processing power than wires can carry. Getting signals from the sili- con out to the real world, which connects to the PCB, is a significant issue. Frankly, we are reaching the industry limita- tions in more ways than one. A Paradigm Shift of Advanced Packaging Occasionally it's good practice to examine how we do things. Advanced packaging tech- nology (APT) is a paradigm shi for the entire industry. It promises to solve the challenges we face. We can define APT as the aggregation and interconnection of components before tradi- tional electronics packaging. Advanced packag- ing allows multiple devices (electrical, mechan- ical, or semiconductor) to be merged and pack- aged as a single electronic device. ey are taking different circuits that were separate chips on the PCB design before and placing them all in a single chip. Although we are not specifically talking about applications when speaking of APT, we will find As things shrink, simply controlling the current flow in such a small area is very difficult.