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Cobalt Could Untangle Chips’ Wiring Problems

Intel and GlobalFoundries are replacing some copper connections with the resilient, conductive metal

3 min read
Photo: Intel
Photo: Intel

imgWired Up: This Intel transistor, seen in cross section, uses cobalt for lower-resistance wiring.Image: Intel

Today’s computer chips contain tens of kilometers of copper wiring, built up in 15 or so layers. As the semiconductor industry has shrunk the size of transistors, it has also had to make these interconnects thinner. Today, some wiring layers are so fine that electrical current can actually damage them. And chipmakers are running out of new ways to deal with this problem.

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3 Ways 3D Chip Tech Is Upending Computing

AMD, Graphcore, and Intel show why the industry’s leading edge is going vertical

8 min read
Vertical
A stack of 3 images.  One of a chip, another is a group of chips and a single grey chip.
Intel; Graphcore; AMD
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A crop of high-performance processors is showing that the new direction for continuing Moore’s Law is all about up. Each generation of processor needs to perform better than the last, and, at its most basic, that means integrating more logic onto the silicon. But there are two problems: One is that our ability to shrink transistors and the logic and memory blocks they make up is slowing down. The other is that chips have reached their size limits. Photolithography tools can pattern only an area of about 850 square millimeters, which is about the size of a top-of-the-line Nvidia GPU.

For a few years now, developers of systems-on-chips have begun to break up their ever-larger designs into smaller chiplets and link them together inside the same package to effectively increase the silicon area, among other advantages. In CPUs, these links have mostly been so-called 2.5D, where the chiplets are set beside each other and connected using short, dense interconnects. Momentum for this type of integration will likely only grow now that most of the major manufacturers have agreed on a 2.5D chiplet-to-chiplet communications standard.

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