For more than 50 years, designers of computer chips have mainly used one tactic to boost performance: They’ve shrunk electronic components to pack more power into each piece of silicon.
Then more than a decade ago, engineers at chip maker Advanced Micro Devices began toying with a radical idea. Instead of designing a large microprocessor with lots of tiny transistors, they thought of creating one from smaller chips that would be tightly coupled together to function like an electronic brain.
The concept, sometimes called chiplets, has caught on in a big way, with AMD, Apple, Amazon, Tesla, IBM and Intel introducing such products. Chiplets have quickly gained traction because small chips are cheaper to manufacture, while bundles of them can top the performance of any single slice of silicon.
The approach, based on advanced packaging technology, has since become an important tool to enable progress in semiconductors. And it represents one of the biggest changes in years for an industry that is driving innovations in fields like artificial intelligence, self-driving cars and military hardware.
“The packaging is where the action is going to be,” said Subramanian Iyer, a professor of electrical and computer engineering at the University of California, Los Angeles, who helped pioneer the chiplet concept. “It happens because there really is no other way.”
The catch is that such packaging, like the production of the chips themselves, is heavily dominated by Asian companies. Although the United States accounts for about 12 percent of global semiconductor production, American companies provide only 3 percent of chip packaging, according to IPC, a trade association.
That issue has now put chiplets at the center of US industrial policy-making. The CHIPS Act, a $52 billion subsidy package passed last summer, was seen as President Biden’s move to reinvigorate domestic chip manufacturing by providing money to build more sophisticated factories called “fabs.” But part of it is also aimed at stimulating advanced packaging factories in the United States to capture more of those important processes.
“As chips get smaller, the way you organize the chips, which is packaging, is more important and we need to do it in America,” said Commerce Secretary Gina Raimondo, in a speech at Georgetown University in February.
The Department of Commerce is now accepting applications for manufacturing grants from the CHIPS Act, including for chip packaging factories. It also funds a research program specifically on advanced packaging.
Some chip packaging companies are moving quickly for funding. One is Integra Technologies in Wichita, Kan., which has announced plans for a $1.8 billion expansion there but said that is contingent on receiving federal subsidies. Amkor Technology, an Arizona packaging service with most of its operations in Asia, also said it was talking to customers and government officials about a US production presence.
Stacking chips together isn’t a new concept and chiplets are the latest iteration of that idea, using technological advances that help squeeze chips closer together – side by side or stacked on top of each other – with faster electrical connections between them. .
“What’s unique about chiplets is the way they’re connected electrically,” said Richard Otte, the chief executive of Promex Industries, a chip packaging service in Santa Clara, Calif.
Chips can’t do anything without a way to connect them to other components, which means they have to be put in some kind of package that can carry electrical signals. That process begins after factories complete the first phase of manufacturing, which can create hundreds of chips on a single silicon wafer. Once that wafer is split, the individual chips are typically glued to a key base layer called a substrate, which can conduct electrical signals.
That combination is coated with protective plastic, forming a package that can be plugged into a circuit board essential for connecting other components in a system.
These processes originally required a lot of manual labor, leading Silicon Valley companies to move packaging to low-wage countries in Asia more than 50 years ago. Most of the chips are usually transported in packaging services in countries such as Taiwan, Malaysia, South Korea and China.
Since then, packaging development has gained importance because of the diminishing returns from Moore’s Law, the shorthand expression for chip miniaturization that for decades drove progress in Silicon Valley. It is named for Gordon Moore, a co-founder of Intel, whose 1965 paper described how quickly companies could double the number of transistors on a typical chip, improving performance at a lower cost.
But these days, smaller transistors aren’t necessarily cheaper, partly because building factories for the top chips can cost $10 billion to $20 billion. Larger, more complex chips are also more expensive to design and tend to have more manufacturing defects, even though companies in fields like generative AI want more transistors than can currently be packed into the largest possible chips manufacturing machines.
“The natural response to that is to put more things in a package,” said Anirudh Devgan, chief executive of Cadence Design Systems, whose software is used to design conventional chips as well as chiplet-style product.
Synopsys, a rival, said it was tracking more than 140 customer projects based on packing multiple chips together. Up to 80 percent of microprocessors will use chiplet-style designs by 2027, according to market research firm Yole Group.
Today, companies typically design all chiplets in one package with their own connectivity technology. But industry groups are working on technical standards so that companies can more easily assemble products from chiplets that come from different makers.
New technology is often used today for extreme performance. Intel recently introduced a processor called Ponte Vecchio with 47 chiplets to be used in a powerful supercomputer at Argonne National Laboratory, near Chicago.
In January, AMD revealed plans for an unusual product, the MI300, which combines chiplets for standard calculations with others designed for computer graphics, along with a large pool of memory chips. That processor, intended to power another advanced supercomputer at Lawrence Livermore National Laboratory, has 146 billion transistors, compared to tens of billions for most advanced conventional chips.
Sam Naffziger, a senior vice president of AMD, said it’s not a slam-dunk for the company to bet its chip business for server computers on chiplets. Packaging complications were a major hurdle, he said, which was eventually overcome with the help of an undisclosed partner.
But the chiplets paid off for AMD. The company has sold more than 12 million chips based on the idea since 2017, according to Mercury Research, and has become a major player in microprocessors that power the web.
Packaging services still need others to provide the substrates the chiplets need to connect to circuit boards and to each other. One company driving the chiplet boom is Taiwan Semiconductor Manufacturing Company, which already makes chips for AMD and hundreds of others and offers an advanced silicon-based substrate called an interposer.
Intel has developed similar technology, as well as improving less expensive conventional plastic substrates in an approach favored by some such as Silicon Valley start-up Eliyan. Intel is also developing new packaging prototypes under a Pentagon program and hopes to win CHIPs Act support for a new pilot packaging plant.
But the United States does not have a major producer of those substrates, which are made primarily in Asia and evolved from technologies used to make circuit boards. Many US companies have also exited that business, another concern that industry groups hope will prompt federal funding to help board suppliers start making substrates.
In March, Mr. Biden issued a determination that advanced packaging and domestic circuit board production is vital to national security, and announced $50 million in Defense Production Act funding for American and Canadian companies in those fields. .
Even with such subsidies, putting together all the elements needed to reduce US dependence on Asian companies is “a big challenge,” said Andreas Olofsson, who ran a research effort by Department of Defense in the field before founding a packaging start-up called Zero ASIC. “You have no suppliers. You don’t have a work force. You have no equipment. You have to start from scratch.”
Ana Swanson contributed reporting.
