Intel Exhibits Off Work on Subsequent-Gen Glass Core Substrates, Plans Deployment Later in Decade #Imaginations Hub

Intel Exhibits Off Work on Subsequent-Gen Glass Core Substrates, Plans Deployment Later in Decade #Imaginations Hub
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Though Intel’s annual Innovation occasion doesn’t kick off till tomorrow, the corporate is already publishing some bulletins forward of the present – and it’s not the trivial stuff, both. This morning the corporate is exhibiting off their preliminary work on growing a glass core substrate and related packaging course of for his or her chips. Because of their progress with analysis and improvement on the glass cores, Intel is now planning on introducing glass core substrates to its merchandise within the second half of this decade, permitting them to package deal chips in additional complicated, and finally higher-performing configurations.

There’s rather a lot to unpack from Intel’s comparatively quick announcement, however at a excessive degree, glass core substrates have been beneath analysis for over a decade as a substitute for natural substrates, that are extensively utilized in current-generation processors. Primarily the medium that typical silicon dies sit on, substrates play an essential half in chip packaging. At the beginning, they supply the structural stability for a chip (silicon dies are fairly fragile and flimsy), and they’re additionally the means by way of which alerts from silicon dies are carried, both to different on-package dies (i.e. chiplets), or to the massive variety of comparatively sizable pins/pads on the again aspect of a chip. And, as chip sizes have elevated over time – and the variety of pins/alerts required by high-end chips has, as nicely – so has the necessity for newer and higher supplies to make use of as a substrate, which is what’s been driving Intel’s newest accomplishment.

In the end, what Intel is aiming to do with glass core substrates is to enhance upon what may be accomplished with current natural substrates, permitting for bigger chips with extra alerts to be routed by way of the substrate extra cleanly. And whereas it will probably have advantages for all chips over a protracted sufficient time, the instant focus is on high-end, multi-chiplet processors, the place glass core substrates will provide higher mechanical stability, higher sign integrity, and the power to extra simply route a bigger variety of alerts by way of a non-silicon medium. Briefly, Intel considers it one of many keys to creating high-performance processors within the subsequent decade.

Substrates: A Fast Recap

The necessity for substrates goes again to a few of the earliest days for large-scale built-in chips, the place chip designs reached hundreds and tens of hundreds of transistors. These small transistors wanted to be wired to a lot bigger pins with a view to be put in in techniques by comparatively large human fingers, main as much as the primary chip packages, equivalent to twin in-line packages. These used a body – sometimes a lead body – to carry the precise silicon die, with the body (or alternatively, wire bonds) offering the sign paths between the die and exterior pins.

Intel 4004 Delidded (Picture Courtesy Science Museum Group Assortment On-line – CC BY-SA 4.0)

Because the 70s, there have been a number of evolutions in substrate designed. Steel frames gave strategy to traditional ceramic chip within the 90s, after which natural packaging across the flip of the millennium. Every iteration of substrate had higher properties than the final, above all else, making it simpler to route a bigger variety of sign and energy pins to more and more complicated dies.

Whilst you’ll nonetheless discover lead body and ceramic chips right here and there, natural substrates have been the bread and butter of the business for the final couple of many years. The natural materials, basically fabricated from PCB-like materials layered with woven glass laminates, permits for a reasonably large variety of alerts to be routed by way of a chip, together with fundamental chiplet designs equivalent to Intel’s cell processors (with PCH separate PCH and CPU dies) in addition to AMD’s chiplet-based Zen processors.

However natural substrates have already been a limiting issue for a while now, particularly in high-end chips. Which is why over the past decade we’ve seen the rise of ultra-high-density interconnect interfaces equivalent to silicon interposers (chip on wafer on substrate), and their derivatives like Intel’s personal EMIB. These have allowed firms to bridge collectively the essential paths of their chips with quick and dense items of silicon, however at pretty excessive prices, and with out solely resolving the drawbacks of natural substrates. Consequently, Intel has additionally been looking for a real substitute for natural substrates, one that may play properly with massive chips, and whereas not changing the necessity for CoWoS/EMIB on the highest degree, would provide higher sign efficiency and denser routing than natural substrates as we speak.

Glass Core Substrates: Finer, But Stronger

This brings us to the subject of as we speak’s announcement from Intel, glass core substrates. The corporate has been engaged on changing natural substrates with glass for over a decade now, and so they’ve lastly reached the purpose of progress the place they’re prepared to indicate it off to the world whereas planning for its use in future merchandise.

At a excessive degree, a glass core substrate is simply that: changing the natural, PCB-like materials of an natural package deal with glass. To make certain, this doesn’t imply changing the whole substrate with glass – so Intel shouldn’t be going to be mounting chips on pure items of glass – however quite, the fabric on the core of the substrate can be fabricated from glass. In the meantime, steel redistribution layers (RDLs) would nonetheless be current on either side of a chip, offering the precise pathways between varied pads and solder joints.

An Intel engineer holds a test glass core substrate panel at Intel's Assembly and Test Technology Development factories in Chandler, Arizona, in July 2023. Intel’s advanced packaging technologies come to life at the company's Assembly and Test Technology Development factories. (Credit: Intel Corporation)
Glass Core Substrates In Panel Kind

Whereas tougher to work with than the now well-established natural substrate, Intel considers glass substrates to be superior each in mechanical and electrical properties, which in flip makes them fascinating to make use of in future chips. Or, conversely, much less undesirable than natural substrates when constructing very massive chips.

Ranging from the mechanical aspect of matter, Intel experiences that tumbler core substrates provide much better mechanical power than natural substrates. They’re capable of stand up to larger temperatures higher than natural substrates throughout packaging, leading to much less warping and distortion. Glass can also be reportedly simpler to get flatter as nicely, which makes packaging and lithography simpler. Lastly, glass has the same coefficient of thermal enlargement as silicon (not like natural substrates), that means that what little warping that also happens from warmth is in step with the dies above, versus having totally different components of a chip increasing at totally different charges.

Most significantly, maybe, is that each one of these objects taken collectively open the door to producing bigger chips. With a extra secure substrate to mount the dies on, it will likely be potential to have bigger dies and a bigger variety of dies all sharing a single substrate – and thus behaving as a single chip.

Bridging the hole between mechanical and electrical, based on Intel, they’re additionally capable of obtain a a lot tighter pitch on the through-glass vias (TGVs) that carry alerts by way of the substrate itself, permitting for a a lot bigger variety of vias total. Intel is reporting that they’re capable of area TGVs lower than 100 microns (µm) aside, permitting for a 10-fold enchancment in TGV density. All of which finally permits for extra flexibility in routing alerts by way of the substrate core, and to some extent makes it simpler to route alerts with fewer RDL layers.

A photo shows glass substrate test units at Intel's Assembly and Test Technology Development factories in Chandler, Arizona, in July 2023. Intel’s advanced packaging technologies come to life at the company's Assembly and Test Technology Development factories. (Credit: Intel Corporation)
Assembled Take a look at Chip Substrates

All of this, in flip, permits for not solely bigger chips, however for extra dies to be positioned on a same-sized chip. Based on Intel, glass packaging would enable them to position 50% extra dies on a chip – or quite, the die complicated space inside a chip might be 50% bigger – permitting for extra densely packed chips than what Intel can do as we speak.

Lastly, on {the electrical} aspect of issues, glass core substrates, and extra particularly the TGVs, reportedly provide higher electrical efficiency as nicely. Owing to the low loss nature of the dielectric utilized in TGVs mixed with the a lot bigger variety of them, Intel says that tumbler core substrates will enable for cleaner sign routing and energy supply. Within the case of the previous, meaning having the ability to do 448G signaling by way of copper, quite than having to make use of optical interconnects. In the meantime, lower-loss energy supply would enhance total chip effectivity by that rather more, by lowering the quantity of vitality that’s misplaced as warmth earlier than it even reaches the processor dies.

Farther down the road nonetheless, glass core substrates must also make co-packaged optics simpler to perform for if you do wish to use optical. A glass substrate would enable for optical interconnects to be built-in proper into the chip, quite than having to tack it on in different manners.

So if glass is so nice, what’s the catch? Whereas Intel is understandably extra excited to speak about what’s good about glass core substrates and what they’ve discovered works nicely to this point, one inescapable ingredient will likely be price. Like several new know-how, glass core substrates will likely be costlier to supply and package deal with than tried and true (and low cost) natural substrates. And whereas Intel isn’t speaking about yields this far out, it will likely be arduous for glass to compete with natural, not less than at first.

Extra broadly talking, glass core substrates additionally signifies that Intel must bootstrap an entire ecosystem for the fabric. They aren’t vertically built-in with natural substrates as we speak, and so they received’t be vertically built-in with glass, both. To that finish, Intel is already working with companions as we speak to develop the mandatory tooling and provide capability, to convey themselves to preliminary business manufacturing. However over the longer-term, Intel might want to work out easy methods to make outsourced testing and meeting potential, particularly as Intel plans to supply glass core substrates to IFS prospects sooner or later.

Lastly, it bears noting that whereas glass core substrates enable for a tighter sign pitch than natural substrates, they aren’t a substitute for EMIB, Foveros, or different extra superior packing strategies primarily based round utilizing silicon mediums. A 75µm pitch for a TGV remains to be a far cry from the 45µm pitch of EMIB, by no means thoughts the <10µm pitch deliberate for Foveros Direct. So all of these packaging applied sciences will stay complementary add-ons to glass core substrates, at finest changing EMIB in fringe instances of merchandise that don’t want the complete density enhancements of EMIB.

Glass In Motion: Intel’s Absolutely Purposeful Take a look at Chip

The ultimate a part of as we speak’s announcement from Intel is predicated across the manufacturing aspect of issues. As famous earlier, Intel has been engaged on glass core substrates for over 10 years now, and extra lately has been embarking on a three-and-a-half-year pathfinding venture to convey glass core substrates to the subsequent step. Backing these efforts, at this level the corporate has a completely built-in R&D line up and working in considered one of their Chandler, Arizona fabs (the identical one which does EMIB). Altogether, Intel has spent over a billion {dollars} on glass core R&D to this point.

The primary fruit of their R&D efforts, Intel has accomplished the meeting of a set of check autos – multi-chip packages constructed over a glass substrate. The chips, which look much like Intel’s ultra-low energy cell chips (Alder Lake-U 9W?), are reportedly totally practical, giving Intel some sensible outcomes to report on. Whereas we don’t have a ton of particulars on the chip, Intel has informed us that it makes use of 3 layers of RDL, and the TGVs have a pitch of 75µm.

A photo shows the ball grid array side of an Intel assembled glass substrate test chip at Intel's Assembly and Test Technology Development factories in Chandler, Arizona, in July 2023. Intel’s advanced packaging technologies come to life at the company's Assembly and Test Technology Development factories. (Credit: Intel Corporation)

A photo shows the multi die assembly side of an Intel assembled glass substrate test chip at Intel's Assembly and Test Technology Development factories in Chandler, Arizona, in July 2023. Intel’s advanced packaging technologies come to life at the company's Assembly and Test Technology Development factories. (Credit: Intel Corporation)

Together with proving {the electrical} properties of glass, the small check chip can also be meant to show a few of the bodily properties, as nicely. The glass core was made very thick – on the order of 1mm – with a view to show that TGVs would work with such a thick core. For the form of large, high-end chips Intel is planning on utilizing glass core packing for, these chips would require a really thick core with a view to hit their dimension targets, so Intel wanted to show that TGVs would (nonetheless) work at such lengths.

Intel Glass Core Substrates: Coming Later This Decade

Wrapping issues up, as we speak’s announcement serves as a kick-off of types for Intel’s glass core substrate period. Following on their decade of R&D work and their pathfinding dash, Intel now believes they’re prepared to start planning for the transition to glass core substrates of their merchandise – albeit a transition that’s nonetheless a number of years out.

If Intel’s product improvement goes based on plan, the corporate intends to start delivery glass core merchandise later this decade. The primary merchandise to get the glass core substrate remedy can be their largest and most worthwhile merchandise, equivalent to high-end HPC and AI chips. These are the merchandise most strained by means of natural substrates as we speak as a result of dimension limits these substrates impose, and people are the boundaries intel believes would most profit from glass core packaging.

Longer-term, the plan is to waterfall down the know-how from HPC chips into smaller and smaller chips, till the know-how is obtainable (and viable) for Intel’s rank and file client chips. The corporate could be very fast to notice that tumbler and natural substrates will co-exist for years to return – and, like previous transitions, there’ll probably nonetheless be chips utilizing natural substrates nicely after glass is launched – however the firm can also be optimistic that they’ll be capable to convey the prices of glass core substrates all the way down to parity with natural substrates, ultimately making it potential to reap the advantages even in lower-priced processors.

And Intel received’t be preserving the know-how to themselves, both. As a part of the corporate’s broader initiative to turn out to be a world class contract foundry, Intel will likely be providing glass core substrates to IFS prospects in due time. Whereas it’s far too early to guess when that may be (even Intel merchandise could also be 6 years out), having the ability to provide glass packaging might give Intel an enormous leg up over its rivals, particularly for producing high-end, highly-profitable chips.

Above all else, it must be reiterated that there’s a substantial amount of work Intel nonetheless must do with a view to convey glass core substrates to the market. But when the corporate is profitable, then the swap to glass will usher within the form of main know-how transition that solely occurs each 15 to twenty years.

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