Friday is here, and the 'Weekend Science Bite' corner is back — number 82.
This time: what makes fiberglass the hottest material in the chip market, and how Intel plans to replace it.
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The stock of a relatively obscure Japanese company has been soaring in recent weeks, as a frantic parade of tech-industry representatives from around the world lines up at its door.
So what exactly does it make, and why has it suddenly become so important?
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Our electronic chips are made of silicon, which barely expands when heated, and they are mounted on a substrate made of an insulating resin that expands considerably with heat.
The substrate's expansion rate is mismatched with that of silicon, which can cause the bond between them to break and the silicon to warp — rendering the chip non-functional.
To solve this problem, the resin is reinforced with a fiberglass fabric. The fabric is woven from ultra-thin glass fibers that reduce the resin's ability to expand and keep the substrate rigid.
Simpler chips use E-glass, in which the cloth is made from glass containing the element boron.
Adding boron to the glass minerals increases their flexibility, which makes it much easier to melt the minerals into glass and weave them into cloth. On the downside, the boron addition reduces the cloth's stiffness, leaving it slightly flexible.
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In recent years, chips have become far more complex. Instead of a single layer, they are built from stacked layers of chips with vertical data channels running between them.
The precision required between layers is far more critical and demanding, which is why T-glass was developed — a fiberglass cloth that contains no boron at all and is therefore stiffer.
Manufacturing T-glass is an extremely complex technical challenge, and a Japanese company called Nittobo controls approximately 80% of global production of this fabric.
The process involves melting at exceptionally high temperatures and extruding the melt through a perforated plate made from an expensive platinum-rhodium alloy to form filaments. The high viscosity of the boron-free glass causes severe wear on these plates, requiring frequent replacement and driving up production costs.
These glass filaments are then fed into an air-jet loom that weaves the fibers into the final cloth.
The latest AI processors are characterized by very large die sizes, a high number of layers, and high power consumption. These properties generate significant heat and demand the exclusive use of T-glass-based substrates.
As demand continues to surge while production capacity barely grows, a frantic wave of tech-company representatives has swept in, reserving inventory in advance through mid-2027 — largely at the expense of Apple, which had been a major customer for the chips in its product lineup.
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Intel, meanwhile, is working on a different solution: a substrate core made entirely of glass.
The challenge with such a substrate is its high brittleness, which requires extremely delicate handling equipment.
In addition, the substrate must be coated with conductive copper layers that do not adhere well to glass — necessitating the use of a special polymer as an adhesive.
Another challenge is the need to drill tiny holes in the substrate to create the vertical conductors between layers in a three-dimensional chip. To address this, Intel developed a method of using a laser to alter the composition of specific points in the glass, then immersing the glass in a chemical that dissolves those points and leaves behind holes — no drilling required.
The video shows the final stage of this process, as demonstrated in 2023. As of today it is not yet viable at commercial scale, but the expectation is that development will be completed within the coming years and it will become the new standard.
Shabbat Shalom 😊
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Video credit: Intel
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