Ce qui se déplace réellement
A silicon crystal is grown in a crucible of fused quartz, and any impurity in that crucible ends up in the chip. Only a few deposits on the planet are clean enough. The sand is not the product — it is the container the product is grown in, and it is consumed every time.
- Le matériau
- High-Purity Quartz
- La variété
- High-purity quartz sand, impurities measured in parts per million
- Où cela commence
- United States — Spruce Pine, North Carolina — the source of most of the world's crucible-grade quartz
Étape par étape, et frontière par frontière
United States · Spruce Pine, North Carolina détenu par Quartz producers (Mineur)
An unremarkable-looking quarry
Pegmatite is mined and the quartz separated from feldspar and mica. It then goes through a long purification sequence — flotation, acid leaching, chlorination — to strip aluminium, iron, titanium and sodium down to parts per million.
Pourquoi ici: An accident of geology. These pegmatites formed with unusually little of the trace elements that ruin quartz for this purpose.
Germany · Fused-quartz manufacturers détenu par Crucible makers (Fabricant)
Made into crucibles
The sand is fused into crucibles — bowls that will hold molten silicon while a crystal is pulled from it.
Pourquoi ici: Fused-quartz manufacture is its own specialised industry, separate from both mining and chipmaking.
China · Polysilicon plant détenu par Polysilicon producers (Chimique)
Meanwhile, the silicon itself
Ordinary quartzite is reduced with carbon to metallurgical silicon at about 99%, then converted to trichlorosilane, distilled and redeposited as polysilicon — up to eleven nines of purity for semiconductors.
Ce qu'il est advenu du reste: This step is essentially electricity turned into purity, which is why it migrated to wherever power is cheapest.
Pourquoi ici: Solar-grade polysilicon needs six or seven nines; semiconductor-grade needs eleven. The extra nines are what separate the two industries.
Japan · Crystal growers détenu par Wafer manufacturers (Fabricant)
Growing the crystal
Polysilicon is melted in the quartz crucible and a seed crystal is slowly pulled and rotated out of it, growing a single cylindrical crystal up to 300 mm across and two metres long.
Ce qu'il est advenu du reste: The crucible is consumed. That is the whole reason this journey starts at a sand quarry rather than a silicon plant.
Pourquoi ici: Crystal growing is dominated by a small number of Japanese, Korean, German and Taiwanese firms.
Taiwan · Fab, Hsinchu or Tainan détenu par Foundry (Fabricant)
Hundreds of steps on a wafer
Deposition, lithography, etch, repeated hundreds of times, building transistors and copper wiring layer by layer. Tungsten fills the contacts; hafnium oxide forms the gate dielectric; neon lases the light that prints the pattern.
Pourquoi ici: Leading-edge fabs are among the most capital-intensive facilities ever built and exist in very few places.
Vietnam · Assembly and test, then the world détenu par Assemblers and device makers (Fabricant)
Millions of chips
Wafers are diced, packaged, tested and soldered onto boards. From 1,000 kg of a specific sand from one American county, a few million finished chips.
Pourquoi ici: Six countries and roughly six months, for something that weighs a few grams.
Il s'agit d'un exemple traité. Il suit une quantité de départ déclarée à travers des rendements et des taux de récupération typiques publiés, de sorte que les proportions sont vérifiables ; ce n'est pas le relevé d'un envoi spécifique. Les données d'itinéraire — quels pays, quels procédés, et pourquoi le matériau ne peut simplement pas être traité ailleurs — sont compilées à partir de sources publiques.