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Material World
Industry

Electronics manufacture

The industry that uses the widest range of elements of any — and the smallest quantity of most of them.

Making the devices that compute, communicate and sense. It is distinctive among industries in the *breadth* of the periodic table it draws on: a smartphone contains a substantial fraction of the stable elements, most in milligram quantities, many with no substitute.

That combination — tiny amounts, no alternatives, and dispersal into a product that is thrown away — is what makes electronics both a small consumer of materials by tonnage and a large one by criticality. Indium in a touchscreen, tantalum in a capacitor, gallium in a power transistor and neodymium in a vibration motor are each irreplaceable at the milligram scale.

History

Vacuum tubes to the transistor in 1947, and to the integrated circuit in 1958. The material story after that is silicon's: a semiconductor that was not the best available and won because it forms a stable, insulating native oxide, which is what made the planar process possible.

Surface-mount assembly and the move away from tin-lead solder under the European RoHS Directive from 2006 are the two changes most visible in the materials themselves.

Economic significance

The industry with the deepest and most concentrated supply chain in the world economy. Leading-edge semiconductor fabrication happens in a handful of facilities, and lithography at the smallest nodes in machines from a single supplier.

Its end-of-life problem is the mirror of its input problem: electronic waste is the fastest-growing waste stream and contains the highest concentration of valuable and hazardous materials of anything discarded, and very little of it is recovered.

Medium confidence Weak evidence

How we know: checked recently · only one source, so there is nothing to cross-check it against · stated directly by the source.

How this connects

Where a connection has been confirmed by an outside reference, that reference is named beside it.

uses

  • Silicon — element · the substrate of essentially all of it, and it won not on being the best semiconductor but on forming a stable insulating native oxide
  • Copper — element · interconnect and every circuit board track
  • Indium tin oxide — material · the transparent conductor of every touchscreen, and one of the clearest single-material supply dependencies there is
  • Solder — alloy · and the move away from tin-lead under RoHS from 2006 is the most visible material change the industry has made
  • Epoxy resin — material · the laminate of every printed circuit board, which is glass fabric in epoxy
  • Gallium arsenide — compound · radio-frequency and optoelectronic devices, where silicon's indirect band gap and lower carrier mobility are the limits
  • Lithium-ion cell — object · and portable computing came first by two decades
  • Transistor — object · the component every other modern technology is assembled from, and one nobody ever sees
  • Fused silica — material · crucibles, tubes and wafer carriers, where purity and temperature tolerance are both required
  • Resin — material · as the flux in rosin-cored solder wire: it strips the oxide off copper at soldering temperature so the solder can wet the metal, and the smell of soldering is the smell of pine
  • Lithium cobalt oxide — compound · phones, laptops and cameras — the applications where the constraint is millimetres of thickness rather than grams of mass
  • Ferrite — material · and its most consequential use is historical: core memory was the working memory of computers for twenty years, which is why a memory image is still called a core dump
  • Smartphone — object · and it is where four separate raw-material arguments meet — the 3TG conflict minerals, cobalt, the rare earths, and everything too dispersed to recover
  • Printed circuit board — object · and it is the change that made electronics manufacturable: assembly stopped being a wiring job and became a printing one

is associated with

  • The semiconductor era — event · and the supply chain it produced is the deepest and most concentrated in the world economy

Sources

  • Material World
    Our own writing
  • Wikidata
    Wikimedia Foundation · Creative Commons CC0 1.0 Universal (public domain dedication)

Questions this page answers

Where it comes from, and what it becomes

Follow Electronics manufacture back to what it starts as, and forward into what it becomes. Each step is a documented one — a real route material takes, not a chain of inference.

Upstream — what it comes from

  • Electronics manufacture → uses (interconnect and every circuit board track) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation → takes as input (the feedstock, and an unusual one in being free, unlimited and available anywhere — the cost is entirely the energy to liquefy it) → Air
  • Electronics manufacture → uses (the substrate of essentially all of it, and it won not on being the best semiconductor but on forming a stable insulating native oxide) → Silicon → is produced by (carbothermic reduction of silica with coke in a submerged arc furnace, which is smelting in the strict sense even though no ore is involved) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation → takes as input (the feedstock, and an unusual one in being free, unlimited and available anywhere — the cost is entirely the energy to liquefy it) → Air
  • Electronics manufacture → uses (and the move away from tin-lead under RoHS from 2006 is the most visible material change the industry has made) → Solder → is composed of (under a per cent, to slow the rate at which the joint dissolves the copper it is sitting on) → Copper → is produced by (as blister copper, refined electrolytically afterwards) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation
  • Electronics manufacture → uses (radio-frequency and optoelectronic devices, where silicon's indirect band gap and lower carrier mobility are the limits) → Gallium arsenide → is produced by (grown as a boule and sliced, though it is harder to keep stoichiometric than silicon because the arsenic evaporates) → Czochralski process → takes as input (charged to the crucible already refined; the process changes its arrangement and its purity, not its identity) → Silicon → is produced by (carbothermic reduction of silica with coke in a submerged arc furnace, which is smelting in the strict sense even though no ore is involved) → Smelting → takes as input (roasted to drive off sulfur, then reduced to copper) → Chalcopyrite
  • Electronics manufacture → uses (the laminate of every printed circuit board, which is glass fabric in epoxy) → Epoxy resin → is produced by (the resin is made first and the network second — cure is a polymerisation carried out by the user rather than the manufacturer) → Polymerisation → takes as input (as vinyl chloride, which is why more than half of PVC's weight is salt rather than oil) → Chlorine → is produced by (at the anode) → Chlor-alkali electrolysis → takes as input (as brine; the salt is the feedstock for both products at once) → Halite
  • Electronics manufacture → uses (the component every other modern technology is assembled from, and one nobody ever sees) → Transistor → is made of (the substrate, purified to around eleven nines — a purity nothing else is produced at in bulk) → Silicon → is produced by (carbothermic reduction of silica with coke in a submerged arc furnace, which is smelting in the strict sense even though no ore is involved) → Smelting → takes as input (as the element removed, not added) → Oxygen → is produced by (the largest output by tonnage, and the reason air separation units sit beside steelworks) → Air separation

These are the most distinct paths back. Electronics manufacture can be traced through others besides.

Downstream — what it becomes