Semiconductor Wafers & Fab Tooling
Flip the wafer over — a genuinely gold-backed wafer has a solid opaque mirror-yellow reverse that stays yellow when scribed; a rainbow, purple, blue, straw or grey backside is oxide, nitride or bare silicon and the whole lot is worth about sixty cents a pound.
How to spot it
Round mirror discs 50–300 mm across and 0.3–0.8 mm thick with an edge flat or notch, frontside either blank or patterned with a fine die grid. GaAs wafers are dark grey-black, semi-transparent to IR, brittle and often only 100–200 µm thick. Carriers are slotted quartz (clear), SiC (matte black), PFA (white), PEEK/PBI (tan) or metal fixtures, from Entegris, Empak, Fluoroware or Ferrotec. Found in fabs, MEMS shops, university cleanrooms, ion implanters and MBE chambers.
Metal content
| Metal | Quantity | Notes |
|---|---|---|
| Gold | 0.0045 g/lb generic research-fab wafer scrap | ~10 g Au per tonne — single forum source. Worthless, about $0.60/lb |
| Gold | 7.4 g/lb for 1 µm gold-backed wafers | 39 mg per 2 in wafer ≈ $960/lb; 3–5 µm GaAs MMIC via-hole wafers run 22–37 g/lb |
| Base metal | quartz and SiC boats: zero metal | They have reuse value at $50–600 each, not metal value |
At 4 Aug 2026 spot prices that works out to $0.65 per pound of contained metal — Gold 0.005 g = $0.65. A refiner paying $1 returns about 153% of that, which is normal: refining costs money and the buyer takes a margin.
Safe removal
Working temperature: No heat; wet crush and leach
For gold-backed wafers do not peel the metal — crush wet in a sealed container and leach the gold; silicon is inert and filters out. Better, sell as-is to a refiner with a semiconductor line. Strip chamber shields chemically or electrolytically, never bead-blast. Clean quartz and SiC boats in HF or piranha and resell as tooling, which is worth 100× any metal in them.
Hazards
NEVER pour any of these down a drain or onto the ground. They are all regulated waste streams.
NEVER torch, incinerate or overheat PTFE insulation, and never smoke around PTFE dust — it converts on the cigarette.
NEVER grind, burn, torch or braze cadmium-plated or AgCdO material, and don't inhale the black contact dust.
NEVER vacuum a mercury spill — it aerosolises it. Use a mercury spill kit or sulphur powder, or call your local hazmat line.
NEVER grind, sand, file, saw, drill, abrasive-cut, sandblast, hammer, crush, shred, torch, melt or incinerate anything that might contain BeO. Sell or dispose of suspect parts intact. Broken beryllium parts are worth nothing; your lungs are worth everything.
NEVER blow on, wipe with bare fingers, or brush away cut optical fibre.
NEVER grind, sand, saw or incinerate anything that might contain thorium or radium. Sealed sources stay sealed.
Before you scrap it
The common trap
Questions
How much gold is in semiconductor wafers & fab tooling?
Gold: 0.0045 g/lb generic research-fab wafer scrap. Gold: 7.4 g/lb for 1 µm gold-backed wafers. At current spot that is about $0.65 of contained metal per pound.
How do you identify semiconductor wafers & fab tooling?
Flip the wafer over — a genuinely gold-backed wafer has a solid opaque mirror-yellow reverse that stays yellow when scribed; a rainbow, purple, blue, straw or grey backside is oxide, nitride or bare silicon and the whole lot is worth about sixty cents a pound.
How do you remove semiconductor wafers & fab tooling safely?
For gold-backed wafers do not peel the metal — crush wet in a sealed container and leach the gold; silicon is inert and filters out. Better, sell as-is to a refiner with a semiconductor line. Strip chamber shields chemically or electrolytically, never bead-blast. Clean quartz and SiC boats in HF or piranha and resell as tooling, which is worth 100× any metal in them.
Is semiconductor wafers & fab tooling worth more working than as scrap?
Split verdict. Quartz boats, SiC paddles and carriers sell intact at $80–600 each, 50–500× any metal. Blank and reclaim wafers sell as wafers at $2–25 each to artists, educators and researchers. Gold-backed wafers have no resale market — refine them.
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