A technical review of wafering and the circular economy
Before a solar cell or a chip can be made, a silicon crystal has to be cut into slices thinner than a fingernail. A large share of that crystal leaves the saw as fine sludge. Kerf & Korn explains how the cutting works, what the sludge contains, what can be recovered from it, and what it takes to run this kind of industry in Europe.
Photo: Don DeBold, Wikimedia Commons, CC BY 2.0
Sourced values from our articles, each linked to its primary source
The name points to the two core subjects. Kerf is the cut a saw leaves behind and the material lost in it. Korn is German for grain or grit: the silicon carbide abrasive that does the cutting in the classic slurry process. The German edition is the original; this English edition is written separately for international readers, with its own articles on siting, energy prices, raw materials and recycling in Europe.
The articles are written for students, process engineers, buyers, environmental officers and investors working around wafer, photovoltaic and semiconductor manufacturing. Technical statements link to the standard, regulation, peer-reviewed paper or patent they come from.
In focus · Slurry & RecoverySolid-liquid separation, hydrocyclones and centrifuges, cleaning the grit, recovering the glycol: the five basic steps, with a flow chart and the yields that patents report.
Read the articleHow multi-wire saws cut silicon ingots into wafers, from loose-abrasive slurry to diamond wire.
What a sawing slurry is made of, why it is reprocessed and what happens to the silicon in the kerf.
Slurry & RecoverySiC grit, polyethylene glycol and additives: what each component does and how the slurry wears out.
Slurry & RecoveryCost, EU waste law and resource value: the case for reusing silicon carbide and glycol, and its limits.
Slurry & RecoveryHow much silicon is lost in the cut, why it is hard to win back and which recovery routes research describes.
The material SiC: Acheson production, abrasive grit and the single crystals used in power electronics.
Siting, energy costs, raw materials and recycling for wafer, solar and chip manufacturing in Europe.
Industry & PolicyWhat the Net-Zero Industry Act and the Chips Act offer a new plant, and the practical criteria for choosing a site.
Industry & PolicyCleanroom classes, ultrapure water, grid connection and zoning: what a wafer or chip site must provide.
Industry & PolicyHow Eurostat measures electricity prices for non-household consumers, and how to read the bands and price levels.
Industry & PolicySilicon metal, gallium and germanium under the EU Critical Raw Materials Act: benchmarks, permits and supply risk.
Industry & PolicyHow the WEEE Directive covers solar panels, which recovery targets apply and where circularity really stands.
If the subject is new to you, start with how multi-wire sawing works, then read what a sawing slurry is made of and how silicon carbide and glycol are recovered. For the industrial and policy side, the article on siting wafer and module plants in Europe brings together the Net-Zero Industry Act, the Chips Act and practical site criteria.
Kerf & Korn is also published in German, the original edition.
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