Wacker hyperpure polysilicon

What it is

Polysilicon is the starting material for silicon wafers and therefore for almost every microchip. Semiconductor grade is one of the purest substances made by industry. Wacker Chemie sells it as chunks to wafer makers, who melt it and grow single crystals.

How it works

Wacker describes a multi-step process. Quartz is reduced to metallurgical silicon, about 98 to 99 per cent pure. That reacts with hydrogen chloride in a fluidised-bed reactor to form trichlorosilane, which is distilled to remove impurities. The purified gas is passed over heated silicon rods at around 1,000 degrees Celsius, where silicon deposits on them. The rods are broken into chunks and etched clean of surface contamination. The Etching Line Next, opened in Burghausen in July 2025, handles this last step.

Why it stands out

• Wacker says the finished material is more than 99.9999999999 per cent pure, with critical impurities in the parts-per-trillion range; it compares this to one grain of sugar in an Olympic swimming pool.
• At the 2025 opening, Wacker's chief executive said every second computer chip is made from Wacker polysilicon, and called Wacker the only European and the largest global producer of ultrapure semiconductor polysilicon. These are company statements.
• The new line cost more than 300 million euros, with up to 46 million euros of EU IPCEI funding, and raises semiconductor-grade cleaning capacity by more than 50 per cent.

Wacker plans to double sales to semiconductor customers by 2030 compared with 2024.

Not directly: it disappears into wafers made by companies such as Siltronic, then into chips in phones, cars, servers and solar panels. Wacker began industrial polysilicon production in 1959 and became the leading producer of semiconductor-grade silicon in the late 1970s.

Sources

• Wacker: New line for semiconductor-grade polysilicon (2025)
• Wacker: Polysilicon profile and process
• chemeurope.com: Wacker commissions new line at Burghausen