A toilet company is the reason your silicon wafers stay flat. TOTO was founded in Kitakyushu in 1917 to make sanitary ceramics. It is best known worldwide for the Washlet. Since 1988 it has also mass produced electrostatic chucks, and that quiet division now rivals the bathroom business for operating profit. An electrostatic chuck is a ceramic disc roughly the size of a steering wheel. It sits inside a plasma etch chamber and clamps a 300 mm silicon wafer using nothing but voltage. Mechanical clamps are unusable here. They shadow the wafer edge, they shed particles, and they cannot pull the centre of a bowed wafer down onto the cold plate. The chuck does three jobs at once: - Clamping. Buried electrodes are driven to hundreds or thousands of volts. Induced charge pulls the wafer down across the entire surface. - Thermal control. Helium is fed into the microscopic gap behind the wafer at a few torr, so gas conduction carries plasma heat out of the silicon. - Contamination control. E...