Hicon - Bell Annealers for Capacitor Foil

The purity of the aluminum increases depending on the operating voltage. For low voltage applications grade AI3N8 is sufficient, while high voltages require AI4N (AI 99.99 %).

An extremely pure process atmosphere is used during the anneal to achieve a uniform Al²O³ layer on the foil surface that in turn promotes the formation of tunnel etching during a subsequent process. The material is processed at annealing temperatures between 550 °C and 620 °C, and the atmosphere dewpoint must be below -30 °C.

To fulfill these strict criteria the anneal has to take place in a furnace with a retort that is both gas-tight and vacuum-tight. The HICON^® annealer is ideal for this application.