Specific Process Knowledge/Etch/Etching of Silicon/Si etch using RIE1 or RIE2

RIE (Reactive Ion Etch) can be used for etching silicon - both crystalline and polycrystalline silicon. The etch can be isotropic or anisotropic with vertical sidewalls depending on the process recipe and the masking material and geometry. The Si is etched by flour radicals that are created from SF₆(g) in a RF generated plasma.

The silicon substrate:

Most be a wafer of 4" or below or small pieces, not higher than about 2mm.

The silicon can be masked by these materials:

• Photoresist
• E-beam resist
• Silicon Oxide
• Silicon Nitride
• Aluminium
• Chromium (ONLY RIE2!)
• Other metals if they cover less than 5% of the wafer area (ONLY RIE2!)