A relatively new method of high aspect ratio material removal is plasma etching using an inductively coupled RF source. The substrate is RF-biased independently of the inductively coupled RF plasma, which results in low ion energies and thus low ion bombardment. Consequently, an ICP system will provide high chemical etch selectivities with high etch rates.
The STS system uses fluorine-based gases for anisotropic deep silicon trench etching for research and development. The 13.56 MHz RF system produces a high-density, low-pressure, low-energy inductively coupled plasma. This type of plasma allows high selectivity and aspect ratio etching for depths greater than 250 microns.
The system control is via a standard PC, which automatically loads a wafer into the process chamber. Once in the chamber, the wafer is placed onto a helium-cooled chuck during the process. The system is designed to etch a 100 mm (4 in.) wafer.
Gases and Materials: