Processes126 μm deep via hole for TSV

High-rate Si DRIE with a depth of 126 μm for a 50 μm hole pattern using a non-Bosch process. The upper part of the etched profile is adjusted to a forward taper of 73° with no bowing. The etch rate is 7.9 μm/min. In principle, sidewall scallops could be a problem in Si DRIE in the bosch process. However, sidewall scallops do not occur in non-bosch process DRIE. This process, which allows Si DRIE of 100 μm or more while maintaining smooth sidewalls, is ideal for application to TSV (Through Silicon Via) for electrode formation of 3D LSIs.