Surface finishing of cleaved SOI films using epi technologies

The use of epi technologies in SOI manufacturing is shown to add flexibility and increased wafer quality, e.g. fewer defects and better top Si-layer uniformity, as well as cluster-tool compatibility. The newly developed smoothing process on the Epi Centura replaces touch-polishing after bond and cleave. RMS values down to 0.08 nm have been achieved on wafers with an initial RMS value as high as 8 nm. The high uniformity of this process offers excellent target thickness control, both through removal and addition of material. It also enables compliant substrate technology for 8" SOI wafers, where the top Si-layer has to be thinned below 20 nm.