| abstract |
The invention relates to improvements to a method of manufacturing a semiconductor device to prevent degradation of characteristics of a transistor by preventing the formation of a channel stop implantation layer in an active region. After defining a pattern in a nitride film, the thickness of an SOI layer is measured (S2) and, using the result of the measurement, etching conditions for the SOI layer are determined (53). The thickness of the SOI layer can be measured by spectroscopic ellipsometry. The etch condition which has been determined is used and a trench is formed (S4) using the nitride film as an etch mask. |