Semiconductor device with buried wiring layer and fabrication process thereof

摘要

An insulation layer is formed on a silicon substrate. An SOI layer is formed on the insulation layer. A groove is selectively formed in the insulation layer. A bit line is buried in a lower half of the groove. A connection conductor layer is selectively formed on the side wall surface of the groove on the buried bit line. The SOI layer and the buried bit line are connected electrically via the connection conductor layer. A cap insulation layer is formed to fill the groove on the buried bit line in a region where said connection conductor layer is not formed.