Patent ID: 7638368
Filing Date: 2009-12-29
Classification: H01L

Abstract:
1. A method for manufacturing a reverse blocking semiconductor device comprising: preparing a substrate of a first conductivity type; forming a MOS gate structure including processes of selectively forming a base layer of a second conductivity type in a front surface region of the substrate, selectively forming an emitter region of the first conductivity type in a surface region of the base layer, forming a gate insulation film on the surface of the base layer, the surface being between the emitter region and the front surface of the substrate without the emitter region, and forming a gate electrode on the gate insulation film; forming an emitter electrode in contact with both the emitter region and the base region of the MOS gate structure; selectively forming a peripheral region of the second conductivity type surrounding the MOS gate structure through a portion of the substrate outside the MOS gate structure, a part of the peripheral region to become an isolation region; removing a rear surface region of the substrate to a predetermined thickness to form the isolation region extending across the entire thickness and to form a drift layer of the first conductivity type inside the isolation region; forming a collector layer of the second conductivity type on a rear surface of the drift layer and connecting to a rear side of the isolation region; and forming a collector electrode in contact with the collector layer; wherein a distance W is greater than a thickness d, in which the distance W is a distance from an outermost position of an portion of the emitter electrode, the portion being in contact with the base layer, to an innermost position of the isolation region, and the thickness d is a dimension in a depth direction of the drift layer; and wherein selectively forming the peripheral region being to become an isolation region is conducted by diffusing impurities using a diffusion mask of an oxide film formed on the front surface of the substrate, the oxide film having a thickness Xox satisfying an inequality of the following Formula (1): wherein D D X