Semiconductor device and manufacturing method thereof

Abstract

A semiconductor substrate is easily warped by the shrink of the insulating film formed within the deep trench according to the thermal processing in the super junction structure. In order to solve the above problem, in a semiconductor device, an element region and a terminal region are defined on one main surface of the semiconductor substrate. The terminal region is arranged to surround the element region. In the terminal region, a plurality of buried insulators are formed from the main surface of the semiconductor substrate in a way of penetrating an n-type diffusion layer and an n-type column layer and arriving at an n-type epitaxial layer. The buried insulator is formed within a deep trench. The plural buried insulators are arranged in island shapes mutually at a distance from each other.

What is claimed is: 
     
         1 . A manufacturing method of a semiconductor device comprising the steps of:
 providing a semiconductor substrate having a first main surface and a second main surface, including a semiconductor layer of a second conductivity type on a side of the first main surface and a substrate of a first conductivity type in contact with the semiconductor layer on a side of the second main surface;   defining an element region and a terminal region on the side of the first main surface of the semiconductor substrate;   forming a plurality of first deep trenches arriving at a first depth from the first main surface mutually at a distance from each other, in the terminal region and forming a second deep trench arriving at the first depth from the first main surface, in the element region;   forming a first region of the first conductivity type arriving at the substrate from the first main surface, in the terminal region and forming a second region of the first conductivity type arriving at the substrate from the first main surface, in the element region, by introducing first dopant of the first conductivity type through the first deep trenches and the second deep trench;   forming a first column layer of the second conductivity type in contact with the first region, along side wall surfaces of the first deep trenches, in the terminal region and forming a second column layer of the second conductivity type in contact with the second region, along a side wall surface of the second deep trench, in the element region, by introducing second dopant of the second conductivity type through the first deep trenches and the second deep trench;   forming first buried insulators respectively within the first deep trenches and forming a second buried insulator within the second deep trench;   forming a semiconductor element of conducting current between the first main surface and the second main surface, in the element region;   forming an interlayer insulating film to cover the first buried insulators and the second buried insulator;   forming a first opening portion in the interlayer insulating film positioned in the terminal region and forming a second opening portion in the interlayer insulating film positioned in the element region; and   forming a first electrode electrically coupled to the substrate of the semiconductor substrate through the first region and a portion filled in the first opening portion, in the terminal region and forming a second electrode electrically coupled to the semiconductor element through a portion filled in the second opening portion, in the element region.   
     
     
         2 . The method according to  claim 1 ,
 wherein in the step of forming the second deep trench, the second deep trench is formed in a plurality of island shapes mutually at a distance from each other, and   wherein in the step of forming the second buried insulator, the second buried insulator is formed within the respective second deep trenches arranged in island shapes.