Method for Producing a Semiconductor Device Having a Beveled Edge Termination

Abstract

A method for producing a semiconductor device includes forming a trench that defines a closed loop in a semiconductor body and extends from a first surface into the semiconductor body. The trench has at least one sidewall that is beveled relative to a vertical direction of the semiconductor body. The method further includes removing material of the semiconductor body at least between a bottom of the trench a second surface opposite the first surface of the semiconductor body.

What is claimed is: 
     
         1 . A method for producing a semiconductor device, the method comprising:
 forming a trench that defines a closed loop in a semiconductor body and extends from a first surface into the semiconductor body, the trench having at least one sidewall that is beveled relative to a vertical direction of the semiconductor body; and   removing material of the semiconductor body at least between a bottom of the trench a second surface opposite the first surface of the semiconductor body.   
     
     
         2 . The method of  claim 1 , wherein the removing comprises:
 reducing an overall thickness of the semiconductor body beginning at the second surface, opposite to the first surface, until a semiconductor material between the second surface and the trench is removed.   
     
     
         3 . The method of  claim 1 , wherein the removing comprises:
 cutting from the second surface through the semiconductor body to the trench.   
     
     
         4 . The method of  claim 1 , wherein the cutting comprises at least one of sawing, water cutting, laser cutting, and plasma etching. 
     
     
         5 . The method of  claim 1 , wherein the removing comprises:
 forming a further trench that extends from the second surface to the trench.   
     
     
         6 . The method of  claim 1 , wherein the closed loop has a form selected from one of:
 an elliptical ring;   a substantially rectangular ring; and   a polygonal ring.   
     
     
         7 . The method of  claim 1 , wherein the trench has a first sidewall defining a first angle with the vertical direction, and a second sidewall defining a second angle with the vertical direction. 
     
     
         8 . The method of  claim 7 ,
 wherein at least one of the first angle, and the second angle varies along the closed loop.   
     
     
         9 . The method of  claim 7 , wherein the first angle and the second angle have substantially the same absolute value and different signs. 
     
     
         10 . The method of  claim 1 , wherein the trench has a substantially trapezoidal cross-section. 
     
     
         11 . The method of  claim 1 , wherein forming the trench comprises a DRIE etching process with a plurality of timely subsequent etching steps. 
     
     
         12 . The method of  claim 11 ,
 wherein at least one of the plurality of timely subsequent etching steps is longer than a preceding etching step.   
     
     
         13 . The method of  claim 9 , wherein each etching step of the plurality of timely subsequent etching steps is longer than a preceding etching step. 
     
     
         14 . The method of  claim 13 , wherein each etching step comprises:
 a plasma etch phase in which the semiconductor body is etched to form a sub-trench; and   a passivation phase in which a passivation layer is formed on surfaces of the sub-trench.   
     
     
         15 . The method of  claim 11 , wherein forming the trench further comprises:
 tempering the semiconductor body in a hydrogen containing atmosphere.   
     
     
         16 . The method of  claim 1 , wherein forming the trench comprises:
 forming a series of pre-trenches arranged next to each other in a horizontal direction of the semiconductor body, each pre-trench extending in a vertical direction from the first surface into the semiconductor body.   
     
     
         17 . The method of  claim 16 , wherein the pre-trenches are formed such that a depth of the individual pre-trenches increases from a first trench, forming one end of the series of pre-trenches, to a last pre-trench, forming another end of the series of pre-trenches. 
     
     
         18 . The method of  claim 17 , wherein forming the trench further comprises:
 tempering the semiconductor body in a hydrogen containing atmosphere so as to form a void in the semiconductor body.   
     
     
         19 . The method of  claim 18 , further comprising:
 forming of an opening that extends from the first surface to the void.   
     
     
         20 . The method of  claim 19 , further comprising:
 placing the semiconductor body on a carrier facing the first surface before reducing the thickness.   
     
     
         21 . A semiconductor device, comprising:
 a semiconductor body;   at least one void in the semiconductor body, wherein the void includes at least one sidewall that is beveled relative to a vertical direction of the semiconductor body.   
     
     
         22 . The semiconductor device of  claim 21 , wherein the void is at least partly filled with an electrically insulating material.