Semiconductor Substrate and Method for Manufacturing the Same

Abstract

A semiconductor substrate is provided in which an alignment mark is formed that can be used for an aligment even after the formation of an impurity diffused layer by the planarization of an epitaxial film. A trench 11 is formed in an alignment region of an N + -type substrate 1. This trench 11 is used to leave voids 3 after the formation of an N − -type layer 2. Then, the voids 3 formed in the N + -type substrate 1 can be used as an alignment mark. Thus, such a semiconductor substrate can be used to provide an alignment in the subsequent step of manufacturing the semiconductor apparatus. Thus, the respective components constituting the semiconductor apparatus can be formed at desired positions accurately.

1 . A semiconductor substrate having a substrate ( 1 ) made of single crystal semiconductor and a semiconductor layer ( 2 ) made of single crystal formed on the surface of the substrate ( 1 ),
 wherein voids ( 3 ) as an alignment mark are formed in the substrate ( 1 ) in an alignment region in the substrate ( 1 ) that is different from a device formation region.   
   
   
       2 . A semiconductor substrate having a substrate ( 21 ) made of single crystal semiconductor and a semiconductor layer ( 22 ) made of single crystal formed on the surface of the substrate ( 21 ),
 wherein voids ( 25 ) as an alignment mark are formed in an alignment region in the semiconductor layer ( 22 ) that is different from a device formation region.   
   
   
       3 . The semiconductor substrate according to  claim 1  or  2 ,
 wherein a trench ( 4 ,  23 ) is formed in a device formation region of the semiconductor layer and an epitaxially-grown impurity diffused layer ( 5 ,  24 ) is formed in the trench.   
   
   
       4 . The semiconductor substrate according to any one of  claims 1  to  3 ,
 wherein a plurality of voids are arranged with an equal interval.   
   
   
       5 . A method for manufacturing a semiconductor substrate comprising:
 a step of preparing a substrate ( 1 ) made of single crystal semiconductor;   a step of arranging, on the substrate ( 1 ), a mask material ( 10 ) in which an opening is formed in the alignment region in the substrate different from a device formation region;   a step of etching the substrate ( 1 ) covered by the mask material ( 10 ) to form an alignment mark formation trench ( 11 ) in the alignment region; and   a step of forming a semiconductor layer ( 2 ) made of single crystal on the surface of the substrate so as to form voids ( 3 ) in the alignment mark formation trench.   
   
   
       6 . The method for manufacturing a semiconductor substrate according to  claim 5 ,
 wherein the step of forming an alignment mark formation trench forms the alignment mark formation trench having a width of 1 to 50 μm.   
   
   
       7 . A method for manufacturing a semiconductor substrate comprising:
 a step of preparing a substrate ( 21 ) made of single crystal semiconductor;   a step of forming a semiconductor layer ( 22 ) made of single crystal on the surface of the substrate ( 21 );   a step of arranging, on the semiconductor layer ( 22 ), a first mask material ( 30 ) in which an opening is formed in the alignment region in the semiconductor layer ( 22 ) different from a device formation region;   a step of etching the semiconductor layer covered by the first mask material ( 30 ) to form an alignment mark formation trench ( 31 ) in the alignment region;   a step of removing the first mask material ( 30 ) to subsequently arrange, on the surface of the semiconductor layer, a second mask material ( 32 ) in which an opening is formed in the device formation region of the semiconductor layer;   a step of etching the semiconductor layer covered by the second mask material ( 32 ) to form a device trench ( 23 ) in the device formation region;   a step of removing the second mask material ( 32 ) to subsequently bury an epitaxial film ( 33 ) in the device trench so as to form voids ( 25 ) in the alignment mark formation trench; and   a step of subjecting, to a planarization processing, a part of the epitaxial film that is formed exterior to the device trench.   
   
   
       8 . A method for manufacturing a semiconductor substrate comprising:
 a step of preparing a substrate ( 21 ) made of single crystal semiconductor;   a step of forming, on the surface of the substrate, a semiconductor layer ( 22 ) made of single crystal;   a step of arranging a first mask material ( 32 ) on the surface of the semiconductor layer, the first mask material ( 32 ) includes an opening formed in the device formation region of the semiconductor layer;   a step of etching the semiconductor layer covered by the first mask material to form a device trench ( 23 ) in the device formation region;   a step of removing the first mask material to subsequently arrange, on the semiconductor layer, a second mask material ( 30 ) including an opening in the alignment region in a semiconductor layer different from a device formation region;   a step of etching the semiconductor layer covered by the second mask material to form an alignment mark formation trench ( 31 ) in the alignment region;   a step of removing the second mask material to subsequently bury an epitaxial film ( 33 ) in the device trench so as to form voids ( 25 ) in the alignment mark formation trench; and   a step of subjecting, to a planarization processing, a part of the epitaxial film that is formed exterior to the device trench.   
   
   
       9 . The method for manufacturing a semiconductor substrate according to  claim 7  or  8 ,
 wherein the step of forming an alignment mark formation trench forms the alignment mark formation trench to have a depth deeper than the width of the device trench.   
   
   
       10 . The method for manufacturing a semiconductor substrate according to  claim 9 ,
 wherein the step of forming an alignment mark formation trench forms the alignment mark formation trench to have a depth at which the substrate can be etched.   
   
   
       11 . A method for manufacturing a semiconductor substrate comprising:
 a step of preparing a substrate ( 21 ) made of single crystal semiconductor;   a step of forming, on the surface of the substrate ( 21 ), a semiconductor layer ( 22 ) made of single crystal;   a step of arranging, on the semiconductor layer ( 22 ), a mask material ( 30 ) in which both of a device formation region and an alignment region of the semiconductor layer include openings;   a step of etching the semiconductor layer covered by the mask material to simultaneously perform the formation of an alignment mark formation trench ( 31 ) in the alignment region and the formation of a device trench ( 23 ) in the device formation region;   a step of removing the mask material to subsequently bury an epitaxial film ( 33 ) in the device trench so as to form voids ( 25 ) in the alignment mark formation trench; and   a step of subjecting, to a planarization processing, a part of the epitaxial film that is formed exterior to the device trench.   
   
   
       12 . The method for manufacturing a semiconductor substrate according to any one of  claims 7  to  11 ,
 wherein the step of forming an alignment mark formation trench forms the alignment mark formation trench to have a width smaller than that of the device trench.   
   
   
       13 . A method for manufacturing a semiconductor substrate comprising:
 (a) a step of growing a first epitaxial film ( 61 ) on the surface of a substrate body ( 63 );   (b) a step of partially etching the first epitaxial film ( 61 ) to form a plurality of first trenches ( 64 );   (c) a step of growing a second epitaxial film ( 62 ) on the entire interior of the plurality of the first trenches ( 64 ) and the surface of the first epitaxial film ( 61 ) except for the plurality of the first trenches ( 64 );   (d) a step of polishing the second epitaxial film ( 62 ) to expose the surface of the first epitaxial film ( 61 ) and planarizing the upper face of the second epitaxial film ( 62 ) buried in the entire interior of the plurality of the first trenches ( 64 );   (e) a step of further growing a third epitaxial film ( 66 ) having the same composition as that of the first epitaxial film ( 61 ) on the upper face of the planarized second epitaxial film ( 62 ) and the exposed face of the first epitaxial film ( 61 );   (f) a step of etching a part of the third epitaxial film ( 66 ) corresponding to the plurality of the first trenches ( 64 ) to form a plurality of second trenches ( 67 ) to extend the plurality of first trenches ( 64 );   (g) a step of further growing a fourth epitaxial film ( 68 ) on the entire interior of the plurality of second trenches ( 67 ) and the surface of the third epitaxial film ( 66 ) except for the plurality of second trenches ( 67 ); and   (h) a step of polishing the fourth epitaxial film ( 68 ) to expose the surface of the third epitaxial film ( 66 ) and planarizing the upper face of the fourth epitaxial film ( 68 ) buried in the entire interior of the plurality of the second trenches ( 67 ).   
   
   
       14 . The method for manufacturing a semiconductor substrate according to  claim 13 ,
 wherein the step (g) is followed by the repetition of the step (d) to the step (g) one or two times or more.