Process for producing a semiconductor substrate
First Claim
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1. A process for producing a semiconductor substrate, comprising successively the steps of:
- a) anodizing a surface layer on one side of a single-crystal semiconductor substrate to make the surface layer porous to form a porous single-crystal semiconductor layer on a non-porous single-crystal semiconductor region;
b) expitaxially growing a non-porous single-crystal semiconductor layer on said porous single-crystal semiconductor layer;
c) bringing the surface of said non-porous single-crystal semiconductor layer into close contact with the surface of an insulator substrate and then bonding both to each other without heating;
d) grinding down said non-porous single-crystal semiconductor region to remove part of said non-porous single-crystal semiconductor region;
e) heating the whole to strengthen the bond between said non-porous single-crystal semiconductor layer and said insulator substrate;
f) etching said non-porous single-crystal semiconductor region remaining after the grinding step d), to entirely remove said non-porous single-crystal semiconductor region to expose said porous single-crystal semiconductor layer; and
g) selectively etching said porous single-crystal semiconductor layer to remove said porous single-crystal semiconductor layer.
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Abstract
A bonded substrate and a process for its production is provided to solve the problem involved in the heat treatment which tends to cause troubles such as break, separation and warpage of the substrates bonded. A single-crystal semiconductor epitaxially grown on a porous semiconductor substrate is bonded to an insulator substrate, and the semiconductor substrate is removed by etching, grinding, or a combination of the both, where no heat treatment is carried out or, even if carried out, only once.
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9 Claims
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1. A process for producing a semiconductor substrate, comprising successively the steps of:
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a) anodizing a surface layer on one side of a single-crystal semiconductor substrate to make the surface layer porous to form a porous single-crystal semiconductor layer on a non-porous single-crystal semiconductor region; b) expitaxially growing a non-porous single-crystal semiconductor layer on said porous single-crystal semiconductor layer; c) bringing the surface of said non-porous single-crystal semiconductor layer into close contact with the surface of an insulator substrate and then bonding both to each other without heating; d) grinding down said non-porous single-crystal semiconductor region to remove part of said non-porous single-crystal semiconductor region; e) heating the whole to strengthen the bond between said non-porous single-crystal semiconductor layer and said insulator substrate; f) etching said non-porous single-crystal semiconductor region remaining after the grinding step d), to entirely remove said non-porous single-crystal semiconductor region to expose said porous single-crystal semiconductor layer; and g) selectively etching said porous single-crystal semiconductor layer to remove said porous single-crystal semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification