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) forming a member comprising a porous semiconductor layer on a non-porous single-crystal semiconductor region and a non-porous single-crystal semiconductor layer on said porous semiconductor layer;
b) bonding said non-porous single-crystal semiconductor layer to a substrate at a first temperature;
c) grinding said non-porous single-crystal semiconductor region so that part of said non-porous single-crystal semiconductor region is removed and part remains;
d) after the grinding, heating said non-porous single-crystal semiconductor layer and said substrate bonded to each other at a second temperature higher than the first temperature;
e) grinding or etching said non-porous single-crystal semiconductor region remaining after the first grinding step c), to entirely remove said non-porous single-crystal semiconductor region and to expose said porous semiconductor layer; and
f) selectively etching said porous semiconductor layer to remove said porous 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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Citations
22 Claims
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1. A process for producing a semiconductor substrate, comprising successively the steps of:
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a) forming a member comprising a porous semiconductor layer on a non-porous single-crystal semiconductor region and a non-porous single-crystal semiconductor layer on said porous semiconductor layer; b) bonding said non-porous single-crystal semiconductor layer to a substrate at a first temperature; c) grinding said non-porous single-crystal semiconductor region so that part of said non-porous single-crystal semiconductor region is removed and part remains; d) after the grinding, heating said non-porous single-crystal semiconductor layer and said substrate bonded to each other at a second temperature higher than the first temperature; e) grinding or etching said non-porous single-crystal semiconductor region remaining after the first grinding step c), to entirely remove said non-porous single-crystal semiconductor region and to expose said porous semiconductor layer; and f) selectively etching said porous semiconductor layer to remove said porous semiconductor layer. - View Dependent Claims (2, 3, 4)
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5. A process for producing a semiconductor substrate, comprising 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, thereby to form a porous single-crystal semiconductor layer on a non-porous single-crystal semiconductor region; (b) epitaxially 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 substantially without heating; (d) removing at least part of said non-porous single-crystal semiconductor region by the following steps; (i) grinding down said non-porous single-crystal semiconductor region to remove a part thereof; (ii) heating the whole to strengthen the bonding between said non-porous single-crystal semiconductor layer and said insulator substrate; and (iii) removing the remainder part of said non-porous single-crystal semiconductor region; and (e) selectively etching said porous single-crystal semiconductor layer to remove said porous single-crystal semiconductor layer. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 21, 22)
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15. 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) epitaxially 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 the both to each other substantially without heating; d) grinding said non-porous single-crystal semiconductor region to remove part of said non-porous single-crystal semiconductor region; d2) heating the whole to strengthen the bond between said non-porous single-crystal semiconductor layer and said insulator substrate; d3) grinding further said non-porous single-crystal semiconductor region having remained after the grinding step d), to entirely remove said non-porous single-crystal semiconductor region to expose said porous single-crystal semiconductor layer; and f) selectively etching said porous single-crystal semiconductor layer to remove said porous single-crystal semiconductor layer.
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Specification