Method for manufacturing SOI wafer and SOI wafer
AssigneeShin-Etsu Handotai Co., Ltd.
InventorIsao Yokokawa
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Abstract
A method for manufacturing an SOI wafer including: a step of forming a silicon oxide film by thermal oxidation on an entire surface of a base wafer containing a dopant; and bonding a main surface of a bond wafer to a first main surface via the silicon oxide film, wherein, prior to the thermal oxidation step, a step of forming a CVD insulator film on a second main surface; and a step of forming, on the first main surface, a barrier silicon layer containing a dopant at a lower concentration than a dopant concentration of the base wafer, and in the thermal oxidation step, the barrier silicon layer is thermally oxidized to produce a barrier silicon oxide film, and in the bonding step, the bond wafer is bonded to the base wafer via the barrier silicon oxide film as a part of the silicon oxide film.
Claims19
A method for manufacturing an SOI wafer, at least comprising:
- a step of providing a base wafer and a bond wafer, the base wafer comprising a silicon single crystal wafer containing a dopant across the wafer and having a first main surface and a second main surface opposite the first main surface, the bond wafer comprising a silicon single crystal wafer containing a dopant at a lower concentration than a dopant concentration of the base wafer;
- a thermal oxidation step of forming a silicon oxide film on an entire surface of the base wafer by thermal oxidation;
- a bonding step of bonding one main surface of the bond wafer to the first main surface of the base wafer via the silicon oxide film on the base wafer;
- and
- a thinning step of thinning the bond wafer to form an SOI layer, wherein
- the method further comprises, prior to the thermal oxidation step for the base wafer:
- a step of forming a CVD insulator film on the second main surface of the base wafer;
- and
- a step of forming a barrier silicon layer on the first main surface of the base wafer, the barrier silicon layer containing a dopant at a lower concentration than the dopant concentration of the base wafer, wherein
- in the thermal oxidation step, the barrier silicon layer is thermally oxidized to produce a barrier silicon oxide film as a part of the silicon oxide film, and
- in the bonding step, the one main surface of the bond wafer is bonded to the first main surface of the base wafer via the barrier silicon oxide film as a part of the silicon oxide film.
An SOI wafer comprising:
- a base wafer;
- a buried oxide film;
- and
- an SOI layer bonded to the base wafer via the buried oxide film, wherein
- the base wafer comprises a silicon single crystal wafer containing a dopant across the wafer and having a first main surface and a second main surface opposite the first main surface, the first main surface being a bonding surface for bonding to the SOI layer,
- a barrier silicon oxide film as at least a part of the buried oxide film is disposed on the first main surface of the base wafer,
- a backside silicon oxide film is disposed on the second main surface of the base wafer,
- a CVD insulator film is disposed on a surface of the backside silicon oxide film facing away from the base wafer,
- the SOI layer comprises a silicon single crystal containing a dopant at a lower concentration than a dopant concentration of the base wafer,
- a concentration of a dopant in the barrier silicon oxide film is lower than a concentration of a dopant in the backside silicon oxide film, and
- a barrier silicon layer is disposed between the base wafer and the barrier silicon oxide film, and a dopant of a same kind as the dopant contained in the base wafer is diffused in the barrier silicon layer.
Dependencies are inferred from the claim text.