Pasted SOI substrate, process for producing the same and semiconductor device
AssigneeSumitomo Mitsubishi Silicon Corporation
InventorsNaoshi Adachi, Masahiko Nakamae
Life of this patent
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Abstract
A plurality of recessed portions having different depths is formed in a surface of the active layer wafer or in a bonding surface of the supporting substrate wafer. Those wafers are bonded to each other with an insulation film interposed therebetween. This allows a cavity of higher dimensional precision to be buried therein. A plurality of cavities may be formed simultaneously in a plurality of locations within the plane of the substrate, which allows the thickness of the SOI layer to be set arbitrarily. Accordingly, such a semiconductor device can be fabricated easily in which a MOS type element and a bipolar element are formed on the same chip in a mixed manner.
Claims10
A bonded SOI substrate comprising:
- a SOI layer in which a device is to be formed;
- and
- a supporting substrate wafer for supporting said SOI layer, said SOI layer and said supporting substrate wafer having been bonded to each other with an insulation layer interposed therebetween, in which
- said insulation layer comprises an insulation film formed on an entire surface of an active substrate forming the SOI layer and/or on an entire surface of said supporting substrate, and a plurality of cavities defined by different heights, said cavities having an opening area having a circular, elliptical, triangular, rectangular or other polygonal shape in plan view.
A manufacturing method of a bonded SOI substrate, comprising:
- a recessed portion forming step for forming a recessed portion having an opening area having a circular, elliptical, triangular, rectangular or other polygonal shape in plan view in a surface of an active layer wafer and/or in a surface of a supporting substrate wafer;
- a bonding step for forming an insulation film on an entire surface of an active substrate and/or on an entire surface of said supporting substrate, and bonding said active layer wafer and said supporting substrate wafer to each other with said surface(s) having said recessed portion(s) formed therein serving as bonding surface (s) to thereby form a cavity;
- and
- a thinning step for thinning said active layer wafer of said bonded wafers to thereby form a SOI layer, wherein
- in said recessed portion forming step, a plurality of recessed portions having varied depth is formed in said surface of said active layer wafer and/or in said surface of said supporting substrate wafer.
A semiconductor device comprising a bonded SOI substrate in which a SOI layer having varied thickness is formed over a plane thereof and a plurality of cavities defined by different heights and having an opening area having a circular, elliptical, triangular, rectangular or other polygonal shape in plan view are formed at the bonding interface between said SOI layer and said substrate, wherein a functional block defined by a CMOS logic is formed in the thinnest region of said SOI layer and a memory functional block and/or an analog block are formed in the other regions of said SOI layer.
Dependencies are inferred from the claim text.