Harris Corporation

Intersil Corporation

Other

Craig J McLachlan

Stephen J Gaul

George V Rouse

Jose Avelino Delgado

John P Short

James Douglas Beasom

Paul S Reinecke

James R Zibrida

Anthony L Rivoli

Charles Messmer

The present invention induces provides a gettering trench on the front surface of a device substrate. In one embodiment it induces stress and simultaneously forms a gettering zone,for gettering impurities in an integrated circuit structure. In another embodiment, the trench is filled with gettering material,such as polysilicon. The two gettering mechanisms may be combined,. The invention is useful for providing gettering in bonded wafers and in silicon-on-insulator devices (FIGS.,).

Defect gettering by induced stress

A method for fabricating a field effect transistor using the supporting substrate as a device layer in accordance with the present invention comprises several steps. To fabricate the field effect transistor, an epitaxial layer is grown on one surface of a substrate having an opposing surface, the epitaxial layer forming a drain for the transistor. Once the epitaxial layer is grown, the substrate is thinned to an appropriate device thickness and then a gate and a source for the transistor are formed on the opposing surface of the substrate. In an alternative embodiment, a polysilicon layer is used instead of the epitaxial layer. A field effect transistor fabricated from the method described above includes an epitaxial layer formed on one surface of a substrate having an opposing surface, the epitaxial layer forming a drain for the transistor and a gate and a source for the transistor formed on the other surface of the substrate. Again, a polysilicon layer may be used instead of the epitaxial layer in the transistor.

Power device

The present invention induces provides a gettering trench on the front surface of a device substrate. In one embodiment it induces stress and simultaneously forms a gettering zone 40 for gettering impurities in an integrated circuit structure. In another embodiment, the trench is filled with gettering material 72 such as polysilicon. The two gettering mechanisms may be combined 82,84. The invention is useful for providing gettering in bonded wafers and in silicon-on-insulator devices (FIGS. 4,5).

Method for fabricating a power device

Warpage in a bonded wafer is limited by maintenance of a stress compensation layer on the backside of the bonded wafer during device fabrication processing. One embodiment applies a sacrificial polysilicon layer over a stress compensation silicon dioxide layer for bonded silicon wafers. The fabrication processing consumes the polysilicon layer but not the stress compensation silicon dioxide.

Bonded wafer processing

bonded wafer processing

Oxygen induced lattice slip defects are reduced in device layer 26 of silicon-on-insulator structure 12, 16, 26. At the bottom of trenches 22 notches 28 are etched into the dielectric layer 16. A thermal oxide process provides protrusions 30 of oxide into the substrate. The protrusions 30 direct defects into the support layer 12.

Defect control in formation of dielectrically isolated semiconductor

A silicon on insulator substrate 8 provides islands of silicon 18 of uniform thickness by using a trench etch process and a silicon nitride layer 20 to provide a thickness control and polish stop for the silicon islands 18.

Sub-micron bonded SOI by trench planarization

A bonding method including pressing a pair of slices together with a liquid oxidant therebetween and subjecting the pair of slices to a temperature to bond the slices together. Preferably a liquid oxidant is applied to one of the slices before they are pressed together and then dried. The heating step for bonding is carried out at a sufficiently high temperature of at least 1100.degree. C. to make the slices pliable so as to comply with each other during the bonding step.

Wafer bonding using trapped oxidizing vapor

Wafer bonding process employing liquid oxidant

A process including forming peaks and valleys in a bonding surface of a first wafer so that the peaks are at the scribe lines which define dice. The peaks and not the valleys of the first wafer is bonded to a bonding surface of a second wafer. The device forming steps are performed on one of the wafers. Finally, the wafer in which the devices are formed is cut through at the peaks to form the dice. The peaks may be substantially the size of the kerf produced by the cutting such that the dice are separated from the other wafer by the cutting step. Alternately, the peaks may have a width greater than the kerf produced by the cutting and remain attached to the other wafer by the remaining peak portions. The dice are then separated from the other wafer at the remaining peak portions by an additional step.

Ultra-thin circuit fabrication by controlled wafer debonding

Integrated circuits are formed by bonding two substrates together on a moat or recess. If the moat is exposed at a side wall, an optical fiber is inserted therein and communicates optically with a photoelectric device in the substrate by a slant side wall of the moat. If the moat is sealed by a cover layer resulting from removing all or most of the top substrate leaving the bonding layer as a cover, a pressure responsive device is formed on the cover layer directly or in the remaining top substrate over the sealed cavity.

Integrated circuits including photo-optical devices and pressure

Method of fabricating integrated circuits including photo optical

A process including bonding a first device wafer to a handle wafer by an intermediate bonding oxide layer and thinning the device wafer to not greater than 7 mils. An epitaxial device layer of under 1 mil may be added. Device formation steps are performed on a first surface of the first device wafer. This is followed by removing the handle wafer to produce a resulting wafer having substantially the thickness of the first device layer. To produce a silicon on insulator (SOI), a third device wafer is bonded to the first surface of the first device wafer by the intermediate oxide layer and the third wafer is thinned to not greater than 40 microns. The first and third device wafers form the resulting SOI wafer.

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Melbourne Beach, FL, United States of America

Craig J McLachlan