Shin-etsu Handotai Co., Ltd.

Toru Ishizuka

Hiroji Aga

Norihiro Kobayashi

Isao Yokokawa

Masatake Nakano

Setsuya Hama

Nobuhiko Noto

Tomohiko Ohta

Masahiro Kato

Yuji Okubo

Takuya Sasaki

Eiichi Yamazaki

Yasuo Nagaoka

Yuta Tamba

Akira Araki

The present invention is a method for manufacturing a bonded SOI wafer, including: preparing, as a base wafer, a silicon single crystal wafer whose initial interstitial oxygen concentration is 15 ppma or more ('79ASTM); forming a silicon oxide film on a surface of the base wafer by heating the base wafer in an oxidizing atmosphere such that a feeding temperature at which the base wafer is fed into a heat treatment furnace for the heat treatment is 800&#xb0; C. or more, and the base wafer is heated at the feeding temperature or higher; bonding the base wafer to the bond wafer with the silicon oxide film interposed therebetween; and thinning the bonded bond wafer to form an SOI layer. This provides a method for manufacturing a bonded SOI wafer by a base oxidation method which suppresses the formation of oxide precipitates in a base wafer while suppressing slip dislocation.

Method for manufacturing bonded SOI wafer

A method for producing a bonded SOI wafer by bonding a bond wafer and a base wafer, each being formed of a silicon single crystal, together with a silicon oxide film placed therebetween, the method including: preparing, as the base wafer, a silicon single crystal wafer whose resistivity is 100 &#x3a9;&#xb7;cm or more and initial interstitial oxygen concentration is 10 ppma or less; forming, on the front surface of the base wafer, a silicon oxide film by performing, on the base wafer, heat treatment in an oxidizing atmosphere at a temperature of 700&#xb0; C. or higher and 1000&#xb0; C. or lower for 5 hours or more; bonding the base wafer and the bond wafer together with the silicon oxide film placed therebetween; and thinning the bonded bond wafer to form an SOI layer.

Method for producing bonded SOI wafer

A method for manufacturing a bonded SOI wafer including a step of performing a heat treatment to each bonded SOI wafer having an oxide film on a back surface thereof in an argon atmosphere to flatten a front surface of an SOI layer, wherein, at the time of performing the heat treatment in the argon atmosphere in a batch processing heat treatment furnace, a silicon wafer is arranged as a dummy wafer between the adjacent bonded SOI wafers housed in the batch processing heat treatment furnace to perform the heat treatment. Consequently, there is the method for manufacturing an SOI wafer which enables suppressing an increase in LPDs at the step of performing the heat treatment to a bonded SOI wafer having an oxide film on a back surface thereof in an argon atmosphere in a batch processing heat treatment furnace to flatten a front surface of an SOI layer.

Method for manufacturing a bonded SOI wafer by bonding a bond wafer and base wafer, each composed of a silicon single crystal, via an insulator film, including the steps: depositing a polycrystalline silicon layer on the base wafer bonding surface side, polishing the polycrystalline silicon layer surface, forming the insulator film on the bonding surface of the bond wafer, bonding the polished surface of the base wafer polycrystalline silicon layer and bond wafer via the insulator film; thinning the bonded bond wafer to form an SOI layer; wherein, in the step of depositing the polycrystalline silicon layer, a wafer having a chemically etched surface as base wafer; chemically etched surface is subjected to primary polishing followed by depositing the polycrystalline silicon layer on surface subjected to the primary polishing, and in the step polishing the polycrystalline silicon layer surface, which is subjected to secondary polishing or secondary and finish polishing.

Method for manufacturing a bonded SOI wafer

A method for manufacturing a bonded wafer using a base wafer which is an epitaxial wafer produced by a method including at least one of: (1) setting a chamfer width of a wafer for epitaxial growth to be 0.20 mm or less on an epitaxial growth side; (2) preparing a wafer for epitaxial growth having a rise shape on an epitaxial growth side periphery, thereby adjusting the wafer to have an amount of sag within a range of &#x2212;30 nm/mmto +10 nm/mmon a bonding surface side periphery; and (3) adjusting epitaxial growth conditions so a change in amount of sag before and after growth becomes a positive value, thereby adjusting the wafer to have sag within a range of &#x2212;30 nm/mmto +10 nm/mm. The method can manufacture a bonded wafer with a small terrace width even when an epitaxial wafer is used as the base wafer.

Method for manufacturing bonded wafer

The present invention provides a method of manufacturing a bonded wafer, including performing RTA under an atmosphere containing hydrogen on a bonded wafer after separating the bond wafer constituting the bonded wafer, and subsequently performing a sacrificial oxidation process to reduce the thickness of the thin film, wherein the RTA is performed under conditions of a retention start temperature of more than 1150&#xb0; C. and a retention end temperature of 1150&#xb0; C. or less. The invention can inhibit the BMD density from increasing and sufficiently flatten the surface of a thin film when the thin film of the bonded wafer is flattened and thinned by the combination of the RTA and sacrificial oxidation processes.

Method of fabricating SOI wafer by ion implantation

The present invention provides a method for manufacturing an SOI wafer including a step of forming an insulator film on an entire surface of a bond wafer before bonding, bringing a bonded wafer before delaminating the bond wafer at an ion implanted layer into contact with a liquid that enables dissolving the insulator film while protecting the insulator film on a back surface on the opposite side of a bonding surface of the bond wafer, or exposing the bonded wafer to a gas that enables dissolving the insulator film, and thus etching the insulator film placed between the bond wafer and a base wafer from an outer peripheral end of the bonded wafer toward a center of the bonded wafer.

Method for manufacturing SOI wafer

The invention provides a reclaiming processing method for a delaminated wafer, by which the delaminated wafer obtained as a by-produce at the time of producing a bonded wafer is subjected to reclaiming polishing and is again available as a bond wafer or a base wafer, wherein, in the reclaiming polishing, the delaminate wafer is polished with use of a double-side polisher in a state that oxide film is not formed on a delaminated surface of the delaminated wafer and oxide film is formed on a back side which is the opposite side of the delaminated surface. As a result, the reclaiming processing method for a delaminated wafer, by which the delaminated wafer obtained as a by-product at the time of manufacturing a bonded wafer based on an ion implantation delamination method is subjected to the reclaiming polishing, which enables sufficiently improving quality.

Reclaiming processing method for delaminated wafer

A method for manufacturing SOI wafer of forming an oxide film on a bond wafer of a semiconductor single crystal substrate, forming an ion implanted layer into the bond wafer by implanting ions of at least one kind of gas in hydrogen and rare gases through the oxide film, bonding together an ion implanted front surface of the bond wafer and base wafer front surface via the oxide film, thereafter delaminating the bond wafer along the ion implanted layer, and thereby fabricating an SOI wafer. The oxide film is formed on the bond wafer such that on a back surface it is made thicker than the oxide film on a bonded face. The method for manufacturing SOI wafer capable of suppressing scratches and SOI film thickness abnormality caused by warped shapes of the SOI and bond wafers after delamination where it has been delaminated by an ion implantation delamination method.

The present invention is a method for manufacturing an SOI wafer, including: implanting one or more gas ion selected from a hydrogen ion and a rare gas ion into a bond wafer composed of a semiconductor single crystal substrate from a surface of the bond wafer to form an ion-implanted layer; bonding the surface from which the ion is implanted into the bond wafer and a surface of a base wafer through an oxide film; and then delaminating the bond wafer at the ion-implanted layer by performing a delamination heat treatment with a heat treatment furnace to form the SOI wafer, wherein after the delamination heat treatment, a temperature of the heat treatment furnace is decreased to 250&#xb0; C. or less at temperature-decreasing rate of less than 3.0&#xb0; C/min, and then the SOI wafer and the bond wafer after delamination are taken out from the heat treatment furnace.

The present invention is directed to a method for manufacturing an SOI wafer in which the bonded SOI wafer after the delamination by the ion implantation delamination method is subjected to a rapid thermal oxidation process such that an oxide film is formed on a surface of the SOI layer, the oxide film is removed, the bonded SOI wafer is then subjected to a flattening heat treatment to flatten the surface of the SOI layer, the flattening heat treatment causing migration of silicon atoms of the surface of the SOI layer, and the bonded SOI wafer is then subjected to a sacrificial oxidation process to adjust a film thickness of the SOI layer. The method enables efficient manufacture of a high quality SOI wafer having an SOI layer with sufficiently reduced surface roughness of the SOI layer surface and fewer deep pits in the SOI layer surface.

According to the present invention, there is provided a method for manufacturing an SOI wafer having the step of performing a first sacrificial oxidation treatment on the aforementioned bonded SOI wafer in which the delamination has been performed after a first RTA treatment has been performed thereon and then performing a second sacrificial oxidation treatment thereon after a second RTA treatment has been performed thereon, wherein the first and second RTA treatments are performed under a hydrogen gas containing atmosphere and at a temperature of 1100&#xb0; C. or more, wherein after a thermal oxide film has been formed on the aforementioned SOI layer front surface by performing only thermal oxidation by a batch type heat treating furnace at a temperature of 900&#xb0; C. or more and 1000&#xb0; C. or less in the first and second sacrificial oxidation treatments, a treatment for removing the thermal oxide film is performed.

The present invention provides a method for manufacturing an SOI wafer, in which an insulator film is formed at least on all surfaces of a base wafer, and while protecting a first part of the insulator film on a back surface on the opposite side from a bonded surface of the base wafer, a bonded wafer before separating a bond wafer along a layer of the implanted ion is brought into contact with a liquid capable of dissolving the insulator film or exposed to a gas capable of dissolving the insulator film, and a second part of the insulator film interposed between the bond wafer and the base wafer is etched from an outer circumferential edge of the bonded wafer and toward the center of the bonded wafer. The method can control the terrace width and inhibit warping of the SOI wafer in a bonding process with a base wafer.

A method for producing a direct bonded wafer comprising: forming a thermal oxide film or a CVD oxide film on a surface of at least one of a bond wafer and a base wafer, and bonding the wafer to the other wafer via the oxide film; subsequently thinning the bond wafer to prepare a bonded wafer; and thereafter conducting a process of annealing the bonded wafer under an atmosphere including any one of an inert gas, hydrogen and a mixed gas of an inert gas and hydrogen so that the oxide film between the bond wafer and the base wafer is removed to bond the bond wafer directly to the base wafer. Thereby, there is provided a method for producing a direct bonded wafer in which generation of voids is reduced, and a direct bonded wafer with a low void count.

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Takasaki, Japan

Toru Ishizuka