Sumco Corporation

Hidehiko Okuda

Tatsumi Kusaba

Akihiko Endo

Etsurou Morita

Yoshihisa Nonogaki

This p-type silicon wafer was subjected to heat treatment to have a resistivity of 10 &#x3a9;&#xb7;cm or more, a BMD density of 5&#xd7;10defects/cmor more, and an n-type impurity concentration of 1&#xd7;10atoms/cmor less at a depth of within 5 &#x3bc;m from a surface of the wafer. This method for heat-treating p-type silicon wafers, the method includes the steps of: loading p-type silicon wafers onto a wafer boat, inserting into a vertical furnace, and holding in an argon gas ambient atmosphere at a temperature of 1100 to 1300&#xb0; C. for one hour; moving the wafer boat to a transfer chamber and discharging the silicon wafers; and transferring to the wafer boat silicon wafers to be heat treated next, wherein after the discharge of the heat-treated silicon wafers, the silicon wafers to be heat-treated next are transferred to the wafer boat within a waiting time of less than two hours.

P-type silicon wafer and method for heat-treating the same

The present invention provides a method of manufacturing a bonded wafer. The method comprises an oxidation step in which an oxide film is formed on at least one surface of a base wafer, a bonding step in which the base wafer on which the oxide film has been formed is bonded to a top wafer to form a bonded wafer, and a thinning step in which the top wafer included in the bonded wafer is thinned. The oxidation step comprises heating the base wafer to a heating temperature ranging from 800 to 1300&#xb0; C. at a rate of temperature increase ranging from 1 to 300&#xb0; C./second in an oxidizing atmosphere, and the bonding step is carried out so as to position the oxide film formed in the oxidation step at an interface of the top wafer and the base wafer.

Method of manufacturing bonded wafer

There is provided a layer transferred wafer subjected to a process for regenerating to be reused many times for an SOI layer wafer which is used to manufacture an SOI wafer with an excellent process yield in which oxygen precipitate nuclei or oxygen precipitates are eliminated and generation of HF defects are inhibited by performing the process for regenerating the layer transferred wafer generated as a by-product by an ion implantation separation method. The process for regenerating a layer transferred wafer in which the layer transferred waferobtained as a by-product in manufacturing a bonded SOI waferby an ion implantation separation method so as to be reused for an SOI layer waferof the bonded SOI wafercomprises: rapidly heating the layer transferred waferin an oxidizing atmosphere, then holding it for a fixed time and subsequently rapidly cooling it; and mirror-polishing a surface of the layer transferred wafer

Process for regenerating layer transferred wafer

A bonded wafer is produced by a method comprising a step of implanting ions of a light element such as hydrogen, helium or the like into a wafer for active layer at a predetermined depth position to form an ion implanted layer, a step of bonding the wafer for active layer to a wafer for support substrate through an insulating film, a step of exfoliating the wafer at the ion implanted layer, a first heat treatment step of conducting a sacrificial oxidation for reducing damage on a surface of an active layer exposed through the exfoliation and a second heat treatment step of raising a bonding strength, in which the second heat treatment step is continuously conducted after the first heat treatment step without removing an oxide film formed on the surface of the active layer.

Method for producing bonded wafer

The object of the invention is to provide a method for manufacturing an SOI layer which is devoid of damages, has a reduced variation in thickness, and is uniform in thickness. The object is met by providing a method for manufacturing an SOI substrate comprising the steps of forming an oxide film at least on one surface of a first silicon substrate, implanting hydrogen ions from the surface of the first silicon substrate thereby forming an ion-implantation zone in the interior of the first silicon substrate, bonding the first silicon substrate over a second silicon substrate with the oxide film interposed thereby forming a laminated assembly, subjecting the laminated assembly to a first heating treatment consisting of heating at a specified temperature, so that the first silicon substrate is split at the ion-implantation zone thereby manufacturing a bonded substrate, flattening the exposed surface of the SOI layer by subjecting the bonded substrate to wet etching, subjecting the bonded substrate to a second heating treatment consisting of heating at 750 to 900&#xb0; C. in an oxidative atmosphere thereby reducing damages inflicted to the SOI layer, and subjecting the resulting bonded substrate to a third heating treatment consisting of heating at 900 to 1200&#xb0; C. thereby enhancing the bonding strength of the bonded substrate.

Method for manufacturing SOI substrate

This method for heat-treating a silicon wafer includes: a step of subjecting a silicon wafer to a high-temperature heat treatment in an ambient gas atmosphere of hydrogen gas, argon gas or a mixture thereof; and a step of lowering a temperature at a rate of 2&#xb0; C./min or less in a nitrogen-gas-containing ambient atmosphere in a portion or all of a process of lowering a temperature to a wafer removal temperature following said high-temperature heat treatment. This silicon wafer has a defect-free layer which is formed by a high-temperature heat treatment and is included in a surface thereof, wherein an average iron concentration in said surface is 1&#xd7;10atoms/cmor less.

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Tokyo, Japan

Hidehiko Okuda