Sumco Corporation | Date: 2017-01-04
An aspect of the present invention relates to a method of managing a DLTS measurement apparatus, wherein the DLTS measurement apparatus comprises a sample stage which has a measurement target sample placement surface and on which a measurement target sample having a semiconductor junction on one surface of a semiconductor sample and an ohmic layer on the other surface is placed in which the ohmic layer and the measurement target sample placement surface face each other; a first wiring having a tip contacting or being to contact with the measurement target sample; and a second wiring having a tip contacting or being to contact with the sample stage, and the method comprising determining whether or not a measurement value measured by the DLTS measurement apparatus is in a preliminarily set allowable range; and performing maintenance processing of exchanging or repairing at least one of a whole or a part of the sample stage, a whole or a part of the first wiring, and a whole or a part of the second wiring, in a case where the measurement value is outside the preliminarily set allowable range as a result of the determination.
SUMCO Corporation | Date: 2016-02-19
Apparatus polishing one side of a wafer to accurately realize the desired wafer edge shape without dependence on the period of use of a polishing cloth is provided. In the apparatus of the present invention, a wafer fixed to a head is brought into contact with a polishing cloth provided on a surface of a surface plate, and the head and the surface plate are rotated, thereby polishing one side of the wafer. The contact angle of the polishing cloth (S1) is measured; the rotation speed of the head and the surface plate is determined based on the measured contact angle of the polishing cloth (S4). One side of the wafer is polished by rotating the head and the surface plate at the determined rotation speed (S5, S6).
Sumco Corporation | Date: 2016-06-22
After determining the precipitated oxygen concentration and the residual oxygen concentration in a silicon wafer after heat treatment performed in a device fabrication process; the critical shear stress _(cri )at which slip dislocations are formed in the silicon wafer in the device fabrication process is determined based on the obtained precipitated oxygen concentration and residual oxygen concentration; and the obtained critical shear stress and the thermal stress applied to the silicon wafer in the heat treatment of the device fabrication process are compared, thereby determining that slip dislocations are formed in the silicon wafer in the device fabrication process when the thermal stress is equal to or more than the critical shear stress _(cri), or determining that slip dislocations are not formed in the silicon wafer in the device fabrication process when the thermal stress is less than the critical shear stress _(cri).
SUMCO Corporation | Date: 2016-06-14
Provided is an epitaxial silicon wafer free of epitaxial defects caused by dislocation clusters and COPs with reduced metal contamination achieved by higher gettering capability and a method of producing the epitaxial wafer. A method of producing an epitaxial silicon wafer includes a first step of irradiating a silicon wafer free of dislocation clusters and COPs with cluster ions to form a modifying layer formed from a constituent element of the cluster ions in a surface portion of the silicon wafer; and a second step of forming an epitaxial layer on the modifying layer of the silicon wafer.
Sumco Corporation | Date: 2016-01-29
A method of producing a silicon single crystal is provided. The method may include taking a real image of a heat shield including a circular opening and a mirror image of the heat shield reflected on a surface of the silicon melt, measuring a spacing between the real image and the mirror image, calculating a position of the surface of the silicon melt, taking an image of a bright zone that appears in a vicinity of an interface between the silicon melt and the silicon single crystal, calculating a position of the surface of the silicon melt based on a center position of the silicon single crystal determined from the image of the bright zone, and controlling the position of the surface of the silicon melt during a pulling of the silicon single crystal while referring to data of the calculated positions of the surface of the silicon melt.
SUMCO Corporation | Date: 2016-05-11
An evaluation method of suitable silica powder for forming a bubble-free layer of a vitreous silica crucible for pulling of a silicon single crystal, includes: a process of measuring a porosity between silica particles in the silica powder, a process of melting the silica powder, a process of measuring a bubble content rate of a vitreous silica block obtained by cooling to harden the melted silica powder, and a process of determining whether the silica powder is suitable from the porosity of the silica powder and the bubble content rate of the vitreous silica block.
Sumco Corporation | Date: 2016-04-07
The method of evaluating an epitaxial wafer includes performing evaluation of an epitaxial wafer by detecting, as a light point defect, an abnormal substance selected from the group consisting of a defect and a surface deposit of an epitaxial wafer to be evaluated with a surface inspection apparatus including two types of incidence systems with different incidence angles and two types of light receiving systems with different light receiving angles, based on two types of measurement results.
Sumco Corporation | Date: 2016-05-04
A pulling-up method of silicon single crystal comprises a process of laying a molded body between a susceptors inner surface and a crucibles outer surface. The molded body is formed based on three-dimensional data of inner surface shape of the susceptor which can hold the vitreous silica crucible and three-dimensional data of the crucible so as to make the susceptors central axis and the crucibles central axis substantially aligned when it is laid between the susceptors inner surface and the crucibles outer surface.
Sumco Corporation | Date: 2016-10-12
A disc-shaped susceptor includes a plurality of recesses that are aligned in a circumferential direction on an upper surface of the susceptor and in which wafers are respectively mounted, in which the susceptor is formed so that a center of the susceptor is dented toward a lower surface thereof from an outer edge thereof.
Sumco Corporation | Date: 2016-04-13
The present invention provides a vitreous silica crucible which inhibits a deformation even when used under a high temperature condition for a long time, and a method for manufacturing the same. The vitreous silica crucible comprises: a substantially cylindrical straight body portion having an opening on the top end and extending in a vertical direction, a curved bottom portion, and a corner portion connecting the straight body portion with the bottom portion and a curvature of which is greater than that of the bottom portion, wherein, the vitreous silica crucible comprises a transparent layer on the inside and a bubble layer on the outside thereof, a compressive stress layer in which compressive stress remains in the inner surface side of the transparent layer, and a tensile stress layer in which tensile stress remains and is adjacent to the compressive stress layer at a gradual rate of change of stress.