Siltronic Ag

Ruediger Schmolke

Wilfried Von Ammon

Thomas Buschhardt

Peter Storck

Guido Wenski

Gerhard Heier

Wolfgang Siebert

A semiconductor wafer is guided in a cutout in a carrier while a thickness of the semiconductor wafer is reduced to a target thickness by material removal from the front and back surfaces simultaneously. The semiconductor wafer is machined until it is thinner than a carrier body and thicker than an inlay used to line the cutout in the carrier to protect the semiconductor wafer. The carrier is distinguished by the fact that the carrier body and the inlay have different thicknesses throughout the entire duration of the machining of the semiconductor wafer, the carrier body being thicker than the inlay, by from 20 to 70 &#x3bc;m. Themethod provides semiconductor wafers polished on both sides, having a front surface, a back surface and an edge, and a local flatness of the front surface, SFQRof less than 50 nm with an edge exclusion of R-2 mm and less than nm with an edge exclusion of R-1 mm, based on a site area of 26 by 8 mm.

Method for machining a semiconductor wafer on both sides in a carrier, carrier, and a semiconductor wafer produced by the method

A process for epitaxially coating the front surface of a semiconductor wafer in a CVD reactor, the front surface of the semiconductor wafer being exposed to a process gas which contains a source gas and a carrier gas, and the back surface of the semiconductor wafer being exposed to a displacement gas, wherein the displacement gas contains no more than 5% by volume of hydrogen, with the result that diffusion of dopants out of the back surface of the semiconductor wafer, which is intensified by hydrogen, is substantially avoided. With this process, it is possible to produce a semiconductor wafer with a substrate resistivity of &#x2266;100 m&#x3a9;cm and a resistivity of the epitaxial layer of &#x3e;1 &#x3a9;cm without back-surface coating, the epitaxial layer of which semiconductor wafer has a resistance inhomogeneity of &#x3c;10%.

Process and apparatus for epitaxially coating a semiconductor wafer and epitaxially coated semiconductor wafer

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Burghausen, Germany

Ruediger Schmolke