Wacker-chemitronic Gesellschaft Fur Elektronik-grundstoffe Mbh

Siltronic Ag

Wolfgang Hensel

Erich Tomzig

Heinz Herzer

Reinhard Wolf

Helmut Schwenk

Heinz Klinger

Rudolf Lehner

Wilfried V Ammon

Gunter Matuszak

Unpolished semiconductor wafers are produced by: (a) pulling a single crystal of a semiconductor material, (b) grinding the single crystal round, (c) separating a semiconductor wafer from this crystal, (d) rounding the edge of the semiconductor wafer, (e) surface-grinding at least one side of the semiconductor wafer, (f) treating the semiconductor wafer with an etchant, and (g) cleaning the semiconductor wafer. The unpolished semiconductor wafers have, on at least the front side, a reflectivity of 95% or more, a surface roughness of 3 nm or less, have a thickness of 80-2500 &#x3bc;m, an overall planarity value GBIR of 5 &#x3bc;m or less with an edge exclusion of 3 mm and a photolithographic resolution of at least 0.8 &#x3bc;m, and which furthermore contain a native oxide layer with a thickness of 0.5-3 nm on both sides.

Unpolished semiconductor wafer and method for producing an unpolished semiconductor wafer

A method and apparatus for pulling single crystals from a melt of semicontor material, in which a monocrystalline seed crystal grows to form a single crystal, the seed crystal being dipped into the melt and raised in a controlled manner in the vertical direction with respect to the melt, while the melt forms a molten pool which is held on a support body only by the surface tension and by electromagnetic forces due to an induction coil. This method includes recharging the melt with semiconductor material in solid or liquid form during the growth of the single crystal.

Method for pulling single crystals

A method for pulling silicon semiconductor rods, in particular having diaers of 10cm and over. The current methods of crucible-free float zoning or float zone pulling can be markedly improved if the molten cap like zone which develops is forced inwardly in the growth process. This is accomplished with the aid of electromagnetic forces in an annular zone situated opposite the coil slot. The electromagnetic forces can be achieved by using induction heating coils whose coil surface facing the molten cap is provided with annular segments whose thickness increases from their inner periphery ouotwardly and which are disposed opposite the coil slot above the peripheral region of the molten cap.

Method for the crucible-free floating zone pulling of semiconductor rods

A method for crucible-free zone pulling of silicon monocrystalline rods is described. According to the invention, a polycrystalline silicon rod obtained by crucible pulling according to the Czochralski procedure is used in lieu of the polycrystalline silicon rod produced by vapor deposition.

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Burghausen, Germany

Wolfgang Hensel