Wacker-chemitronic Gesellschaft Fur Elektronik-grundstoffe Mbh

Siltronic Ag

Wacker Siltronic Gesellschaft F&uuml;r Halbleiter Materialien Ag

Karlheinz Langsdorf

Maximilian Stadler

Gerhard Brehm

Johann Niedermeier

G&uuml;nter Schwab

Johann Glas

Günter Schwab

Diego Feijóo

Edeltraut Pichelmeier

Semiconductor wafers are cut from a crystal and subjected to a series of processing steps in which material is removed from a front side and a rear side of the semiconductor wafers, comprising the following processing steps:

Method for producing a polished semiconductor

A process for the wet-chemical surface treatment of a semiconductor wafer following a mechanical surface treatment, in particular following a mechanical surface treatment in a lapping machine, includes a sequence of treatment steps. The process essentially includes a wet-chemical surface cleaning, preferably for neutralizing and eliminating the lapping slurry, an acid etching treatment, preferably for eliminating the mechanically imposed damage and for surface smoothing and removal of metals. There is a final step of drying and rendering the cleaned and etched surface hydrophilic.

Process for the wet-chemical surface treatment of a semiconductor wafer

Ingot-type semiconductor single crystals having diameters of more than 200 m can be sawed into thin wafers using an annular saw if the crystal is fed towards the cutting edge of the annular saw while rotating around its longitudinal axis. The method includes having a wafer sawed out in this way until a residual joint is created between a wafer and the end face of the ingot. Ingot and wafer are finally separated by means of a residue separation technique which leaves behind various central material projections on the ingot and the wafer. Particularly suitable for residue separation are torsion separation and separation by a wire saw. This procedure reliably prevents the frequently observable, uncontrollable breaking-off of the wafer in the final phase of the annular sawing if this is exclusively used as the method of separation. The method, whose final step involves the removal of the material projection on the wafer by rotation grinding, proves to be particularly suitable for crystals having diameters of more than 200 mm. In this case, the material saving is exceedingly high as a result of the absence of chips from the ingot or wafer as a consequence of uncontrolled breaking-off of the wafer.

Method and apparatus for the rotary sawing of brittle and hard materials

A process for the sawing of crystal rods or blocks into thin wafers by innal-hole saws is specified. In this process, the deviation of the saw blade from the intended cutting line, occurring in virtually every sawing operation, is countered by the force of a fluid being applied, at least periodically, to the side surfaces of the blade. This allows the force conditions in the saw cut and thus the deflection of the saw blade, to be influenced. This process results in an improved geometrical quality of the wafers obtained and in prolonged service life of the saw blades which have to be resharpened less often.

Process for sawing crystal rods or blocks into thin wafers

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Burghausen, Germany

Karlheinz Langsdorf