Saint-gobain Ceramics & Plastics, Inc.

Robert A Rizzuto

Brahmanandam V Tanikella

Ramanujam Vedantham

Matthew A Simpson

Palaniappan Chinnakaruppan

Isaac K Cherian

Elizabeth Thomas

Jadwiga Jaroniec

Eric Virey

Frank L Csillag

A sapphire substrate includes a generally planar surface having a crystallographic orientation selected from the group consisting of a-plane, r-plane, m-plane, and c-plane orientations, and having a nTTV of not greater than about 0.037 &#x3bc;m/cm, wherein nTTV is total thickness variation normalized for surface area of the generally planar surface, the substrate having a diameter not less than about 9.0 cm.

Sapphire substrate

Sapphire substrates and methods of making same

Wafer suitable for semiconductor deposition application can be fabricated to have low bow, warp, total thickness variation, taper, and total indicated reading properties. The wafers can be fabricated by cutting a boule to produce rough-cut wafers, lapping the rough-cut wafers, etching the lapped wafers to remove a defect, deformation zone and relieve residual stress, and chemically mechanically polishing the etched wafers to desired finish properties. Etching can be performed by immersion in a heated etching solution comprising sulfuric acid or a mixture of sulfuric and phosphoric acids. A low pH slurry utilized in chemical mechanical polishing of the spinel wafer can comprise &#x3b1;-AlOand an organic phosphate.

Spinel wafers and methods of preparation

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Worcester, MA, United States of America

Robert A Rizzuto