Nanophase, Schott Develop Nanomaterials

ROMEOVILLE, Ill., May 6 -- Nanophase Technologies Corp., a developer of nanomaterials and nanoengineered products, and Schott Lithotec AG, of Meiningen, Germany, have developed nanomaterials that improve the surface finish of photomask blanks used for integrated circuit production.

Nanophase will present a paper on the results of their partnership, "Nanocrystalline Ceria Dispersions for Ultrafine Polishing and Defect Reduction in EUVL (Extreme Ultraviolet Lithography) Photomask Blank Manufacture," at Optifab 2003, May 20-22 in Rochester, N.Y.

The companies developed the materials and process parameters to allow for final-stage, ultrafine polishing of quartz glass and low thermal expansion material photomask blanks, which are used to transfer precision images of an integrated circuit onto a silicon wafer. They said the program achieved an acceptable removal rate while meeting the extreme "roughness" and "flatness" requirements for next-generation photomasks. Roughness, the peak-to-valley (P-V) heights over short distances, measured approximately three angstroms, and flatness, the P-V over broad areas of the substrate, measured approximately 34 angstroms. They said the process produced essentially zero defects, or "microscratches."

Schott Lithotec introduced advanced technology steps to manufacture quartz glass substrates and EUV mask blanks in its plant -- including high-quality substrate polishing, special cleaning steps and low-defect blank manufacturing. Nanophase engineered the ceria nanomaterial to obtain the required average particle size and tight distribution, and said its NanoArc synthesis process produced the nanocyrstalline ceria used for the application and created unique nanoparticle surface chemistry to obtain a very stable dispersion of the nanomaterial.

For more information, visit: www.nanophase.com