Quartz substrates: options, life, quality

At present, the production of the 64K devices has been accelerated. The R/D manufacturing of the 256K is almost complete and production has begun in the US and Japan. In the making of these types of VLSI, especially the 256K, quartz masks have been predominately used for wafer fabrication, utilizing the wafer stepper and project aligner. Also, the characteristics of the quartz glass with extremely low thermal expansion and high transmittance to DUV light, allows it to be used for contact printing.