Tosoh Corporation

Tosoh Sgm Corporation

Tosoh Quartz Corporation

Tsutomu Takahata

Kazuyoshi Arai

Yoshinori Harada

Osamu Matsunaga

Nobusuke Yamada

Hideaki Kiriya

Shinkichi Hashimoto

Satoshi Kurosawa

Hideharu Horikoshi

Shinkichi Hasimoto

Masahito Uchida

Osamu Mochizuki

Yuichi Nagasaki

Masato Uchida

Fused silica glass having an internal transmittance of UV with 245 nm wavelength, being at least 95% at 10 mm thickness, a OH content of not larger than 5 ppm, and a content of Li, Na, K, Mg, Ca and Cu each being smaller than 0.1 ppm. Preferably the glass has a viscosity coefficient at 1215&#xb0; C. of at least 10Pa&#xb7;s; and a Cu ion diffusion coefficient of not larger than 1&#xd7;10cm/sec in a depth range of greater than 20 &#x3bc;m up to 100 &#x3bc;m, from the surface, when leaving to stand at 1050&#xb0; C. in air for 24 hours. The glass is made by cristobalitizing powdery silica raw material; then, fusing the cristobalitized silica material in a non-reducing atmosphere. The glass exhibits a high transmittance of ultraviolet, visible and infrared rays, has high purity and heat resistance, and exhibits a reduced diffusion rate of metal impurities, therefore, it is suitable for various optical goods, semiconductor-production apparatus members, and liquid crystal display production apparatus members.

Fused silica glass and process for producing the same

Highly durable silica glass comprising silica having incorporated therein aluminum and at least one element (M) selected from group 2A elements, group 3A elements and group 4A elements of the periodic table. Preferably, the sum of aluminum and element (M) is at least 30 atomic % based on the amount of total metal elements in the silica glass, and the atomic ratio of aluminum to element (M) is in the range of 0.05 to 20. The silica glass has a high purity and exhibits enhanced durability while good processability and machinability, and reduced dusting property are kept, and the glass is suitable for members of a semiconductor production apparatus or liquid crystal display production apparatus using a halogenated gas and/or its plasma.

Highly durable silica glass, process for producing same, member comprised thereof, and apparatus provided therewith

A mixture of zinc sulfide and silicon dioxide as starting material powder mixed with zinc oxide in an amount of from 0.5 to 5 wt % is subjected to hot pressing sintering to obtain a sintered body. In this manner, a high density sputtering target using the sintered body can be obtained at a high yield.

Sputtering target and process for the preparation thereof

An indium oxide-tin oxide (ITO) sintered body is prepared by mixing a tin oxide powder with an indium oxide powder, molding the resulting mixed powder to obtain a green body, and sintering the resulting green body. At least the tin oxide powder has beforehand been pulverized by colliding tin oxide particles with each other or against a collision substance in gas streams. At least 90 wt % of the pulverized tin oxide powder is preferably particles having a particle size of 0.2-10 .mu.m. A jet mill can be used for the pulverization. The ITO sintered body has a density as high as 7.08 g/cm.sup.3 or more and, during sputtering, is free from nodule formation and is inhibited from generating particles.

Process for producing ITO sintered body

Growing community of inventors

Yokohama, Japan

Tsutomu Takahata