Tosoh Corporation

Tosoh Quartz Corporation

Nippon Silica Glass Co., Ltd.

Tosoh Sgm Corporation

Tosoh Smg Corporation

Shinkichi Hashimoto

Yoshinori Harada

Tomoyuki Akiyama

Koji Tsukuma

Kazuyoshi Arai

Tsutomu Takahata

Nobusuke Yamada

Yoshikazu Kikuchi

Hideaki Segawa

Hideaki Kiriya

Masakazu Kudoh

Shuzo Mizutani

Naoki Miura

Katsufumi Takahashi

Hideki Kiyohara

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

Highly durable silica glass containing 0.01% to 2% by weight of at least one element selected from magnesium, calcium, strontium, barium, yttrium, hafnium and zirconium. The silica glass is produced by melting a powdery material comprising a finely divided silica powder and a finely divided zirconium-containing substance by oxyhydrogen flame or plasma are to form an accumulated molten material layer, and extending the molten material layer outwardly in radial directions.

Highly durable silica glass, process and apparatus for producing same, and member and apparatus provided with same

A high-purity transparent silica glass containing Fe, Na and K impurities each in an amount of 0.01-0.3 ppm, and an OH group in an amount of 0-3 ppm; among the Fe impurities, the content of metallic Fe having a valency of +0 being not larger than 0.1 ppm. This transparent silica glass exhibits, even when it is maintained at 900-1,400.degree. C. for at least 20 hours, an extinction coefficient of not larger than 0.009 at a wavelength of 400 nm, and does not become colored as visually examined. The silica glass is made by a process wherein powdery silica filled in a mold cavity is melted at 1,700.degree. C. or higher, characterized in that the melting is conducted in a graphite mold having a porous high-purity graphite layer provided on the mold inner surface so that the filled silica is not contacted with the mold; said porous layer having a bulk density of 0.1-1.5 g/cm.sup.3, and the content of each of Fe, Na and K impurities in the porous layer being not larger than 1 ppm.

High purity transparent silica glass

Growing community of inventors

Sagamihara, Japan

Shinkichi Hashimoto