Abstract: A quartz glass component having a projection on a flat face is manufactured by molding a quartz glass body at a high temperature and under high pressure. The heating temperature is set to a range of from 1800.degree. to 2000.degree. C. and slight pressure is applied by the female die which forms the projection, or pressure in a direction against gravity. The molding die includes a graphite frame surrounding a molding space formed by a female die and a receiving die sandwiching the quartz glass body in the graphite frame. The space between the receiving die and the female die is width-reducible, the compositions of the graphite frame and the two graphite dies are made to differ, the female die and receiving die contacting the quartz glass body during pressure molding have a plurality of gas-permeable micropores such as in sintered graphite for example and are formed by a high-purity graphite material having air permeability.

Abstract: A reactor vessel includes a quartz glass body having sidewalls and a ceiling formed as a single unit without welds. Translucent or opaque portions are formed by bubbles in the glass where heat insulation is desired and transparent portions are formed by absence of bubbles where heat transmission and visibility are desired. The body is formed by adding quartz glass powder to a mold which is rotated about a central axis so that centrifugal force causes a layer of powder to form on the inside of the mold. The layer is then heated until it melts.

Abstract: A rotating cylindrical quartz glass tube is partitioned into at least 3 chambers comprising a pre-heating chamber, a reaction chamber, and a gas desorption chamber. The process comprises pre-heating the starting quartz powder by continuously supplying it into the pre-heating chamber, refining the powder by transferring it into the reaction chamber in which the powder is brought into contact with a chlorine-containing gas atmosphere, and transferring the powder into the gas desorption chamber; the chambers may be partitioned using a sectioning plate having an opening. Alkali metal elements such as sodium and potassium, as well as transition metal elements such as iron, copper, chromium, and nickel are removed from a powder of naturally occurring quartz. The process also removes alkaline earth metal elements such as magnesium and calcium. Furthermore, it is of high productivity because it can be operated continuously to yield high purity quartz powder at a low cost.

Abstract: It is an object of the present invention to provide a vertical heat treatment apparatus having a heat insulator, which has sufficient heat insulation, heat retention and high load pressure bearing properties to cope with increased size dimensions and number of layers of wafer workpieces and can be particularly advantageously used as a semiconductor and TFT substrate heat treatment apparatus. The apparatus features the use of a heat insulator casing 40 supporting a substrate holder 3 on its top and receiving a heat insulator 50 having numerous inner microspaces in its lower space, and defining a substrate holder or boat insulator receiving space A and a heat insulator receiving space B such that these spaces are hermetically sealed with respect to each other by the heat insulator casing.

Abstract: Method and apparatus for supplying a gaseous raw material to plural users. A liquid raw material is evaporated by a single evaporation means and supplied to a gaseous raw material takeout portion provided with a plurality of takeout ports. The gas pressure is varied according to amounts of the gaseous raw material taken out of the takeout ports. The pressure variations are regulated by a main pressure-adjusting means mounted downstream of the gaseous raw material takeout portion. Extra gaseous raw material is sent to a gaseous raw material-condensing means, where the material is liquified. Then, the liquified material is fed back to the evaporation means. Thus, a closed circulatory loop circuit is formed. The gas pressure in the gaseous raw material takeout portion is regulated. The gaseous raw material is distributed to plural users at any desired time at their respective flow rates such that supply of the raw material to each individual user is carried out independent of supply to other users.

Abstract: It is an object of the present invention to provide a vertical heat treatment apparatus having a heat insulator, which has sufficient heat insulation, heat retention and high load pressure bearing properties to cope with increased size dimensions and number of layers of wafer workpieces and can be particularly advantageously used as a semiconductor and TFT substrate heat treatment apparatus. The apparatus features the use of a heat insulator casing 40 supporting a substrate holder 3 on its top and receiving a heat insulator 50 having numerous inner microspaces in its lower space, and defining a substrate holder or boat insulator receiving space A and a heat insulator receiving space B such that these spaces are hermetically sealed with respect to each other by the heat insulator casing.

Abstract: This invention relates to an optical member made of highly transparent, high-purity synthetic silica glass, to a method for manufacturing a blank or an optical member of such glass, and to the optical members themselves. The optical members have an absolute refractive index, n.sub.d, of 1.460 or more and a hydrogen molecule concentration of at least 5.times.10.sup.16 molecules/cm.sup.3 uniformly distributed throughout the glass and are particularly well suited for use in apparatus in which they are exposed to a high-power laser beam such as that produced by an excimer laser.

Abstract: The invention relates to lenses, prisms or other optical members which are subjected to high-power ultraviolet light having a wavelength of about 360 nm or less, or ionizing radiation, particularly optical members for use in laser exposure apparatus for lithography, and to blanks for such optical members. The homogeneity of the refractive index distribution and the resistance to optical deterioration when the optical members are exposed for a long period of time to short wavelength ultraviolet light from a laser beam are improved. The optical members are made of high-purity synthetic silica glass material containing at least about 50 wt. ppm of OH groups, and are doped with hydrogen.

Abstract: A quartz glass crucible for use in a process for pulling a single crystal silicon and having an outer layer and an inner layer. The outer layer contains less than 0.3 ppm each of Na, K and Li and more thant 5 ppm of Al. The outer layer further contains bubbles to present an opaque appearance. The inner layer is made by melting powders of high purity non-crystalline synthetic silica and contains less then 200 ppm of OH group. There is also disclosed a method for producing the crucible.

Abstract: The invention relates to lenses, prisms or other optical members which are subjected to high-power ultraviolet light having a wavelength of about 360 nm or less, or ionizing radiation, particularly optical members for use in laser exposure apparatus for lithography, and to blanks for such optical members. The homogeneity of the refractive index distribution and the resistance to optical deterioration when the optical members are exposed for a long period of time to short wavelength ultraviolet light from a laser beam are improved. The optical members are made of high-purity synthetic silica glass material containing at least about 50 wt. ppm of OH groups, and are doped with hydrogen.

Abstract: A quartz glass crucible adapted for use in a process for pulling a single crystal semiconductor material having an opaque outer substrate of a quartz glass with a relatively high bubble content and an inner transparent glass layer which is substantially free from bubbles. The crucible is produced while the substrate is supported by a rotating mould by forming an atmosphere of high temperature gas and supplying a metered quantity of powders of quartz to the high temperature gas atmosphere to have the quartz powders molten at least partly and directed toward an inner surface of the substrate to be adhered thereon.

Abstract: A quartz glass crucible adapted for use in a process for pulling a single crystal semiconductor material having an opaque outer substrate of a quartz glass with a relatively high bubble content and an inner transparent glass layer which is substantially free from bubbles. The crucible is produced while the substrate is supported by a rotating mould by forming an atmosphere of high temperature gas and supplying a metered quantity of powders of quartz to the high temperature gas atmosphere to have the quartz powders molten at least partly and directed toward an inner surface of the substrate to be adhered thereon.