Abstract: To provide a quartz glass tool, for silicon wafer heat treatment, having a transparent grooving face, which is free from the deposition of particles of a transition metal element foreign material derived from glass dust or diamond blade produced by breakdown of acute irregularities based on opening of very small concaves and convexes and microcracks, causes no significant change in dimension also in cleaning with hydrofluoric acid, and can maintain a high degree of cleanness even after use of a long period of time, and to provide a process for producing the same. A quartz glass tool for silicon wafer heat treatment, comprising a wafer mounting member having a grooving face formed by machining, characterized in that the whole grooving face of the wafer mounting member is transparent, the surface roughness is 0.03 to 0.3 ?m in terms of center line average roughness (Ra) and 0.2 to 3.

Abstract: To provide a quartz glass tool, for silicon wafer heat treatment, having a transparent grooving face, which is free from the deposition of particles of a transition metal element foreign material derived from glass dust or diamond blade produced by breakdown of acute irregularities based on opening of very small concaves and convexes and microcracks, causes no significant change in dimension also in cleaning with hydrofluoric acid, and can maintain a high degree of cleanness even after use of a long period of time, and to provide a process for producing the same. A quartz glass tool for silicon wafer heat treatment, comprising a wafer mounting member having a grooving face formed by machining, characterized in that the whole grooving face of the wafer mounting member is transparent, the surface roughness is 0.03 to 0.3 ?m in terms of center line average roughness (Ra) and 0.2 to 3.

Abstract: A light-weight base body of a reflecting mirror, such as those used in reflecting astronomical telescopes, is proposed which is made from fused silica glass or high-silica glass and is advantageous in respect of the excellent thermal and mechanical stability in dimensions to ensure high performance of the reflecting mirror. The base body is composed of a front plate, i.e. a surface plate to provide the optical surface, and a supporting body of porous foamed glass integrally bonded to the front plate. These two parts of the base body can be bonded together by sandwiching a layer of a finely divided silica powder therebetween and heating the assemblage at a temperature higher than the softening point of the silica powder so that the silica powder is softened or melted to firmly join the two parts sandwiching the powder layer.

Abstract: A light-weight base body of a reflecting mirror, such as those used in reflecting astronomical telescopes, is proposed which is made from fused silica glass or high-silica glass and is advantageous in respect of the excellent thermal and mechanical stability in dimensions to ensure high performance of the reflecting mirror. The base body is composed of a front plate, i.e. a surface plate to provide the optical surface, and a supporting body of porous foamed glass integrally bonded to the front plate. These two parts of the base body can be bonded together by sandwiching a layer of a finely divided silica powder therebetween and heating the assemblage at a temperature higher than the softening point of the silica powder so that the silica powder is softened or melted to firmly join the two parts sandwiching the powder layer.

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: A vertical wafer supporting boat is provided in which adequate reaction gas is supplied to the portion of a wafer surface to be treated which is inserted in holding grooves in members of the wafer supporting boat during the heat treatment and thus uniform heat treatment is achieved across the surface of each wafer. The particular groove shape preferably exploits the rotation of the boat in a vertical furnace to thereby uniformly supply the reaction gas on the entire surface to be treated of each of the wafers disposed in the boat. The holding grooves are inclined relative to a direction tangent to a wafer edge in order that the clearance facing the surface to be treated of a wafer is profiled to have an edge-like space by gradually increasing the width in the tangential direction of the wafer and, preferably, the internal groove surface opposed to the surface to be treated of the wafer is inclined to increase in width toward the center of the wafer.

Abstract: A light-weight base body of a reflecting mirror, such as those used in reflecting astronomical telescopes, is proposed which is made from fused silica glass or high-silica glass and is advantageous in respect of the excellent thermal and mechanical stability in dimensions to ensure high performance of the reflecting mirror. The base body is composed of a front plate, i.e. a surface plate to provide the optical surface, and a supporting body of porous foamed glass integrally bonded to the front plate. These two parts of the base body can be bonded together by sandwiching a layer of a finely divided silica powder therebetween and heating the assemblage at a temperature higher than the softening point of the silica powder so that the silica powder is softened or melted to firmly join the two parts sandwiching the powder layer.

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.