Shin-Etsu Quartz Products Co., Ltd.

Heraeus Quarzglas Gmbh & Co Kg

Tsukasa Sakaguchi

Akira Sato

Akira Fujinoki

Hiroyuki Nishimura

Hiroshi Matsui

Rainer Koeppler

Fritz-Ulrich Kreis

Klaus Arnold

Kasumi Hoshikawa

Disclosed is a printed wiring board which attains aims of printed wiring boards required for realizing high-speed, high-frequency semiconductor devices, namely a printed wiring board having low dielectric constant, low dielectric loss tangent and low linear expansion coefficient. Also disclosed is a composite woven fabric suitably used as a base material for such a printed wiring board. Specifically disclosed is a composite woven fabric containing quartz glass fibers and polyolefin fibers, in which the ratio of the quartz glass fibers to the composite woven fabric is set at 10 vol % or more and 90 vol % or less. It is preferred that the quartz glass fibers each have a filament diameter of 3 &#x3bc;m or more and 16 &#x3bc;m or less, and the composite woven fabric has a thickness of 200 &#x3bc;m or less.

Composite woven fabric and printed wiring board

The granule consists of individual granules approximately spherical in shape, having a pore volume of 0.5 cm, a mean diameter of pores of 50 nm or less, a specific surface area of 100 m/g or less, and a bulk density of 0.7 g/cmor higher. It is produced by dispersing a fumed silica obtained by hydrolysis of a silicon compound into pure water to obtain a slurry, and drying the slurry. The granule is used for producing high purity synthetic quartz glass powder. The method further comprises: a first heat treatment under an oxygen-containing atmosphere, a second heat treatment in a temperature range of from 600 to 1100&#xb0; C., and a third heat treatment in a temperature range of from 1100 to 1300&#xb0; C. under an atmosphere containing hydrogen chloride; and a step of densification comprising calcining the product at a temperature not higher than 1500&#xb0; C. under vacuum or in an atmosphere of gaseous hydrogen or gaseous helium. To calcine the powder without causing fusion adhesion of the particles, bubbling fluidization of said porous silica granule is conducted by supplying gaseous helium and calcining thereof in a temperature range of from 1000 to 1600&#xb0; C.

Porous silica granule, method for producing the same, and method for producing synthetic quartz glass powder using the porous silica granule

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Koriyama, Japan

Tsukasa Sakaguchi