Ebara Research Co., Ltd.

Kazuhiko Sakamoto

Toshiaki Fujii

Hidetomo Suzuki

Tsukuru Suzuki

Naoaki Ogure

A method and apparatus for preventing contamination of a substrate or a substrate surface, and particularly relates to prevention of contamination of raw materials, semi-finished products, base materials of products and substrate surface in a high-tech industry such as an in the production of semiconductors and liquid crystals. A gas coming into contact with a base material or substrate is purified by dust removing apparatus and adsorption and/or absorption apparatus so that the concentration of fine particles in the gas is below class 1,000 and a non-methane hydrocarbon concentration is below 0.2 ppm. Thereafter, the base material or the substrate surface is exposed to this gas.

Method and apparatus for the preparation of clean gases

A method and apparatus for preventing contamination of a substrate or a substrate surface, and particularly relates to prevention of contamination of raw materials, semi-finished products, base materials of products and substrate surface in a high-tech industry such as in the production of semiconductors and liquid crystals. A gas coming into contact with a base material or substrate is purified by dust removing apparatus and adsorption and/or absorption apparatus so that the concentration of fine particles in the gas is below class 1,000 and a non-methane hydrocarbon concentration is below 0.2 ppm. Thereafter, the base material or the substrate surface is exposed to this gas.

Cleaning a closed space such as safety cabinets, clean boxes, safes and wafer storage spaces are performed by irradiating a photoelectron emitting member with ultraviolet rays and/or other forms of radiation to emit photoelectrons into the closed space, electrically charging the fine particles in the closed space with the emitted photoelectrons, and removing the charged fine particles from the closed space.

Method for cleaning closed spaces with ultraviolet rays

A photoelectron emitting member and method of electrically charging fine particles with photoelectrons, wherein the member includes a matrix that is at least composed of a material capable of transmitting ultraviolet rays and a material that is provided on the surface of the matrix or in its neighborhood and which emits photoelectrons upon irradiation with ultraviolet rays or sunlight. The member emitting photoelectrons upon irradiation with ultraviolet rays or sunlight is disposed in an electric field from the side opposite to the irradiated side. The member permits efficient utilization of the energy of ultraviolet rays. When sunlight is applied to the member to have it emit photoelectrons, particles can be electrically charged with energy costs being reduced to substantially zero.

Photoelectron emitting member and method of electrically charging fine

A photoelectron emitting member having a multiplex structure comprises a matrix and a protective film. The matrix being selected from the group consisting of elements, inorganic compounds, alloys, mixtures thereof and composites thereof which emit photoelectrons upon exposure to uv rays and other forms of radiation, the protective film comprising at least one material selected from the group consisting of metals, metallic compounds, plastics, polycyclic aromatic hydrocarbon, derivatives thereof or a mixture thereof which is film-forming and not thicker than 0.2 .mu.m. The member can be used in a consistent way over a prolonged period as well as being capable of effective emission of photoelectrons. Fine particles electrically charged with photoelectrons which are emitted upon applying uv rays and/or other forms of radiation to the photoelectron emitting member, can be used in various applications such as (a) separation and classification of fine particles, as well as modifying their surfaces and controlling an electrically charged amount thereof; (b) the measurement of the concentration and size of fine particles in gases such as air and waste gases by using electrically charged fine particles; and (c) trapping and removal of charged fine particles to produce clean gases.

Growing community of inventors

Saitama-ken, Japan

Kazuhiko Sakamoto