Mitsubishi Denki Kabushiki Kaisha

Taiyo Sanso Co., Ltd.

Taiyo Toyo Sanso Co., Ltd.

Other

Tsiyo Sanso Co., Ltd.

Masuo Tada

Takaaki Fukumoto

Toshiaki Ohmori

Takeki Hata

Itaru Kanno

Norio Yamazaki

Masashi Mizuno

Nobuyoshi Hattori

Mitsuhiro Ogawa

Tadashi Hyono

Hiroi Takahiko

Hiroyuki Oura

Kazuhiko Akamatsu

Super clean air having therein chemical components&mdash;such as hydrocarbons, organic halogens, acidic gases, basic gases, aldehydes, nitrogen oxides, and H,O (that is, all components other than oxygen, nitrogen, and noble gases&mdash;the types of chemical components differ depending on the source of the air)&mdash;in concentrations no more than 1 ppb and a dew point lower than &minus;40&deg; C., is obtained from the atmosphere by low-temperature adsorption treatment in stages at temperatures ranging from &minus;40&deg; C. to &minus;180&deg; C. Material air collected from the atmosphere is pretreated in a room-temperature adsorption step to remove moisture and carbon dioxide. The pretreated air is then low-temperature adsorption treated by absorbents in a plurality of steps to adsorb the gaseous chemical components, the treatment temperature being lower in each succeeding step. Treatment at &minus;40&deg; C. may remove, for example, HF, SO,, and/or NH,. Treatment at &minus;100&deg; C. may remove, for example, SF,, C,F,, H,S, and/or N,O. Treatment at &minus;150&deg; C. may remove, for example, CF,, NO, CH,, and/or CO. The last treatment step produces super clean air suitable for use in processing semiconductor wafers.

Method for producing super clean air

Super clean air suitable for use in a tunnel-type wafer transport system, etc., is produced efficiently with the specific energy consumption reduced and the yield improved by making good use of part of cooling energy and gas produced in a low temperature separation type nitrogen producing apparatus. Material air 1a collected from the atmosphere is pretreated in a room temperature adsorption tower 7, this pretreated air is adsorption treated at -60.degree. C. in a first low temperature adsorption tower 9, and the treated air 1c is further adsorption treated at -150.degree. C. in a second low temperature adsorption tower 10, thereby producing super clean air 1e containing not higher than 1 ppb of the chemical components other than nitrogen, oxygen and noble gases and having a dew point of not higher than -100.degree. C. The airs 1b and 1c are cooled in heat exchangers 12, 13 and 14 by utilizing cooling energy produced in the low temperature separation type nitrogen producing apparatus, that is, the low temperature gas 3f passed through an expansion turbine 38 from a rectifying tower 37.

Method and apparatus for producing super clean air

A two-fluid cleaning jet nozzle has an atomizing unit provided with an atomizing tube in which a liquid is atomized by a pressurized gas into liquid droplets, and an accelerating unit provided with an accelerating tube which accelerates and jets the liquid droplets against the surface of a workpiece to remove dust particles adhering to the surface of the workpiece. The sectional area of the atomizing tube available for gas flow is greater than the sectional area of the accelerating tube available for flow of the gas and the liquid droplets. The accelerating tube has the shape of a straight cylindrical tube or a Laval nozzle.

Two-fluid cleaning jet nozzle and cleaning apparatus, and method

A cleaning device for semiconductor wafers includes a cleaning vessel, a frozen particle supply unit, a jet nozzle for ejecting the frozen particles toward the semiconductor wafer supported within the cleaning vessel, an exhaust duct coupled to the cleaning vessel, and an exhaust blower. First and second exhausts guide to the exhaust duct frozen particles and contaminants from within the cleaning vessel near the wafer and near the walls of the vessel, respectively. The first exhaust includes a first exhaust guide pipe whose upper and lower ends open to an interior of the cleaning vessel near the wafer and to the exhaust duct, respectively. The second exhaust may include a tapered exhaust guide pipe surrounding the first exhaust guide pipe or a plurality of exhaust guide pipes disposed circumferentially uniformly around the first exhaust guide pipe.

Cleaning device for semiconductor wafers

A method in which a liquid is sprayed through a nozzle to form minute droplets of substantially uniform size. These uniform droplets are sprayed into and frozen by a refrigeration medium, such as liquid nitrogen, to form uniform diameter frozen particles. The frozen particles are ejected onto the surface of a substrate used in a liquid crystal display device to orient the liquid crystal material applied to the surface.

Method of preparing or rubbing a substrate to be used in a LCD device by

A cleaning method and a gettering method for semiconductor wafers comprises blasting frozen particles at the surface of a semiconductor wafer. A processing apparatus for a semiconductor wafer comprises means for forming ultrafine frozen particles and means for blasting the frozen particles at the surface of a semiconductor wafer to perform either the gettering or the cleaning of the semiconductor wafer. In one form of the invention, the frozen particles are formed by spraying a mist of water into a chamber partially filled with liquid nitrogen, which freezes the mist to form ice particles. In another form of the invention, the frozen particles are formed by spraying a mist of water into a chamber containing cold nitrogen gas, which freezes the mist to form ice particles. In another form of the invention, the frozen particles are formed by heating water to form water vapor and introducing the water vapor into a freezing chamber containing a two-phase mixture of a coolant which freezes the vapor into ultrafine particles. The frozen particles are blasted at a semiconductor wafer through a blasting nozzle by a gas such as nitrogen gas. When the frozen particles are used for gettering, they may further include nuclei of particles such as silica powder.

Processing method for semiconductor wafers

A cleaning method and a gettering method for semiconductor wafers comprises blasting frozen particles at the surface of a semiconductor wafer. A processing apparatus for a semiconductor wafer comprises means for forming ultrafine frozen particles and means for blasting the frozen particles at the surface of a semiconductor wafer to perform either the gettering or the cleaning of the semiconductor wafer. In one form of the invention, the frozen particles are formed by spraying a mist of water into a chamber partially filled with liquid nitrogen, which freezes the mist to form ice particles. In another form of the invention, the frozen particles are formed by spraying a mist of water into a chamber containing cold nitrogen gas, which freezes the mist to form ice particles. In another form of the invention, the frozen particles are formed by heating water to form water vapor and introducing the water vapor into a freezing chamber containing a two-phase mixture of a coolant which freezes the vapor into ultrafine particles. The frozen particles are blasted at a semiconductor wafer through a blasting nozzle by a gas such as nitrogen gas. When the frozen particles are used for gettering, they may further include abrasive particles such as silica powder.

Processing apparatus for semiconductor wafers

A solid surface cleaning device utilizes a jet of ice particles of ultrapure water for removing contaminants from a surface of a solid such as a semiconductor wafer. The electrical resistivity of ultrapure water stored in a tank is reduced by means of a gas such as dry air or carbon dioxide evolving into the water from a bubble tube disposed in the tank. The water whose resistivity is thus reduced is sprayed from a nozzle into an ice-making container which is refrigerated by the vaporization of a refrigerant discharged into the container. The fine ice particles that are thus generated in the container are sprayed and blasted from a jet spray nozzle onto the surface of the cleaned solid supported within a jet spray chamber. The air inside the chamber is exhausted by a blower together with the ice particles that have been ejected from the jet spray nozzle.

Ice particle forming and blasting device

A method for forming a fine unevenness over a surface of a base plate (9) for a magnetic disc comprises the step of bombarding the surface of the base plate (9) with a jet of gas mixed with fine ice particles (4) that are formed by mixing a flow of fine pure water droplets from a spray (2) and a counter directed flow of nitrogen gas cooled by being bubbled through a quantity of liquid nitrogen held in a reservoir (6). The obtained unevenness can be controlled by varying the size of the ice particles, the jet pressure, the distance between the jet nozzle providing the size of the ice particle jet and the receiving surface of base plate (9), the duration of spraying and the spraying angle with respect to the base plate.

Method of processing base plate for magnetic disc

A method for the production of microfine frozen particles comprises filling a vessel with a cold gas which may be a cooled gas or mixed gas obtainable by mechanical refrigeration of a refrigerant gas, air, or the like, atomizing a material to be frozen, such as water, into the cold gas so that the atomized particles become frozen by heat exchange with the cold gas, and collecting the fine frozen particles thus produced. An apparatus for carrying out the method comprises a heat-insulated vessel, a screen dividing the inside of the vessel into a region of cold gas phase and a region of cold gas source, an atomizer for atomizing a material to be frozen into the region of cold gas phase, and a means for filling the region of cold gas phase with a cold gas whether by generating a refrigerant gas by injecting nitrogen gas or the like into a refrigerant contained in the region of cold gas source, or by supplying a cool gas, such as mechanically refrigerated air, to the region of cold gas source, or by ejecting a refrigerant together with a cooled gas into the region of cold gas source, and apparatus for collecting frozen particles.

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Yao, Japan

Masuo Tada