Taiyo Sanso Co., Ltd.

Mitsubishi Denki Kabushiki Kaisha

Tsiyo Sanso Co., Ltd.

Takeki Hata

Masuo Tada

Takaaki Fukumoto

Toshiaki Ohmori

Norio Yamazaki

Sekiji Imaike

Hiroyuki Oura

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 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.

Method and apparatus for producing microfine frozen particles

A method of producing microfine frozen particles from water, liquid drugs, juices, etc. comprises the steps of atomizing a mixture of a liquid with a gas and directing the mixture toward a body of a refrigerant liquid whose surface is stirred by application of kinetic energy to form ripples. The refrigerant liquid being liquid nitrogen, liquid air, a cooled organic solvent or the like, so that the atomized liquid undergoes heat exchange with the refrigerant liquid to form fine frozen particles. An apparatus for practicing the method, comprises a vessel for containing the refrigerant liquid, apparatus for forming ripples at the surface of the refrigerant liquid by injecting a gas, or by applying vibrations to the vessel or the refrigerant liquid, an atomizer functioning as a mixer and atomizer for a liquid and a gas, and an apparatus for collecting the microfine frozen particles from the refrigerant liquid.

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Kobe, Japan

Takeki Hata