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US4932168A Expired / Lapsed US ⏱️ 0.0 years remaining

Processing apparatus for semiconductor wafers

Assignee: Taiyo Sanso Co Ltd
•
Filing: 1988-04-05
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Granted: 1990-06-12
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Expires: 2008-04-05
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Abstract

Abstract 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.

Inventors

  • 👤 Masuo Tada
  • 👤 Takeki Hata
  • 👤 Takaaki Fukumoto
  • 👤 Toshiaki Ohmori

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 17:09
CPC Classifications
H; H10; H10P; H10P70/00; H10P70/10; B; B08; B08B; B08B7/00; B08B7/0064; B08B7/0092; B24; B24C; B24C1/00; B24C1/003; B24C3/00; B24C3/32; B24C3/322; F; F25; F25C; F25C1/00; H10P36/00; H10P36/03; Y; Y10; Y10S; Y10S438/00; Y10S438/906

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 134 words
An apparatus for producing and propelling frozen particles against a surface comprising: a freezing chamber for containing a first gas and a first liquid at a temperature below the freezing point of a second liquid for freezing a mist of the second liquid to form frozen particles; a diffuser disposed in said chamber for injecting a second gas into the first liquid to produce waves in the first liquid; a reservoir for storing the second liquid; an atomizer in communication with said reservoir and said chamber for converting the second liquid from the reservoir into a mist in the gas in said chamber; a nozzle for directing the frozen particles formed from the mist in the freezing chamber against a surface; and means for propelling the frozen particles through and out of said nozzle.
Claim 2
Independent Claim 134 words
An apparatus for producing and propelling frozen particles against a surface comprising: a freezing chamber for containing a first gas and a first liquid at a temperature below the freezing point of a second liquid for freezing a mist of the second liquid to form frozen particles; a diffuser disposed in said chamber for injecting a second gas into the first liquid to produce waves in the first liquid; a reservoir for storing the second liquid; an atomizer in communication with said reservoir and said chamber for converting the second liquid from the reservoir into a mist in the gas in said chamber; a nozzle for directing the frozen particles formed from the mist in the freezing chamber against a surface; and means for propelling the frozen particles through and out of said nozzle.
Claim 3
Dependent Claim 34 words
The apparatus of claim 1 including a liquefied gas reservoir for storing a liquefied gas as the first liquid and means for supplying the liquefied gas from said liquefied gas reservoir to said chamber.
Claim 4
Dependent Claim 37 words
The apparatus of claim 2 including a heat exchanger in communication with said liquefied gas reservoir and said diffuser for converting the liquefied gas into the second gas and for supplying the second gas to said diffuser.
Claim 5
Dependent Claim 38 words
The apparatus of claim 3 wherein said means for propelling includes means interconnecting said heat exchanger with said nozzle for supplying the second gas to said nozzle for propelling the frozen particles through and out of the nozzle.
Claim 6
Dependent Claim 34 words
The apparatus of claim 3 wherein said heat exchanger is in communication with said atomizer for supplying the second gas to said atomizer for propelling the second liquid from the reservoir into said chamber.
Claim 7
Dependent Claim 19 words
The apparatus of claim 2 wherein said liquefied gas reservoir is a liquid nitrogen reservoir for storing liquid nitrogen.
Claim 8
Dependent Claim 18 words
The apparatus of claim 1 wherein said frozen particles have a diameter on the order of 20 microns.
Claim 9
Dependent Claim 23 words
The apparatus of claim 1 wherein said nozzle is disposed at an angle of 30° to 80° relative to a surface being cleaned.
Claim 10
Dependent Claim 18 words
The apparatus of claim 1 wherein the second liquid is water and the frozen particles are ice particles.
Claim 11
Dependent Claim 28 words
The apparatus of claim 1 including a storage hopper for storing the frozen particles, and means for conveying frozen particles from the first liquid to said storage hopper.
Claim 12
Dependent Claim 14 words
The apparatus of claim 10 wherein said means for conveying comprises a screw feeder.
Claim 13
Dependent Claim 29 words
A processing apparatus as claimed in claim 9 wherein said heating means comprises means for heating the wafer on a side opposite the frozen particles to a prescribed temperature.

References Cited (Backward Citations)

US2699403A Cited
US3162019A Cited
GB1397102A Cited
US4073158A Cited
US4402193A Cited
US4389820A Cited
US4655847A Cited
US4731125A Cited
US4806171A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1993-06-11 1993-12-11 1994-06-12 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1997-06-11 1997-12-11 1998-06-12 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2001-06-11 2001-12-11 2002-06-12 $7700.00 Window Closed / Lapsed

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