Patent US5496778A successfully refreshed from Google Patents.
US5496778A
Expired / Lapsed
US
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Point-of-use ammonia purification for electronic component manufacture
Assignee: LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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Filing: 1994-01-07
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Granted: 1996-03-05
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Expires: 2014-01-07
Abstract
Abstract Highly purified ammonia for use in processes for the production of high-precision electronic components is prepared on-site by drawing ammonia vapor from a liquid ammonia reservoir, passing the vapor through a filter capable of filtering out particles of less than 0.005 micron in size, and scrubbing the filtered vapor in a high-pH aqueous scrubber.
Inventors
- 👤 Joe G. Hoffman
- 👤 R. Scot Clark
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:40
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0402; H10P72/0404; C; C01; C01B; C01B7/00; C01B7/01; C01B7/07; C01B7/0706; C01B7/0712; C01B7/0731; C01B7/19; C01B7/191; C01B7/195; C01B7/196; C01B7/197; C01B7/198; C01C; C01C1/00; C01C1/02; C01C1/024; C01C1/16; C01C1/162; Y; Y10; Y10S; Y10S203/00; Y10S203/17
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
90 words
A system for the preparation of ultra-high purity ammonia, said system comprising: (a) a reservoir of liquid ammonia with a vapor space above said liquid ammonia; (b) means for drawing vapor containing ammonia gas from said vapor space; (c) a filtration membrane removing particles greater than 0.005 micron from vapor thus drawn; and (d) an aqueous ammonia scrubber containing an aqueous solution of ammonia in deionized water, arranged to contact filtered vapor having passed through said filtration membrane with said aqueous solution, the vapor thus scrubbed being purified ammonia gas.
Claim 2
Independent Claim
90 words
A system for the preparation of ultra-high purity ammonia, said system comprising: (a) a reservoir of liquid ammonia with a vapor space above said liquid ammonia; (b) means for drawing vapor containing ammonia gas from said vapor space; (c) a filtration membrane removing particles greater than 0.005 micron from vapor thus drawn; and (d) an aqueous ammonia scrubber containing an aqueous solution of ammonia in deionized water, arranged to contact filtered vapor having passed through said filtration membrane with said aqueous solution, the vapor thus scrubbed being purified ammonia gas.
Claim 3
Dependent Claim
20 words
A system in accordance with claim 1, further comprising a distillation column arranged to distill vapor emerging from said scrubber.
Claim 4
Independent Claim
248 words
A system for the manufacture of a high-precision electronic component, said system comprising: (a) a production line containing a plurality of workstations successively arranged for treating a workpiece to be formed into said electronic component, one such workstation selected for application of ammonia to said workpiece; (b) means for conveying said workpiece to said workstations in succession along said production line; and (c) a subunit adjoining said production line at said selected workstation to supply said ammonia in ultra-high purity form, said subunit comprising: (i) a reservoir of liquid ammonia with a vapor space above said liquid ammonia; (ii) means for drawing vapor containing ammonia gas from said vapor space; (iii) a filtration membrane removing particles greater than 0.005 micron from vapor thus drawn; and (iv) a scrubber arranged to contact filtered vapor having passed through said filtration membrane with an aqueous solution of ammonia in deionized water, the vapor thus scrubbed being purified ammonia gas; and (d) means for applying the product of step (c) directly to a workpiece at said workstation; said production line, said conveying means and said subunit all being free of contamination by semiconductor manufacturing standards defined as a resistivity of at least about 15 megohm-cm at 25° C., less than about 25 ppb of electrolytes, a particulate content of less than about 150/cm 3 and a particle size of less than 0.2 micron, a microorganism content of less than about 10/cm 3 , and total organic carbon of less than 100 ppb.
Claim 5
Independent Claim
248 words
A system for the manufacture of a high-precision electronic component, said system comprising: (a) a production line containing a plurality of workstations successively arranged for treating a workpiece to be formed into said electronic component, one such workstation selected for application of ammonia to said workpiece; (b) means for conveying said workpiece to said workstations in succession along said production line; and (c) a subunit adjoining said production line at said selected workstation to supply said ammonia in ultra-high purity form, said subunit comprising: (i) a reservoir of liquid ammonia with a vapor space above said liquid ammonia; (ii) means for drawing vapor containing ammonia gas from said vapor space; (iii) a filtration membrane removing particles greater than 0.005 micron from vapor thus drawn; and (iv) a scrubber arranged to contact filtered vapor having passed through said filtration membrane with an aqueous solution of ammonia in deionized water, the vapor thus scrubbed being purified ammonia gas; and (d) means for applying the product of step (c) directly to a workpiece at said workstation; said production line, said conveying means and said subunit all being free of contamination by semiconductor manufacturing standards defined as a resistivity of at least about 15 megohm-cm at 25° C., less than about 25 ppb of electrolytes, a particulate content of less than about 150/cm 3 and a particle size of less than 0.2 micron, a microorganism content of less than about 10/cm 3 , and total organic carbon of less than 100 ppb.
Claim 6
Dependent Claim
24 words
A system in accordance with claim 3 in which said subunit further comprises a distillation column arranged to distill vapor emerging from said scrubber.
Claim 7
Dependent Claim
29 words
A system in accordance with claim 3 in which said subunit further comprises means for combining said purified ammonia gas with purified water to form an aqueous ammonia solution.
Claim 8
Dependent Claim
37 words
A system in accordance with claim 3 further comprising an ammonia outlet on said scrubber, said ammonia outlet positioned within approximately 30 cm of said means for applying the product of step (c) directly to said workpiece.
Claim 9
Dependent Claim
31 words
A system in accordance with claim 3 in which said subunit is sized to produce said purified ammonia gas at a rate of from about 200 cc/h to about 2 L/h.
Claim 10
Dependent Claim
24 words
A system in accordance with claim 3 in which components (ii), (iii) and (iv) of said subunit are arranged for continuous or semi-continuous flow.
Claim 11
Independent Claim
100 words
A method for supplying a high-purity ammonia reagent to a workstation in a production line for the manufacture of a high-precision electronic component, said method comprising: (a) drawing ammonia gas from a vapor space above liquid ammonia in an ammonia-containing reservoir; (b) passing said ammonia gas through a filtration membrane removing particles greater than 0.005 micron therefrom; (c) passing said ammonia gas thus filtered through a scrubber wherein said ammonia gas is contacted with an aqueous solution of ammonia in deionized water; and (d) recovering said ammonia gas emerging from said scrubber and directing said ammonia gas to said workstation.
Claim 12
Independent Claim
100 words
A method for supplying a high-purity ammonia reagent to a workstation in a production line for the manufacture of a high-precision electronic component, said method comprising: (a) drawing ammonia gas from a vapor space above liquid ammonia in an ammonia-containing reservoir; (b) passing said ammonia gas through a filtration membrane removing particles greater than 0.005 micron therefrom; (c) passing said ammonia gas thus filtered through a scrubber wherein said ammonia gas is contacted with an aqueous solution of ammonia in deionized water; and (d) recovering said ammonia gas emerging from said scrubber and directing said ammonia gas to said workstation.
Claim 13
Dependent Claim
29 words
A method in accordance with claim 9 further comprising dissolving said ammonia gas emerging from said scrubber in purified water prior to directing said ammonia gas to said workstation.
Claim 14
Dependent Claim
29 words
A method in accordance with claim 9 further comprising passing said ammonia gas through a distillation column for further purification prior to directing said ammonia gas to said workstation.
Claim 15
Dependent Claim
46 words
A method in accordance with claim 9 further comprising: (c') passing said ammonia gas from said scrubber through a distillation column for further purification, and dissolving said ammonia gas emerging from said distillation column in purified water prior to directing said ammonia gas to said workstation.
Claim 16
Dependent Claim
25 words
A method in accordance with claim 9 in which step (c) is conducted at a temperature ranging from about 10° C. to about 50° C.
Claim 17
Dependent Claim
25 words
A method in accordance with claim 9 in which step (c) is conducted at a temperature ranging from about 15° C. to about 35° C.
Claim 18
Dependent Claim
27 words
A method in accordance with claim 12 in which steps (c) and (c') are conducted at a temperature ranging from about 15° C. to about 35° C.
Claim 19
Dependent Claim
41 words
A method in accordance with claim 9 in which step (c) is conducted at a temperature ranging from about 15° C. to about 35° C. and at a pressure of from about atmospheric pressure to about 30 psi above atmospheric pressure.
Claim 20
Dependent Claim
43 words
A method in accordance with claim 12 in which steps (c) and (c') are conducted at a temperature ranging from about 15° C. to about 35° C. and at a pressure of from about atmospheric pressure to about 30 psi above atmospheric pressure.
Claim 21
Dependent Claim
20 words
A method in accordance with claim 9 in which said scrubber is positioned within approximately 30 cm of said workstation.
Claim 22
Dependent Claim
21 words
A method in accordance with claim 12 in which said distillation column is positioned within approximately 30 cm of said workstation.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-05 | 1999-09-04 | 2000-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-05 | 2003-09-04 | 2004-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-05 | 2007-09-04 | 2008-03-05 | $7700.00 | Window Closed / Lapsed |