US4778532A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and apparatus for treating wafers with process fluids
Assignee: CFMT Inc
•
Filing: 1985-08-13
•
Granted: 1988-10-18
•
Expires: 2005-08-13
Abstract
Abstract Contamination of wafers is reduced by an enclosed full-flow method and apparatus for the cleaning and other wet processing of semiconductor wafers. Process fluids flow sequentially and continuously past the wafers such that the processing does not require movement or operator handling of the wafers between processing steps. The vessel containing the wafers is hydraulically full during each process step. Wafers may be cleaned using a hot corrosive fluid, such as sulfuric acid; rinsed using high purity water at high flow rates; and dried using a drying fluid such an isopropanol. In addition, chemical reagents such as dilute hydrofluoric acid or hydrogen peroxide may be precisely mixed in situ and applied to the wafer surface for a precisely controlled period, by injecting concentrated reagent into rinse water purified by multipass filtration.
Inventors
- 👤 Christopher F. McConnell
- 👤 Alan E. Walter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 09:00
CPC Classifications
H; H10; H10P; H10P72/00; H10P72/04; H10P72/0402; H10P72/0406; B; B05; B05C; B05C3/00; B05C3/02; B05C3/09; B05C3/109; B08; B08B; B08B3/00; B08B3/04; B08B7/00; B08B7/0064; B08B7/0092; C; C23; C23C; C23C16/00; C23C16/44; C23C16/54; C30; C30B; C30B33/00; H10P72/0404; H10P72/30; H10P72/33; H10P72/3311; H10P72/34; H10P72/3411; H10P72/3412; B08B2203/00; B08B2203/002
Claims Analysis
Total Claims: 63
Claim 1
Independent Claim
111 words
An enclosed, full flow method for the cleaning of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids sequentially and continuously past said wafers in said vessel, including the steps of (a) contacting said wafers with at least one cleaning fluid to remove contaminants from said wafers; (b) removing said cleaning fluid from said wafers with a rinsing fluid; and (c) removing said rinsing fluid from said wafers with a drying fluid; whereby the processing does not requirement movement or operator handling of said wafers between said steps; and maintaining the vessel containing said wafers hydraulically full during each process step.
Claim 2
Dependent Claim
111 words
An enclosed, full flow method for the cleaning of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids sequentially and continuously past said wafers in said vessel, including the steps of (a) contacting said wafers with at least one cleaning fluid to remove contaminants from said wafers; (b) removing said cleaning fluid from said wafers with a rinsing fluid; and (c) removing said rinsing fluid from said wafers with a drying fluid; whereby the processing does not requirement movement or operator handling of said wafers between said steps; and maintaining the vessel containing said wafers hydraulically full during each process step.
Claim 3
Dependent Claim
49 words
A process according to claim 1 wherein process fluids are in continuous flow so that when any process fluid is not being used to contact said wafers, said non-contacting process fluid is continuously recirculated, such that the recirculation fluid flow paths do not include said vessel containing said wafers.
Claim 4
Dependent Claim
22 words
A process according to claim 1 wherein process fluids contact said wafers as a single fluid phase substantiaIly free of phase boundaries.
Claim 5
Dependent Claim
37 words
A method according to claim 1 comprising the additional steps of (d) reacting the surface of said wafers with at least one chemical reagent and (e) removing said chemical reagent from said wafers with a rinsing fluid.
Claim 6
Dependent Claim
23 words
A method according to claim 4 wherein said chemical reagent is followed by said rinsing fluid without an intervening fluid contacting said wafers.
Claim 7
Dependent Claim
25 words
A method according to claim 4 wherein said additional steps follow rinsing said cleaning fluid and precede removing said rinsing fluid with said drying fluid.
Claim 8
Dependent Claim
18 words
A method according to claim 1 wheren said wafers comprise a body selected from silicon and gallium arsenide.
Claim 9
Dependent Claim
26 words
A method according to claim 1 wherein said cleaning fluid comprises at least one acid selected from the group consisting of sulfuric acid and nitric acid.
Claim 10
Dependent Claim
21 words
A method according to claim 8 wherein said cleaning fluid additionally comprises an oxidizing agent selected from ozone and hydrogen peroxide.
Claim 11
Dependent Claim
28 words
A method according to claim 9 wherein said oxidizng agent is ozone and is injected into said acid as a gas whereby said gaseous ozone agitates said acid.
Claim 12
Dependent Claim
14 words
A method according to claim 8 wherein said acid is a hot, concentrated acid.
Claim 13
Dependent Claim
15 words
A method according to claim 1 wherein said cleaning fluid comprises at least one base.
Claim 14
Dependent Claim
12 words
A method according to claim 12 wherein said base is ammonium hydroxide.
Claim 15
Dependent Claim
35 words
A method according to claim 1 wherein said cleaning fluid is prefiltered through a particle filter which effectively removes particles having an average particle size greater than about 0.2 microns prior to contacting said wafers.
Claim 16
Dependent Claim
16 words
A method according to claim 1 wherein said cleaning fluid is recycled through said particle filter.
Claim 17
Dependent Claim
22 words
A method according to claim 15 wherein said particle filter is periodically backwashed to rejuvenate the filtration capability of said particle filter.
Claim 18
Dependent Claim
61 words
A process according to claim 1 wherein the flow of said cleaning fluid is effected by application of pressure to a surface of said cleaning fluid in a first storage reservoir, and said pressure effects the flow of cleaning fluid from said first storage reservoir, through a particle filter, into contact with said wafers, and subsequently to a second storage reservoir.
Claim 19
Dependent Claim
33 words
The process of claim 17 wherein the flow of fluid from first to second resevoir is reversed, wherein the direction of fluid flow through said particle filter and past said wafers is maintained.
Claim 20
Dependent Claim
29 words
A method according to claim 17 wherein said pressure application is effected by gas under pressure and said gas is a gas selected from nitrogen, argon, and compressed air.
Claim 21
Dependent Claim
12 words
A method according to claim 1 wherein said rinsing fluid is water.
Claim 22
Dependent Claim
24 words
A method according to claim 20 wherein said rinsing fluid is water which has been deionized and filtered to remove dissolved and suspended matter.
Claim 23
Dependent Claim
28 words
A method according to claim 21 wherein said water is continuously recirculated through cationic ion exchange resin and anionic ion exchange resin prior to use in rinsing wafers.
Claim 24
Dependent Claim
24 words
A method according to claim 22 wherein said water is continuously recirculated through at least one filtration membrane prior to use in rinsing wafers.
Claim 25
Dependent Claim
23 words
A method according to claim 23 wherein said filtration membrane is selected from micron filtration membranes, ultrafiltration membranes and reverse osmosis filtration membranes.
Claim 26
Dependent Claim
17 words
A method according to claim 20 wherein said water is irradiated and circulated to avoid bacterial growth.
Claim 27
Dependent Claim
20 words
A method according to claim 25 wherein the circulation of said water is by means of a vertical immersion pump.
Claim 28
Dependent Claim
35 words
A method according to claim 15 wherein filtration is effected by flow of said water through at least one filtration membrane which effectively removes particulate matter having an average particle size greater than 0.2 microns.
Claim 29
Dependent Claim
15 words
A method according to claim 23 wherein said filtration membrane is regenerated by periodically backwashing.
Claim 30
Dependent Claim
23 words
A method according to claim 1 wherein said wafers are rinsed at a fluid velocity of about 0.01 to 0.2 meters per second.
Claim 31
Dependent Claim
37 words
A method according to claim 1 where the effluent of said rinsing fluid is evaluated by measuring the electrical resistivity to sense the concentration of dissolved ions as a measure of fluid quality and the rinsing endpoint.
Claim 32
Dependent Claim
33 words
A method according to claim 1 wherein the effluent of said rinsing fluid is evaluated by measuring the population density of suspended particles as a measure of fluid quality and the rinsing endpoint.
Claim 33
Dependent Claim
20 words
A method according to claim 1 wherein said cleaning fluid is displaced by pressurized gas prior to rinsing step (b).
Claim 34
Dependent Claim
28 words
A method according to claim 32 wherein said cleaning fluid is allowed to drain by gravity from the surface of said wafers prior to said rinsing step (b).
Claim 35
Dependent Claim
13 words
A method according to claim 4 wherein said chemical reagent is an etchant.
Claim 36
Dependent Claim
16 words
A method according to claim 34 wherein said etchant is an aqueous solution of hydrofluoric acid.
Claim 37
Dependent Claim
24 words
A method according to claim 5 wherein said chemical reagent in concentrated form is diluted with said rinsing fluid to give diluted chemical reagent.
Claim 38
Dependent Claim
47 words
A method according to claim 36 wherein said chemical reagent in concentrated form is metered into said rinsing fluid at a predetermined rate after completion of rinsing step (b), wherein said rinsing fluid is deionized and filtered to give diluted chemical reagent which subsequently contacts said wafers.
Claim 39
Dependent Claim
36 words
A method according to claim 37 wherein said concentrated chemical reagent is injected into said rinsing fluid by valve means through which said chemial reagent is continuously recirculated when not being metered into said rinsing fluid.
Claim 40
Dependent Claim
45 words
The method of claim 38 wherein said valve has at least two flow paths within the body of said valve means such that while said chemical reagent is continuously recirculated through one of said flow paths rinsing fluid circulates through another of said flow paths.
Claim 41
Dependent Claim
31 words
A method according to claim 36 wherein said concentrated chemical reagent and said rinsing fluid are mixed by means of a static mixer prior to said chemical reagent contacting said wafers.
Claim 42
Dependent Claim
54 words
A method according to claim 38 wherein subsequent to completing injection of said concentrated reagent, a portion of the flow of said rinsing fluid is directed to flow through said valve means to rinse said valve means and to rinse associated fluid communication means, whereby the injection of concentrated reagent may be abruptly terminated.
Claim 43
Dependent Claim
18 words
A method according to claim 41 whereby said rinsing fluid is diverted by means of an orifice plate.
Claim 44
Dependent Claim
25 words
A method according to claim 1 wherein said drying fluid is miscible with said rinsing fluid and substantially nonreactive with the surface of said wafers.
Claim 45
Dependent Claim
29 words
A method according to claim 1 wherein said drying fluid is selected from organic compounds having a boiling point of less than about 140 degrees centigrade at atmospheric pressure.
Claim 46
Dependent Claim
13 words
A method according to claim 43 wherein said drying fluid is superheated steam.
Claim 47
Dependent Claim
24 words
A method according to claim 45 herein said super heated steam is diluted with a carrier gas selected from nitrogen, argon and dry air.
Claim 48
Dependent Claim
22 words
A method according to claim 44 wherien said drying fluid is an alcohol selected from isopropanol, methanol, 1-propanol, tert-butanol and mixtures thereof.
Claim 49
Dependent Claim
27 words
A method according to claim 47 wherein rinsed wafers are contacted with a stream of alcohol vapor as said rinsing fluid is displaced by said alcohol vapor.
Claim 50
Dependent Claim
25 words
A method according to claim 47 wherein said wafers have a temperature lower than said alcohol vapor and liquid alcohol consequently condenses on said wafers.
Claim 51
Dependent Claim
25 words
A method according to claim 48 wherein alcohol is evaporated from said wafers after said alcohol has substantially replaced the rinsing fluid on said wafers.
Claim 52
Dependent Claim
23 words
A method according to claim 50 wherein the evaporation of said alcohol is assisted by a stream of gas flowing past said wafers.
Claim 53
Dependent Claim
24 words
A method according to claim 51 wherein said alcohol and residual rinsing fluid are collected as an effluent from the vessel containing said wafers.
Claim 54
Dependent Claim
22 words
A method according to claim 52 wherein effluent alcohol is stripped from effluent water by passing a gas through effluent water/alcohol mixture.
Claim 55
Dependent Claim
69 words
An enclosed, full flow method for the treatment of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of exposing the surface of said wafers to at least one cleaning fluid, whereby the processing does not require movement or handling of said wafers between said steps.
Claim 56
Dependent Claim
69 words
An enclosed, full flow method for the treatment of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of exposing the surface of said wafers to at least one cleaning fluid, whereby the processing does not require movement or handling of said wafers between said steps.
Claim 57
Dependent Claim
82 words
An enclosed, full flow method for the treatment of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of reacting the surface of said wafers with at least one chemical reagent, whereby the processing does not require movement or handling of said wafers between said steps and maintaining the vessel containing said wafers hydraulically full during each process step.
Claim 58
Dependent Claim
82 words
An enclosed, full flow method for the treatment of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of reacting the surface of said wafers with at least one chemical reagent, whereby the processing does not require movement or handling of said wafers between said steps and maintaining the vessel containing said wafers hydraulically full during each process step.
Claim 59
Dependent Claim
19 words
A method according to claim 55 including the additional step of removing said chemical reagent with a rinsing fluid.
Claim 60
Dependent Claim
82 words
An enclosed, full flow method for the cleaning of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of rinsing the surface of said wafers with at least one rinsing fluid whereby the processing does not require movement or handling of said wafers between process steps and maintaining said vessel containing said wafers hydraulically full during each process step.
Claim 61
Dependent Claim
82 words
An enclosed, full flow method for the cleaning of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of rinsing the surface of said wafers with at least one rinsing fluid whereby the processing does not require movement or handling of said wafers between process steps and maintaining said vessel containing said wafers hydraulically full during each process step.
Claim 62
Dependent Claim
93 words
An enclosed, full flow method for the treatment of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of rinsing the surface of said wafers with at least one rinsing fluid and subsequently removing said rinsing fluid with a drying fluid whereby the processing does not require movement or handling of said wafers between process steps and maintaining the vessel containing said wafers is hydraulically full during each process step.
Claim 63
Dependent Claim
93 words
An enclosed, full flow method for the treatment of semiconductor wafers comprising positioning said wafers in a vessel, closing said vessel to the environment, and flowing process fluids in sequential steps continuously past said wafers in said vessel, including the step of rinsing the surface of said wafers with at least one rinsing fluid and subsequently removing said rinsing fluid with a drying fluid whereby the processing does not require movement or handling of said wafers between process steps and maintaining the vessel containing said wafers is hydraulically full during each process step.
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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) | 1991-10-18 | 1992-04-18 | 1992-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-18 | 2000-04-18 | 2000-10-18 | $7700.00 | Window Closed / Lapsed |