Method and apparatus for cleaning surfaces to absolute or near-absolute cleanliness
First Claim
1. A method of cleaning a surface to absolute or near-absolute cleanliness such that when dry nitrogen is filtered through a 0.01 μ
- filter, passed over the cleaned, dried surface and through a laser particle counter, the laser particle counter will detect less than five particles having a diameter ≧
0.1 μ
per cubic foot of gas flow, a condensation nucleating counter will detect no more than five particles having a diameter of 0.02 μ
or larger, and wherein residual surface ions and residual surface organics, if any, are present in a concentration of less than one part per million, said method comprising contacting a surface of a member to be cleaned with jets of a cleaning solution which impinge on the surface at high speed and flow over the surface so as to create a scrubbing action on the surface and flowing a rinse liquid in contact with the surface to be cleaned to rinse the surface, wherein the rinse liquid is recirculated into contact with the surface during said rinsing, the recirculating rinse liquid being filtered during recirculation to remove all particles having a diameter equal to or greater than 0.2 μ
.
8 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for cleaning surfaces to absolute or near-absolute cleanliness involves spraying jets of heated cleaning solution so that it flows over and scrubs the surfaces to be cleaned. The cleaning solution is continuously recirculated and filtered during cleaning to remove over 99% of all particles having a diameter equal to or greater than 0.02μ. The cleaned surface is rinsed with heated, filtered deionized water and dried to provide a surface having absolute or nearly-absolute cleanliness to the limit of the best commercial instrumentation, e.g., ≦ five particles with a diameter of ≧0.02μ per cubic foot of gas flowed over a cleaned surface as detected by a laser particle counter. The method is useful for cleaning gas valves and regulators and components thereof as well as existing gas flow equipment, for example, for use in semiconductor processing equipment. The cleaned surfaces are sterile and therefore also useful in the health and pharmaceutical industries.
-
Citations
38 Claims
-
1. A method of cleaning a surface to absolute or near-absolute cleanliness such that when dry nitrogen is filtered through a 0.01 μ
- filter, passed over the cleaned, dried surface and through a laser particle counter, the laser particle counter will detect less than five particles having a diameter ≧
0.1 μ
per cubic foot of gas flow, a condensation nucleating counter will detect no more than five particles having a diameter of 0.02 μ
or larger, and wherein residual surface ions and residual surface organics, if any, are present in a concentration of less than one part per million, said method comprising contacting a surface of a member to be cleaned with jets of a cleaning solution which impinge on the surface at high speed and flow over the surface so as to create a scrubbing action on the surface and flowing a rinse liquid in contact with the surface to be cleaned to rinse the surface, wherein the rinse liquid is recirculated into contact with the surface during said rinsing, the recirculating rinse liquid being filtered during recirculation to remove all particles having a diameter equal to or greater than 0.2 μ
. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
- filter, passed over the cleaned, dried surface and through a laser particle counter, the laser particle counter will detect less than five particles having a diameter ≧
-
21. An apparatus for cleaning a surface to absolute or near-absolute cleanliness such that when dry nitrogen is filtered through a 0.01 μ
- filter, passed over the cleaned, dried surface and through a laser particle counter, the laser particle counter will detect less than five particles having a diameter ≧
0.1μ
per cubic foot of gas flow, a condensation nucleating counter will detect no more than five particles having a diameter of 0.02 μ
or larger, and wherein residual surface ions and residual surface organics, if any, are present in a concentration of less than one part per million, said apparatus comprising means for contacting a surface of a member to be cleaned with a cleaning solution which impinges on the surface at high speed and flows over the surface to create a scrubbing action on the surface, and means for flowing a rinse liquid in contact with the surface to rinse the surface, said means for flowing a rinse liquid including means for recirculating the rinse liquid into contact with the surface during rinsing and means for filtering the recirculating liquid immediately before it is flowed into contact with the surface to remove all particles having a diameter greater than or equal to 0.2 μ
. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
- filter, passed over the cleaned, dried surface and through a laser particle counter, the laser particle counter will detect less than five particles having a diameter ≧
-
32. An apparatus for cleaning a surface to absolute or near-absolute cleanliness such that when dry nitrogen is filtered through a 0.01 μ
- filter, passed over the cleaned, dried surface and through a laser particle counter, the laser particle counter will detect less than five particles having a diameter ≧
0.1 μ
per cubic foot of gas flow, a condensation nucleating counter will detect no more than five particles having a diameter of 0.02 μ
or larger, and wherein residual surface ions and residual surface organics, if any, are present in a concentration of less than one part per million, said apparatus comprising a cleaning chamber within which a member having a surface to be cleaned can be placed, a first container holding a cleaning solution, a second container holding a rinse liquid, a pump, a filter, fluid supply line means connecting each of said first and second containers to an input of said pump and connecting an output of said pump with said chamber by way of the filter for filtering the cleaning solution and rinse liquid immediately before introduction into the cleaning chamber, supply valve means in said fluid supply line means for selectively pumping one of the cleaning solution and rinse liquid from its container through the fluid supply line means to the cleaning chamber by way of the pump and filter, fluid return line means for returning the cleaning solution from the chamber to the first container for recirculation and for returning the rinse liquid from the chamber to the second container for recirculation, and return valve means for selectively returning one of the cleaning solution and the rinse liquid to its corresponding container by way of said return line means for recirculation, wherein at least one spray head is provided in said cleaning chamber, said spray head having a plurality of apertures therein for forming jets of cleaning solution and rinse liquid for impinging upon a surface being cleaned, said pump maintaining a pressure of cleaning solution and rinsing liquid of at least 40 psi whereby jets of cleaning solution and rinse liquid impinge upon the surface being cleaned at speeds ≧
60 mph. - View Dependent Claims (33, 34, 35, 36, 37, 38)
- filter, passed over the cleaned, dried surface and through a laser particle counter, the laser particle counter will detect less than five particles having a diameter ≧
Specification