Liquid purification or separation – Processes – Separating
Reexamination Certificate
2001-10-26
2003-10-21
Drodge, Joseph (Department: 1723)
Liquid purification or separation
Processes
Separating
C222S001000, C222S189060, C222S252000, C417S053000, C417S313000, C417S413100, C417S505000
Reexamination Certificate
active
06635183
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a pumping system useful in dispensing fluids, especially those that are expensive, viscous, high purity, and/or sensitive to molecular shear. The invention also relates to microelectronic components such as silicon chips and wafers, microelectronic substrates, and circuits fabricated by such pumping systems and methods, including the potentially improved quality and yield of such products achievable with the invention as compared to prior art systems.
General aspects of the relevant background of the invention are discussed in prior U.S. Pat. Nos. 5,167,837; 5,772,899; and 5,516,429. Among other things, the invention has numerous applications, but is especially useful in the microelectronics industry. The trend in that industry continues to be to squeeze greater quantities of circuitry onto smaller substrates. Circuit geometries continue to shrink, the use of expensive materials continues, and the corresponding need for decontaminated “cleanroom” environments and equipment for manufacturing, filtering, and processing continues and even increases. Perhaps as importantly, the need for improved yield of final product continues, for economic and other reasons.
The equipment and methods of the aforementioned U.S. Pat. Nos. 5,167,837; 5,772,899; and 5,516,429 addresses many situations and applications very well. The present invention is directed to further improvements in that technology, as well as potential applications of such improvements in unrelated technologies.
Among other things, further simplification and upright orientation of the flow path for the processed fluids through a pumping and dispensing system can reduce the risk of contamination, air entrapment, or similar concerns, while providing similar or improved reliability and precise control for desired filtration, dispense, and other handling of the process fluids. Further manufacturing and design improvements in the instant invention allow the entire process fluid flow path to be coated or machined from Teflon® or some similar non-contaminating material, further reducing the likelihood of any contamination problems.
As indicated above, many problems were addressed and solved by the aforementioned U.S. Pat. Nos. 5,167,837, 5,516,429, and 5,772,899. Among other things, those devices introduced a diaphragm-type fluid dispense system which, in certain embodiments, included two separate computer-controlled pumps to dispense precise amounts of fluid. However, the preferred embodiments in those patents show the process fluid traveling in a somewhat meandering path through the pump system. In certain applications, that path does not afford optimal venting for any contaminating air bubbles that may become entrapped in the fluid or the system. For example, some small amount of air bubbles may be unavoidably introduced when the source fluid container is periodically changed, even if no re-priming is required. Portions of the flow path that are metal or otherwise relatively potentially contaminating result in some risk (however small) of corresponding undesirable contamination of the fluid.
As indicated in those prior patents, such bubbles or contaminants could potentially compromise the end product to some degree in some small percentage of applications. Alternatively, such bubbles or contaminants might require some period of “flushing” bubbles from the system upon changing the source fluid container, for example, or might otherwise compromise the accuracy of the fluid dispense system (again, in a small percentage of applications and situations). Although those prior patents and inventions function well in that regard and are a dramatic advance over the prior art before them, and although those prior patents can be readily adapted to deal with the aforementioned potential problems, the instant invention provides improvements in that regard.
Other benefits derive from simplifying the flow path of the fluid. By simplifying and reducing the number of components involved in the system, assembly and maintenance can be correspondingly simplified. Perhaps more importantly, the number of connection points, seals, fittings, and related potential leak-spots can be reduced, thereby directly reducing the risk of contamination, air-entrainment, or similar problems. Additionally, reducing and realigning the fluid flow path can reduce the size of the “foot-print” for the housing of the system and otherwise make the system more compact as compared to prior art systems, thereby correspondingly reducing valuable factory space for the users of the pump system.
OBJECTS AND ADVANTAGES OF THE INVENTION
It is, therefore, an object of my invention to provide a fluid dispensing system that provides the improved performance and benefits discussed herein. The system is characterized by substantially vertical fluid flow from its inlet to its outlet when the system is in its normally upright position, and by providing Teflon® or similar non-contaminating wetted surfaces throughout the flowpath. In its preferred embodiment, the flow path is simplified as compared to prior art systems, including fewer fittings and connections (in part resulting from integrally forming various components into single unitary structures).
A further object of the invention is the provision of a device for processing fluid in a precisely controlled manner, including the combination of first pumping means and second pumping means in fluid communication with each other, in which the fluid travel path that is substantially consistently upward as the fluid flows through the first pumping means and the second pumping means. As indicated above, the first and second pumping means surfaces that contact the fluid are preferably all fabricated from or coated with a relatively non-contaminating material, such as Teflon® or the like. Among other things, this facilitates using the system for high-purity fluids, in cleanroom environments, etc.
The device can further include filter means between the first pumping means and the second pumping means, in which case the fluid travel path preferably remains substantially consistently upward as the fluid flows through the first pumping means, the filter means, and the second pumping means, and all or substantially all contacting surfaces are non-contaminating. In the preferred embodiment, the pump head and the valve therein are actually fabricated from Teflon®, and all fittings along the flow path are flare fittings formed from Teflon® or otherwise having wetted surfaces that are non-contaminating to the subject fluid. For the non-contaminating aspect of the invention, the particular material may be any suitable non-contaminating material, including without limitation various forms of Teflon® (TFE & PFA), Kalrez (a fluorinated, Teflon®-like elastomer), or other materials. Among the many suitable fittings usable in the invention, commercially available Furon Flare Grip® PFA tube fittings can be readily utilized.
Another object of the invention is the provision of a system or device of the aforementioned character, in which the first pumping means includes an upper head portion removable from a lower portion, and means are provided for temporarily attaching the upper head portion to a lower portion to form a pumping chamber therebetween. Preferably, the upper head portion includes integrally formed valve means configured to thereafter direct the process fluid in a substantially upward path toward a filter chamber integrally formed in the upper head portion. Among other things, the integral valve facilitates filtering viscous and other fluids under relatively low pressure, and decreases molecular shear on the fluids, in part by providing relatively larger and less obstructed flow paths through the valve (as compared to prior art systems). The valve also reduces differential pressure, or pressure drop, as the fluids move through the valve.
An additional object of the invention is the provision of a system or device of the aforementioned character, in which the second pumping means includes an upper h
Drodge Joseph
Holland J. Mark
Mykrolis Corporation
LandOfFree
Apparatus and methods for pumping high viscosity fluids does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and methods for pumping high viscosity fluids, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and methods for pumping high viscosity fluids will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3115494