Apparatus and methods for pumping high viscosity fluids

Abstract

A system for dispensing and filtering fluid is disclosed, in which the fluid flow path is substantially vertical from the fluid inlet through fluid dispense. Substantially all wetted surfaces are Teflon® or some similar non-contaminating fluid, for applications such as cleanroom processes. A valve and a filter chamber are incorporated into a pump head to simplify the flow path and reduce potential contamination points. Preferred methods, and chips or other microelectronic devices fabricated from the apparatus or methods, are also disclosed.

I claim:  
     
         1 . In a device for processing fluid in a precisely controlled manner, the combination of: first pumping means and second pumping means in fluid communication with each other; said first pumping means and said second pumping means providing a fluid travel path that is substantially consistently upward as the fluid flows through said first pumping means and said second pumping means.  
     
     
         2 . The device of  claim 1 , in which each of said first and second pumping means includes surfaces that contact the fluid, substantially all of said contacting surfaces being fabricated from or coated with a relatively non-contaminating material.  
     
     
         3 . The device of  claim 1 , further including filter means between said first pumping means and said second pumping means, in which said fluid travel path is substantially consistently upward as the fluid flows through said first pumping means, said filter means, and said second pumping means.  
     
     
         4 . The device of  claim 3 , in which each of said first and second pumping means and said filter means includes surfaces that contact the fluid, substantially all of said contacting surfaces being fabricated from or coated with a relatively non-contaminating material.  
     
     
         5 . The device of  claim 1  or  claim 2  or  claim 3  or  claim 4 , in which said first pumping means includes an upper head portion removable from a lower portion, and means for temporarily attaching said upper head portion to said lower portion to form a pumping chamber therebetween, in which said upper head portion includes integrally formed valve means therein.  
     
     
         6 . The device of  claim 5 , in which said valve means is configured to receive inflow of the process fluid from a source of such fluid, and is configured to thereafter direct such fluid in a substantially direct upward path toward a filter chamber integrally formed in said upper head portion, said filter chamber forming a portion of said filter means.  
     
     
         7 . The device of  claim 5 , in which said valve means is configured to provide a substantially direct upward flowpath for the subject fluid from said pumping chamber toward a filter chamber integrally formed in said upper head portion, said filter chamber forming a portion of said filter means.  
     
     
         8 . The device of  claim 1  or  claim 2  or  claim 3  or  claim 4  in which said second pumping means includes an upper head portion removable from a lower portion, and means for temporarily attaching said upper head portion to said lower portion to form a pumping chamber therebetween, in which said upper head portion includes an integrally formed tee fluid flowpath therein, wherein said tee provides a substantially direct upward flowpath for the subject fluid from said pumping chamber toward a dispense from said upper head portion.  
     
     
         9 . The device of  claim 8 , in which said tee includes an input portion thereof for receiving the subject fluid after it has been pumped by said first pumping means and in which said dispense from said upper head portion is positioned higher than said input portion when said device is in its normal, upright orientation.  
     
     
         10 . The device of  claim 1  or  claim 2  or  claim 3  or  claim 4 , in which said second pumping means is positioned generally above said first pumping means, and said fluid travel path from an exit of said first pumping means to an inlet into said second pumping means does not include any downwardly directed portions when said device is in its normal, upright orientation.  
     
     
         11 . In a device for dispensing fluid, the combination of: a first diaphragm-type pump having a pumping head, said head including an integrally formed three-way valve to control flow of fluid into said first diaphragm-type pump.  
     
     
         12 . The device of  claim 11 , further including a second diaphragm-type pump positioned generally above said first diaphragm-type pump and configured to receive fluid pumped by said first diaphragm-type pump, a fluid path from said first diaphragm-type pump to said second diaphragm-type pump being generally upward.  
     
     
         13 . The device of  claim 11  or  claim 12 , further including a filter housing integrally formed in said first diaphragm-type pump pumping head.  
     
     
         14 . The device of  claim 13 , in which said pumping head and valve provide a generally directly upward flow path for said fluid from said first diaphragm-type pump to said filter housing.  
     
     
         15 . The device of  claim 14 , further including a vent valve above said filter housing to permit selective venting of any gas entrained in the subject fluid.  
     
     
         16 . The device of  claim 13 , in which substantially all surfaces wetted by the subject fluid are fabricated from or coated with a relatively non-contaminating material.  
     
     
         17 . A method for filtering and dispensing fluid, including the steps of: providing a valve means integrally formed in an upper head of a first pumping member, said valve means configured to received the subject fluid and direct it in a substantially upward path from said first pumping member; actuating said first pumping member to draw the subject fluid from a source; and further actuating said first pumping member to dispense the subject fluid upwardly from said first pumping member.  
     
     
         18 . The method of  claim 17 , further including the steps of providing a filter chamber integrally formed in said upper head of said first pumping member and providing a substantially direct upward flow path within said upper head from said first pumping member through said valve means to said filter chamber, whereby said further actuation of said first pumping member directs the subject fluid upwardly from said first pumping member to said filter chamber.  
     
     
         19 . The method of  claim 17  or  claim 18 , further including the steps of providing a second pumping member substantially above said first pumping member and providing fluid flow means therebetween, whereby the subject fluid does not flow downwardly between said first pumping member and said second pumping member; and pumping the subject fluid along said non-downward flowpath.  
     
     
         20 . The method of  claim 17  or  claim 18 , further including the steps of providing at least one vent means along the subject fluid's flowpath to vent any undesirable entrained gas from the subject fluid.  
     
     
         21 . The method of  claim 17  or  claim 18 , further including the steps of providing a valve downstream of said second pumping member for selectively dispensing the subject fluid or returning the subject fluid to said source, in which said downstream valve is a substantially zero displacement valve that does not undesirably displace subject fluid.  
     
     
         22 . The method of  claim 17  or  claim 18 , in which substantially all surfaces wetted by the subject fluid are fabricated from or coated with a relatively non-contaminating material.  
     
     
         23 . Apparatus for filtering and dispensing fluid, the combination of: first diaphragm-type pumping means; second diaphragm-type pumping means in fluid communication with said first diaphragm-type pumping means; and filtering means between said first and second pumping means, whereby said first pumping means pumps the fluid substantially vertically upwardly through said filtering means; and fluid flow means between said filtering means and a housing for second pumping means in which said fluid flow means does not include downward flow of the subject fluid as it travels from said filtering means to said housing for second pumping means.  
     
     
         24 . The apparatus of  claim 23 , including fittings adjacent an inlet to said first pumping means and incorporated in said fluid flow means, in which said fittings are flare fittings having wetted surfaces that are non-contaminating to the subject fluid.  
     
     
         25 . Apparatus for filtering and dispensing fluid, including: a first pump having a pumping chamber defined in part by an upper head portion, said upper head portion including a valve and filter chamber integrally formed therein, said filter chamber being disposed substantially above said valve and said filter chamber including a removable lid member forming an upper closure of said filter chamber, an outlet and vent disposed at a relatively upward location on said filter chamber; and a substantially vertical fluid pathway formed integrally in said upper head portion to permit flow from said pumping chamber to said filter chamber.  
     
     
         26 . The apparatus of  claim 25 , in which said upper head portion is retained on a lower head portion by a threaded nut formed of metal.  
     
     
         27 . The apparatus of  claim 25 , including an  0 -ring seal between said lid member and said upper head portion, in which said  0 -ring is positioned on the interior diameter of said upper head portion.  
     
     
         28 . A combination of a master pump and a slave pump for dispensing fluid in cleanroom type applications, in which said master pump includes a pump head having a valve and a filter chamber formed integrally therein, including a fluid flow path through said combination which path is comprised by materials that are non-contaminating to the subject fluid and which path flows substantially upwardly from an inlet into said master pump through said filter chamber and subsequently through said slave pump.  
     
     
         29 . The combination of  claim 28 , in which said pump head and said valve therein are fabricated from Teflon®.  
     
     
         30 . The combination of  claim 28  or  claim 29 , including a vent valve positioned at a high point within said filter chamber.  
     
     
         31 . The combination of  claim 30 , in which said vent valve can both vent entrained air from the subject fluid and provide pressure relief if the pumping pressure on the subject fluid exceeds a selected level.  
     
     
         32 . A microelectronic substrate fabricated by deposition of fluid from a diaphragm-type pump having a pumping head, said head including an integrally formed valve to control flow of fluid into said diaphragm-type pump.  
     
     
         33 . The combination of  claim 29 , including a vent valve positioned at a high point within said filter chamber.  
     
     
         34 . The combination of  claim 33 , in which said vent valve can both vent entrained air from the subject fluid and provide pressure relief if the pumping pressure on the subject fluid exceeds a selected level.