Semiconductor device manufacturing: process – Chemical etching – Liquid phase etching
Reexamination Certificate
2001-10-12
2004-05-11
Chen, Kin-Chan (Department: 1765)
Semiconductor device manufacturing: process
Chemical etching
Liquid phase etching
C134S001100, C216S083000
Reexamination Certificate
active
06734112
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to densified gas based systems, more particularly to divided pressure vessel apparatus for carbon dioxide based systems and methods of using same.
BACKGROUND OF THE INVENTION
An important operational consideration for many, if not all, carbon dioxide processing systems is throughput, which may be defined as the amount of articles or materials that may be processed in a given period of time. In various processes that utilize carbon dioxide as a solvent, multiple solvent baths may be used to improve operational efficiency by increasing throughput. For example, in a carbon dioxide based dry cleaning system, it may be desirable to provide pre-washing, washing, rinsing, and distillation operations. The pre-wash, wash, and rinse solutions may each have a different chemical composition. If a single tank were used to store the various baths, the composition of the solution in the tank would need to be adjusted between each operation, which may increase cycle time and decrease throughput. By utilizing a tank for storing a pre-wash solution, a separate tank for storing wash solution, another separate tank for storing a rinse solution, and yet another separate distillation tank, the dry cleaning system may be able to cycle through the operations of pre-washing, washing, rinsing, and distillation in a more timely manner.
U.S. Pat. No. 5,267,455 to Dewees et al. proposes a dry cleaning system particularly suited for employing supercritical carbon dioxide as the cleaning fluid consisting of a sealable cleaning vessel containing a rotatable drum adapted for holding soiled substrate, a cleaning fluid storage vessel, and a separate gas vaporizer vessel for recycling used cleaning fluid.
While utilizing multiple solvent baths in carbon dioxide based systems may improve operational efficiency, the increased capital costs associated with such systems may outweigh some of the operational benefits. Carbon dioxide based systems may be required to operate at elevated pressures in order to maintain the carbon dioxide solvent in either a liquid or a supercritical state. As a result, each of the separate tanks must be a stamp coded and certified pressure vessel, which can be quite expensive. Additionally, each of the separate tanks must be in constant fluid communication with a pressure relief valve. Thus, the capital cost of constructing a carbon dioxide based system having multiple solvent baths may outweigh some, if not all, of the operational benefits that may be gained by utilizing such a system.
WO 97/33031 proposes a storage/still vessel that both distills and stores the liquid gas for use in another cleaning cycle. The storage/still vessel includes a tube located within an inner cavity of an outer tank. At the top of the tube is an opening that provides fluid communication between the inner cavity and an inner chamber of the tube. The bottom of the tube has a one-way control valve that allows the liquid gas to flow from the inner cavity to the inner chamber. The vessel has a heating element that can heat and vaporize the liquid gas within the inner chamber of the tube. The still vaporizes the liquid gas within the tube, which causes liquid to flow from the inner cavity to the inner chamber. Vaporized liquid gas condenses and falls into the inner cavity, which then forms a layer of distilled “clean” liquid, on top of a layer of undistilled “dirty” liquid. The cycle is continued until the level of dirty liquid falls below the one way control valve.
WO 97/33031 does not provide an apparatus utilizing a carbon dioxide based solvent that will allow two or more fluids having different chemical compositions to be stored and/or processed within the same pressure vessel while maintaining the different chemical compositions of the two or more fluids.
SUMMARY OF THE INVENTION
According to the present invention, divided pressure vessels for use in a carbon dioxide based system are provided. Divided pressure vessels of the present invention may allow multiple solvent baths each having a different chemical composition to be stored and/or processed in a single pressure vessel while maintaining the different chemical compositions of the multiple solvent baths. Thus, divided pressure vessels of the present invention may provide the improved operational efficiency of a carbon dioxide based system having multiple solvent baths while decreasing the capital costs that may be associated with such systems. Methods of utilizing such divided pressure vessels in processing systems employing carbon dioxide based solvents are also be provided.
According to the present invention, methods of utilizing a divided storage vessel include transferring a first densified gas based treating solution from a first liquid chamber in a divided storage vessel having a plurality of liquid chambers to a processing vessel, returning the first treating solution from the processing vessel to the divided storage vessel, transferring a second carbon dioxide based treating solution having a composition different from the first treating solution from a second liquid chamber in the divided storage vessel to a processing vessel, and returning the second treating solution from the processing vessel to the divided storage vessel. The processing system may be a batch processing system, a semi-batch processing system, or a continuous processing system.
In embodiments of the present invention, the methods of utilizing a divided storage vessel include contacting an article in the processing vessel with the first treating solution, and contacting the article in the processing vessel with the second treating solution. The first treating solution may be a pre-wash solution, a wash solution, or a coating solution, and the second treating solution may be a wash solution, a coating solution, or a rinse solution. The articles may be various substrates including, but not limited to, fabric substrates, metal substrates, and electronic devices, to name just a few. The operation of contacting the article with the wash solution may include removing polymeric materials, such as resins, adhesive, coatings, and inks, from the article.
In other embodiments of the present invention, at least one of the first or second treating solutions is an impregnating solution that includes an impregnating agent. The operation of contacting the article with the impregnating solution includes impregnating the article with the impregnating agent. The article may be a porous material and the impregnating agent may be insect treatments, pigments, strength enhancers, water repellants or pollution repellants.
In still other embodiments of the present invention, at least one of the first or the second treating solutions is an extracting solution, and the operation of contacting the article with the extracting solution includes extracting a substance from the article using the extracting solution.
In yet other embodiments of the present invention, at least one of the first or the second treating solutions is a developing solution. The operation of contacting the article with the developing solution includes developing a resist on a semiconductor substrate using the developing solution.
In other embodiments of the present invention, the methods of utilizing a divided storage vessel includes the operation of synthesizing a chemical compound by combining the first treating solution with the second treating solution. The first treating solution is a first reacting solution that includes a first reactant and the second treating solution is a second reacting solution that includes a second reactant.
In still other embodiments of the present invention, the methods of utilizing a divided storage vessel includes polymerizing one or more monomers by combining the first treating solution with the second treating solution where the first treating solution includes a first monomer and the second treating solution includes an initiator or a second monomer.
In yet other embodiments of the present invention, the methods of utilizing a divided storage vessel inc
Brainard David E.
DeYoung James P.
McClain James B.
Worm Steven L.
Chen Kin-Chan
Micell Technologies
Myers Bigel & Sibley & Sajovec
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