Abstract: A process for fluoride removal from wastewater streams produced during industrial operation for further industrial use or to comply with environmental regulations. The process segregates the removal of fluoride and fluorosilicate ions, from the totality of ions in the waste water stream, thus improving treatment efficiency and reducing costs. Ion-exchange chromatography is used to remove the fluoride and fluorosilicate ions by passing the wastewater stream through one or more columns that contain a charged resin which selectively binds cations/anions in the stream. The fluoride ions are washed from the column and then collected for removal or use in other processes.

Abstract: A process for fluoride removal from wastewater streams produced during industrial operation for further industrial use or to comply with environmental regulations. The process segregates the removal of fluoride and fluorosilicate ions, from the totality of ions in the waste water stream, thus improving treatment efficiency and reducing costs. Ion-exchange chromatography is used to remove the fluoride and fluorosilicate ions by passing the wastewater stream through one or more columns that contain a charged resin which selectively binds cations/anions in the stream. The fluoride ions are washed from the column and then collected for removal or use in other processes.

Abstract: A method for pretreating waste water for use in reverse osmosis filtration is provided. Small amounts of chemicals are added to the waste water to promote formation of filterable particles from colloidal and dissolved solids. These particles are then removed via a closed-end, low pressure, high flowrate filtration system prior to reverse osmosis treatment.

Abstract: A method of cleaning a filter clogged with flocculating materials is provided. The method comprises determining the flocculated materials clogged on the filter and adding a dispersing agent to break up said flocculated materials to form dispersed precipitates. Then the dispersed precipitates are removed from the filter in a regular cleaning such as backflushing.

Abstract: An improved method of treating wastewater to remove ammonia and fluoride is provided. The method comprises the steps of chemical destruction of ammonia with an oxidizing agent, followed by treatment with calcium salts to precipitate insoluble calcium fluoride, and filtration to remove the precipitate.

Abstract: A system for removing fluoride from wastewater is provided. The system comprises a reaction tank for processing said wastewater by adding calcium salts, a filtration tank for removing the precipitated fluoride formed in the reaction tank, a single fluoride electrode disposed at the reaction tank for measuring a concentration of fluoride in the influent wastewater and providing an output signal, and a programmable controller for controlling addition of said calcium salts into said reaction tank. The programmable controller defines a setpoint of fluoride concentration in the reaction tank and automatically controls addition of calcium salts based on the setpoint and the output signal provided by the single fluoride electrode. A method of removing fluoride from wastewater is also provided.

Abstract: A method of removing arsenic and fluoride from aqueous solutions in the same process is provided. Specifically, the pH of the aqueous solution is adjusted to a pH in the range of about 5 to 8. A combination of calcium salts, and ferric or aluminum salts are added to form insoluble arsenic and fluoride bearing solids. The solids are then removed from the aqueous solution.

Abstract: A method of treating industrial wastewaters is provided. Specifically, the wastewater includes one or more organic contaminant materials and is pre-treated prior to filtering by the following steps The pH of the wastewater is adjusted to a pH in the range of about 2 to 6, and a combination of iron salts and peroxide are added to the wastewater and allowed to react for a period of at least about three minutes. Next, the pH of the wastewater is adjusted upwards to a value of at least 7 and precipitating or flocculating agents are added to form an insoluble contaminant bearing compound. The compound is then filtered from the wastewater thereby removing the contaminant materials from the wastewater. This invention is particularly suited for use with single pass flow-through filters, and most particularly suitable for high flow rate single pass flow-through filters.

Abstract: An improved method of treating wastewater to remove ammonia and fluoride is provided. The method comprises the steps of chemical destruction of ammonia with an oxidizing agent, followed by treatment with calcium salts to precipitate insoluble calcium fluoride, and filtration to remove the precipitate.

Abstract: A method of cleaning a filter clogged with flocculating materials is provided. The method comprises determining the flocculated materials clogged on the filter and adding a dispersing agent to break up said flocculated materials to form dispersed precipitates. Then the dispersed precipitates are removed from the filter in a regular cleaning such as backflushing.

Abstract: A system for removing fluoride from wastewater is provided. The system comprises a reaction tank for processing said wastewater by adding calcium salts, a filtration tank for removing the precipitated fluoride formed in the reaction tank, a single fluoride electrode disposed at the reaction tank for measuring a concentration of fluoride in the influent wastewater and providing an output signal, and a programmable controller for controlling addition of said calcium salts into said reaction tank. The programmable controller defines a setpoint of fluoride concentration in the reaction tank and automatically controls addition of calcium salts based on the setpoint and the output signal provided by the single fluoride electrode. A method of removing fluoride from wastewater is also provided.

Abstract: A method of removing arsenic and fluoride from aqueous solutions in the same process is provided. Specifically, the pH of the aqueous solution is adjusted to a pH in the range of about 5 to 8. A combination of calcium salts, and ferric or aluminum salts are added to form insoluble arsenic and fluoride bearing solids. The solids are then removed from the aqueous solution.

Abstract: A method of treating industrial wastewaters is provided. Specifically, the wastewater includes one or more organic contaminant materials and is pre-treated prior to filtering by the following steps The pH of the wastewater is adjusted to a pH in the range of about 2 to 6, and a combination of iron salts and peroxide are added to the wastewater and allowed to react for a period of at least about three minutes. Next, the pH of the wastewater is adjusted upwards to a value of at least 7 and precipitating or flocculating agents are added to form an insoluble contaminant bearing compound. The compound is then filtered from the wastewater thereby removing the contaminant materials from the wastewater. This invention is particularly suited for use with single pass flowthrough filters, and most particularly suitable for high flow rate single pass flow-through filters.

Abstract: Simultaneous non-contact plating and planarizing of copper interconnections in semiconductor wafer manufacturing is performed by providing relative motion between a bipolar electrode and a metallized surface of a semiconductor wafer without necessary physical contact with the wafer or direct electrical connection thereto.

Abstract: Plating of metal interconnections in semiconductor wafer manufacturing is performed by providing relative motion between a bipolar electrode assembly a single metallized surface of a semiconductor wafer without necessary physical contact with the wafer or direct electrical connection thereto.

Abstract: Planarization of metal interconnections in semiconductor wafer manufacturing is performed by providing relative motion between a bipolar electrode assembly scanned and a single metallized surface of a semiconductor wafer without necessary physical contact with the wafer or direct electrical connection thereto.

Abstract: A method for the removal and purification of substantially all of the fluoride ions contained in a solution containing greater than 10 parts per million (ppm) fluoride ion, a mixture of other anions, silicon in the form of a fluorosilicic acid, silicic acid, silicates, or silicon tetrafluoride, and optionally also containing complex metal fluorides, to produce an ultrapure hydrofluoric acid, comprising the steps of (a) adjusting the pH of the solution to an alkaline pH to hydrolyze the fluorosilicic acid and any complex metal fluorides; (b) removing the fluoride ions and other anions from the solution by passing the solution through an ion exchange resin, where the ion exchange resin is adapted to adsorb substantially all of the fluoride passed over the ion exchange resin; (c) displacing the fluoride ions and other anions bound to the ion exchange resin, thereby forming a mixture of anions in an effluent emanating from resin; (d) optionally concentrating the effluent at a high pH and then lowering the pH; and

Abstract: A method for the on-site reprocessing of isopropyl alcohol used in semiconductor manufacturing, to generate an ultradry and ultrapure isopropyl alcohol. This ultradry and ultrapure isopropyl alcohol is produced through a pervaporation step, followed by double distillation. In the first distillation step, an autonomous azeotropic self-stripping distillation column is used to produce an ultradry and partially purified isopropyl alcohol. In the next step, the isopropyl alcohol is distilled in an overhead product distillation column, to produce an ultrapure and ultradry isopropyl alcohol. Alternatively, if the feed isopropyl alcohol contains less than 2000 ppm water, the pervaporation step may be omitted.The resulting isopropyl alcohol has between a high of 100 parts per million (ppm) and a low of 0.1 ppm of water in the isopropyl alcohol. It also has zero particles per milliliter of a size larger than 2.0 microns, zero to 2 particles per milliliter of a size of 0.5 micron to 2.

Abstract: Waste water from an apparatus that rinses particles from semiconductor wafers is collected in a tank. A pump sends waste water from the tank through a particle filter and onward to a supply inlet for initial rinse stages of the processing apparatus. Some of the waste water is bleed from the tank and replenished by fresh water introduced into the final rinse stage of the apparatus. If the semiconductor processing so dictates, chemicals may be added to the waste water to alter the pH and/or prevent the precipitation of solids in the tank. The addition of such chemicals can be controlled automatically in response to sensed characteristics of the waste water.

Abstract: This invention relates to a method for increasing the effective process life and chemical efficiency of use of aqueous-based developer solutions used for chemical development of photoresists such as are used in the printed circuit industry. The activity is maintained by regenerating some of byproducts during the process to active carbonate, by controlled additions of alkaline hydroxide instead if conventional carbonate solution. The pH and thus the development speed can automatically be controlled at any desired constant value. This invention allows simple automation of printed circuit photoresist development, with reduced chemical costs and increased chemical usage efficiency and thus reducing the industrial waste volume.