Abstract: A device for concentrating chemical substances for use during the fabrication of a semiconductor device uses a sample container for holding chemical substances. A feed tube in gas flow communication with the sample container introduces a carrier gas. A vapor outlet in gas flow communication with the sample container discharges a mixture of a vapor and the carrier gas. A sample heater, disposed above and apart from the sample container, heats the chemical substances to a first predetermined temperature. A gas source supplies the carrier gas, and a gas heater, in gas flow communication with both the gas source and the feed tube, heats the carrier gas to a second predetermined temperature. A condenser in flow communication with the vapor outlet produces a liquid from the vapor, and a collecting container collects the liquid.

Abstract: Semiconductor wafer processing methods and apparatus recirculates etching solution from a lowermost point of a container hosting wafers through a filtration device and back to a point above the location of the wafers within the container. The container includes an inclined bottom wall and an outlet located below an uppermost portion of the inclined bottom wall.

Abstract: The present invention allows the reproduction of a crystalline aluminum hydroxide having a high particle strength and a high purity which can find wide application such as abrasive from a supersaturated sodium aluminate solution which is being recycled in the production of aluminum hydroxide or lithographic printing plate. In a process for the purification of aluminum hydroxide which comprises the hydrolysis reaction of a supersaturated solution of sodium aluminate to crystallize aluminum hydroxide, the improvement which comprises the steps of keeping the temperature of a suspension formed by mixing a mother liquor having a total caustic soda concentration of from 50 to 700 g/l and an aluminum concentration or from 0 to 300 g/l with crystalline aluminum hydroxide at a range of from 10.degree. C. to 200.degree. C. for at least 1 to 48 hours, mixing the suspension with the supersaturated solution of sodium aluminate, and then causing the crystallization reaction at the crystallization reaction temperature.

Abstract: A method and apparatus for economically regenerating chemical etch solutions for aluminum and the alloys thereof without the use of large, complex and expensive processing apparatus. The method of the invention can be accomplished substantially at ambient temperature thereby avoiding the necessity for substantial investment in complex temperature control instrumentation. In accordance with the method of the invention, the spent etchant which is to be regenerated is first mixed with water in a separate storage tank and is then cold filtered prior to being transferred to the reactor or regeneration vessel. This step substantially reduces contamination buildup within the reactor vessel and thereby avoids costly periodic shut down of operations for clean-up. Due to the unique nature of the regeneration process of the invention, the alumina produced as a by product of the process is of extremely high quality and is snow white in color.

Abstract: Method for upgrading waste material comprising sheet metal with a zinc plating on at least one side thereof, including a) subjecting the waste material to a mechanical processing step to improve the accessibility of said zinc layers to a subsequent chemical etching by increasing the accessible etching surface of the zinc layer portions, this being achieved by crushing the waste material to separate the sheets from each other and by producing cracks in said zinc layers; this step is advantageously conducted in a shredder/mill; b) subjecting the waste material to a chemical etching step to dissolve the zinc by immersing it in a basic bath; and c) separating the zinc-free sheets from the chemical etching bath continuing the dissolved zinc, which is then recovered by electrolysis. The invention particularly discloses the use of the above method for recovering and upgrading fresh scraps of zinc plated sheets in the automotive industry.

Abstract: A silicon substance is etched by using alkaline etchant containing additive (Cu, Pb, Mg). The content of the additive is controlled intentionally to provide desired etching quality during an etching operation.

Abstract: A process for the preparation of an analytical sample characterized by depositing and separating solely the impurity to be analyzed from phosphoric acid; a process for analysis of the impurity characterized by depositing and separating solely the impurity from phosphoric acid and applying the separated material to analysis; a process for preparation of high grade phosphoric acid characterized by depositing and separating solely the impurity from phosphoric acid to be purified; a process for the fabrication of a semiconductor device characterized by using phosphoric acid, the impurity content of which is not more than 10.sup.-3 Bq/mL, defined by the concentration of a contained radioactive element selected from the group consisting of Pb, Bi and Po, as a processing solution.

Abstract: A method of stripping a nitride layer from a wafer includes the steps of putting the wafer into a process bath containing a stripping solution, passing the stripping solution from the process bath through a filter to remove the nitride particles contained therein, heating the filtered stripping solution through an in-line electrical heater with two heating parts connected in parallel to allow the stripping solution to quickly return to the proper etching temperature, and returning the temperature recovered stripping solution to the process bath. The filtered stripping solution is branched through the parallel heating parts to enable it to be quickly heated. The stripping solution may be a phosphoric acid solution, whose proper etching temperature is about 163.degree. C. The in-line heater consists of at least two heating parts connected in parallel, each with an electrical capacity of 6 KW.

Abstract: In accordance with the present invention, a wet bench processing apparatus equipped with a rapid drain and rinse system is provided. The system stores reserved liquids and air pressure during normal operation for use during a situation where a power or mechanical failure may occur. When such a failure occurs, a controller unit, which is connected to an uninterrupted power supply or other types of energy storage devices, provides an electrical control signal to a solenoid actuated valve. The solenoid actuated valve receives a pneumatic input that is received from a pressurized air reservoir. When the electrical signal is received by the solenoid actuated valve, the reserved pneumatic pressure is released to operate one or more valves. A reservoir of rinse fluid is provided such that when one of the valves is activated by the solenoid actuated valve, gravity forces rinse fluid through the valve and into the tank to remove the chemicals from the wafers.

Abstract: An improved method for stripping or removing tin or tin/lead plating materials from copper-based alloys is provided. This method is essentially a two-stage process whereby the bulk of the plating layer is removed in the first stage and the remaining intermetallic layer (i.e., the interface between the copper-based substrate and the plating materials) is removed in the second stage. The first stage uses an aqueous etchant solution containing either sulfuric acid and nitric or an alkane sulfonic acid and nitric acid. An aqueous immersion solution containing either sulfuric acid and copper (II) ions or an alkane sulfonic acid and copper (II) ions (which can form complexes with the alkane sulfonic acid such as copper mesylate) is used in the second stage to remove the remaining intermetallic layer. The copper-based substrate, after rinsing with water and is drying (if appropriate), can then be treated using conventional metal-recycling procedures.

Abstract: In a developing, etching and stripping apparatus, photoresist developing and stripping chemicals are drawn off into separate circulatory paths in each of which they are pumped through a heat exchanger, a series of tangential filters, an ultraviolet contactor and a collection tank. Permeate from the filters is returned to the developing or stripping stage, and solutions with high concentrations of solids are removed from the collection tanks for disposal.

Abstract: The purity of a liquid chemical agent is improved simultaneously with obtaining a homogeneous concentration of a specific chemical in the agent, thereby improving the quality of substrate processing steps. Pure water is supplied from a pure water supply (30) into a process tank (1) by opening an opening/closing valve (33) on a pure water supply system (7) and by closing an opening/closing valve (19) on a circulation system (5). After the process tank (1) is completely charged with pure water, the opening/closing valve (33) is closed while the opening/closing valve (19) is opened. This closes a pipe conduit (11) of the circulation system (5) and allows pure water in the process tank (1) to be circulated through the circulation system (5) by a pump (13). A first opening/closing valve (49) on a gas supply system (9) is subsequently opened to allow hydrogen chloride gas from a hydrogen chloride gas supply (40) to be fed into a mixing unit (17) of the circulation system (5).

Abstract: Methods and compositions are disclosed for cleaning oxides and metals from surfaces of silicon wafers in a two-phase liquid system. The two-phase system comprises a fluorine containing oxide etchant, such as hydrofluoric acid, that is soluble within two immiscible liquids of different densities such that the two liquids form separate layers. Silicon wafers are immersed into the top layer which is a nonpolar organic liquid. The bottom layer is polar liquid, preferably water. The nonpolar organic liquid includes ketones, ethers, alkanes and alkenes, but is preferably pentanone. Metal ions are transported from surfaces of the silicon wafers through the pentanone top layer to the polar water bottom layer, thereby eliminating metal ions from the pentanone. Due to relative solubilities, the concentration of hydrofluoric acid in the water bottom layer is greater than in the pentanone top layer.

Abstract: An apparatus for removing polymer particles from the stripping solution used in the treatment of printed wireboards comprises passing a solution having resist particles dispersed therein over a screen having openings of 100 microns, where the screen is maintained at an angle of from 40 to 70.degree. to the horizontal. The apparatus comprises a curtain tube consisting of an inner concentric tube with a plurality of holes and an outer concentric tube with a slot wherein the position of the slot is adjustable, a filter comprising a screen, and a pump for circulating the solution. In one embodiment, the filter comprises a cylindrical screen.The stripping solution comprises an aqueous solution of an organoamine, ionic nitrogen compound or alkali or alkaline-earth hydroxide, or mixtures thereof.

Abstract: A wet etching process (10) etches sacrificial oxide on a substrate without damaging a polycrystalline silicon structure on the substrate. The etching process (10) includes dipping the substrate in a surfactant (11), submerging a portion of the substrate in a recirculating bath of the etchant while injecting an inert gas into the etchant (12) to purge the etchant of oxygen, rinsing the substrate in deionized water (14), submerging a portion of the substrate in a hydrogen peroxide solution (15), rinsing the substrate for a second time (17), and drying the substrate in isopropyl alcohol vapor (18). The inert gas injected into the etchant displaces oxygen dissolved in the etchant and protects the polycrystalline silicon structure from being etched.

Abstract: Cupric chloride etchant waste is converted into non-hazardous material consisting of copper oxide and salt water. The cupric chloride etchant is preheated and a stream of the etchant is combined with a stream of preheated caustic solution. A neutralization reaction occurs in the mixed stream which is directed to a mixing tank. The reaction completes in the mixing tank without addition of heat, producing fine copper oxide which is filtered out from the salt water. The entire apparatus for carrying out the process can be integrated into a single portable unit.

Abstract: A process for control of recycle of ammoniacal copper etchant which uses metallic aluminum to remove copper without substantially adding undesirable byproducts, by controlling the temperature and mixture rate of the removal process. The very rapid reaction can be controlled by using a diluent of copper-free etchant, heating to process temperature, then adding spent, copper containing etchant at a controlled rate while actively cooling the system to control the temperature. The copper concentration can be monitored by colorimetry while maintaining the pH above pH 8. The separated metallic copper and aluminum hydroxide sludge are easily filtered from the etchant. The purified etchant is now suitable for chemical adjustment and reuse.

Abstract: A method for removing polymer particles from the stripping solution used in the treatment of printed wireboards comprises passing a solution having resist particles dispersed therein over a screen having openings of 100 microns, where the screen is maintained at an angle of from 40 to 70.degree. to the horizontal. The apparatus comprises a curtain tube consisting of an inner concentric tube with a plurality of holes and an outer concentric tube with a slot wherein the position of the slot is adjustable, filter means comprising a screen, and a pump for circulating the solution. In one embodiment, the filter means comprises a cylindrical screen.The stripping solution comprises an aqueous solution of an organoamine, ionic nitrogen compound or alkali or alkaline-earth hydroxide, or mixtures thereof.

Abstract: A method of improved control of recycle of ammoniacal copper etchant which uses metallic aluminum to remove copper without substantially adding undesirable byproducts. The very rapid reaction can be controlled by using a diluent of copper-free etchant, eliminating overheating. The separated copper and aluminum hydroxide sludge are easily filtered from the etchant. The purified etchant is now suitable for chemical adjustment and reuse.

Abstract: A molybdenum etching process which reduces hazardous treatment waste is disclosed. Etchants which can be used are ferric sulfate and ferric ammonium sulfate. Waste products resulting from this etch are Fe(OH).sub.3 and CaSO.sub.4.

Abstract: This invention relates to the removal of lead from spent ferric nitrate based solder strippers, the regeneration of the spent ferric nitrate based solder strippers, and the reuse of these solutions at least one time. It comprises a method and process for precipitating lead salts from used acidic solder strippers which are employed to strip solder coatings, including the underlying tin-copper alloy, from the copper substrate of a printed circuit board. The method includes the use of sulfate ions which are directly added to an aqueous solution of spent solder stripper, without neutralization of the spent solder stripper, optionally in combination with nitric or methylsulfonic acid addition. After precipitation and removal of the lead salts, additional components of the solder stripper composition may be added to substantially restore the initial functioning of the solder stripper.

Abstract: An aqueous mixture etchant containing hydroiodic acid and ferric chloride is suitable for etching ITO to form a minute electrode pattern as used in a liquid crystal display device. When the etchant has caused a decrease in etching performance due to a compositional change, it can be effectively regenerated by replenishing appropriate amounts of hydrochloric acid and pure water, or an appropriate amount of a dilute hydrochloric acid at a constant concentration, while minimizing the use of hydroiodic acid and ferric chloride which are rather expensive compared with hydrochloric acid and pure water.