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US 6,391,209 B1Granted
Regeneration of plating baths
AssigneeMykrolis Corporation
InventorsBrett Matthew Belongia, Zhen Wu Lin, John E. Pillion, Jieh-Hwa Shyu
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AssigneeMykrolis Corporation
InventorsBrett Matthew Belongia, Zhen Wu Lin, John E. Pillion, Jieh-Hwa Shyu
Estimating the term…
The present invention provides a system and method for selectively removing organic and inorganic contaminants from plating baths. More particularly, the invented method relates to the use of a source of energy in combination with chemical oxidants, alone or in conjunction with a catalyst to oxidize organic contaminants in the plating bath to a level such that the electroplating bath can be recovered and reused after appropriate chemical adjustment. The oxidative treatment method may be a continuous process or a batch process that is performed in a single pass and the endpoint of the oxidative process detected by a sensor. Residual organics, and chloride ions in the bath are removed from the solution by a chemisorption or physisorption treatment. Inorganic contaminants are removed from the electroplating bath by selective ion exchange resins or electrodialysis, while particulate and suspended colloidal particles are removed by filtration before the treated plating bath is recycled.
A system for the recycling of spent fluid from a plating bath comprising an outlet from a plating bath, one or more oxidation units connected to the outlet from the bath, each said oxidation unit coupled to one or more controlled sources of energy and chemical oxidants that are directed to the fluid of the bath as it passes through the oxidation unit in order to break down any organics, one or more sensors for sensing the state of an oxidation reaction;
The system of claim of 1 wherein unused oxidant is removed by a catalytic material in a form selected from the group consisting of beds and filters.
The system of claim of 1 wherein oxidized organics are removed using an organic scavenger in the form selected from the group consisting of absorptive filters and absorptive beds.
The system of claim of 1 wherein oxidized organics are removed using an organic scavenger selected from the group consisting of carbon, activated carbon, charcoal, and one or more modified resins.
The system of claim of 1 wherein oxidized organics are removed using an organic scavenger and a fiber matrix is used to immobilize the organic scavenger medium.
The system of claim of 1 wherein chloride ions are removed along with oxidized organics.
The system of claim of 1 wherein chloride ions are removed using anionic and/or cationic exchange resins.
The system of claim of 1 wherein ozone is introduced by porous or fritted PTFE resin, or ceramic, or sintered metal diffusers.
The system of claim of 1 wherein the oxidants used in the system can be used singly or in combination and are selected from the group consisting of hydrogen peroxide, ozone, oxygen, peroxydisulfuric acid and its salts, potassium peroxymonosulfate and mixtures thereof.
The system of claim of 1 wherein the sources of energy can be used singly or in combination and are selected from the group consisting of electric, thermal, acoustic, microwave, electromagnetic and combinations of these.
The system of claim of 1 wherein sparging of a controlled flow of gas through the solution maintains the concentration of the fluid by evaporation of a diluting fluid selected from the group consisting of solvent, liquid oxidant, and water.
The system of claim of 1 wherein oxidant gas is heated prior to injection into the fluid and is used to heat the fluid, control liquid evaporation, and accelerate the oxidation.
A process for the recycling of spent fluids of a plating bath comprising the steps of providing a conduit from an electroplating bath to one or more oxidation units, said units comprising one or more controlled sources of thermal energy and chemical oxidants, supplying a spent bath to the oxidation unit, exposing the spent fluids to the one or more sources of thermal energy and oxidant within the one or more oxidation units so as to reduce organic in the fluid as determined by a sensor, removing the thermal energy, chemical oxidant, and oxidized organics from the fluid, and returning the fluid to the electroplating bath.
Dependencies are inferred from the claim text.