Patents Assigned to Sigma Engineering AB
  • Method for etching copper and recovery of the spent etching solution
    Patent number: 8236189
    Abstract: An etching and recovery method is described, wherein articles made of copper are etched with an acid aqueous solution of etching chemicals containing Cu2+ for oxidizing Cu0 to Cu+, chloride ions, oxidizing agent which oxidizes Cu+ to Cu2+, and pH-adjusting hydrochloric acid. The technical problem to be solved is to make it possible to circulate the etching solution between the etching process and the recovery process during the recovery of used etching solution in such a manner that a closed circuit can be maintained between the processes.
    Type: Grant
    Filed: July 7, 2008
    Date of Patent: August 7, 2012
    Assignee: Sigma Engineering AB
    Inventor: Harald Ottertun