Patents Assigned to Nisso Engineering Company, Ltd.
  • Method for recirculating high-temperature etching solution
    Patent number: 4980017
    Abstract: A method for recirculating a high-temperature etching solution according to the present invention comprises the steps of continuously removing, from a bath for etching a wafer for a semiconductor device, a portion of an etching solution contained in the etching bath, injecting a predetermined amount of pure water for adjusting the concentration of the etching solution into the removed etching solution, heating the resulting solution to a predetermined temperature, and recirculating the heated solution into the etching bath.
    Type: Grant
    Filed: September 26, 1989
    Date of Patent: December 25, 1990
    Assignee: Nisso Engineering Company, Ltd.
    Inventors: Toshimitsu Kaji, Tadao Takeuchi, Tsutomu Kawashima, Eiichi Miyakoshi, Yasukatsu Nishikata, Yasuya Hisatome