IBM developed a new process for etching Kapton polyimide film to enable flexible circuits. John Glenning led the development effort, which included defining a new etching chemistry using potassium hydroxide, developing photoresist that could withstand the etching, and building a pilot production line. Initial tests showed defects from redeposited etched Kapton and scalloping near circuit lines, but refinements to the rinsing and photoresist application addressed these issues. Understanding of how the etching was similar to developing polyamic acid helped optimize the process parameters.