POLYMERS AS MASKS FOR ION-IMPLANTATION

Polymers such as polyimides and photoresists, commonly used in semiconductor processing, have been investigated as high resolution masks for ion implantation. Thin films consisting of these materials were subjected to various implant doses of H** plus , Ne** plus and Ar** plus ions and the post implantation surface morphologies investigated. Polyimides maintained their integrity under severe H** plus and Ne** plus implant doses as high as 2. 4 multiplied by 10**1**6 cm** minus **2 and 1. 0 multiplied by 10**1**6 cm** minus **2, respectively, whereas photoresists began to degrade at implant doses of 9. 6 multiplied by 10**1**5 cm** minus **2 and 1. 9 multiplied by 10**1**5 cm** minus **2, respectively. When polyimide was H** plus implanted with doses up to 10**1**6 cm** minus **2 its dielectric constant and breakdown strength remained unchanged at 3. 5 and 150 V/ mu m, respectively. However, a gradual increase in the dielectric constant was observed for doses above this level. It was also observed that under the influence of H** plus implants with beam current densities exceeding 10** minus **7 A-cm** minus **2 a hardening of the polyimide occurs, resulting in reduction of the etching rate in an O//2 plasma.