TW337039B - Process for producing IC capacitor by an oxygen ion implantation technique - Google Patents

Abstract

A process for producing an IC polysilicon structure, which comprises the following steps: forming a dielectric layer on a semiconductor substrate; using a photolithography technique and an etching technique to etch the dielectric layer to form holes; forming a layer of first polysilicon filling the holes; using a photolithography technique to form a first photoresist pattern on the hole region; using the first photoresist pattern as the etching protective mask and using an etching technique to etch the first polysilicon excluding the hole region to form a first polysilicon pattern; laterally etching the first photoresist pattern to modify the first photoresist pattern into a second photoresist pattern, the width of the first photoresist pattern being larger than the width of the second photoresist pattern to expose the upper surface of the first polysilicon pattern; using the second photoresist pattern as the ion implantation protective mask to implant oxygen ions into the upper surface of the first polysilicon pattern to form an oxygen-doped region; removing the second photoresist pattern; carrying out a thermal process on the oxygen-doped region to convert the oxygen-doped region into a silicon oxide region; using the silicon oxide region as the etching protective mask, and using an etching technique to etch off the middle portion of the first polysilicon pattern to form a trench; and removing the silicon oxide region.