MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PURPOSE:To provide an opening of a desired cross section in a PSG film or to flatten the surface of the same by a method wherin B ions are selectively driven into the PSG film and the difference in etching rates is made use of in provding the PSG film with an opening or a flattened surface. CONSTITUTION:The etching rate slows down then B ions are driven into a PSG film undergoing the treatment. Suitable conditons are chosen for the injection of B ions so that the ions may be concentrated more in the lower layer of a PSG film 6 than in its upper layer. After the implantation of B ions, a resist mask 8 is provided before etching is effected by using buffering HF solution, which furnishes the edge (b) of a hole 16 with a gentle gradient preventing wirings thereon from disconnection. A similar etching process after a selective implantation of B ions through the intermidiary of a resist 18 results in the formation of a through-hole 20. The surface may be flattened by a process wherein a step 24 on the PSG film 6 is covered by a resist mask 26 before B ions implantation and said surface is exposed to a similar etchant after a reflow process with the resist mask 26 removed.