Forming method of contact hole

Abstract

Abstract PURPOSE:To improve an Al-wiring step coverage, and to enhance the yield of a wiring and reliability by using an intermediate insulating film, which consists of BPSG, AsSg or the like and can be reflowed at a low temperature. CONSTITUTION:An intermediate insulating film 13 is formed onto an silicon substrate 11, the surface thereof has a thermal-growth silicon oxide film 12. The intermediate insulating film 13 is shaped by a film, which can be reflowed at a low temperature and is composed of a substance such as BPSG or AsSg, at that time. A contact hole 14 is formed to the intermediate insulating film 13 and the thermal-growth silicon oxide film 12, the silicon substrate 11 is inserted into a diffusion furnace set at a temperature of approximately 800 deg.C, the temperature of the silicon substrate is elevated to 900 deg.C for 20min, and the silicon substrate is held for 20-30min at 900 deg.C when the temperature of the silicon substrate reaches 900 deg.C. An silicon oxide film 15 is shaped on the surface of the substrate (the surface of the substrate in the contact hole 14), but an impurity does not diffuse outward from the intermediate insulating film 13 at a temperature lower than 900 deg.C. The temperature of the inside of the furnace is elevated to 900 deg.C, and the intermediate insulating film 13 is reflowed during a time when the substrate is held at the temperature for 20-30min, and the contact hole 14 is formed to a smooth shape.

Inventors

• 👤 Akira Arimatsu
• 👤 有松　明

Bibliographic Details