Method for making an insulating film

Abstract

In a method for manufacturing an insulating film using a fluid source material without inviting corrosion of metal wiring or the problem of poisoned via, after making a SiO2 film as a base layer on an Si substrate defining an uneven surface with an Al alloy wiring by plasma CVD using SiH4 and N2O, and further making an inter-layer insualting film having a fluidity on the SiO2 film by low pressure CVD using SiH4 or organosilane and H2O2, O2 plasma processing is applied to the inter-layer insulating film. After that, a SiO2 film as a cap layer is made on the inter-layer insulating film by plasma CVD using SiH4 and N2O. Rapid thermal annealing using lamp heating or O3 annealing may be done in lieu of O2 plasma processing.

Description

[0001] 1. Field of the Invention[0002] This invention relates to a method for making an insulating film particularly suitable for use in making an inter-layer insulating film in a semiconductor device.[0003] 2. Description of the Related Art[0004] In a process of manufacturing a semiconductor device, a method for making an inter-layer insulating film using a fluid source material is often used to level the surface of a substrate by smoothing unevenness made by wiring or the like. Such an inter-layer insulating film contains much moisture (H.sub.2O) and is highly fluid.[0005] In conventional techniques, a non-fluid cap layer was formed directly on a fluid inter-layer insulating film containing much H.sub.2O by plasma CVD (for example, 1995 Dry Process Symposium, pp.261-268) to prevent cracks in the fluid inter-layer insulating film containing H.sub.2O during post-annealing. Typically used as the cap layer was a SiO.sub.2 film made of SiH.sub.4 and N.sub.2O by plasma CVD because N.sub...

AI Technical Summary

Benefits of technology

[0026] The above, and other, objects, features and advantage of the present invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.

[0027] FIGS. 1A through 1E are cross-sectional views for explaining a method for making an inter-layer insulating film according to the first

Problems solved by technology

Under the condition, if the inter-layer insulating film underlying the SiO.sub.2 film contains H.sub.2O and has a fluidity, then NH.sub.3 produced in vapor is incorporated (absorbed) into the underlying inter-layer insulating film. NH.sub.3 incorporated into the underlying inter-layer insulating film is released from the film when the inter-layer insulating film is heated or etched in a later process, and probably cause the problems of corrosion of metal wiring and poisoned via.

Images