Low temperature interlayer formation technology using a new siloxane polymer film

Abstract

A new technology for low-temperature dielectric film formation under Al wirings is described. This technology utilizes spin-on film formed from the organic siloxane polymer solution optimized to have minimal film shrinkage/stress generation during heat treatment. The optimized solution is composed of 62-mol.% tetra-ethoxy-silane (Si(OEt)/sub 4/), 31-mol.% methyl-tri-ethoxy-silane (Me-Si(OEt)/sub 3/), and 7-mol.% phosphorus-triethoxide (PO(OEt)/sub 3/) oligomer in ethyl alcohol. Crack-free thick siloxane polymer film with no carbon is formed by three-step heat treatment processes (150 degrees C hot plate baking, 400 degrees C furnace annealing in N/sub 2/, and 800 degrees C furnace annealing in O/sub 2/). The planarization capability of this film is superior to that of the conventional BPSG reflow film, and other film properties are as good as those of the CVD-PSG film.<>