Method for forming an inter-layer dielectric layer

Abstract

The invention describes a method for fabricating an inter-layer dielectric layer. In this method, a plurality of first polysilicon lines, a first inter-layer dielectric layer, and a plurality of second polysilicon lines are formed in sequence on the substrate. A second inter-layer dielectric layer is formed between the plurality of second polysilicon lines and entirely covers the plurality of second polysilicon lines. Afterwards, a spin-on glass layer is formed on the second inter-layer dielectric layer, and then, while using the upper surfaces of the second polysilicon lines as etch end points, the spin-on glass layer and the second inter-layer dielectric layer are etched back to entirely remove the spin-on glass layer and partially remove the second inter-layer dielectric layer over the second polysilicon lines. Subsequently, a cover layer is formed to cover the second polysilicon lines and the remainder of the inter-layer dielectric layer. Finally, an oxide layer is formed to cover the resulting structure.