US Patent 7560357 Method for creating narrow trenches in dielectric materials

A method for producing narrow trenches in semiconductor devices. The narrow trenches are formed by chemically changing the properties of a first dielectric layer locally, such that the side walls of a patterned hole in the first dielectric layer is converted locally and becomes etchable by a first etching substance. Subsequently a second dielectric material is deposited in the patterned structure and the damaged part of the first dielectric material is removed such that small trenches are obtained.