1. A method of forming a device comprising: providing a substrate prepared with a dielectric layer; and processing the dielectric layer to serve as an intermetal dielectric (IMD) layer, wherein the IMD layer comprises a hybrid IMD layer comprising a plurality of dielectric materials with different k values, wherein processing the dielectric layer comprises providing a second dielectric material having a second k value, forming interconnects in the second dielectric material, depositing a passivation layer covering the second dielectric material and surface of the interconnects after forming the interconnects, patterning the passivation layer to cover only top surfaces of the interconnects, providing a patterned soft mask layer covering the patterned passivation layer and in direct contact with a portion of the second dielectric material adjacent to the passivation layer and interconnects, removing exposed portions of the second dielectric material not covered by the patterned soft mask layer to form openings, providing a first dielectric material to fill the openings and between the interconnects, wherein the first dielectric material comprises a first k value which is lower than the second k value, and wherein the second dielectric material surrounds and contacts sides and bottom surface of the first dielectric material, and processing the first and second dielectric materials such that top surfaces of the first dielectric material, the second dielectric material and the interconnects are coplanar with each other.