Patent ID: 7816253

Claim:
A method of forming an interconnect structure in an inter-layer dielectric (ILD) material, the method comprising: forming a cap layer directly on top of said ILD material, wherein said ILD material is a porous material of hydrogenated amorphous silicon carbide (SiCH) with ultra-low dielectric constant (ULK), using a sputtering deposition process; creating an opening in said cap layer using a photo-mask through a lithographic process for forming a via; said opening exposes at least a portion of said porous ILD material of SiCH due to misalignment; treating the exposed portion of said porous ILD material of SiCH; wherein the treating includes using a gas cluster ion beam (GCIB) at a dosage of approximately between 0.1 and 10.0×10 15 ion-clusters/cm 2 , preferably between 0.5 and 2.5×10 15 ion-clusters/cm 2 , to bombard and irradiate said exposed portion of said porous ILD material of SiCH to create a densified area on the exposed portion of said porous ILD material of SiCH to prevent a metal element from penetrating into said porous material of SiCH, wherein said densified area forms a layer having a thickness from 10 Åto 500 Å; said exposed portion is a bottom surface of said via created in said porous ILD material of SiCH; and wherein a size of ion cluster of said GCIB is about 5 nm and is bigger than a size of about 1 to 2 nm of pore in said porous material of SiCH; and metallizing said densified area, wherein said metallizing includes depositing a barrier metal film subsequently on top of said densified area in the bottom of said via; forming a conductive material directly on top of said barrier metal film; and planarizing said conductive material to form said interconnect structure.