A novel pretreatment technology for organic low-dielectric material to suppress copper diffusion and improve ashing resistance

new novel pretreatment technology for integration of organic low-dielectric material in copper interconnects for ultralarge scale integration applicat ions is developed. Using NH3 plasma treatment, two extremely important adva ntages were achieved in spin-on organic polymer (SOP), including the reduct ion of copper diffusion and the improvement of ashing resistance. A copper/ SOP/Si capacitor structure is used to study the electrical characteristics of SOP film after ashing treatment or postanneal. Higher barrier capability and better ashing resistance can be achieved by the SOP layer after NH3 pl asma treatment. After annealing at 500 degrees C for 60 min, secondary ion mass spectroscopy depths profile shows that the Cu atoms do not penetrate i nto the SOP when they are pretreated by NH3 plasma. Furthermore after the a shing step, the carbon atoms in the SOP film almost remain the same when th ey are pretreated by NH3 plasma. On the other hand, the concentration of ca rbon in as-cured SOP is no longer seen. The reason of improving ashing resi stance and better barrier capability was due to the organic polymer film re arranging to form a carbon-containing silicon nitride film. (C) 2000 The El ectrochemical Society. S0013-4651(99)10-007-7. Ail rights reserved.