Abstract
In this thesis, three major topics are studied: The first topic is the reduction of RC delay with combining low dielectric constant material such as hydrogen silsesquioxane (HSQ) and selective CVD-W HSQ maybe used as an intermetal dielectric in multilevel metallization due to its low dielectric constant as compared to SiO2. But during via etching process, HSQ is susceptible to the attack from O2 ashing, this will result in formation of moisture in the film exposed to the via sidewall and generation poison via problem. In this work, hydrogen plasma post-treatment is used to release the poison via problem. HSQ performed by hydrogen plasma post-treatment exhibits robust resistance to O2 ashing. The via resistance of CVD-W plug with HSQ as intermetal dielectric decreases with increasing the plasma treatment time. The second topic is the characterization of the multilayered Ti/TiN grown by CVD technique. When TiN film is used as an diffusion barrier between two materials, the diffusion of the two original materials should be occurred under high temperature processing due to the grains of TiN film are of columnar structure.We proposed a novel multilayered Ti/TiN structure to enhance the barrier property of TiN. After annealing at elevated temperature, low leakage current can be still achieve by multilayered Ti/TiN film when compared to a PVD-Tin barrier. In addition, The resistivity of these multilayered Ti/TiN films can be reduced to 120uΩ-cm with NH3 plasma post-treatment for 300 sec. Increasing number of multilayered of Ti/TiN fIlms and plasma post-treatment technique contributed to reduce the resistivity of TiN films effectively. The concentration of CI in the multilayered Ti/TiN sample was found to be 1.6 at%so that corrosion on the AI was minimal. The thired topic is the pre-clean of AI via for selective CVD-W deposition. For the AI substrate, pre-clean of AI via is critical to the selective CVD-W process.Various pre-clean solutions are tried to clean the AI surface. We used pre-clean solutions such as (NH2OH2)2H2SO4 and (NH2OH)2H2SO4 combined with CuSO4 to treat the aluminum surface prior to W deposition. We expected that the role of CuSO4 in the new pre-clean solution is to provide Cu to passivate AI surface. The (NH2 OH2) H2SO4 can efficient to remove A12O3 and leave the cleam AI in the surface of via. CU2+ can passivate AI surface to prevent AI2O3 appearance. Excellent selective CVD-W deposition and low via resistance can be obtained by using (NH2 OH)2H2SO4 mixed with CUSO4 mixed with CUSO4 to pre-clean for 1min at 50℃.