Electrical chemical mechanical polish

Electric chemical polish (ECP) and electric chemical mechanical polish (ECMP) [53] have been developed as promising methods for global planarization of LSI fabrication and abrasive-free polish. 

Method (10) is an ECMP (electrical chemical mechanical polish method). Electricity is applied to the film to be polished like di-plating of the plating electrode. This method was developed for polishing metal, especially Cu interconnect wire. For various reasons, this method has not become the mainstream. 

T. Park, T. Tugbawa, D. Boning, J. Chung, S. Hymes, R. Muralidhar, B. Wilks, K. Smekalin, and G. Bersuker, Electrical Characterization of Copper Chemical Mechanical Polishing, Proc. CMP-MIC, Santa Clara, CA, Feb. 1999,... 

B. Stine, D. Boning, J. Chung, L. Camilletti, F. Kruppa, E. Equi, W. Loh, S. Prasad, M. Muthukrishnan, D. Towery, M. Berman, and A. Kapoor, The Physical and Electrical Effects of Metal Fill Pattern Practices for Oxide Chemical Mechanical Polishing Processes, IEEE Ti ans. Electr. Dev., Feb 1998. 

Metal-RIE process was/is used in the fabrication of Al inter-coimects on chips." This process is depicted in four steps in Fig. 2. The first step in the metal-RIE process is sputter deposition of a blanket thin film of Al (or Al alloys, such as Al-Cu, Al-Si) over a planerized dielectric (e.g., silicon dioxide). In the next step, the unwanted metal is etched away by reactive ion etching (RIE) through a photoresist mask. The features produced this way are separated, electrically isolated, metal Al conductor lines. In the RIE process chemicaly active ions such as F or Cl bombard the Al surface and form volatile aluminum fluorides or chlorides, which are then pumped away in the vacuum system. After etcliing, a dielectric is deposited in such a fashion that it fills the gaps between the lines as well as above them. In the last step, the dielectric is planarized using the chemical mechanical polishing (CMP) technique. ... 

The ER polishing slurries are obviously superior to the conventional colloidal slurries, as the mechanical properties of RR fluids can be easily adjusted via the applied electric field. The semiconductor wafers, even more complex semiconductor devices, can be efficiently and elTectively polished using the cheap and smart ER slurries, Wc believe the ER slurries may revolutionize the chemical-mechanical-polishing (CMP) technology, which now plays a key role in the polishing industry. Of course the magnetorheological fluid can also function as a smart fluid for polishing purposes [56,57]... 

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