Cleaning process in high density plasma chemical vapor deposition

One of the major emitters of perfluorocompounds (PFCs) in semiconductor manufacturing is the in situ plasma cleaning procedure performed after the chemical vapor deposition of dielectric thin films. The release of these man-made gases can contribute to the greenhouse effect. To reduce emissions of PFCs, it has developed a new plasma cleaning technology that uses a remote plasma source (RPS) to completely break down fluorine-containing gases into an effective cleaning chemical. The downstream plasma reactor consists of a plasma source, where the inductive discharge occurs; a transport region, which connects the source to the chamber; and the actual chemical vapor deposition chamber, where the fluorine radicals react with the deposition residues to form non-global-warming volatile byproducts that are pumped through the exhaust. From environmental point of view the overall method has clear benefits, however, with the new technology several new optimization problems arise. In recent years, semiconductor equipment manufacturers have put in a great effort to improve the production worthiness and the overall effectiveness of the tools. Equipment qualification procedures can be quite expensive and lengthy. The film deposition process stability is of great importance since it can be correlated to the final integrated circuit quality and yield. The chamber cleaning process can affect the stability of the film properties. The objective of this work is to concern the main aspects of the problems that prevent the remote clean process for achieving both superior chamber cleaning performance and improved environmental friendliness. In order to meet these significant technical challenges we have developed detailed numerical models of the systems involved in the downstream cleaning process. For the remote plasma source, the detailed plasma-kinetic model has been developed to describe the atomic fluorine production from NF3, CF4, and C2F6 and provided comparison of the effectiveness in decomposition of these parent molecules. In the transport tube the homogeneous and heterogeneous kinetic model was developed to analyze the recombination mechanism of atomic fluorine. To study the optimization process of gas and power consumption in the processing chamber, the numerical 2D modeling of complex plasma-chemical processes was performed.Ph.D., Mechanical Engineering -- Drexel University, 200