AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS-MoP

Paper PS-MoP12
High Aspect Ratio Contact Hole Etching in C@sub 4@/F@sub 6@/O@sub 2@/Ar/CH@sub 2@F@sub 2@ and c-C@sub 4@/F@sub 8@/O@sub 2@/Ar/CH@sub 2@F@sub 2@ Plasmas

Monday, November 15, 2004, 5:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: C.B. Shin, Ajou University, Korea
Authors: H.-K. Ryu, LG Chem, Ltd., Korea
C.B. Shin, Ajou University, Korea
Y.-W. Kim, Hynix Semiconductor, Inc., Korea
C.-K. Kim, Ajou University, Korea
Correspondent: Click to Email
A high aspect ratio contact hole etching of dielectrics (e.g., SiO@sub 2@) is one of the key processes in developing the next generation ultra large scale integrated devices because of the rapid shrinkage of the design rule to the nanometer level. To meet the several requirements for a high aspect ratio contact hole etching, a high etch selectivity to mask (e.g., photo resist) is practically required to maintain the critical dimension (CD) of the small-size contact hole. Also, bowing-free structures are needed for the etched profiles. Perfluorocarbons (PFCs) such as c-C@sub 4@F@sub 8@ are widely used as etchant gases for contact hole etching. These PFCs, however, are considered to be problematic from an environmental point of view because of their long atmospheric lifetimes and high global warming potentials (GWP). Several classes of environmentally benign chemistries have been examined as alternatives to PFCs and unsaturated fluorocarbons (UFCs) are one of the attractive candidates due to their shorter atmospheric lifetimes and lower GWP. In this study, we reports on an etching of a SiO@sub 2@ contact hole with a diameter of 0.17 µm and an aspect ratio of 15 using C@sub 4@F@sub 6@/O@sub 2@/Ar and C@sub 4@F@sub 6@/O@sub 2@/Ar/CH@sub 2@F@sub 2@ plasmas (UFC-containing plasmas). It was shown that the addition of CH@sub 2@F@sub 2@ gas made the CD of the contact hole to be maintained, reduced the degree of bowing, and enhanced the etch selectivity to photo resist during a high aspect ratio contact hole etching in a C@sub 4@F@sub 6@/O@sub 2@/Ar plasma. A SiO@sub 2@ contact hole etching in a c-C@sub 4@F@sub 8@/O@sub 2@/Ar/CH@sub 2@F@sub 2@ plasma (PFC-containing plasma) was also conducted to compare the etch profiles and contact resistances obtained in the two different gas discharges: C@sub 4@F@sub 6@/O@sub 2@/Ar/CH@sub 2@F@sub 2@ and c-C@sub 4@F@sub 8@/O@sub 2@/Ar/CH@sub 2@F@sub 2@ plasmas.