AVS 47th International Symposium
    Incorporating Principles of Industrial Ecology Wednesday Sessions
       Session IE+PS+MS+SE-WeM

Paper IE+PS+MS+SE-WeM6
Low-k Materials Etching in Magnetic Neutral Loop Discharge Plasma

Wednesday, October 4, 2000, 10:00 am, Room 304

Session: Environmentally Friendly Process Development
Presenter: T. Hayashi, ULVAC JAPAN Ltd.
Authors: Y. Morikawa, ULVAC JAPAN Ltd.
S. Yasunami, ULVAC JAPAN Ltd.
W. Chen, ULVAC JAPAN Ltd.
T. Hayashi, ULVAC JAPAN Ltd.
H. Yamakawa, ULVAC JAPAN Ltd.
T. Uchida, ULVAC JAPAN Ltd.
Correspondent: Click to Email
Many low-k materials, like Si containing inorganic / organic compounds, purely organic compounds and porous silicate glass, are proposed and examined as the interlayer dielectric one. The magnetic neutral loop discharge ( NLD ) plasma is very useful for very fine pattern etching process, because the NLD plasma has high density and low temperature characteristics and tends to form uniform density distribution on the substrate, at lower pressure region than 1 Pa under 13.56 MHz oscillating induction field.@footnote 1-3@ So we adopted the NLD plasma to etch organic low-k materials, with very high etch rate over 900 nm/min by using NH@sub 3@. An etching issue for the purely organic low-k materials is bowing in the hole smaller than 200nm in diameter, probably caused by reaction of the hole-wall surface with hydrogen atoms. Based on this consideration, we carried out the etching by using nitrogen gas mixed with a low concentration of hydrogen gas in low pressures below 1 Pa. The etch rate increased abruptly at hydrogen addition of a few quantity and approached gradually to a constant value at 20%. But the bowing size became larger above hydrogen mixed ratio of 20%. So we measured mass spectra of ion species produced in the plasma to know the mechanism. It was found that intensity of N2H+ also increased abruptly and then was close to a constant value at 20%. The other species did not show similar tendency. It is deduced from this result that N2H+ ion may participate in main etching reaction to obtain the conformal etched profile. Etching characteristics for OSG, pure organic low-k materials and porous silicate glass will be shown. @FootnoteText@@footnote 1@W.Chen, T.Hayashi, M.Itoh, Y.Morikawa, K.Sugita, H.Shindo and T.Uchida : Jpn. J. Appl. Phys., 38 (1999) 4296 @footnote 2@W.Chen, T.Hayashi, M.Itoh, Y.Morikawa, K.Sugita and T.Uchida : Vacuum, 53 (1999) 29 @footnote 3@W.Chen, T.Hayashi, M.Itoh, Y.Morikawa, K.Sugita, H.Shindo and T.Uchida : J. Vac. Sci. Technol. A17(5), (1999) 2546.