Kim, Jeong-Ho;
Yu, Jae-Seon;
Ku, Ja-Chun;
Ryu, Choon-Kun;
Oh, Su-Jin;
Kim, Si-Bum;
Kim, Jin-Woong;
Hwang, Jeong-Mo;
Lee, Su-Youb;
Kouichiro, Inazawa
Plasma enhanced chemical vapor deposition Si-rich silicon oxynitride films for advanced self-aligned contact oxide etching in sub-0.25 μm ultralarge scale integration technology and beyond
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Media type:
E-Article
Title:
Plasma enhanced chemical vapor deposition Si-rich silicon oxynitride films for advanced self-aligned contact oxide etching in sub-0.25 μm ultralarge scale integration technology and beyond
Contributor:
Kim, Jeong-Ho;
Yu, Jae-Seon;
Ku, Ja-Chun;
Ryu, Choon-Kun;
Oh, Su-Jin;
Kim, Si-Bum;
Kim, Jin-Woong;
Hwang, Jeong-Mo;
Lee, Su-Youb;
Kouichiro, Inazawa
Published:
American Vacuum Society, 2000
Published in:
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 18 (2000) 4, Seite 1401-1410
Description:
We intentionally introduced excessive Si during the SiOxNy film deposition in order to increase the etch selectivity-to-SiOxNy for advanced self-aligned contact (SAC) etching in sub-0.25 μm ultralarge scale integration devices. The SiOxNy layer was deposited at a conventional plasma enhanced chemical vapor deposition chamber by using a mixture of SiH4, NH3, N2O, and He. The gas mixing ratio was optimized to get the best etch selectivity and low leakage current. The best result was obtained at 10% Si–SiOxNy. In order to employ SiOxNy film as an insulator as well as a SAC barrier, the leakage current of SiOxNy film was evaluated so that SiOxNy may have the low leakage current characteristics. The leakage current of 10% Si–SiOxNy film was 7×10−9 A/cm2. Besides, the Si-rich SiOxNy layer excellently played the roles of antireflection coating for word line and bit line photoresist patterning and sidewall spacer to build a metal–oxide–semiconductor transistor as well as a SAC oxide etch barrier. The contact oxide etching with the Si-rich SiOxNy film was done using C4F8/CH2F2/Ar in a dipole ring magnet plasma. As the C4F8 flow rate increases, the oxide etching selectivity-to-SiOxNy increases but etch stop tends to happen. Our optimized contact oxide etch process showed the high selectivity to SiOxNy larger than 25 and a wide process window (⩾5 sccm) for the C4F8 flow rate. When the Si-rich SiOxNy SAC process was applied to a gigabit dynamic random access memory of cell array, there was no electrical short failure between conductive layers.