AVS 53rd International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS2-TuA

Paper PS2-TuA8
Dry Etch Process of Contact holes using Multi-Functional Hard Mask

Tuesday, November 14, 2006, 4:20 pm, Room 2011

Session: Etch for Advanced Interconnect II
Presenter: W.K. Kim, Hynix, Korea
Authors: W.K. Kim, Hynix, Korea
S.K. Lee, Hynix, Korea
J.H. Cho, Hynix, Korea
J.H. Sun, Hynix, Korea
K.L. Lee, Hynix, Korea
G.S. Lee, Hynix, Korea
S.C. Moon, Hynix, Korea
J.W. Kim, Hynix, Korea
Correspondent: Click to Email
As feature size continuously shrinks, pattern collapse has dramatically increased, which has led to decrease photoresist thickness and use hard mask materials as a pattern transfer layer. Amorphous carbon (a-C) is expected to be used in the nano technology regime because of its strong merits such as superior etching durability and low damage during strip. However it is not cost effective and complex in dry etching process. To overcome these problems, many of researchers focus on the new material development. Multi-functional hard mask (MFHM) is very useful in terms of cost reduction and process simplicity compared to a-carbon process. We call Si-ARC as a MFHM because it has to have both functions of anti-reflective and pattern transfer layer. We have evaluated the reactive ion etching characteristic of MFHM on spin-on carbon (SOC). In this study, we planned to form very fine pattern semiconductor of sub-80nm technology and beyond in combination of N2/O2 or N2/H2 without additional etching gas. The stack tested in this study was a Photoresist (100-150nm) / MFHM (100-200nm) / SOC (500-800nm) on insulator film (~2500nm). We focused on investigating etch rate, etch selectivity and etch profile. These are highly dependant to the polymer types of MFHM, SOC grain size, and Si content in MFHM. We also found that MFHM having Si-O-Si bond showed higher etch selectivity than that having Si-Si-O bond if their Si content is same. The small grain size in SOC and high Si content in MFHM are required to get better selectivity and profile. Especially, we obtained vertical fine pattern contact holes with minimized bowed profile by using N2/O2 plasma only and by partially oxidizing MFHM to SiO2-like surface (SiON layer in case of a-C process). We confirmed the surface of MFHM was oxidized about 10~50nm in depth during etching process using AES, XPS, and TEM observation