AVS 46th International Symposium
    Nanometer-scale Science and Technology Division Friday Sessions
       Session MS+PS-FrM

Paper MS+PS-FrM8
Etching of Organic Low Dielectric Constant Materials on the Lam Research 4520XLE

Friday, October 29, 1999, 10:40 am, Room 611

Session: Diagnostics and Processes in Etching
Presenter: S.L. Ellingboe, Lam Research Corporation
Authors: C. Janowiak, Lam Research Corporation
S.L. Ellingboe, Lam Research Corporation
J. Flanner, Lam Research Corporation
I. Morey, Lam Research Corporation
Correspondent: Click to Email
The low dielectric constant (k) of the polymeric materials SiLK and BCB have made them an attractive possible alternative to silicon dioxide as an intermetal dielectric in IC circuits. The lower dielectric constant is desirable to reduce capacitance and RC delay for higher chip speed, less cross talk, and lower power consumption. The forming of via and trench patterns in these low-k materials using a dry etch chemistry was investigated. Because SiLK and BCB is a polymeric material, oxygen is used as the primary etch gas, nitrogen as a dilulent and a hydrocarbon for sidewall passivation. Typically the organic low-k etch has a selectivity of low-k:PR ~1:1. Depending on the film structure, the PR can clear during the low-k etch, exposing the oxide hardmask for the latter portion of the etch. In the 4520XLE, this corresponds to a change in the etch process from a chemically dominated etch to an ion-dominated etch. Consequently, the plasma chemistry changes upon PR clearing and TEOS exposure, which can result in changes to etch rate, etch rate uniformity, and etch rate profile. Simulations of the SiLK etch results will be shown along with process results. The effects of process parameters such as RF power and oxygen-hydrocarbon ratio on etch performance will be discussed.