AVS 47th International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS2-MoA

Paper PS2-MoA7
Improving Al Etch Processing in a High Density Plasma Reactor with a Faraday Shield

Monday, October 2, 2000, 4:00 pm, Room 311

Session: Plasma Etching of Conductors
Presenter: D.A. Outka, Lam Research Corp.
Authors: D.A. Outka, Lam Research Corp.
S.C. Siu, Lam Research Corp.
N. Williams, Lam Research Corp.
Correspondent: Click to Email
As etch geometries become smaller, the uniformity of the reactor environment becomes increasingly important in achieving consistent results within a wafer and from wafer-to-wafer. This study examines the addition of a Faraday shield (FS) to an HDP (high-density plasma) reactor to aid in achieving this goal. The effect of the FS on Al etching is examined with wafer-level, plasma, and electrical diagnostics. The FS is an electrostatic shield inserted between the RF coil and the plasma. With this shield there is approximately a 10% reduction in the Al and oxide etch rates depending upon the RF power. Langmuir probe measurements indicate that this reduction is due mainly to a decrease in the plasma density. Electrical measurements of the impedance of the load with a RF probe were also performed and the results compared with a circuit model. These results also indicate a reduced coupling between the RF coil and the plasma. Based upon these results the impact of adding a FS to a commercial etch tool in terms of wafer performance and productivity is discussed.