AVS 53rd International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS1-FrM

Paper PS1-FrM8
On-wafer Monitoring of Charge Accumulation during Plasma Etching Processes

Friday, November 17, 2006, 10:20 am, Room 2009

Session: Plasma-Surface Interactions III
Presenter: B. Jinnai, Tohoku University, Japan
Authors: B. Jinnai, Tohoku University, Japan
T. Orita, STARC, Japan
M. Konishi, STARC, Japan
J. Hashimoto, STARC, Japan
S. Samukawa, Tohoku University, Japan
Correspondent: Click to Email
The high aspect-ratio (AR) contact hole etching of dielectrics, especially silicon dioxide, is a key process in the manufacture of ULSI devices. During the plasma etching process, a large amount of charge accumulates in the contact hole due to electron shading effect, and leads to many problems, such as charge-build-up damage, etching-stop, and microloading effects. For overcoming these problems, it is indispensable to monitor the amount of charge in the real patterns and control the charge accumulation. In this paper, we evaluated the amount of charging in the real contact holes using our developed on-wafer monitoring sensor. We fabricated more than 100 sensor chips on an 8 inch wafer in a mass production line. The sensor had Poly-Si/SiO@sub 2@/Poly-Si layered structure on silicon substrate and contact holes with two kinds of AR: 10 and 3.3. We measured the potential differences between the top and bottom Poly-Si electrodes during plasma etching processes. It is corresponding to the actual charge accumulation in the contact holes. By increasing AR of contact holes, the potential was drastically enlarged. This result clarified that electron-shading effects were enhanced in higher aspect contact holes and that our developed on-wafer monitoring sensor could achieve in situ monitoring of charge accumulation in the real contact holes.