AVS 51st International Symposium
    Plasma Science and Technology Friday Sessions
       Session PS1+DI-FrM

Paper PS1+DI-FrM10
Characterization of the Sputtering Process in an rf Plasma for the Patterning of Nonvolatile Materials

Friday, November 19, 2004, 11:20 am, Room 213A

Session: High K and Difficult Materials Etch
Presenter: T.J. Kropewnicki, Applied Materials, Inc.
Authors: T.J. Kropewnicki, Applied Materials, Inc.
A.M. Paterson, Applied Materials, Inc.
T. Panagopoulos, Applied Materials, Inc.
J.P. Holland, Applied Materials, Inc.
Correspondent: Click to Email
With the integration of nonvolatile materials into microelectronic devices, such as NiFe in magnetic random access memory, perovskites in ferroelectric random access memory, and HfO@sub 2@ as a transistor gate dielectric, it has become necessary to develop methods of characterizing the patterning of these materials. Removal of these nonvolatile materials by sputtering with heavy ions is probably a key component of the etching mechanism. Sputtering of materials by ion bombardment has typically been characterized using high energy ion beam systems, leading to sputtering yield probabilities as a function of ion energy. Since typical commercial plasma etch reactors use rf power to energize the ion bombardment, the usefulness of these sputtering probabilities in understanding the reaction mechanism is limited by the much lower energy levels being produced by the rf sheath, and by the spread of ion bombardment energies typically produced by an rf plasma sheath. Ion energies less than 1000 eV are common in many plasma etch systems. To create a more realistic picture of the etching process, direct measurements of the actual rf waveforms occurring on the wafer are transformed using a simple plasma sheath model into ion energy distribution functions which are then used in combination with the reported sputtering yield data to predict more accurate sputter yields for these conditions. Langmuir probe measurements of ion fluxes are then used to determine the etch rates. Comparison of these predicted rates and actual measured rates will be presented as well as possible reasons for discrepancies between the two rates.