AVS 46th International Symposium
    Plasma Science and Technology Division Wednesday Sessions
       Session PS-WeA

Paper PS-WeA3
Surface Kinetics Study of Silicon Dioxide Etching with Fluorocarbons in Inductively-coupled Plasmas

Wednesday, October 27, 1999, 2:40 pm, Room 609

Session: Dielectric Etching
Presenter: H. Chae, Massachusetts Institute of Technology
Authors: H. Chae, Massachusetts Institute of Technology
H.H. Sawin, Massachusetts Institute of Technology
Correspondent: Click to Email
High-density fluorocarbon plasma for silicon dioxide etching has various ion and neutral compounds. Depending upon the plasma condition, many difficulties arise such as RIE lag, inverse RIE lag, etch stop, and low selectivity of photoresist. Profile evolution modeling can provide understanding of these difficulties in etching as well as trenching, bowing, and faceting. In this research we have measured etching and deposition rates as function of ion bombardment energy, ion impinging angle, ion-to-neutral flux ratio, which are necessary for profile evolution modeling of silicon dioxide etching in inductively coupled plasma. In this work, ions and neutrals are extracted directly from plasma to differentially pumped side chambers. Surface reaction is studied by measuring etching and deposition rate with quartz crystal microbalance (QCM). At the same time, ion and neutral composition of the plasma is determined with mass spectrometer. Etching or deposition rate is measured with QCM as function of ion acceleration energy, ion-impinging angle, ion-to-neutral flux ratio, with various fluorocarbon plasmas. Ion flux is characterized by measuring physical sputtering rate of oxide with Ar plasma and neutral flux is characterized by measuring fluorocarbon deposition rate with CHF@sub 3@ plasma. Three different fluorocarbon plasmas-C@sub 2@HF@sub 5@, C@sub 2@HF@sub 5@ + C@sub 2@H@sub 4@F@sub 2@, C@sub 4@F@sub 8@- are studied for oxide and photoresist etching. Hydrogen rich chemistry - C@sub 2@HF@sub 5@ + C@sub 2@H@sub 4@F@sub 2@ (20%)- has high deposition rate at low ion bombardment energy less than 100V. That hydrogen rich chemistry has the smallest neutral flux and the largest ion flux among them while C@sub 4@F@sub 8@ has the largest neutral flux and the smallest ion flux at the same given power and flowrate.