AVS 46th International Symposium
    Vacuum Technology Division Thursday Sessions
       Session VT-ThM

Paper VT-ThM11
Decay Rate of Photoresist Outgassing from Ion Implantation

Thursday, October 28, 1999, 11:40 am, Room 610

Session: Outgassing, Leaks, and Mass Flow Controllers
Presenter: A.S. Perel, Eaton Corporation
Authors: A.S. Perel, Eaton Corporation
T.N. Horsky, Eaton Corporation
Correspondent: Click to Email
Outgassing of hydrocarbons results from ion implantation into wafers covered with photoresist. Depending on the implant energy and current, the quantity of gas can be large and therefore high effective pumping speeds are important to minimize interference with the ion beam. We measured the time dependence of this outgassing to determine the rate that the outgassing decays. This information is relevant for design of implanter process chambers with rotating disks. The photoresist outgassing decay rate determines the geometry of the gas load, and can be used to determine pump placement and chamber design. The experiment involved a single photoresist wafer and 12 dummy wafers on a 13 pad disk. By measuring the collector current directly from the ion gauges we were able to time-resolve pressure measurements to better than 1 ms. Two pressure pulses were measured, the pulse that results from the implant and a pulse that results from the outgassing wafer passing the gauge. The relative difference in amplitude and time, as observed from two gauges, were used to calculate the outgassing decay rate. We reduce several data sets collected at different disk rotational speeds to fit a candidate model for the time-dependence and mechanism of photoresist outgassing.