AVS 51st International Symposium
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP18
Induced Charge during Vacuum-Ultraviolet Irradiation of Al@sub 2@O@sub 3@, SiO@sub 2@, and Si@sub 3@N@sub 4@@footnote 1@

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: J.L. Shohet, University of Wisconsin-Madison
Authors: J.L. Shohet, University of Wisconsin-Madison
J.L. Lauer, University of Wisconsin-Madison
R.W. Hansen, University of Wisconsin-Madison
G.S. Upadhyaya, University of Wisconsin-Madison
R.D. Bathke, University of Wisconsin-Madison
K. Kukkady, University of Wisconsin-Madison
J.M. Kalwitz, University of Wisconsin-Madison
Correspondent: Click to Email
Plasma damage, contamination, and thermal budget are key concerns in the microelectronics industry. In particular, dielectric charging plays a key role in processing damage of semiconductor devices. During the last decade, plasma-induced damage research has mainly focused on the role of charged particles in the plasma with little or no consideration being given to photon bombardment. VUV radiation with energies in the range of 4-30 eV can induce charge on electronic materials. Radiation charging of Si wafers coated with 3000A of Al@sub 2@O@sub 3@, SiO@sub 2@, and Si@sub 3@N@sub 4@ from synchrotron VUV exposure with photon fluxes in the range of 10@super 9@-10@super 13@ photons/sec cm@super -2@ was measured. The total charge induced on the dielectrics during VUV exposure, which can be measured with a Kelvin Probe, consists of charge due to photoemission and electron-hole pair creation. The photoemission current and substrate voltage were monitored during each exposure for various bias voltages. For photon energies of 7-21 eV, the integral of photoemission current was compared to the net charge measured with the Kelvin probe which allows us to separate the charging affects of photoemission from that of electron-hole pair creation within the dielectric. Since the threshold photon energy for photoemission is higher than that for electron-hole pair production, it is seen that photoemission can be minimized if the photon energies are below the threshold energy. This produced the possibility to reduce dielectric charging, especially that induced by electron-shading effects during plasma etching of high aspect-ratio devices, by providing a safe way to discharge these structures and, thus, minimize plasma-charging damage. The enhanced conductivity may benefit etching properties such as reduction of notching, sidewall bowing, and trenching. @FootnoteText@ @footnote 1@This work is supported by NSF under grant DMR-0306582. The UW Synchrotron workis funded by NSF under grant DMR-0084402.