Reliability of fluorinated silicon oxide film prepared by temperature difference-based liquid phase deposition

Abstract

Fluorinated silicon oxide film prepared by using temperature difference-based liquid phase deposition is very potential for use as an intermetal dielectric owing to its high fluorine concentration (8.6 atom %), low dielectric constant (3.46), low stress (41 MPa) low leakage current density (4.6 X 10(-9) A/cm(2) at 2 MV/cm), and low deposition temperature (room temperature). In this work, we closely examine reliability issues including resistance to water absorption and thermal stability by adopting the repeatedly annealing (400 degreesC) and boiling test. After the test, the net increase in the dielectric constant is only 0.02; the stress changes within -24 to 41 MPa with a resultant zero stress; the leakage current density increases slightly to 8.0 X 10(-9) A/cm(2). Obviously the film will preserve its attractive properties in a back-end process similar to the test. Accompanied with the investigation of p-etch rate, thermal desorption spectroscopy, and Fourier transform infrared spectroscopy, a feasible mechanism that accounts for the variation of the properties during the test is proposed. A high temperature (>400 degreesC) annealing effect is also studied. The film is thermally stable up to 600 degreesC, which is limited by the decomposition of Si-F bonds. The thermal stability of 600 degreesC is obviously sufficient for intermetal dielectric application. (C) 2000 The Electrochemical Society. S0013-4651(99)12-019-6. All rights reserved.