Ž . Applied Surface Science 126 1998 43–56 Characterization and aluminum metallization of a parylene AF-4 surface R. Sutcliffe a,1 , W.W. Lee a , J.F. Gaynor a , J.D. Luttmer a , D. Martini b , J. Kelber b, ) , M.A. Plano c a Semiconductor Process and DeÕice Center, Texas Instruments Incorporated, Dallas, TX 75265, USA b Department of Chemistry, UniÕersity of North Texas, P.O. Box 30507, Denton, TX 76203-0068, USA c NoÕellus Systems Incorporated, San Jose, CA 95134, USA Received 1 April 1997; accepted 19 October 1997 Abstract w Ž X X .x The surface of vapor deposited parylene AF-4 poly a , a , a , a -tetrafluoro-p-xylylene was characterized by atomic Ž . Ž . force microscopy AFM and X-ray photoelectron spectroscopy XPS . Subsequent interactions with trimethylaluminum Ž . Ž . TMA were studied by XPS. TMA was adsorbed onto an unmodified parylene AF-4 sample 30 L, 112 K . The sample was Ž . then annealed to 300, 550 and 600 K sequentially in ultra-high vacuum. A reaction occurs between the precursor, the polymer surface and physisorbed water at or below 300 K, producing Al–C, Al–O and Al–F bonds as evidenced by changes in the XPS spectra. The reaction produces a thermally stable, aluminum-oxide film bound to the polymer through aluminum–carbon bonds. A fluorine concentration gradient exists in the form of a fluorinated aluminum oxide across the film, with increasing fluorination toward the adlayerrpolymer interface. q 1998 Elsevier Science B.V. 1. Introduction The study of low dielectric constant materials is an area of rapidly growing interest due to their applications in the microelectronics industry. The application of materials with lower dielectric con- stants than the materials currently used in microelec- tronic applications would significantly reduce RC delay and enhance interconnect performance. A number of organic polymers have been investigated ) Corresponding author. Tel.: q1-817-5652713; fax: q1-817- 5654318; e-mail: kelber@bob.unt.edu. 1 Current address: Motorola Inc., Phoenix, AZ, USA. w x for use as interlayer dielectrics 1–11 , including Ž . fluoropolymers and parylenes p-xylene polymers . Though fluoropolymers generally have lower dielec- Ž . tric constants 2.1 to 1.9 , their application has thus w x far been limited by poor metal adhesion 1,7,8,12 . While the dielectric constants for parylene vari- Ž . ants are slightly higher 2.6 to 2.3 , they exhibit better adhesion properties and lower moisture uptake w x than fluoropolymers 9,13 . Parylenes can be vapor deposited, a process which is inherently cleaner than w x the conventional spin-on process 13 . A fluorinated version, called parylene AF-4, has recently become Ž available and has excellent thermal stability m.p. ) . w x 773 K and a dielectric constant of 2.28 13 . Pary- Ž . lene AF-4 also known simply as AF-4 is 0169-4332r98r$19.00 q 1998 Elsevier Science B.V. All rights reserved. Ž . PII S0169-4332 97 00585-0