Ž . Applied Surface Science 141 1999 89–100 Modification of parylene AF-4 surfaces using activated water vapor D. Martini a , K. Shepherd a , R. Sutcliffe a , J. Kelber a, ) , H. Edwards b , R. San Martin b a Department of Chemistry, UniÕersity of North Texas, Denton, TX 76203, USA b Components and Materials Research Center, Texas Instruments, Dallas, TX 75265, USA Received 10 June 1998; accepted 4 October 1998 Abstract In this study, we investigate the addition of oxygen functionalities to parylene AF-4 using X-ray photoelectron Ž . Ž . spectroscopy XPS . Subsequent reactions with trimethylaluminum TMA were also studied by XPS. Samples were exposed to water vapor that was passed over a heated W filament, and comparison is made with similarly exposed polystyrene. Oxygen incorporation occurred in both polymers and was substantially greater in polystyrene. Defluorination occurred in the parylene sample, and X-ray photoelectron spectra indicate that the oxygen is chemically bound to the polymer surface. TMA was dosed at room temperature onto the parylene samples, and prior modification of the AF-4 surface resulted in enhanced Ž . reactivity toward TMA. Atomic force microscopy AFM is used to characterize the surfaces and demonstrates that no significant surface roughness occurred due to the modification process. q 1999 Elsevier Science B.V. All rights reserved. Keywords: Parylene AF-4; Water vapor; X-ray photoelectron spectroscopy 1. Introduction Ž . The study of low dielectric constant low-k poly- mers is a rapidly growing field, in part due to their possible use as interconnect materials in integrated circuit technology. As microelectronic devices be- come smaller and more complex and processing times become shorter, there is an increasing need to Ž . reduce resistance–capacitance RC delay and signal loss due to ‘cross-talk’ voltages. To accomplish this, metals used for conducting lines must have lower ) Corresponding author. Tel.: q1-940-565-3265; Fax: q1-940- 565-4824; E-mail: kelber@bob.unt.edu electrical resistance, and materials with lower dielec- tric constants must be incorporated. Low-k poly- mers, aerogels and xerogels are all being studied as materials to replace SiO as gate and interconnect 2 dielectrics. Fluorinated polymers are appealing because of their low dielectric constants, relative ease of deposi- tion and excellent gap-filling properties. Fluoropoly- mers generally have dielectric constants between 1.9 Ž . and 2.1, much lower than that of SiO k s 3.9 2 w x 1–6 . Poor metal adhesion and thermal stability, however, have limited their application in microelec- Ž w X X tronics. Parylene AF-4 poly a , a , a , a -tetrafluoro- x.Ž . p-xylylene Fig. 1 has a dielectric constant of 2.28, 0169-4332r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S0169-4332 98 00609-6