Methods for porosity characterization of porous SiLK dielectric films

PMSE 444

Brian G. Landes, bglandes@dow.com1, Carol E. Mohler, MohlerCE@dow.com2, Gregory F. Meyers, GFMEYERS@dow.com3, Brandon J. Kern, Bjkern@dow.com3, Sergei Maganov, Sergei.Magonov@veeco.com4, John Quintana5, and Steven J. Weigand, weigansj@northwestern.edu5. (1) Core R&D, The Dow Chemical Company, Midland, MI 48674, (2) Core R&D - New Products, The Dow Chemical Company, 1712 Building, Midland, MI 48674, (3) Analytical Sciences, The Dow Chemical Company, 1897E Building, Midland, MI 48667, (4) Veeco Metrology Group, Digital Instruments, Santa Barbara, CA 93110, (5) DND-CAT Synchrotron Research Center, Northwestern University, DND-CAT, APS/ANL, 9700 S. Cass Ave., Argonne, IL 60439
The continual drive for faster interconnects in integrated circuits requires the development of new interlayer dielectric materials with k values less than 2.0. Porous SiLK semiconductor dielectric resin was developed to achieve this low dielectric constant by introducing nanometer-sized pores into the SiLK matrix. The development of metrology to characterize the pores in porous SiLK films is critical for successful adoption of the material in the industry, both to ensure the film attains the desired dielectric properties and to monitor pore characteristics that may impact the integration process. Due to the complex nature of the porous structure, multiple on-wafer methods are being investigated to quantify the porosity in porous SiLK films. The use of ellipsometry, small angle X-ray scattering (SAXS), X-ray reflectivity (XRR), and atomic force microscopy to measure void fraction, pore size and size distribution, pore morphology and their uniformity across a porous SiLK film will be described. The combination of these techniques provides critical metrics of the porosity of porous SiLK films needed to enable successful integration of this material.