학술논문
Supercritical Fluid Treatment to Improve Dielectric and Mechanical Properties of Porous ULK Thin Films
Document Type
Original Paper
Author
Source
MRS Online Proceedings Library. 914(1)
Subject
Language
English
ISSN
0272-9172
1946-4274
1946-4274
Abstract
Spin-on glass organosilicate films are promising Ultra Low-ĸ (ULK) interlevel dielectric candidates in which porosity can be created by incorporating thermally labile porogens. The as-deposited film (called the hybrid film) consists of a methylsilsesquioxane (MSQ) matrix and an organic porogen. The standard porogen removal step consists of a 450°C thermal annealing. However, it leaves polymeric residues suspected to cause an incomplete matrix crosslinking and, consequently, to be detrimental to the porous film’s electrical and mechanical properties. In this work, a supercritical fluid (SCF) treatment, performed on a 200 mm tool, was added before the thermal annealing with the intent of improving the dielectric properties. Electrical and mechanical properties were greatly enhanced: the dielectric constant was reduced from 2.5 to 2.1 and the Young’s modulus was increased from 2 GPa to 3 GPa. Porogen residue removal and cross-linking improvements were investigated by Fourier Transform Infrared (FTIR) spectroscopy in transmission and multiple internal reflection (MIR) mode.