Professor James Economy's Group
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[Polymer Blends] [Microelectronic Polymers]
[Liquid Crystalline
Polyesters] [Polyester Thermosetting Resins] New Low-k
Porous Materials for Interconnects Planned
increases in IC performance, such as faster clock speeds
and lower power consumption, require the use of low-k
materials for interconnects in chip manufacturing.
Implementation of low k dielectrics can reduce RC delay,
power dissipation, crosstalk noise and number of metal
lever. Dense low-k materials with k values in the range
of 2.8-3.0 are in manufacturing at the 90 nm node (see
Figure 1). The International Technology Roadmap for
Semiconductors indicates that porous low-k materials with
k < 2.4 will be required for the 65 nm node by 2006. Low-k
dielectric materials alone is expected to grow from $16
million in 2002 to nearly $400 million in 2006. Poly(m-diethynyl
benzene) is a good candidate as a low-k dielectric
because it has low dielectric constant (k=2.7), high
thermal stability (> 450°C), relatively low moisture
pick-up and capability of planarizing over complex
geometries. However, its low solubility in most common
spin-coating solvents and tendency to crack due to its
easy crystallizing limit its application as a low-k
material in microelectronic devices. We modified its
chemical structure by copolymerizing diethynyl benzene
with triethynyl benzene. As a result, the new polymers display greatly improved solubility in common spin-coating solvents, such as
THF, NMP and cyclohexanone. The bulk dielectric constant
of this material is 2.7, which can be lowered to 2.3 by
adding porogens to form porous structure.
Characterization of other properties and further
modification of its structure to improve its properties
is underway.
Figure.
Cross-section of seven-lever 90 nm node interconnect * * Ref.
http://www.eeel.nist.gov/812/conference/Presentations/Ho.pdf/copper.pdf |
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