Damage by radicals and photons during plasma cleaning of porous low-k SiOCH. I. Ar/O{sub 2} and He/H{sub 2} plasmas

Journal Article · Sun Jul 15 00:00:00 EDT 2012 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4718444· OSTI ID:22098895

Shoeb, Juline; Mingmei, Wang; Kushner, Mark J. ^[1]

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1. Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States)

Porous dielectric materials offer lower capacitances that reduce RC time delays in integrated circuits. Typical porous low dielectric (low-k) materials include SiOCH-silicon dioxide with carbon groups, principally -CH{sub 3}, lining the pores. Fluorocarbon plasmas are often used to etch such low-k materials. These processes leave a fluorocarbon polymer on the SiOCH surface that must be removed, often with oxygen or hydrogen containing plasmas. Pores open to the surface and that are internally connected provide pathways for reactive species to enter into the porous network and produce damage. For example, during cleaning using O{sub 2} containing plasmas, reactions of O atoms with -CH{sub 3} groups can increase the k-value by removing C atoms. Vacuum ultraviolet (VUV) photons produced by the plasma and that penetrate into the material can scission -Si-CH{sub 3} bonds and accelerate the removal of -CH{sub 3} groups. This paper reports on results from a computational investigation of Ar/O{sub 2} and He/H{sub 2} plasma cleaning of porous SiOCH when including the effects of VUV photons. The authors found that He/H{sub 2} plasmas are able to clean CF{sub x} polymers deposited during etching while producing milder damage to underlying -CH{sub 3} sites compared to O{sub 2} plasmas due to the lower reactivity of H atoms and the shorter penetration distance of photons produced in He/H{sub 2} plasmas.

• OSTI ID: 22098895
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 30, Issue 4; Other Information: (c) 2012 American Vacuum Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ARGON
CAPACITANCE
DAMAGE
DIELECTRIC MATERIALS
ETCHING
HELIUM
HYDROGEN
INTEGRATED CIRCUITS
METHYL RADICALS
OXYGEN
PHOTONS
PLASMA
POLYMERS
POROUS MATERIALS
SILICON OXIDES
SURFACE CLEANING
SURFACES
ULTRAVIOLET RADIATION