A quantitative analysis of multi-scale response of CMP pad: quasi-static and dynamic characterization of dry and wet pad

dc.contributor.author Doddabasanagouda, Sunil
dc.contributor.department Mechanical Engineering
dc.date 2020-11-06T02:23:05.000
dc.date.accessioned 2021-02-26T08:52:26Z
dc.date.available 2021-02-26T08:52:26Z
dc.date.copyright Thu Jan 01 00:00:00 UTC 2004
dc.date.issued 2004-01-01
dc.description.abstract <p>The characteristics of pad deformation and its surface morphology control the quality and efficacy of chemical mechanical planarization (CMP) process. The salient structural features of the pad (cell size, cell wall thickness & surface roughness) constitute structures that have several small length scales. The effect of these various length scales (micro & nano) on the mechanical response of the pad under different condition remains largely unexplored due to the deficiency of appropriate experimental techniques to characterize local deformation. To reveal the intricacy involved in the deformation of the CMP pad, an experimental and theoretical approach has been devised. The dry and wet IC-1000 pad responses are examined at different length scales using a nano-indenter with a conical tip of 1[mu]m radius and a flat-punch of 30[mu]m radius. The wet pad measurements showed degradation of the pad stiffness, which is attributed to water absorption within a micron of pad cell membrane. This reduction of stiffness is not significant because the pad material is impermeable to water and most of the water penetrates only the topmost layer of voids in the material. The load-indentation depth plots showed different characteristic trends with varying stiffness at different loading ranges. The measurements showed the competition between the local indentation, cell membrane bending and the bulk response of the porous pad. These different deformation mechanisms are utilized to construct an analytical model for effective pad stiffness. The model prediction matches well with the force-indentation depth measurements. An experimental measurement of the linear viscoelastic behavior of the surface of the pad in contact with a conical indenter is obtained. Variation of stiffness, damping coefficient, relaxation time with frequency and depth is obtained using a simple mechanical Voigt model in the Dynamic Model for Nanoindenter system, which is in contact with specimen. Such physically based model can be utilized to optimize the pad microstructure and morphology to control the applied force partitioning and the characteristics of the material removal rates.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/20402/
dc.identifier.articleid 21401
dc.identifier.contextkey 19953129
dc.identifier.doi https://doi.org/10.31274/rtd-20201023-76
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/20402
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/97769
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/20402/Doddabasanagouda_ISU_2004_D63.pdf|||Fri Jan 14 22:24:44 UTC 2022
dc.subject.keywords Mechanical engineering
dc.title A quantitative analysis of multi-scale response of CMP pad: quasi-static and dynamic characterization of dry and wet pad
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication 6d38ab0f-8cc2-4ad3-90b1-67a60c5a6f59
thesis.degree.discipline Mechanical Engineering
thesis.degree.level thesis
thesis.degree.name Master of Science
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