Title:
Effect of UV/Ozone Treatment on Surface Tension and Adhesion in Electronic Packaging
Effect of UV/Ozone Treatment on Surface Tension and Adhesion in Electronic Packaging
Author(s)
Wong, C. P.
Luo, Shijian
Luo, Shijian
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Abstract
Surface tension of material surfaces and interfaces
is an important parameter that affects wetting and adhesion. Surface
tension can be divided into three components: Lifshitz–van
der Waals component, acid component, and base component. In
this study, the three-liquid-probe method was used to investigate
the surface tension and its three components of various surfaces
of electronic packaging materials: benzocyclobutene (BCB) passivation,
FR-4 board, polyimide board, and alumina board. When
UV/ozone was employed to treat the surfaces, the surface tension
increased, and the base component increased the most. The change
in surface tension due to UV/O3 treatment decayed with time after
the treatment. The difference in surface tension between untreated
and treated surface became smaller with the increase of time after
UV/O3 treatment. Different substrates showed different rate of
decay in surface tension change. Among the surfaces studied, BCB
passivation showed the fastest decay after treatment, while alumina
showed the slowest decay. The contact angles of several liquid
underfill materials on BCB passivation and their surface tension
before and after curing were also measured. It was found that the
wetting was not the controlling factor in adhesion of the system investigated.
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Date Issued
2001-03
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156441 bytes
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Text
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Article