The evaluation of fast-flow, fast-cure underfills for flip chip on organic substrates

Wun, Kai-Lam Bill; Margaritis, Georgios

doi:10.1109/ectc.1996.517441

Cited by 19 publications

(2 citation statements)

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“…Some factors that affect the flow of the underfill are the filler particle loading, size, and shape, the underfill resin rheology and surface tension, and surface factors such as surface energy and contamination (Wong et al, 1997). Many papers have been written concerning the flow of underfill encapsulant between the die and substrate (Lehmann et al, 1997;Park, 1995;Park et al, 1997;Wun and Margaritis, 1996;Schwiebert and Leong, 1995;Han et al, 1996;Han and Wang, 1997;Zoba and Edwards, 1995). Improvement of the cure is also important to reduce production costs by reducing time needed to cure the underfill.…”

Section: Assemblymentioning

confidence: 99%

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Enhancement of underfill encapsulants for flip‐chip technology

Vincent

Wong

1999

Soldering &Amp; Surface Mount Technology

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This paper presents results on adding silane coupling agents to the underfill encapsulant to enhance the rheology and wetting of the underfill. These results include rheology measurements, contact angle measurements, and in situ flows using a simulated test chip on an FR4 with solder mask substrate. Three properties of the underfill encapsulant that can affect the mechanical reliability of the die and substrate assembly are: CTE; elastic modulus; and adhesion to the die and substrate surfaces. The approach taken in this paper is to add silane coupling agents with different chemistries to the underfill encapsulant to provide interfacial coupling of the underfill material to different die and substrate materials. This paper presents results on the enhancement of the adhesion of underfill encapsulant to silicon (Si), silicon nitride (SiN) die passivation, benzocyclobutene (BCB) die passivation, and solder mask surfaces. The adhesion strength was measured by die shear testing.

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Section: Assemblymentioning

confidence: 99%

“…Improvement of the cure is also important to reduce production costs by reducing time needed to cure the underfill. Wun and Margaritis (1996) have developed underfill encapsulants that can cure in 15 minutes at 150°C. This curing schedule seems to be common in industry.…”

Section: Assemblymentioning

confidence: 99%

Enhancement of underfill encapsulants for flip‐chip technology

Vincent

Wong

1999

Soldering &Amp; Surface Mount Technology

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Solder wetting in a wafer-level flip chip assembly

Busch

Baldwin

2001

IEEE Trans. Electron. Packag. Manufact.

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Fast-flow underfill encapsulant: flow rate and coefficient of thermal expansion

Wong

Vincent

Shi

1998

IEEE Trans. Comp., Packag., Manufact. Technol. A

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In the flip-chip on board assembly method, an underfill encapsulant material is applied in the gap between the integrated circuit (IC) chip and substrate to distribute the shear stresses at the solder interconnects. These shear stresses are imposed on the solder interconnects due to a coefficient of thermal expansion (CTE) mismatch between the IC chip and substrate. Different technologies such as fast-flow, no-flow, and reworkable underfills are currently being studied for flip-chip underfill encapsulant materials. This paper looks at the underfill encapsulant used in the fast-flow method of underfilling the IC chip/substrate gap. The effect of filler loading, particle size, and particle size distribution on the flow rate and CTE of the fastflow underfill material are discussed in this work. The material used for the experiments is an epoxy resin with added silica filler to decrease the CTE. This study focuses on what effect different filler characteristics have on the underfill encapsulant. Also, an underfill encapsulant that can compete with one of industry's faster fast-flow underfills was developed as a result of this work.

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The evaluation of fast-flow, fast-cure underfills for flip chip on organic substrates

Cited by 19 publications

References 1 publication

Enhancement of underfill encapsulants for flip‐chip technology

Enhancement of underfill encapsulants for flip‐chip technology

Solder wetting in a wafer-level flip chip assembly

Fast-flow underfill encapsulant: flow rate and coefficient of thermal expansion

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