Effects of mechanical stress and moisture on packaging interfaces

Buchwalter, Stephen L.; Brofman, Peter J.; Feger, C.; Gaynes, Michael; Lee, K.-W.; Matienzo, Luis J.; Questad, D.

doi:10.1147/rd.494.0663

Cited by 21 publications

(14 citation statements)

References 26 publications

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“…The primary reason for this could be the inability of many conductive chains to maintain effective conductive paths, on a rough surface when compared to a smooth surface, as the adhesive starts delaminating from the surface. A similar phenomenon was identified by Buchwalter et al [12]. This could also be the reason for the reduction in the shear force required as T&H aging continues.…”

Section: Contact Resistance Of Jointsupporting

confidence: 78%

Influence of PCB Surface Finish and Thermal and Temperature/Humidity Aging on the Performance of a Novel Anisotropic Conductive Adhesive for Lead-free Surface Mount Assembly

Ramkumar

Srihari

2007

2007 Proceedings 57th Electronic Components and Technology Conference

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The electronics industry, in recent years, has been focusing primarily on product miniaturization and lead-free assembly. The need to eliminate lead-based materials as a means of interconnection has renewed the industry's interest in exploring other means of assembling surface mount devices reliably, especially using conductive adhesives. This paper will discuss the performance characteristics and research findings pertaining to a novel anisotropic conductive adhesive for lead-free electronics packaging applications.The applicability of the novel conductive adhesive in board level assembly has been demonstrated successfully. The IV characteristics and the breakdown current characteristics have shown the importance of achieving very low initial contact resistance after assembly, in order to enable longer life under thermal and temperature-humidity aging conditions. Thermal aging of the adhesive material has revealed improvement in contact resistance and temperature/humidity aging has shown deterioration in performance within the first 100 hours of aging. Area array packages with and without bumps have shown variations in performance and their has revealed the importance of placement pressure, placement speed and placement dwell in achieving low initial contact resistance. Preliminary experiment has shown that the HASL finish performs better than OSP.

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Section: Contact Resistance Of Jointsupporting

confidence: 78%

Influence of PCB Surface Finish and Thermal and Temperature/Humidity Aging on the Performance of a Novel Anisotropic Conductive Adhesive for Lead-free Surface Mount Assembly

Ramkumar

Srihari

2007

2007 Proceedings 57th Electronic Components and Technology Conference

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“…We measured how much the plasma treatment improved the adhesion strength by using a CLB test [13]. The stainless steel beams were 17  12.7  0.18 mm and one of the beams was coated with silicon dioxide to represent the silicon chip sidewall (Fig.…”

Section: Adhesion Testmentioning

confidence: 99%

No Clean Flux technology for large die flip chip packages

Horibe

Lee

Okamoto

et al. 2013

2013 IEEE 63rd Electronic Components and Technology Conference

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“…To solve this problem, we improved the adhesion strength and toughness of the material by selecting appropriate ingredients and surface treatments for the filler. We used a Cantilever Beam (CLB) test to measure the adhesion strength [9]. Fig.…”

Section: Thermal Underfill Evaluation On 2d Packagementioning

confidence: 99%

Thermally enhanced pre-applied underfills for 3D integration

Horibe

Okamoto

Mori

et al. 2013

2013 IEEE 63rd Electronic Components and Technology Conference

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One of the biggest challenges for future high-performance three dimensional (3D) integrated devices is heat removal from the stacked dies. In this study, thermally enhanced preapplied type underfills were studied. These materials were formulated considering fillet cracks and delaminations that appeared in thermal cycling tests on 2D organic package. Finally, the applicability for 3D integration processing with the new material was evaluated on a 3D test vehicle assembly. IntroductionThree-dimensional (3D) chip integration with throughsilicon-vias (TSVs) supports higher performance, lower power, and smaller footprints. Highly integrated 3D devices create higher heat densities due to their small sizes. One of the biggest challenges for future 3D devices is to accelerate the heat transfer within chip stacks. To cool the stack, improving the thermal conductivity of the underfills between the dies is one of the more promising approaches. However, since standard silica-filler-base capillary type underfills do not have good thermal properties due to the low thermal conductivity of the silica filler, some other highly thermally conductive filler must to be selected for these thermally enhanced underfills. Such high-filler-loaded underfills with high thermal conductivity have high viscosities. Therefore, the industry-standard capillary method to add underfills after the chip-join step will not work well for proposed 3D devices with narrow gaps, large dies, or multi-stacked dies. In this study, pre-applied type thermal conductive underfills were studied. The materials with flux chemicals can be applied to wafer, die, or substrate, and then bond the chips and substrates with solder joints. With this type of underfill, not only the reliability but also the processing windows for good solderjoint yield and process capability strongly depend on the material properties. Therefore, some trial and error is necessary in the development. Thermal modeling is used to understand the heat flows and the efficacy of various thermal underfill materials for the 3D stacks [1]. As shown in Fig. 1, a joint layer consisting of solder bumps and a standard underfill (0.4 W/mK) will increase the thermal resistance within a package structure. In this model, if a thermally conductive underfill (2.0 W/mK) is used, then the thermal resistance will be dramatically reduced. At the same time, such thermally enhanced underfills must contain highly thermally conductive fillers. However, since the material properties of such fillers differ from those of standard silica fillers, the formulation of the thermal underfill must be carefully optimized by considering all of the material properties of the compound. It is a major challenge to discover the optimal properties of a

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Effects of mechanical stress and moisture on packaging interfaces

Cited by 21 publications

References 26 publications

Influence of PCB Surface Finish and Thermal and Temperature/Humidity Aging on the Performance of a Novel Anisotropic Conductive Adhesive for Lead-free Surface Mount Assembly

Influence of PCB Surface Finish and Thermal and Temperature/Humidity Aging on the Performance of a Novel Anisotropic Conductive Adhesive for Lead-free Surface Mount Assembly

No Clean Flux technology for large die flip chip packages

Thermally enhanced pre-applied underfills for 3D integration

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