Effect of bump height on the strain variation during the thermal cycling test of ACA flip-chip joints

Pinardi, Kuntjoro; Lai, Zonghe; Vogel, Dietmar; Kang, Yi Lan; Liu, J.; Liu, S.; Haug, R.; Willander, Magnus

doi:10.1109/6144.868843

Cited by 38 publications

(13 citation statements)

References 3 publications

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“…However, the failure rate of the corner bumps exceeds 80%. It has been argued that larger stress acts on the outmost bump joints during thermal cycling [11][12][13][14]. Conversely, the center bumps maintain their initial contact even after 1000 T/C cycles.…”

Section: Methodsmentioning

confidence: 99%

Studies on the thermal cycling reliability of fine pitch Cu/SnAg double-bump flip chip assemblies on organic substrates: Experimental results and numerical analysis

Son

Kim

Park

et al. 2008

2008 58th Electronic Components and Technology Conference

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Section: Methodsmentioning

confidence: 99%

Studies on the thermal cycling reliability of fine pitch Cu/SnAg double-bump flip chip assemblies on organic substrates: Experimental results and numerical analysis

Son

Kim

Park

et al. 2008

2008 58th Electronic Components and Technology Conference

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“…It is clear that the chip with high bump height might suffer a maximum increase in contact resistance during thermal shock, which has also been noted by other researchers. 11,12 Figure 5 shows the bump height of Au/Ni and bumpless chips. Figure 6a and b compares the variation of the online contact resistance for three different thermal-cycling profiles with respect to the number of cycles in the hot chamber for Au/Ni bump and bumpless chips.…”

Section: Effect Of Bump Height On Online Contact Resistancementioning

confidence: 99%

Effect of bump characteristics and temperature variation on the online contact resistance of anisotropic conductive joints

Ali

Chan

Alam

2004

Journal of Elec Materi

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Anisotropic conductive film (ACF) suffers a major drawback in regard to reliability even though it has merits, such as reduction in interconnection distance, high performance, and environmental friendliness. The factor of thermal warpage may lead to a highly unreliable electrical connection in the assembly. The work presented in this paper focuses on the online contact-resistance behavior of the ACF joint during thermal shock and compares the results of two different types of dies (Au/Ni bump and bumpless). For this work, we used a flip chip of 11 ϫ 3 mm 2 in dimension. The flex substrate used was made of polyimide film with an Au/Ni/Cu electrode and daisy-chained circuit for a matching die-bump pattern. The ACF that was used is an epoxy resin in which nickel and gold-coated polymer balls are dispersed. Tests for three different thermal-cycling profiles (125°C to Ϫ55°C, 140°C to Ϫ40°C, and 150°C to Ϫ65°C) were carried out. The samples bonded at a temperature of 180°C, and a pressure of 80 N was used. The initial contact resistances of Au/Ni bump and bumpless samples were 0.25 Ω and 0.4 Ω, respectively. A comparative study was carried out from the results obtained. The results showed that for the flip-chip-on-flex (FCOF) packages having an Au/Ni bump, the increase in online contact resistance is higher than that of the FCOF packages having bumpless chips. For example, in the thermal-cycling profile of 140°C to Ϫ40°C, the online contact resistance for the Au/Ni bump raised to 4.6 Ω after 180 cycles, whereas it was only 1.3 Ω for the bumpless sample. The bump height and bump materials were found to be the main factor for such variation. Results show that, above the glass-transition temperature (T g ), the ACF matrix becomes less viscous, which reduces its adhesive strength and lets the higher bump height of the chip result in a higher standoff of the package and thus sliding is easier to take place. The responses by the assemblies in hot and cold conditions are examined, and in-chamber behavior of the assembly is studied and explained.

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“…Compared with other joining methods, ACFs provide exceptional advantages, including improved environmental compatibility, extremely fine pitch capability, a simple structure and manufacturing process with low process temperature, light weight and small size of product (Sarkar et al, 1999;Pinardi et al, 2000;Chiriac and Lee, 2001;Zhang et al, 2002;Kwon and Paik, 2004). Due to the lack of direct contact between the conductive particles, ACF joints are very suitable for fine pitch assembly and are applied more and more in the packaging of flip chips, such as chip-on-glass (COG) attachment, and chip-on-film (COF) attachment.…”

Section: Introductionmentioning

confidence: 99%

Recent advances in mechanical properties of anisotropic conductive adhesive film for microelectronic packaging

Gao

Chen

2015

Soldering &Amp; Surface Mount Technology

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Purpose -This review paper aims to provide a better understanding of formulation and processing of anisotropic conductive adhesive film (ACF) material and to summarize the significant research and development work for the mechanical properties of ACF material and joints, which helps to the development and application of ACF joints with better reliability in microelectronic packaging systems. Design/methodology/approach -The ACF material was cured at high temperature of 190°C, and the cured ACF was tested by conducting the tensile experiments with uniaxial and cyclic loads. The ACF joint was obtained with process of pre-bonding and final bonding. The impact tests and shear tests of ACF joints were completed with different aging conditions such as high temperature, thermal cycling and hygrothermal aging. Findings -The cured ACF exhibited unique time-, temperature-and loading rate-dependent behaviors and a strong memory of loading history. Prior stress cycling with higher mean stress or stress amplitude restrained the ratcheting strain in subsequent cycling with lower mean stress or stress amplitude. The impact strength and adhesive strength of ACF joints increased with increase of bonding temperature, but they decreased with increase of environment temperature. The adhesive strength and life of ACF joints decreased with hygrothermal aging, whereas increased firstly and then decreased with thermal cycling. Originality/value -This study is to review the recent investigations on the mechanical properties of ACF material and joints in microelectronic packaging applications.

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Effect of bump height on the strain variation during the thermal cycling test of ACA flip-chip joints

Cited by 38 publications

References 3 publications

Studies on the thermal cycling reliability of fine pitch Cu/SnAg double-bump flip chip assemblies on organic substrates: Experimental results and numerical analysis

Studies on the thermal cycling reliability of fine pitch Cu/SnAg double-bump flip chip assemblies on organic substrates: Experimental results and numerical analysis

Effect of bump characteristics and temperature variation on the online contact resistance of anisotropic conductive joints

Recent advances in mechanical properties of anisotropic conductive adhesive film for microelectronic packaging

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