Material properties of anisotropic conductive films (ACFs) and their flip chip assembly reliability in NAND flash memory applications

Jang, Kyung-Woon; Chung, Chee Won; Lee, Woong-Sun; Paik, Kyung‐Wook

doi:10.1016/j.microrel.2008.03.002

Cited by 17 publications

(8 citation statements)

References 6 publications

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“…It can be seen from this graph that the bonding temperature and the force had a positive the value ranging from ∼0.5 to 10 MPa. The die shear strength values of NW-ACFs were comparable with the conventional ACFs, which are ranging from 5 to 15 kgf per 9 mm 2 bonding area (equal to 5.4-16.3 MPa) according to [5].…”

Section: Bonding Influence On Shear Strengthmentioning

confidence: 75%

“…The advantages of ACF [4], [5] over solder [6]- [8] include lower processing temperature (which makes it applicable to flex bonding), less environmental impact (no flux), reduced cost (no underfill and fewer process steps) and decreased intermetallic (IMC) reliability concern. Conventional ACFs have spherical conductive particles of 3-15 μm in size, which are randomly dispersed throughout a polymer matrix with a filling ratio of 5%-20%.…”

Section: Investigation Of Process Parameters and Characterization Of mentioning

confidence: 99%

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Investigation of Process Parameters and Characterization of Nanowire Anisotropic Conductive Film for Interconnection Applications

Tao

Hasan

et al. 2014

IEEE Trans. Compon., Packag. Manufact. Technol.

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In this paper, the assessment of the electrical and mechanical performance of the Cu nanowire anisotropic conductive film (NW-ACF) flip-chip interconnects has been performed. The influence of bonding conditions (bonding temperature and bonding force) has been studied in order to understand their impact on bonding resistance and shear strength for two types of NW-ACF based on different templates with varying porosity and thickness. An overgrowth-stripping method has been employed to obtain uniform NW (200 and 220 nm) arrays in the tracketch polymer membranes. The bonding substrate was coated with indium so that a diffusion soldering between Cu NWs and bulk In film can occur at a relatively low eutectic point (156.6°C). The bonding interface and the fractural surface of NW-ACFs have been characterized by scanning electron microscope and energy dispersive X-ray analysis. Under optimized fabrication conditions, process at the bonding profile of 200°C, 20 N shows that the z-axis resistance can be below 1 m and the shear strength can be above 10 MPa, which is very promising for the fine pitch, 3-D interconnection applications in the future.Index Terms-Electrochemical deposition, fractural surface, nanowire anisotropic conductive film (NW-ACF), shear strength, thermocompression bonding, z-axis resistance.

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Section: Bonding Influence On Shear Strengthmentioning

confidence: 75%

Section: Investigation Of Process Parameters and Characterization Of mentioning

confidence: 99%

Investigation of Process Parameters and Characterization of Nanowire Anisotropic Conductive Film for Interconnection Applications

Tao

Hasan

et al. 2014

IEEE Trans. Compon., Packag. Manufact. Technol.

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“…Several different accelerated life tests have been used to study the reliability of ACA joints; see for example (Frisk & Ristolainen, 2005;Frisk & Cumini, 2006;Jang et al, 2008;Kim et al, 2004;Lai & Liu, 1996;Saarinen et al, 2011). These include high temperature aging tests, temperature cycling tests, high temperature and high humidity tests, and humidity and temperature cycling tests.…”

Section: Failure Mechanisms Of the Aca Flip Chip Jointsmentioning

confidence: 99%

“…Due to the versatility of electronics packages concerning materials, structures, and functions a plethora of different methods have been used. These include for example electrical characterization technologies, x-ray, scanning electron microscopy (SEM), scanning acoustic microscopy (SAM), optical microscopy, differential scanning calorimetry (DCS), and thermomechanical analysis (TMA) Jang et al, 2008;Yim & Paik, 2001). …”

Section: Introductionmentioning

confidence: 99%

Study of Structure and Failure Mechanisms in ACA Interconnections Using SEM

Frisk¹

2012

Scanning Electron Microscopy

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“…Three types of single-layer ACA with 3m, 3.5m and 5m conductive particles in diameter and a single-layer NCA are also adopted to compare their electrical insulation resistance with those by the double-layer ACA, respectively. For the purpose of the study, we make no distinction between the ACAs and the NCA [13]. Five types of bonding materials are used and denoted as A DL , A 1 , A 2 , A 3 , and N 1 .…”

Section: Fabrication Of the Cof Interconnectsmentioning

confidence: 99%

A novel compliant-bump structure for ACA-bonded chip-on-flex (COF) interconnects with ultra-fine pitch

Lin

Chuang

et al. 2009

2009 59th Electronic Components and Technology Conference

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As the growing demand for high-density electronic applications, a novel COF package with sidewall-insulated Au-coated polyimide (PI) compliant-bumps using a doublelayer ACA that can meet the assembly requirement is thus developed for ultra-fine pitch interconnects in this work.The reliability of the ACA-bonded COF package with 20m pitch using both Au-bumps and compliant-bumps is examined, respectively. The double-layer ACA consists of an ACA layer with 2.8m conductive particles in diameter and a NCA layer selected as an interlayer to bind the silicon chip and the flexible substrate together. Bonding accuracy for ultra-fine pitch is inspected through X-ray works after bonding. To evaluate the bonding quality, both the electrical insulation test and the contact resistance measurement of daisy chain with 606 I/Os around the peripheral of chip are performed. Three types of single-layer ACA with 3m, 3.5m and 5m conductive particles in diameter and a single-layer NCA are also adopted to compare their electrical insulation resistance with those by the double-layer ACA, respectively. The compliant-bump bonded samples using the double-layer ACA show their excellent electrical insulation performance even at 5m joint space whereas the Au-bump bonded ones present more than 50% short-circuiting rate no matter what ACA used. It is worthwhile to mention that the compliantbump assembled with 20m pitch COF also passes its reliability evaluation by both the 85°C/85% RH thermal humidity storage test (THST) for 1,000 hours and -55°C ~125°C thermal cycling test (TCT) for 1,000 cycles. The interfaces between silicon chip and substrate for failed samples from the reliability tests are then inspected through the cross-section SEM images.From the results presented, reliable bonding quality and stable contact resistance of the COF package bonded with the compliant-bump structure using the double-layer ACA demonstrate its high potentiality for ultra-fine pitch applications.

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Material properties of anisotropic conductive films (ACFs) and their flip chip assembly reliability in NAND flash memory applications

Cited by 17 publications

References 6 publications

Investigation of Process Parameters and Characterization of Nanowire Anisotropic Conductive Film for Interconnection Applications

Investigation of Process Parameters and Characterization of Nanowire Anisotropic Conductive Film for Interconnection Applications

Study of Structure and Failure Mechanisms in ACA Interconnections Using SEM

A novel compliant-bump structure for ACA-bonded chip-on-flex (COF) interconnects with ultra-fine pitch

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