Influence of Bump Geometry, Adhesives and Pad Finishings on the Joint Resistance of Au Bump and A/NCA Flip Chip Interconnection

Min, Tan Ai; Lim, Suo Hon; Yeo, Anders; Lee, C.

doi:10.1109/eptc.2005.1614507

Cited by 9 publications

(1 citation statement)

References 13 publications

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“…However, NCF is short of conductive particles so it could be difficult to maintain the contact between upper and down electrodes under reliability test, making it difficult to achieve the needed yield of COF. Extensive studies have been done for this issue to change geometry of bump or pad, especially with gold stud-bumps [1][2][3][4]. Therefore, there is little work done on changing material of bump.…”

Section: Introductionmentioning

confidence: 99%

Evaluating fine-pitch chip-on-flex with non-conductive film by using multi-points compliant bump structure

Huang

Chen

2006

2006 8th Electronics Packaging Technology Conference

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High density packaging increasingly dominates the market share in LCD highlighting the need not only to decrease the pitch of bonding joints, but also to increase the I/O numbers of driver IC for high-end display applications. However, the shortage between two adjacent electrodes is a major problem when using conventional packaging technologies. Non-Conductive Film (NCF) is one of the interconnection materials which are increasingly used in LCD package and flip chip technology.There are many advantages using NCF in package, such as low cost, simplified process, and low temperature process. On the contrary, NCF bonded faces a challenge of yield. In this paper, we have developed a multi-points compliant bump (MPCB) using in NCF-bonded Chip-on-Flex (COF) process. Evaluating the effect of temperature, time, and load on electric resistance and peeling strength. A higher peeling strength is obtained at higher bonding load, temperature, and time. This indicated that the NCF with high curing degree is sufficient to hold the interconnection joints. The changes in daisy chain after 85 o C/85%RH Thermal Humidity Storage Test (THST) for 500 hrs are measured. Due to MPCB deforms in bonding process, and releases counterforce in reliability test. Experimental results show that low bonding load, high bonding temperature and high bonding time is good for reliability.

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Section: Introductionmentioning

confidence: 99%

Evaluating fine-pitch chip-on-flex with non-conductive film by using multi-points compliant bump structure

Huang

Chen

2006

2006 8th Electronics Packaging Technology Conference

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Review paper: Flip chip bonding with anisotropic conductive film (ACF) and nonconductive adhesive (NCA)

Kim¹,

Kim²

2013

Current Applied Physics

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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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Influence of Bump Geometry, Adhesives and Pad Finishings on the Joint Resistance of Au Bump and A/NCA Flip Chip Interconnection

Cited by 9 publications

References 13 publications

Evaluating fine-pitch chip-on-flex with non-conductive film by using multi-points compliant bump structure

Evaluating fine-pitch chip-on-flex with non-conductive film by using multi-points compliant bump structure

Review paper: Flip chip bonding with anisotropic conductive film (ACF) and nonconductive adhesive (NCA)

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

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