Development of chip-on-flex using SBB flip-chip technology

Kumano, Yutaka; Tomura, Y.; Itagaki, Minehiro; Bessho, Y.

doi:10.1016/s0026-2714(00)00258-4

Cited by 22 publications

(9 citation statements)

References 5 publications

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“…LCD module production using COF technology is accelerated due to its advantages of fine-pitch interconnection, low contact resistance and pre-test capability compared with COG in the high-density, multi-functional LCD modules. In COF technologies, there are several alternatives for interconnect materials and processes, such as Au-Sn joining [71], stud bump bonding (SBB) joining [72], ACF joining [73], and NCF and NCP joining [74]. Among them, ACF joining method has been applied as the main bonding method similar to COG technology.…”

Section: Acfs For Fine Pitch Interconnectionsmentioning

confidence: 99%

Review of Recent Advances in Electrically Conductive Adhesive Materials and Technologies in Electronic Packaging

Yim

Moon

et al. 2008

Journal of Adhesion Science and Technology

159

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Electrically Conductive Adhesives (ICAs: Isotropic Conductive Adhesives; ACAs: An-isotropic Conductive Adhesives; and NCAs: Non-conductive Adhesives) offer promising material solutions for fine pitch interconnects, low cost, low-temperature process and environmentally clean approaches in the electronic packaging technology. ICAs have been developed and used widely for traditional solder replacement, especially in surface mount devices and flip chip application. These also need to be lower cost with higher electrical/mechanical and reliability performances. ACAs have been widely used in flat panel display modules for high resolution, lightweight, thin profile and low power consumption in film forms (Anisotropic Conductive Films: ACFs) for last decades. Multi-layered ACF structures such as double and triple-layered ACFs were developed to meet fine pitch interconnection, low-temperature curing and strong adhesion requirements. Also, ACAs have been attracting much attention for their simple and lead-free processing as well as cost-effective packaging method for semiconductor packaging applications. High mechanical reliability, good electrical performance at high frequency level and effective thermal conductivity for high current density are some of required properties for ACF materials to be pursued for a wide usage in flip chip technology. Recently, NCAs are becoming promising for ultra-fine pitch interconnection and low cost joining materials in electronic packaging applications.In this paper, an overview of the recent developments and applications of electrically conductive adhesives for electronic packaging with focus on fine pitch capability, electrical/mechanical/thermal performance and wafer level packaging application is presented.

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Section: Acfs For Fine Pitch Interconnectionsmentioning

confidence: 99%

Review of Recent Advances in Electrically Conductive Adhesive Materials and Technologies in Electronic Packaging

Yim

Moon

et al. 2008

Journal of Adhesion Science and Technology

159

View full text Add to dashboard Cite

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“…To optimal parameter design, three evaluative bonding methods including Taguchi .. SBB (stud bump bonding) and OE-COF (optoelectronic COF) were also investigated recently. They focus on find approaches and recipes to development bonding parameter [5][6][7]. Besides the failure modes and new bonding methods, transient IR image was used to detect defects on the level ofa single interconnection with a pitch of80 Jim [8].…”

Section: Methodsmentioning

confidence: 99%

Effect of bonding temperature on eutectic interconnections in Chip-On-Film packages

Liu

Yeh

Tsai³

et al. 2008

2008 International Conference on Electronic Materials and Packaging

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Chip-On-Film (COF) packaging is an attractive solution for the direct attachment of chips onto a polyimide (PI) substrate patterned with copper leads. However, despite its many advantages, the eutectic Au-Sn alloy formed in the high temperature bonding process has a number of unsolved reliability issues. Accordingly, the current study performs a series of experiments to investigate the heat dissipation characteristics of the COF process in order to develop a design tool to predict the optimum eutectic bonding parameters. In the experiments, the temperature is measured at three separate positions on the inner lead bonding (ILB) apparatus using a thermocouple wire. The heat transfer characteristics of the bonding tool surface are also measured using a system comprising a PID controller, a solid state relay and a thermocouple extension wire. An finite element (FE) model is then constructed to simulate the temperature distribution within the COF/ILB system under equivalent temperature conditions. The validity FE model is used to construct a design chart which specifies the temperatures of the bonding tool and chip support stage which ensure that the Au-Sn eutectic temperature is achieved at the bump / inner lead interface. The results indicate that the tool temperature should be no lower than 100°C (with a stage temperature of 312°C) and no higher than 300°C (with a stage temperature of 302°C ).

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“…One promising approach is employing polymeric foils as carrier substrates for the circuits and systems. As a standard, high-heat resistant materials, typically polyimide or polyimide-based modified materials as well as liquid crystal polymer (LCP), are used [3,4,5], thus being compatible with most manufacturing processes. However, nowadays, the costs of materials account for one of the most primary considerations.…”

Section: Introductionmentioning

confidence: 99%

Fine-pitch chip-on-flex packaging of optoelectronic devices using low temperature optodic bonding

Wang

Gauch

Ristau

et al. 2016

2016 Pan Pacific Microelectronics Symposium (Pan Pacific)

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With the growing demand for mechanically flexible circuits or systems in consumer electronics, e.g. mobile phones, portable computers, TFT displayers, RFID tags etc., chipon-flex packaging has been developed to a great extent and is increasingly being implemented in a variety of applications. High-performance colored polymer films, such as polyimide, are most commonly employed as flex substrates. However, taking the feasibility for a wide range of optical applications and a low-cost procurement into account, transparent polymer foils, such as polymethyl methacrylate (PMMA), exhibit a greater prospect. A major challenge in using these polymer foils as flexible carriers lies in the thermal loading control depending on their low glass transition temperatures (Tg). Thus, we propose flip chip-based optodic bonding for chip-on-flex packaging by employing these cost-effective transparent polymer foils. In this bonding technology, conventional thermal loading is minimized since UV curable adhesives are used as bonding materials and an optode is correspondingly adopted. Additionally, the fine-pitch circuits on the flex substrates are designed according to the chips and fabricated by screen printing technology using silver nanoparticles. Considering the effects on the bonding performance, which result from the rheological behavior of the adhesives during dispensing and applying, contact angles between the adhesives and polymer foils are measured for determining the appropriate volume. In order to protect the silver interconnects as well as the applied adhesives from oxidation and thus attaining a long-term stability in respect to the electrical conductivity, a functionalized coating against ambient moisture is implemented onto the flex circuit. Through the performance tests of the final packages for a test chip and a bare optoelectronic component, this novel technology is verified as a promising solution for fine-pitch chip-on-flex packaging.

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Development of chip-on-flex using SBB flip-chip technology

Cited by 22 publications

References 5 publications

Review of Recent Advances in Electrically Conductive Adhesive Materials and Technologies in Electronic Packaging

Review of Recent Advances in Electrically Conductive Adhesive Materials and Technologies in Electronic Packaging

Effect of bonding temperature on eutectic interconnections in Chip-On-Film packages

Fine-pitch chip-on-flex packaging of optoelectronic devices using low temperature optodic bonding

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