Effects of nanofiber materials of nanofiber anisotropic conductive adhesives (nanofiber ACAs) for ultra-fine pitch electronic assemblies

2013 ◽  
Author(s):  
Kyoung-Lim Suk ◽  
Kyung-Wook Paik
Keyword(s):  
Conductive Adhesives ◽  
Fine Pitch ◽  
Electronic Assemblies

Highly reliable, fine pitch chip on glass (COG) joints fabricated using Sn/Cu bumps and non-conductive adhesives

2011 ◽  
Vol 51 (4) ◽  
pp. 851-859 ◽  
Author(s):  
Byeung-Gee Kim ◽  
Sang-Mok Lee ◽  
Yun-Song Jo ◽  
Sun-Chul Kim ◽  
Kyoung-Moo Harr ◽  
...  
Keyword(s):  
Conductive Adhesives ◽  
Fine Pitch

Characterization of nano-enhanced interconnect materials for fine pitch assembly

2014 ◽  
Vol 26 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Yan Zhang ◽  
Janusz Sitek ◽  
Jing-yu Fan ◽  
Shiwei Ma ◽  
Marek Koscielski ◽  
...  
Keyword(s):  
Filler Content ◽  
Nano Particles ◽  
Differential Scanning Calorimetry Measurement ◽  
Conductive Adhesives ◽  
Scanning Calorimetry ◽  
Loading Test ◽  
Content Type ◽  
Fine Pitch ◽  
Silver Flakes ◽  
Silver Spheres

Purpose – Multiple fillers are adopted to study the filler influences on electrical and mechanical properties of the conductive adhesives. The performances of the developed nano-enhanced interconnect materials in printing process are also evaluated. The paper aims to discuss these issues. Design/methodology/approach – Micron-sized silver flakes are used as the basic fillers, and submicro- and nano-sized silver spheres and carbon nanotubes (CNTs) are adopted to obtain conductive adhesives with multiple fillers. Differential scanning calorimetry measurement is carried out to characterize the curing behavior of the samples with different fillers, four-probe method is used to obtain the bulk resistivity, shear test is conducted for adhesive strength, and environmental loading test is also involved. Furthermore, printing trials with different patterns have been carried out. Findings – The electrical resistivity of the adhesives with submicro-sized silver spheres does not monotonically change with the increasing sphere proportion, and there exists an optimized value for the ratio of silver flakes to spheres. Samples with relatively small amount of CNT additives show improved electrical properties, while their mechanical strengths tend to decrease. For the printing application, the adhesives with 18.3 volume% filler content behave much better than those with lower filler content of 6 percent. The presence of the nano-particles makes a slight improvement in the printing results. Research limitations/implications – More detailed printing performance and reliability test of the samples need to be carried out in the future. Originality/value – The conductive adhesives as interconnect materials exhibit some improved properties with optimized bimodal or trimodal fillers. The additive of the nano-fillers affects slightly on the printing quality of the bimodal conductive adhesives.

Nano-scale Conductive Films for High Performance Fine Pitch Interconnect

2007 ◽  
Vol 990 ◽  
Author(s):  
Yi Li ◽  
Myung Jin Yim ◽  
Kyung Sik Moon ◽  
ChingPing Wong
Keyword(s):  
High Performance ◽  
Electrical Conductance ◽  
Conductive Adhesives ◽  
Bonding Pressure ◽  
Nano Scale ◽  
Fine Pitch ◽  
Conductive Film ◽  
Joint Resistance ◽  
Conductive Fillers ◽  
Free Solder

ABSTRACTIn this paper, a novel nano-scale conductive film which combines the advantages of both traditional anisotropic conductive adhesives/films (ACAs/ACFs) and nonconductive adhesives/films (NCAs/NCFs) is introduced and developed for next generation high performance ultra-fine pitch packaging applications. This novel interconnect film possesses the properties of electrical conduction along the z-direction with relatively low bonding pressure (ACF-like) and the ultra-fine pitch (< 100 nm) capability (NCF-like). Unlike typical ACF which requires 1–5 vol% of conductive fillers, the novel nano-scale conductive film only needs less than 0.1 vol% conductive fillers to achieve good electrical conductance in the z direction. The nano-scale conductive film also allows a lower bonding pressure than NCF to achieve a much lower joint resistance (over two orders of magnitude lower than typical ACF joints) and higher current carrying capability. With low temperature sintering of nano-silver fillers, the joint resistance of the nano-scale conductive film could be as low as 10−5 Ohm, even lower than the NCF and lead-free solder joints. The reliability of the nano-scale conductive film after high temperature and humidity test (85°C/85%RH) was also improved compared to the NCF joints. As such, a high performance, fine pitch conductive film was developed.

Interfacial Adhesion of Anisotropic Conductive Adhesives on Polyimide Substrate

2005 ◽  
Vol 127 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Liqiang Cao ◽  
Zonghe Lai ◽  
Johan Liu
Keyword(s):  
Flip Chip ◽  
Peel Test ◽  
Peel Strength ◽  
Processing Temperature ◽  
Total System ◽  
High Humidity ◽  
Conductive Adhesives ◽  
Polyimide Substrate ◽  
Fine Pitch ◽  
Simple Processing

There has been steadily increasing interest in using electrically conductive adhesives as interconnecting materials in electronics manufacturing. Simple processing, low processing temperature and fine pitch capability are the major advantages of conducting adhesive technology. A new and innovative connection technology geared towards achieving increased functionality at a lower total system cost is anisotropic conductive adhesive (ACA) interconnection. ACAs, when used for flip chip assembly, provide electrical as well as mechanical interconnections for fine pitch applications. This work deals with adhesion issues between ACA on polyimide materials. The paper presents a reliability assessment of adhesive joints using ACA on polyimide substrate that was conducted by testing samples at various aging temperature, high humidity and high pressure environments. The effects of high temperature and high humidity on the bond strength of ACA joints were measured using 90 deg peel test as well as by microstructural examination. It was found that aging generally caused a decrease in peel strength, especially the results of scanning electronic microscopy showed that the pressure cooker test could most effectively reveal the adhesion behavior.

Stencil Printing Process Guidelines for 0.3mm Pitch Chip Scale Packages

2013 ◽  
Vol 2013 (1) ◽  
pp. 000569-000573
Author(s):  
Mark Whitmore ◽  
Jeff Schake ◽  
Clive Ashmore
Keyword(s):  
Form Factor ◽  
Area Ratio ◽  
Solder Paste ◽  
Assembly Process ◽  
Aperture Size ◽  
Stencil Printing ◽  
Printing Process ◽  
Fine Pitch ◽  
New Process ◽  
Electronic Assemblies

With the form factor of electronic assemblies continuing to shrink, designers are being forced towards smaller, more complex components with decreasing interconnection pitches. As a consequence, the Surface Mount assembly process is becoming increasingly challenged. For the stencil printing process, todays accepted stencil area ratio rules, (which dictate what can or cannot be printed), need to be significantly pushed to extend the printing process for next generation ultra -fine pitch components. With aperture geometries shrinking, anything which can influence solder paste transfer efficiency has to be considered. New process technologies such as ultrasonic squeegees have emerged in recent years to assist the process with some degree of success. However, something which is often overlooked in terms of stencil design influence is that a square shaped aperture, size for size, has a volume which is 21.5% than its circular counterpart. In a process where quite literally every solder particle that can be printed is becoming significant then this fact can be utilized to the process engineer's advantage. In this paper, the merits of stencil aperture shape, in conjunction with ultrasonic squeegees are investigated with the purpose of developing stencil printing guidelines for ultra-fine pitch components such as 0.3mm pitch CSP's.

High Performance Conductive Adhesives for Lead-Free Interconnects

2006 ◽  
Vol 968 ◽  
Author(s):  
Yi Li ◽  
ChingPing Wong
Keyword(s):  
High Power ◽  
High Performance ◽  
High Current Density ◽  
High Reliability ◽  
Nano Particles ◽  
Electrical Performance ◽  
Conductive Adhesives ◽  
Molecular Monolayers ◽  
Fine Pitch ◽  
Novel Approach

ABSTRACTTin-lead solder alloys are widely used in the electronic industry. With the recognition of toxicity of lead, however, electrically conductive adhesives (ECAs) have been considered as one of the most promising alternatives of tin-lead solder. While silver is the most widely used conductive fillers for ECA, silver migration has been the major concern for the high power and fine pitch applications. In this paper, a novel approach of using self-assembled monolayers (SAMs) passivation has been introduced to control the silver migration in nano-Ag ECAs. The protection of silver nano particles with SAMs reduced the silver migration dramatically and no migration was observed upon application of high voltages (up to 500 V) due to the formation of surface chelating compounds between the SAM and nano silver fillers. Unlike other migration control approaches which sacrifice electrical performance, the SAM passivated nano Ag fillers also enhanced the electrical conductivity and current carrying capability of adhesive joints significantly due to the improved interfacial properties and high current density of those molecular monolayers. The joint resistance of the SAM incorporated nano-Ag conductive adhesive could be achieved as low as 10−5 Ohm (the contact area is 100 ×100 μm2) and the maximum allowable current was higher than 3500 mA. As such, a fine pitch, high performance, non-migration and high reliability adhesives are developed for potential solder replacement in high voltage, high power device applications.

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