Thermal–mechanical optimization of a novel nanocomposite-film typed flip chip technology

Cheng, Hsien‐Chie; Hsieh, Kun-Yu; Chen, Kuo-Ming

doi:10.1016/j.microrel.2010.11.007

Cited by 8 publications

(1 citation statement)

References 19 publications

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“…AAO templates have the advantage of the high pore density and ordered pore structure, but not suitable for direct bonding due to the brittleness of the template. Cheng et al developed a novel Ag/Co-nanowire/polymer nanocomposite-film typed flip-chip technology, by fabricating the nanowires through AAO template, removing the AAO by chemical etching and refilling the nanowire arrays under a magnetic field with polyimide [9]. On the other hand, investigation on NW-ACF formed by TEM templates shows preliminary electrical and mechanical results in terms of bonding conditions with the unpatterned chips [10,11].…”

Section: Introductionmentioning

confidence: 99%

Study of fine pitch micro-interconnections formed by low temperature bonded copper nanowires based anisotropic conductive film

Tao

Mathewson

Razeeb

2014

2014 IEEE 64th Electronic Components and Technology Conference (ECTC)

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In this paper, Cu nanowire based anisotropic conductive film (ACF) has been systematically investigated in terms of its fine-pitch potential, electrical/ mechanical properties, process related issues and failure mechanisms. A test chip module including daisy-chain and 4-point structures was fabricated by electroplating and photolithography process, which has 160, 80, 40 and 30 µm bond pad pitches. The selection of membrane templates and the template based open/short failures have been discussed. Bond pads were finished with electroplated In to lower the bonding temperature and contact resistance. The electrical and mechanical performance of the interconnections has been studied in term of bonding force. The interconnect resistance of various pad sizes was 0.3-0.6 Ω per pad at the low bonding force of 1.5 N and dropped to 0.02-0.04 Ω per pad at the high bonding force of 10 N. The influence of bonding pressure on such nanowires formed interconnects was studied by microsectional analysis. For all pitch sizes, the electrical insulation was maintained for an applied voltage of 20 V. A shear strength of 1-5 MPa was achieved as a function of the bonding force and the fractural surface analysis verifies the Cu-In joint formed in such interconnections. IntroductionThe fabrication of stacked and vertically interconnected device layers (3D integration) with through Si via (TSV) technology [1] has provided a path to system scaling and performance enhancement. One of the key challenges in 3D integration is the fine pitch interconnection scheme, which has to accommodate various thermal and mechanical constraints, especially for the non-Si elements in the future 3D integrated package [2]. For advanced 3D stacking, various interconnection schemes and process technology have been proposed and most of them require a temperature higher than 250 °C and the underfill process during the bonding process [3,4]. As an alternative, anisotropic conductive film (ACF) can be a low-temperature, low-cost fine-pitch interconnection solution for future 3D integration. The conventional ACF, composed of randomly dispersed conductive micro particles in an adhesive polymer matrix, faces agglomeration problem when the size is reduced, resulting in potentially unstable electrical properties [5]. Moreover, the micro particles in the film have to be deformed to create electrical contact with high pressure, which constrains the minimum pitch size to ~ 100 µm for most commercial ACFs [6]. In order to further relax the thermal and mechanical constraints of interconnection process, nanowire based ACF (NW-ACF), containing metallic nanowire arrays vertically distributed in a porous polymer template, has been proposed as a low-temperature

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Section: Introductionmentioning

confidence: 99%