Investigation on growth of the orientation-preferred Cu6Sn5 on (001)Cu during the temperature-increased multiple reflow process

Wettability for lead free solder 99.0Sn-0.3Ag-0.7Cu (SAC237) with addition of different weight percentage carbon nanotube after thermal treatment was investigated. SAC 237 solder powder with flux was mixed with 0.01%, 0.02%, 0.03% and 0.04% carbon nanotubes (CNTs) to form SAC-CNTs solder paste. Printed solder paste on test board with Cu surface finish was then reflow under 270°C temperature and isothermal aging at 150°C for 0,200 and 400 hours. Wettability of SAC-CNT solder was determined by measuring contact angle using optical microscope and image analyzer. As a result, from reflow process right through 400 hours of thermal aging, SAC237 with 0.04% CNT has the lowest contact angle as compared to other SAC-CNTs and SAC237 solder. As a conclusion, addition of carbon nanotubes into solder SAC237 improved their wettability on Cu substrate, especially at 0.04% of CNTs.

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Stencil Design for Lead-Free Reflow Process

10.1109/isse.2007.4432873 ◽

2007 ◽

Cited By ~ 2

Author(s):

W. Steplewski ◽

G. Koziol

Keyword(s):

Lead Free ◽

Reflow Process

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Effects of doping trace Ni element on interfacial behavior of Sn/Ni (polycrystal/single-crystal) joints

Soldering & Surface Mount Technology ◽

10.1108/ssmt-08-2021-0053 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Jianing Wang ◽

Jieshi Chen ◽

Zhiyuan Zhang ◽

Peilei Zhang ◽

Zhishui Yu ◽

...

Keyword(s):

Solder Joint ◽

Single Crystal ◽

Microstructure Evolution ◽

Thermal Aging ◽

Interfacial Layer ◽

Aging Treatment ◽

Growth Behavior ◽

Reflow Process ◽

Content Type ◽

Ni Substrate

Purpose The purpose of this article is the effect of doping minor Ni on the microstructure evolution of a Sn-xNi (x = 0, 0.05 and 0.1 wt.%)/Ni (Poly-crystal/Single-crystal abbreviated as PC Ni/SC Ni) solder joint during reflow and aging treatment. Results showed that the intermetallic compounds (IMCs) of the interfacial layer of Sn-xNi/PC Ni joints were Ni3Sn4 phase, while the IMCs of Sn-xNi/SC Ni joints were NiSn4 phase. After the reflow process and thermal aging of different joints, the growth behavior of interfacial layer was different due to the different mechanism of element diffusion of the two substrates. The PC Ni substrate mainly provided Ni atoms through grain boundary diffusion. The Ni3Sn4 phase of the Sn0.05Ni/PC Ni joint was finer, and the diffusion flux of Sn and Ni elements increased, so the Ni3Sn4 layer of this joint was the thickest. The SC Ni substrate mainly provided Ni atoms through the lattice diffusion. The Sn0.1Ni/SC Ni joint increases the number of Ni atoms at the interface due to the doping of 0.1Ni (wt.%) elements, so the joint had the thickest NiSn4 layer. Design/methodology/approach The effects of doping minor Ni on the microstructure evolution of an Sn-xNi (x = 0, 0.05 and 0.1 Wt.%)/Ni (Poly-crystal/Single-crystal abbreviated as PC Ni/SC Ni) solder joint during reflow and aging treatment was investigated in this study. Findings Results showed that the intermetallic compounds (IMCs) of the interfacial layer of Sn-xNi/PC Ni joints were Ni3Sn4 phase, while the IMCs of Sn-xNi/SC Ni joints were NiSn4 phase. After the reflow process and thermal aging of different joints, the growth behavior of the interfacial layer was different due to the different mechanisms of element diffusion of the two substrates. Originality/value In this study, the effect of doping Ni on the growth and formation mechanism of IMCs of the Sn-xNi/Ni (single-crystal) solder joints (x = 0, 0.05 and 0.1 Wt.%) was investigated.

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Continuous Wetiability Measurement for Solder Reflow

MRS Proceedings ◽

10.1557/proc-226-29 ◽

1991 ◽

Vol 226 ◽

Author(s):

Cynthia M. Melton ◽

Susan M. Yarling ◽

Carl J. Raleigh

Keyword(s):

Contact Angle ◽

Continuous Monitoring ◽

Solder Ball ◽

Nitrogen Atmosphere ◽

Molten Solder ◽

Reflow Process ◽

Base Diameter ◽

Solder Flux ◽

Full Factorial ◽

Final Degree

AbstractA quantitative dynamic solder wettability mesurement technique was utilized to evaluate the effects of reflow processing on the wettability parameters associated with solder ball alloys. This technique enables the examination of the final degree of solder wetting and the continuous monitoring of wetting as a function of time during the reflow process under nitrogen atmosphere. An experimental design approach employing a 24 full factorial experiment was formulated to illustrate the use of this measurement technique investigating the final result of wetting. Solder wettability was determined with respect to the contact angle, base diameter and height of the reflowed solder ball alloy. The most significant effect estimates with respect to contact angle were solder flux and pad metallization. Solder ball alloy was found to significantly impact the base diameter and height of the reflowed solder. The effect of solder flux activators and pad metallizations on the subsequent continuous solder wettability wetting rates and amount of molten solder spread of solder ball alloys during reflow were measured. Reflow with a relatively more activated solder flux material was found to enhance the rate of solder wetting of the the pad metallization.

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Toward the High-Quality Graphene for Optoelectronic Applications by Optimization of the Growth and Transfer Parameters

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.834-836.33 ◽

2013 ◽

Vol 834-836 ◽

pp. 33-36

Author(s):

Lang Wang ◽

Jian Hua Zhang ◽

Lian Qiao Yang

Keyword(s):

Surface Condition ◽

Chemical Vapor ◽

Reflow Process ◽

High Quality ◽

Cu Substrate ◽

Nucleation Sites ◽

Higher Temperature ◽

Transfer Parameters ◽

Optoelectronic Applications ◽

Pre Treatment

In this paper, the process parameters of graphene during fabrication and transfer are investigated. Cu is utilized as the substrate and chemical vapor deposition are used to obtain graphene. The results show that, the surface condition of the Cu substrate tends to be worse than as-received after a relatively higher temperature (1035°C) annealing and growth process, which lead to bad graphene quality. In addition, pre-treatment of Cu substrate by acetic acid is helpful to reduce the nucleation sites. Reflow process before PMMA etching is an effective method to eliminate the wrinkles formed during transfer. High-quality graphene for optoelectronic applications were obtained based on the optimized fabrication and transfer process.

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An Investigation on the Profile of Microlens by the Thermal Reflow Process Due to Surface Tension and Gravity

Volume 4: 20th International Conference on Design Theory and Methodology; Second International Conference on Micro- and Nanosystems ◽

10.1115/detc2008-50077 ◽

2008 ◽

Author(s):

Jhy-Cherng Tsai ◽

Yong-Sung Hsu

Keyword(s):

Surface Tension ◽

Critical Radius ◽

Critical Size ◽

Liquid Droplet ◽

Bond Number ◽

Diameter Ratio ◽

Experimental Result ◽

Critical Number ◽

Reflow Process ◽

Thermal Reflow

Microlens and its mold fabricated by thermal reflow using photoresist have been widely used for forming patterns in different scales. When the photoresist solidifies from melting condition, for example by the reflow process, its profile is formed based on the balance between surface tension and gravity. This research is aimed to investigate the influence of surface tension and gravity on the profile of microlens in thermal reflow process. Theoretical analysis based on the interaction between surface tension and gravity of liquid droplet is first investigated. The result showed that the height to diameter ratio (h/D), or the sag ratio, of the liquid droplet is affected by the Bond number (Bo), a number defined as the ratio of gravity to surface tension. The sag ratio is not sensitive to Bo when Bo is small but the ratio decreases as Bo increases if Bo is over the critical number. Based on the analysis, the critical number for the AZ4620 photoresist on a silicon substrate is 1, corresponding to the critical radius of droplet R = 2,500μm. When the size of the droplet is less then the critical size, the profile is mainly controlled by the surface tension and thus the sag ratio is about the same regardless the size. The profile, in contrast, is highly affected by the gravity if the size of the droplet is larger then the critical size. The sag ratio decreases exponentially with respect to Bo in this case. Experiments are also designed and conducted to verify the analysis. Experimental result showed that the sag ratio of the photoresist reduces to 0.065 from 0.095 when Bo increases from 0.0048 to 0.192. The results showed that the trend is consistent to the theoretical model.

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