Influence of copper pillar bump structure on flip chip packaging during reflow soldering: a numerical approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammad Hafifi Hafiz Ishak ◽  
Mohd Sharizal Abdul Aziz ◽  
Farzad Ismail ◽  
M.Z. Abdullah
Keyword(s):  
Flip Chip ◽  
Fluid Dynamic ◽  
Reflow Process ◽  
Reflow Soldering ◽  
Content Type ◽  
Soldering Process ◽  
Cu Pillar ◽  
Computational Fluid Dynamics Analysis ◽  
Flip Chip Packaging ◽  
The Impact

Purpose The purpose of this paper is to present the experimental and simulation studies on the influence of copper pillar bump structure on flip chip packaging during reflow soldering. Design/methodology/approach In this work, solidification/melting modelling and volume of fluid modelling were used. Reflow soldering process of Cu pillar type FC was modelled using computational fluid dynamic software (FLUENT). The experimental results have been validated with the simulation results to prove the accuracy of the numerical method. Findings The findings of this study reveal that solder volume is the most important element influencing reflow soldering. The solder cap volume reduces as the Cu pillar bump diameter lowers, making the reflow process more difficult to establish a good solder union, as less solder is allowed to flow. Last but not least, the solder cap height for the reflow process must be optimized to enable proper solder joint formation. Practical implications This study provides a basis and insights into the impact of copper pillar bump structure on flip chip packaging during reflow soldering that will be advancing the future design of 3D stack package. This study also provides a superior visualization and knowledge of the melting and solidification phenomenon during the reflow soldering process. Originality/value The computational fluid dynamics analysis of copper pillar bump structure on flip chip packaging during reflow soldering is scant. To the authors’ best knowledge, no research has been concentrated on copper pillar bump size configurations in a thorough manner. Without the in-depth study, copper pillar bump size might have the impact of copper pillar bump structure on flip chip packaging during reflow soldering. Five design of parameter of flip chip IC package model was proposed for the investigation of copper pillar bump structure on flip chip packaging during reflow soldering.

Influence of moisture concentration and hydrophobic material on induced stress in FCBGA package under reflow

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Elwin Heng ◽  
Mohd Zulkifly Abdullah
Keyword(s):  
Reflow Process ◽  
Test Vehicle ◽  
Moisture Concentration ◽  
Reflow Soldering ◽  
Content Type ◽  
Soldering Process ◽  
Induced Stress ◽  
Microelectronics Industry ◽  
Hydrophilic Materials ◽  
Hydrophobic Material

Purpose This paper focuses on the fluid-structure interaction (FSI) analysis of moisture induced stress for the flip chip ball grid array (FCBGA) package with hydrophobic and hydrophilic materials during the reflow soldering process. The purpose of this paper is to analyze the influence of moisture concentration and FCBGA with hydrophobic material on induced pressure and stress in the package at varies times. Design/methodology/approach The present study analyzed the warpage deformation during the reflow process via visual inspection machine (complied to Joint Electron Device Engineering Council standard) and FSI simulation by using ANSYS/FLUENT package. The direct concentration approach is used to model moisture diffusion and ANSYS is used to predict the Von-Misses stress. Models of Test Vehicle 1 (similar to Xie et al., 2009b) and Test Vehicle 2 (FCBGA package) with the combination of hydrophobic and hydrophilic materials are performed. The simulation for different moisture concentrations with reflows process time has been conducted. Findings The results from the mechanical reliability study indicate that the FSI analysis is found to be in good agreement with the published study and acceptable agreement with the experimental result. The maximum Von-Misses stress induced by the moisture significantly increased on FCBGA with hydrophobic material compared to FCBGA with a hydrophilic material. The presence of hydrophobic material that hinders the moisture desorption process. The analysis also illustrated the moisture could very possibly reside in electronic packaging and developed beyond saturated vapor into superheated vapor or compressed liquid, which exposed electronic packaging to higher stresses. Practical implications The findings provide valuable guidelines and references to engineers and packaging designers during the reflow soldering process in the microelectronics industry. Originality/value Studies on the influence of moisture concentration and hydrophobic material are still limited and studies on FCBGA package warpage under reflow process involving the effect of hydrophobic and hydrophilic materials are rarely reported. Thus, this study is important to effectively bridge the research gap and yield appropriate guidelines in the microelectronics industry.

Thermo-mechanical challenges of reflowed lead-free solder joints in surface mount components: a review

2016 ◽  
Vol 28 (2) ◽  
pp. 41-62 ◽  
Author(s):  
Chun Sean Lau ◽  
C.Y. Khor ◽  
D. Soares ◽  
J.C. Teixeira ◽  
M.Z. Abdullah
Keyword(s):  
Solder Joints ◽  
Simulation Modelling ◽  
Lead Free ◽  
Lead Free Solder ◽  
Reflow Process ◽  
Reflow Soldering ◽  
Content Type ◽  
Surface Mount ◽  
Soldering Process ◽  
Free Solder

Purpose The purpose of the present study was to review the thermo-mechanical challenges of reflowed lead-free solder joints in surface mount components (SMCs). The topics of the review include challenges in modelling of the reflow soldering process, optimization and the future challenges in the reflow soldering process. Besides, the numerical approach of lead-free solder reliability is also discussed. Design/methodology/approach Lead-free reflow soldering is one of the most significant processes in the development of surface mount technology, especially toward the miniaturization of the advanced SMCs package. The challenges lead to more complex thermal responses when the PCB assembly passes through the reflow oven. The virtual modelling tools facilitate the modelling and simulation of the lead-free reflow process, which provide more data and clear visualization on the particular process. Findings With the growing trend of computer power and software capability, the multidisciplinary simulation, such as the temperature and thermal stress of lead-free SMCs, under the influenced of a specific process atmosphere can be provided. A simulation modelling technique for the thermal response and flow field prediction of a reflow process is cost-effective and has greatly helped the engineer to eliminate guesswork. Besides, simulated-based optimization methods of the reflow process have gained popularity because of them being economical and have reduced time-consumption, and these provide more information compared to the experimental hardware. The advantages and disadvantages of the simulation modelling in the reflow soldering process are also briefly discussed. Practical implications This literature review provides the engineers and researchers with a profound understanding of the thermo-mechanical challenges of reflowed lead-free solder joints in SMCs and the challenges of simulation modelling in the reflow process. Originality/value The unique challenges in solder joint reliability, and direction of future research in reflow process were identified to clarify the solutions to solve lead-free reliability issues in the electronics manufacturing industry.

The Study of Underfill Epoxy Hardness in Reducing Curing Process Time for Flip Chip Packaging

2011 ◽  
Vol 462-463 ◽  
pp. 1194-1199
Author(s):  
Zainudin Kornain ◽  
Azman Jalar ◽  
Rozaidi Rashid ◽  
Shahrum Abdullah
Keyword(s):  
Thermal Expansion ◽  
Flip Chip ◽  
Ball Grid Array ◽  
Process Time ◽  
Curing Process ◽  
Curing Time ◽  
Hold Temperature ◽  
Flip Chip Packaging ◽  
Time Cycle ◽  
The Impact

Underfilling is the vital process to reduce the impact of the thermal stress that results from the mismatch in the co-efficient of thermal expansion (CTE) between the silicon chip and the substrate in Flip Chip Packaging. This paper reported the pattern of underfill’s hardness during curing process for large die Ceramic Flip Chip Ball Grid Array (FC-CBGA). A commercial amine based underfill epoxy was dispensed into HiCTE FC-CBGA and cured in curing oven under a new method of two-step curing profile. Nano-identation test was employed to investigate the hardness of underfill epoxy during curing steps. The result has shown the almost similar hardness of fillet area and centre of the package after cured which presented uniformity of curing states. The total curing time/cycle in production was potentially reduced due to no significant different of hardness after 60 min and 120 min during the period of second hold temperature.

Thermal decomposition of solder flux activators under simulated wave soldering conditions

2017 ◽  
Vol 29 (3) ◽  
pp. 133-143 ◽  
Author(s):  
Kamila Piotrowska ◽  
Morten Stendahl Jellesen ◽  
Rajan Ambat
Keyword(s):  
Thermal Treatment ◽  
Heat Exposure ◽  
Copper Surface ◽  
Substrate Material ◽  
Content Type ◽  
Soldering Process ◽  
Wave Soldering ◽  
Solder Flux ◽  
Solder Mask ◽  
The Impact

Purpose The aim of this work is to investigate the decomposition behaviour of the activator species commonly used in the wave solder no-clean flux systems and to estimate the residue amount left after subjecting the samples to simulated wave soldering conditions. Design/methodology/approach Changes in the chemical structure of the activators were studied using Fourier transform infrared spectroscopy technique and were correlated to the exposure temperatures within the range of wave soldering process. The amount of residue left on the surface was estimated using standardized acid-base titration method as a function of temperature, time of exposure and the substrate material used. Findings The study shows that there is a possibility of anhydride-like species formation during the thermal treatment of fluxes containing weak organic acids (WOAs) as activators (succinic and DL-malic). The decomposition patterns of solder flux activators depend on their chemical nature, time of heat exposure and substrate materials. Evaporation of the residue from the surface of different materials (laminate with solder mask, copper surface or glass surface) was found to be more pronounced for succinic-based solutions at highest test temperatures than for adipic acid. Less left residue was found on the laminate surface with solder mask (∼5-20 per cent of initial amount at 350°C) and poorest acid evaporation was noted for glass substrates (∼15-90 per cent). Practical implications The findings are attributed to the chemistry of WOAs typically used as solder flux activators. The results show the importance WOA type in relation to its melting/boiling points and the impact on the residual amount of contamination left after soldering process. Originality/value The results show that the evaporation of the flux residues takes place only at significantly high temperatures and longer exposure times are needed compared to the temperature range used for the wave soldering process. The extended time of thermal treatment and careful choice of fluxing technology would ensure obtaining more climatically reliable product.

A computational fluid dynamics analysis of the wave soldering process

2015 ◽  
Vol 25 (5) ◽  
pp. 1231-1247 ◽  
Author(s):  
M.S. Abdul Aziz ◽  
M.Z. Abdullah ◽  
C.Y. Khor ◽  
M. Mazlan ◽  
A.M. Iqbal ◽  
...  
Keyword(s):  
Flow Behavior ◽  
Three Dimensional ◽  
Flow Profile ◽  
Content Type ◽  
Fountain Flow ◽  
Soldering Process ◽  
Wave Soldering ◽  
Computational Fluid Dynamics Analysis ◽  
Filling Time ◽  
Propeller Blades

Purpose – The purpose of this paper is to present a three-dimensional finite volume-based analysis on the effects of propeller blades on fountain flow in a wave soldering process and performs an experimental validation. Design/methodology/approach – Solder pot models with various numbers of propeller blades were developed and meshed by using hybrid elements and simulated by using the FLUENT fluid flow solver. The characteristics of the fountain, such as flow profile, velocity vector, filling time, and fountain advancement, were investigated. Molten solder (Sn63Pb37) material, a temperature of 250°C, and a propeller speed of 830 rpm were applied in the simulation. The predicted results were validated by the experimental fountain profile. Findings – The use of a six-blade propeller in a solder pot increased the fountain thickness profile and reduced the filling time. Moreover, a six-blade propeller design resulted in a stable fountain profile and was considered the best choice for current wave soldering processes. Practical implications – This study provides a better understanding of the effects of propeller blades on the fountain flow in the wave soldering process. Originality/value – The study explores the fountain flow behavior and provides a reference to the engineers and designers in order to improve the fountain flow of the wave soldering.

Simulations of the PC boiler equipped with complex swirling burners

2014 ◽  
Vol 24 (4) ◽  
pp. 845-860 ◽  
Author(s):  
Wojciech P. Adamczyk ◽  
Pawel Kozolub ◽  
Gabriel Węcel ◽  
Arkadiusz Ryfa
Keyword(s):  
Fluid Dynamic ◽  
Exchange Process ◽  
Combustion Process ◽  
Accurate Solution ◽  
Flue Gases ◽  
Discrete Phase Model ◽  
Complex Flow ◽  
Content Type ◽  
Combustion Technology ◽  
The Impact

Purpose – The purpose of this paper is to show possible approaches which can be used for modeling complex flow phenomena caused by swirl burners combined with simulating coal combustion process using air- and oxy-combustion technologies. Additionally, the response of exist boiler working parameter on changing the oxidizer composition from air to a mixture of the oxygen and recirculated flue gases is investigated. Moreover, the heat transfer in the superheaters section of the boiler was taken into account by modeling of the heat exchange process between continuum phase and three stages of the steam superheaters. Design/methodology/approach – An accurate solution of the flow field is required in order to predict combustion phenomena correctly for numerical simulations of the industrial pulverized coal (PC) boilers. Nevertheless, it is a very demanding task due to the complicated swirl burner construction and complex character of the flow. The presented simulations were performed using the discrete phase model for tracking particles and combustion phenomena in a dispersed phase, whereas the Eulerian approach was applied for the volatile combustion process modeling in a gaseous phase. Findings – Applying the air- to oxy-combustion technology the temperature in the combustion chamber, decreased for investigated oxidizer compositions. This was caused by the higher heat capacity of flue gases which also influences on the level of the heat flux at the boiler walls. Simulations shows that increasing the O2 concentration to 30 percent of volume base in the oxidizer mixture provided the similar combustion conditions as those for the conventional air firing. Moreover, the evaluated results give a good overview of differences between approaches used for complex swirl burners simulations. Practical implications – Nowadays, the numerical techniques such as computational fluid dynamic (CFD) can be seen as an useful engineering tool for design and processes optimization purposes. The application of the CFD gives a possibility to predict the combustion phenomena in a large industrial PC boiler and investigate the impact of changing the combustion technology from a conventional air firing to oxy-fuel combustion. Originality/value – This paper gives good overview on existing technique, approaches used for modeling PC boiler equipped with complex swirl burners. Additionally, the novelty of this work is application of the heat exchanger model for predicting heat loses in convective section of the boiler. This usually is not taken into account during simulations. The reader can also find basic concept of oxy-combustion technology, and their impact on boiler working conditions.

scholarly journals Analysis of Defects Generated by the Reflow Soldering in SMT (Surface Mount Technology) Assembly Applying the Six Sigma Method

2004 ◽  
Vol 1 (2) ◽  
pp. 17-25
Author(s):  
Ana C. Bueno ◽  
Maíra P. Shiki ◽  
Valdemir R. De Lima ◽  
Luis G. Brandão ◽  
Maurício M. Oka
Keyword(s):  
Six Sigma ◽  
Failure Modes ◽  
Solder Paste ◽  
Reflow Process ◽  
Reflow Time ◽  
Reflow Soldering ◽  
Effect Analysis ◽  
Soldering Process ◽  
Memory Modules ◽  
Edge Connector

The Six Sigma method using the DMAIC methodology is being applied for analyzing the reflow soldering process in an SMT assembly line. The Define phase (D) and Measure phase (M) were concluded, the Analysis (A) phase is being implemented, and the Improve (I) and Control (C) phases will be the next ones. Defects generated during the reflow process were classified and measured both on assembled memory modules and on virgin laminates that were passed through the oven during the reflow of these modules. Spots of solder and flux were found on the edge connector of the modules and also on the surface of the virgin laminates. It was found that these defects are generated inside the reflow oven, indicating that the oven is contaminated. Two solder pastes were analyzed and consequently, two temperature profiles were used. The amount of defects generated by the oven was found to be independent on the temperature profile. On the other hand the amount of defects depends on the solder paste that is used. The FMEA (Failure Mode and Effect Analysis) was also accomplished. As a result, the main failure modes of the reflow process were determined, namely, the heating rate, the soak temperature, the conveyor velocity, the reflow temperature, the reflow time, and the cooling rate.

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