CFD Prediction of Multiple Jet Impingement in a Reflow Soldering Process

2019 ◽  
pp. 141-158
Author(s):  
Flávia V. Barbosa ◽  
João P. V. Silva ◽  
Senhorinha F. C. Teixeira ◽  
Delfim F. Soares ◽  
Duarte N. F. Santos ◽  
...  
Keyword(s):  
Jet Impingement ◽  
Reflow Soldering ◽  
Soldering Process

scholarly journals Head-on-Pillow Defect Detection: X-Ray Inspection Limitations

2019 ◽  
Vol 16 (2) ◽  
pp. 91-102
Author(s):  
Lars Bruno ◽  
Benny Gustafson
Keyword(s):  
Solder Joints ◽  
Solder Paste ◽  
Wafer Level ◽  
Reflow Soldering ◽  
X Ray ◽  
Soldering Process ◽  
Irregular Shapes ◽  
Fine Pitch ◽  
Solder Balls ◽  
Ball Grid Array Packages

Abstract Both the number and the variants of ball grid array packages (BGAs) are tending to increase on network printed board assemblies with sizes ranging from a few millimeter die size wafer level packages with low ball count to large multidie system-in-package (SiP) BGAs with 60–70 mm side lengths and thousands of I/Os. One big challenge, especially for large BGAs, SiPs, and for thin fine-pitch BGA assemblies, is the dynamic warpage during the reflow soldering process. This warpage could lead to solder balls losing contact with the solder paste and its flux during parts of the soldering process, and this may result in solder joints with irregular shapes, indicating poor or no coalescence between the added solder and the BGA balls. This defect is called head-on-pillow (HoP) and is a failure type that is difficult to determine. In this study, x-ray inspection was used as a first step to find deliberately induced HoP defects, followed by prying off of the BGAs to verify real HoP defects and the fault detection correlation between the two methods. The result clearly shows that many of the solder joints classified as potential HoP defects in the x-ray analysis have no evidence at all of HoP after pry-off. This illustrates the difficulty of determining where to draw the line between pass and fail for HoP defects when using x-ray inspection.

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.

Strength Evaluation of Conductive Adhesive Paste for Die Bonding During Reflow Soldering

2009 ◽  
Author(s):  
Kisho Ashida ◽  
Kenya Kawano ◽  
Naotaka Tanaka ◽  
Atsushi Nishikizawa ◽  
Nobuya Koike
Keyword(s):  
Fracture Strength ◽  
Bending Test ◽  
Lead Frame ◽  
Reflow Soldering ◽  
Strength Evaluation ◽  
Silver Paste ◽  
Three Point Bending ◽  
Soldering Process ◽  
Die Bonding ◽  
Copper Lead

Evaluating silver paste strength for die bonding during the reflow soldering process is important, as silver paste fracturing is one of the main causes of package failure. First, we assumed that the fracturing was caused by thermal stress and vapor pressure at the interface between the resin and the copper lead frame. Next, we measured the silver paste fracture strength using a three-point bending test and a bonded specimen with silver paste. Finally, we predicted the occurrence of silver paste fracturing by calculating the silver paste stress during reflow soldering process and comparing it with the measured fracture strength. Results obtained in strength evaluation analysis were consistent with those obtained in package reflow tests, indicating that this method can be used to predict the occurrence of silver paste fracturing.

Influence of Reflow Soldering Process Parameters on the Lead-Free Reflow Profile

2013 ◽  
Vol 690-693 ◽  
pp. 2578-2582
Author(s):  
Wan Lei Liang ◽  
Xiao Dan Guan ◽  
Peng Zhao
Keyword(s):  
Process Parameters ◽  
Influential Factors ◽  
Lead Free ◽  
Heating Zone ◽  
Reflow Time ◽  
Reflow Soldering ◽  
Soldering Process ◽  
Key Indicators ◽  
The Relationship ◽  
Set Value

Reflow soldering process parameters have distinct effect on the lead-free reflow profile and its key indicators. To determine the relationship between reflow soldering process parameters and lead-free reflow profile is significant for obtaining the correct reflow profile. The result of orthogonal experimental shows that the most influential factors of the change rate of heat-up RS are conveyor speed S, temperature set value of the heating zone 1 T1 and the temperature set value of heating zone 2 T2 in sequence; the most influential factors of the soaking time TS are conveyor speed S, the temperature set value of heating zone 4 T4 and the temperature set value of heating zone 2 T2 in sequence; the most influential factors of the reflow peak temperature PT are conveyor speed S, the temperature set value of heating zone 7 T7 and the temperature set value of heating zone 6 T6 in sequence; the most influential factors of the reflow time TAL are conveyor speed S and the temperature set value of heating zone 6 T6 in sequence.

Analysis and Optimization for Lead-Free Reflow Soldering Process Parameters of SMA Based on 6 σ Method

2014 ◽  
Vol 602-605 ◽  
pp. 180-184
Author(s):  
Xuan Jun Dai ◽  
Hong Yan Huang
Keyword(s):  
Process Parameters ◽  
Lead Free ◽  
Analysis Method ◽  
Reflow Soldering ◽  
Soldering Process ◽  
Hot Air

The reflow soldering process under infrared hot air environment was simulated based on a typical BGA SMA and a twelve-zone reflow oven. Then the optimal soldering process parameters were obtained based on 6σ analysis method and related software. The results could be used to direct the lead-free soldering process parameters setting, and the soldering quality was ensured effectively.

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