CFD Analysis of Molten Solder Flow Behavior and Bridging Mechanism During Solder Bump Formation

2019 ◽  
Author(s):  
Risa Miyazawa ◽  
Keishi Okamoto ◽  
Hiroyuki Mori
Keyword(s):  
Flip Chip ◽  
Solder Bump ◽  
Cfd Simulation ◽  
Simulation Analysis ◽  
Flow Behavior ◽  
Molten Solder ◽  
Factors Affecting ◽  
Fine Pitch ◽  
Flow Motion ◽  
Free Solder

Abstract Technology of fine pitch interconnect with lead-free solder joint has been developed to enhance the performance of flip-chip high density packages. This study presents an investigation of solder bump forming behavior by means of CFD simulation analysis. The flow motion of molten solder is analyzed with 3D model we developed, and the simulation result is validated with the experiment. Moreover, the investigation of factors affecting solder bridging across adjacent pads is also performed. It is revealed that wettability between liquid solder and organic insulator, which is represented as contact angle in the calculation has large effect on the solder bridging phenomena. The simulation result suggests that worsening the wettability of the insulator can reduce the occurrence of bridging.

Thermally Activated Bumping Process using Sn3.0Ag0.5Cu Solder Powder for Low-Cost Interposers

2013 ◽  
Vol 2013 (1) ◽  
pp. 000420-000423
Author(s):  
Kwang-Seong Choi ◽  
Ho-Eun Bae ◽  
Haksun Lee ◽  
Hyun-Cheol Bae ◽  
Yong-Sung Eom
Keyword(s):  
Screen Printing ◽  
Flip Chip ◽  
Solder Bump ◽  
Low Cost ◽  
Organic Substrate ◽  
Lead Free ◽  
Lead Free Solder ◽  
Thermally Activated ◽  
Fine Pitch ◽  
Free Solder

A novel bumping process using solder bump maker (SBM) is developed for fine-pitch flip chip bonding. It features maskless screen printing process with the result that a fine-pitch, low-cost, and lead-free solder-on-pad (SoP) technology can be easily implemented. The process includes two main steps: one is the thermally activated aggregation of solder powder on the metal pads on a substrate and the other is the reflow of the deposited powder on the pads. Only a small quantity of solder powder adjacent to the pads can join the first step, so a quite uniform SoP array on the substrate can be easily obtained regardless of the pad configurations. Through this process, an SoP array on an organic substrate with a pitch of 130 μm is, successfully, formed.

Precise Quantitative Evaluation of Nano-Ordered Intermetallic Compounds in Sn-3.0Ag-0.5Cu Lead-Free Solder Bump by Using TEM

2008 ◽  
Vol 47-50 ◽  
pp. 907-911
Author(s):  
Chang Woo Lee ◽  
Y.S. Shin ◽  
J.H. Kim
Keyword(s):  
Intermetallic Compounds ◽  
Flip Chip ◽  
Solder Bump ◽  
Lead Free Solder ◽  
Growth Behaviour ◽  
Sic Particles ◽  
Imcs Growth ◽  
Ordered Intermetallic ◽  
Free Solder ◽  
The One

The growth behaviour of the intermetallic compounds (IMCs) in Pb-free solder bump is investigated. The Pb-free micro-bump, Sn-50%Bi, was fabricated by binary electroplating for flip-chip bond. The diameter of the bump is about 506m and the height is about 60 6m. In order to increase the reliability of the bonding, it is necessary to protect the growth of the IMCs in interface between Cu pad and the solder bump. For control of IMCs growth, SiC particles were distributed in the micro-solder bump during electroplating. The thickness of the IMCs in the interface was estimated by FE-SEM, EDS, XRF and TEM. From the results, The IMCs were found as Cu6Sn5 and Cu3Sn. The thickness of the IMCs decreases with increase the amount of SiC particles until 4 g/cm2. The one candidate of the reasons is that the SiC particles could decrease the area which be reacted between the solder and Cu layer. And another candidate is that the particle can make to difficult inter-diffusion within the interface.

Control of Bump Morphology in Lead Free Solder Plating for Higher Density Packaging

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 001643-001669
Author(s):  
Koji Tatsumi ◽  
Kyouhei Mineo ◽  
Takeshi Hatta ◽  
Takuma Katase ◽  
Masayuki Ishikawa ◽  
...  
Keyword(s):  
High Speed ◽  
Flip Chip ◽  
New Technologies ◽  
Short Circuit ◽  
Lead Free Solder ◽  
Cu Pillar ◽  
Fine Pitch ◽  
Different Shapes ◽  
Free Solder ◽  
High Density Packaging

Solder bumping is one of the key technologies for flip chip connection. Flip chip connection has been moving forward to its further downsizing and higher integration with new technologies, such as Cu pillar, micro bump and Through Silicon Via (TSV). Unlike some methods like solder printing and ball mounting, electroplating is a very promising technology for upcoming finer bump formation. We have been developing SnAg plating chemical while taking technology progress and customers' needs into consideration at the same time. Today, we see more variety of requests including for high speed plating to increase the productivity and also for high density packaging such as narrowing the bump pitch itself and downsizing of the bump diameter. To meet these technical needs, some adjustments of plating chemical will be necessary. This time we developed new plating chemicals to correspond to bump miniaturization. For instance, our new SnAg chemical can control bump morphology while maintaining the high deposition speed. With our new plating chemicals, we can deposit mushroom bumps that grow vertically against the resist surface, also this new chemicals work effectively to prevent short-circuit between mushroom bumps with fine pitch from forming. In addition, we succeeded in developing high speed Cu pillar plating chemicals that can control the surface morphology to create different shapes. We'd like to present our updates on controlling bump morphology for various applications.

Sub process challenges in ultra fine pitch stencil printing of type‐6 and type‐7 Pb‐free solder pastes for flip chip assembly applications

2005 ◽  
Vol 17 (1) ◽  
pp. 24-32 ◽  
Author(s):  
G.J. Jackson ◽  
M.W. Hendriksen ◽  
R.W. Kay ◽  
M. Desmulliez ◽  
R.K. Durairaj ◽  
...  
Keyword(s):  
Flip Chip ◽  
Stencil Printing ◽  
Fine Pitch ◽  
Solder Pastes ◽  
Flip Chip Assembly ◽  
Free Solder

A new Ni-Zn under bump metallurgy for Pb-free solder bump flip chip application

2010 ◽  
Author(s):  
Hae-Young Cho ◽  
Tae-Jin Kim ◽  
Young Min Kim ◽  
Sun-Chul Kim ◽  
Jin-Young Park ◽  
...  
Keyword(s):  
Flip Chip ◽  
Solder Bump ◽  
Free Solder

CFD Simulation Analysis on Fire Feature of Tunnel with Different Sections of Smoke Outlet

2011 ◽  
Vol 271-273 ◽  
pp. 995-999
Author(s):  
Bei Hua Cong ◽  
Xin Han ◽  
Jun Lin
Keyword(s):  
Large Scale ◽  
Cfd Simulation ◽  
Simulation Analysis ◽  
Effective Control ◽  
Outlet Section ◽  
Road Tunnel ◽  
Factors Affecting ◽  
Tunnel Fire ◽  
Fire Scenarios ◽  
Section Form

With regard to road tunnel fire situation, the smoke extraction system is very important for effective control of fire temperature as well as crowd safe evacuation. The section form of smoke outlet is one of the main factors affecting smoke extraction. Taking a certain large scale cross-section road tunnel as physical model, this paper carried out simulation analysis on several fire scenarios with the help of software FDS. By comparing with different flow rates of each section of smoke outlet as well as the corresponding calculated danger approaching time, the appropriate smoke outlet section was attained which could be a reference for practical projects.

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