scholarly journals Random Voids Generation and Effect of Thermal Shock Load on Mechanical Reliability of Light-Emitting Diode Flip Chip Solder Joints

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 94 ◽  
Author(s):  
Jiajie Fan ◽  
Jie Wu ◽  
Changzhen Jiang ◽  
Hao Zhang ◽  
Mesfin Ibrahim ◽  
...  
Keyword(s):  
Solder Joint ◽  
Thermal Shock ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Solder Joints ◽  
Light Emitting Diode ◽  
Shock Load ◽  
Thermal Shock Test ◽  
Mechanical Reliability ◽  
Light Emitting

To make the light-emitting diode (LED) more compact and effective, the flip chip solder joint is recommended in LED chip-scale packaging (CSP) with critical functions in mechanical support, heat dissipation, and electrical conductivity. However, the generation of voids always challenges the mechanical strength, thermal stability, and reliability of solder joints. This paper models the 3D random voids generation in the LED flip chip Sn96.5–Ag3.0–Cu0.5 (SAC305) solder joint, and investigates the effect of thermal shock load on its mechanical reliability with both simulations and experiments referring to the JEDEC thermal shock test standard (JESD22-A106B). The results reveal the following: (1) the void rate of the solder joint increases after thermal shock ageing, and its shear strength exponentially degrades; (2) the first principal stress of the solder joint is not obviously increased, however, if the through-hole voids emerged in the corner of solder joints, it will dramatically increase; (3) modelling of the fatigue failure of solder joint with randomly distributed voids utilizes the approximate model to estimate the lifetime, and the experimental results confirm that the absolute prediction error can be controlled around 2.84%.

Evaluation of solder joint reliability in flip chip package under thermal shock test

2006 ◽  
Vol 504 (1-2) ◽  
pp. 426-430 ◽  
Author(s):  
Dae-Gon Kim ◽  
Jong-Woong Kim ◽  
Seung-Boo Jung
Keyword(s):  
Solder Joint ◽  
Thermal Shock ◽  
Flip Chip ◽  
Thermal Shock Test ◽  
Solder Joint Reliability ◽  
Shock Test ◽  
Joint Reliability

scholarly journals Thermal Performance of LED Filament in Flip-Chip Packaging Manufactured for Different Correlated Color Temperature

2021 ◽  
Vol 11 (19) ◽  
pp. 8844
Author(s):  
He Jiang ◽  
Jiming Sa ◽  
Cong Fan ◽  
Yiwen Zhou ◽  
Hanwen Gu ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Color Difference ◽  
Junction Temperature ◽  
Color Temperature ◽  
Constant Current ◽  
Light Emitting ◽  
Flip Chip Packaging

The effect of correlated color temperature (CCT) on the thermal performance of light emitting diode (LED) filament in flip-chip packaging was investigated in detail. Two filaments with different lengths were selected as the research object, and the thermal resistance of filaments under three CCT (2200 K, 2400 K, 2700 K) were studied. The optical properties and thermal parameters of the two groups of filaments were measured, and the results were analyzed combined with the color coordinate. The experimental results show that thermal properties of LED filaments is closely related to CCT. Under constant current condition, junction temperature decreases with the increase of color difference. With the change of phosphor glue and phosphorus powder ratio, the color temperature of LED filament also changes. In the filaments with the same chip structure and packaging mechanism, the higher the proportion of red phosphorescent powder, the worse the heat dissipation performance of the filament. These results show that in the design and manufacture of LED filament, it is helpful to control the CCT of LED filament under the premise of meeting the use requirements.

High Power 325 Light Emitting Diode Arrays by Flip-Chip Packaging

2002 ◽  
Vol 743 ◽  
Author(s):  
Ashay Chitnis ◽  
Maxim Shatalov ◽  
Vinod Adivarahan ◽  
Jian Ping Zhang ◽  
Shuai Wu ◽  
...  
Keyword(s):  
Thermal Management ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Light Emitting ◽  
Flip Chip Packaging ◽  
Ultraviolet Light Emitting Diodes ◽  
Emission Light

ABSTRACTWe report flip-chip 325 nm emission light emitting diodes over sapphire with dc powers as high as 0.84 mW at 180mA and pulse powers as high as 6.68 mW at 1A. These values to date are the highest reported powers for such short wavelength emitters. Our data shows the device output power under dc operation to be limited by the package heat dissipation. A study is presented to determine the role of thermal management in controlling the power output for the reported 325 nm ultraviolet light emitting diodes.

Solder joint reliability in flip chip package with surface treatment of ENIG under thermal shock test

2009 ◽  
Vol 15 (4) ◽  
pp. 655-660 ◽  
Author(s):  
Sang-Su Ha ◽  
Sang-Ok Ha ◽  
Jeong-Won Yoon ◽  
Jong-Woong Kim ◽  
Min-Kwan Ko ◽  
...  
Keyword(s):  
Solder Joint ◽  
Surface Treatment ◽  
Thermal Shock ◽  
Flip Chip ◽  
Thermal Shock Test ◽  
Solder Joint Reliability ◽  
Shock Test ◽  
Joint Reliability

Characteristics of Sn-2.5Ag flip chip solder joints under thermal shock test conditions

2009 ◽  
Vol 23 (2) ◽  
pp. 435-441 ◽  
Author(s):  
Kyoung Chun Yang ◽  
Seong Hyuk Lee ◽  
Jong-Min Kim ◽  
Young Ki Choi ◽  
Dave F. Farson ◽  
...  
Keyword(s):  
Thermal Shock ◽  
Flip Chip ◽  
Solder Joints ◽  
Thermal Shock Test ◽  
Shock Test ◽  
Test Conditions

Mechanical reliability of Cu cored solder ball in flip chip package under thermal shock test

2020 ◽  
Vol 112 ◽  
pp. 113918
Author(s):  
Haksan Jeong ◽  
Kyung Deuk Min ◽  
Choong-Jae Lee ◽  
Jae-Ha Kim ◽  
Seung-Boo Jung
Keyword(s):  
Thermal Shock ◽  
Solder Ball ◽  
Flip Chip ◽  
Thermal Shock Test ◽  
Mechanical Reliability ◽  
Shock Test

Reliability of High-Power Light Emitting Diode Attached With Different Thermal Interface Materials

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Xin Li ◽  
Xu Chen ◽  
Guo-Quan Lu
Keyword(s):  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Temperature Cycling ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Die Attach ◽  
Nanosilver Paste ◽  
Interconnection Material

As a solid electroluminescent source, white light emitting diode (LED) has entered a practical stage and become an alternative to replace incandescent and fluorescent light sources. However, due to the increasing integration and miniaturization of LED chips, heat flux inside the chip is also increasing, which puts the packaging into the position to meet higher requirements of heat dissipation. In this study, a new interconnection material—nanosilver paste is used for the LED chip packaging to pursue a better optical performance, since high thermal conductivity of this material can help improve the efficiency of heat dissipation for the LED chip. The bonding ability of this new die-attach material is evaluated by their bonding strength. Moreover, high-power LED modules connected with nanosilver paste, Sn3Ag0.5Cu solder, and silver epoxy are aged under hygrothermal aging and temperature cycling tests. The performances of these LED modules are tested at different aging time. The results show that LED modules sintered with nanosilver paste have the best performance and stability.

scholarly journals High-Power GaN-Based Vertical Light-Emitting Diodes on 4-Inch Silicon Substrate

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1178 ◽  
Author(s):  
Qiang Zhao ◽  
Jiahao Miao ◽  
Shengjun Zhou ◽  
Chengqun Gui ◽  
Bin Tang ◽  
...  
Keyword(s):  
High Power ◽  
Silicon Substrate ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diodes ◽  
Light Output ◽  
Current Spreading ◽  
Light Emitting ◽  
Fabry Perot ◽  
Lift Off

We demonstrate high-power GaN-based vertical light-emitting diodes (LEDs) (VLEDs) on a 4-inch silicon substrate and flip-chip LEDs on a sapphire substrate. The GaN-based VLEDs were transferred onto the silicon substrate by using the Au–In eutectic bonding technique in combination with the laser lift-off (LLO) process. The silicon substrate with high thermal conductivity can provide a satisfactory path for heat dissipation of VLEDs. The nitrogen polar n-GaN surface was textured by KOH solution, which not only improved light extract efficiency (LEE) but also broke down Fabry–Pérot interference in VLEDs. As a result, a near Lambertian emission pattern was obtained in a VLED. To improve current spreading, the ring-shaped n-electrode was uniformly distributed over the entire VLED. Our combined numerical and experimental results revealed that the VLED exhibited superior heat dissipation and current spreading performance over a flip-chip LED (FCLED). As a result, under 350 mA injection current, the forward voltage of the VLED was 0.36 V lower than that of the FCLED, while the light output power (LOP) of the VLED was 3.7% higher than that of the FCLED. The LOP of the FCLED saturated at 1280 mA, but the light output saturation did not appear in the VLED.

Manufacture and Evaluation of Light Emitting Diode Package Substrate Using Flexible Printed Circuit Board

2015 ◽  
Vol 15 (10) ◽  
pp. 7578-7581
Author(s):  
Jung-Kab Park ◽  
Jin-Ha Shin ◽  
Mun-Gi Jung ◽  
Tomabechi Shigehisa ◽  
Hwa-Sun Park ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Light Emitting Diode ◽  
Thermal Conductance ◽  
Polyimide Film ◽  
Luminous Efficiency ◽  
Circuit Board ◽  
Light Sources ◽  
Thermal Shock Test ◽  
Light Emitting ◽  
Au Electrode

Unlike other light sources such as fluorescent lamps and incandescent bulbs, light-emitting diodes (LED) convert 70∼80% of energy into heat. If the heat produced an LED chip is not effectively released, its luminous efficiency and lifespan are reduced. Therefore, as a method effectively release heat, an LED PKG substrate containing a heat-releasing material with excellent thermal conductance was fabricated, and its thermal resistance and luminous efficiency were analyzed. In this experiment, a thin polyimide film with excellent ductility was used to fabricate the LED PKG substrate. A 35-μm-thick Cu foil with excellent thermal conductance was subjected to high temperature and pressure and attached to both sides of the polyimide film. By electroplating Ag or Au, which has excellent thermal conductance, for us as the electrode and heat-releasing material, LED PKG substrate was fabricated with a thickness of approximately 170 μm. (−40 °C → RT → 120 °C). The results revealed that the LED PKG substrate having a Ag electrode with excellent thermal conductance had an excellent thermal resistance of approximately 4.2 °C/W (Au electrode: 5.6 °C/W). The luminous flux after 100 cycles in the thermal shock test was reduced by approximately 0.09% (Au electrode: 2.77%), indicating that the LED PKG substrate had excellent thermal resistance without any mechanical and material defects in a rapid-temperature-changing environment. The advantages and excellent thermal resistance can be exploited in cellular phones and LCD panels, and heat-releasing problems in thin panels be solved.

Sign in / Sign up

Export Citation Format

Share Document