Analysis of edge and corner bonded PSvfBGA reliability under thermal cycling conditions by experimental and finite element methods

Shi, Hang; Che, F.X.; Tian, Cuihua; Zhang, Rui; Park, Jong-Tae; Ueda, T.

doi:10.1016/j.microrel.2012.06.089

Cited by 18 publications

(5 citation statements)

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“…To reveal the temperature distribution at the bonding interface and uncover the thermal diffusion mechanism, finite element simulation was investigated using COMSOL in both isothermal bonding and temperature gradient bonding [26][27][28][29]. The bonding model is the same as the bonding structure in Figure 1.…”

Section: Bonding Temperature Distribution Simulationmentioning

confidence: 99%

A Method for Fast Au-Sn Bonding at Low Temperature Using Thermal Gradient

Wang,

Liu,

Qiu

et al. 2023

Micromachines

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Flip chip bonding technology on gold–tin (Au-Sn) microbumps for MEMS (Micro Electro Mechanical Systems) and 3D packaging is becoming increasingly important in the electronics industry. The main advantages of Au-Sn microbumps are a low electrical resistance, high electrical reliability, and fine pitch. However, the bonding temperature is relatively high, and the forming mechanism of an intermetallic compound (IMC) is complicated. In this study, Au-Sn solid-state diffusion (SSD) bonding is performed using the thermal gradient bonding (TGB) method, which lowers bonding temperature and gains high bonding strength in a short time. Firstly, Au-Sn microbumps with a low roughness are prepared by using an optimized process. Then, Au-Sn bonding parameters including bonding temperature, bonding time, and bonding pressure are optimized to obtain a higher bonding quality. The shear strength of 23.898 MPa is obtained when bonding in the HCOOH environment for 10 min at the gradient temperature of 150 °C/250 °C with a bonding pressure of more than 10 MPa. The IMC of Au-Sn is found to be Au-Sn and Au5Sn. The effect of annealing time on the IMC is also investigated. More and more Au5Sn is generated with an increase in annealing time, and Au5Sn is formed after Sn is depleted. Finally, the effect of annealing time on the IMC is verified by using finite element simulation, and the bonding strength of IMC was found to be higher when the bonding temperature is 150 °C at the cold side and 250 °C at the hot side. The temperature in the bonding area can reach 200 °C, which proves that the Au-Sn bonding process is solid-state diffusion because the temperature gradient reaches 2500 °C/cm.

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Section: Bonding Temperature Distribution Simulationmentioning

confidence: 99%

A Method for Fast Au-Sn Bonding at Low Temperature Using Thermal Gradient

Wang,

Liu,

Qiu

et al. 2023

Micromachines

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“…In order to prevent the conformal coating penetration underneath the package, an edgebond adhesive can be applied on the edge of the QFNs prior to the application of the conformal coating. Previous studies [7,8] has revealed that using edgebond adhesive can improve thermal cycling reliability of BGA type area-array packages if the chosen adhesive has a lower CTE which matches the CTE of the solder material. The material properties of the edgebond adhesive tested in this work are shown in Table 3.…”

Section: A Impact Of Coating Penetration Levelmentioning

confidence: 99%

Modelling the impact of conformal coating penetration on QFN reliability

Yin

Stoyanov

Bailey

et al. 2017

2017 18th International Conference on Electronic Packaging Technology (ICEPT)

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The impact of conformal coating penetration on the solder joints' thermal fatigue reliability in QFNs was studied using computational modeling techniques. 3D finite element models were developed with consideration of realistic solder joint shape and the actual coating profile. Thermal mechanical simulations were carried out for three cycles under accelerated thermal test conditions of-25 to 100°C, 10 minutes ramp and 10 minutes dwell. The inelastic strain energy density accumulated over one temperature cycle was used as an indicator for solder damage in the QFNs under the applied thermal cycling load. The impact of coating penetration level on the solder damage in QFNs was investigated for two types of coatings with different properties. The results show that coating penetrated underneath the package has significant impact on the solder joint damage in QFNs and the level of this impact depends on the coating properties and penetration level. When coating penetration level decreases, damage in the solder joint does not always decrease. In order to prevent coating penetration underneath the package, an edgebond adhesive was applied on the edge of the QFN assemblies prior to the application of the conformal coating. The modelling results show that using edgebond adhesive can reduce the solder joint damage in the investigated QFNs and thus improve their thermal fatigue reliability. When edgebond adhesive is used, the impact of conformal coating on the reliability of solder joints in QFNs is significantly reduced.

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“…However, the stresses were not modeled and the effect of the adhesive fillet size was not considered. Shi et al [20] also found that the thermal fatigue life of edge-bonded BGA-PCB assemblies, made with three adhesives having tensile modulus between 0.67 GPa and 7.0 GPa, improved significantly with higher modulus and lower coefficient of thermal expansion.…”

Section: Introductionmentioning

confidence: 98%