Monitoring of thermo-mechanical stress via CMOS sensor array: Effects of warpage and tilt in flip chip thermo-compression bonding

Laor, Ari; Athia, Depayne; Rezvani, Alireza; Clauberg, Horst; Mayer, Michael

doi:10.1016/j.microrel.2017.03.001

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…So, at the cold end, thermal migration accelerated the growth of Cu 6 Sn 5 , while inhibiting the dissolution of the Cu substrate; at the hot end, thermal migration inhibited the growth of Cu 6 Sn 5 and accelerated dissolution of the Cu substrate. Previous studies reported this phenomenon (Zhao et al , 2016, 2015; Swinnen et al , 2006; Laor et al , 2017). Moreover, the Cu/SAC105/Cu solder joints had smaller thicknesses of IMCs at the cold end in comparison to the Cu/Sn/Cu solder joints.…”

Section: Resultsmentioning

confidence: 51%

Microstructure evolution and growth behavior of Cu/SAC105/Cu joints soldered by thermo-compression bonding

Guo

Sun

Zhang

2019

SSMT

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Purpose This paper used a novel technique, which is thermo-compression bonding, and Sn-1.0Ag-0.5Cu solder to form a full intermetallic compound (IMC) Cu3Sn joints (Cu/Cu3Sn/Cu joints). The purpose of the study is to form high-melting-point IMC joints for high-temperature power electronics applications. The study also investigated the effect of temperature gradient on the microstructure evolution and the growth behavior of IMCs. Design/methodology/approach In this paper, the thermo-compression bonding technique was used to form full Cu3Sn joints. Findings Experimental results indicated that full Cu/Cu3Sn/Cu solder joints with the thickness of about 5-6 µm are formed in a short time of 9.9 s and under a low pressure of 0.016 MPa at 450°C by thermo-compression bonding technique. During the bonding process, Cu6Sn5 grew with common scallop-like shape at Cu/SAC105 interfaces, which was followed by the growth of Cu3Sn with planar-like shape between Cu/Cu6Sn5 interfaces. Meanwhile, the morphology of Cu3Sn transformed from a planar-like shape to wave-like shape until full IMCs solder joints were eventually formed during thermo-compression bonding process. Asymmetrical growth behavior of the interfacial IMCs was also clearly observed at both ends of the Cu/SAC105 (Sn-1.0Ag-0.5Cu)/Cu solder joints. Detailed reasons for the asymmetrical growth behavior of the interfacial IMCs during thermo-compression bonding process are given. The compound of Ag element causes a reduction in Cu dissolution rate from the IMC into the solder solution at the hot end, inhibiting the growth of IMCs at the cold end. Originality/value This study used the thermo-compression bonding technique and Sn-1.0Ag-0.5Cu to form full Cu3Sn joints.

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Section: Resultsmentioning

confidence: 51%

Microstructure evolution and growth behavior of Cu/SAC105/Cu joints soldered by thermo-compression bonding

Guo

Sun

Zhang

2019

SSMT

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“…Warping is one major problem, especially when multiple components are bonded and stacked vertically. 2 Because of the high melting points of Sn solders (∼230 • C), serious warping can occur in microelectronics packages because there is a large mismatch in the coefficient of thermal expansion (CTE) between the die and the substrate, 3 and this warping effect can lead to open joints, bridging, or non-wetting of solder bumps that degrade device performance. 4,5 Another reliability issue is delamination of the low-k dialectic layer.…”

mentioning

confidence: 99%

Materials Merging Mechanism of Microfluidic Electroless Interconnection Process

Yang

Hung

et al. 2018

J. Electrochem. Soc.

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A low-temperature, pressureless bonding process, referred to as the microfluidic electroless interconnection process, has been developed for chip-stacking applications, in which electroless Ni plating is employed to bond copper pillars in an attempt to reduce the risk of thermo-mechanical damage during the assembly process. Copper pillar joints with a low standoff height were used to assess the bonding performance of the microfluidic electroless interconnection process on a smaller scale. The results showed that a striking lamellar structure formed in the deposits when electroless Ni solution was fed into a microfluidic platform intermittently, and through this visible structure, the bonding mechanism of the process can be characterized fully. Preliminary results showed that a high level of plating uniformity across the die could be obtained using the microfluidic interconnection process, and that the copper pillars were joined completely by electroless Ni plating without voids or seams. Further, it was found that the process is able to compensate not only for non-uniform copper surfaces, but also for the misalignment of copper pillars, which provides a competitive edge over other bonding methods. In addition, the direct shear test showed that the bond strength of the electroless Ni bonds was quite strong.

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Optimal design of thermo-compression bonder via ANN-based surrogate modeling under uncertainty

Hwang

Lee

Choi

et al. 2023

Journal of Engineering Design

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Monitoring of thermo-mechanical stress via CMOS sensor array: Effects of warpage and tilt in flip chip thermo-compression bonding

Cited by 4 publications

References 11 publications

Microstructure evolution and growth behavior of Cu/SAC105/Cu joints soldered by thermo-compression bonding

Microstructure evolution and growth behavior of Cu/SAC105/Cu joints soldered by thermo-compression bonding

Materials Merging Mechanism of Microfluidic Electroless Interconnection Process

Optimal design of thermo-compression bonder via ANN-based surrogate modeling under uncertainty

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