Fluctuation Mechanism of Mechanical Properties of Electroplated-Copper Thin Films Used for Three Dimensional Electronic Modules

Miura, H.; Suzuki, Ken; Tamakawa, Kinji

doi:10.1109/esime.2007.360064

Cited by 13 publications

(4 citation statements)

References 10 publications

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“…Electroplated Cu is commonly used for the filling of blind-holes (BHs)/vias in high-density interconnections (HDIs) in printed circuit boards (PCBs) and integrated circuits (ICs) because of its high electrical and thermal conductivities, good signal performance, and efficient utilization of packaging space (e.g., via-in-pad design). [1][2][3][4][5] The Cu deposition profile and its crystallographic microstructure in BH/via structures might govern the electrical, thermal, and mechanical properties of the Cu interconnections, 1,[5][6][7][8][9][10][11][12][13][14][15][16][17] affecting the overall HDI-PCB/IC-package reliability. For instance, the formation of voids/seams in BH Cu fillings inevitably traps some electrolyte inside, which might ultimately degrade the thermomechanical reliability of Cu interconnects.…”

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confidence: 99%

“…For instance, the formation of voids/seams in BH Cu fillings inevitably traps some electrolyte inside, which might ultimately degrade the thermomechanical reliability of Cu interconnects. 5,13,15 In addition, nonoptimal Cu electrodeposition might result in material defects (e.g., microvoids and impurities) between the electroplated Cu and laminated Cu, 14,16 and the undesired microstructure (e.g., columnar Cu grains), 17 thereby inducing delamination at the electroplated/laminated Cu interface and microcracks in the electroplated Cu during subsequent thermal processing. Thus, a detailed investigation of the Cu electrodeposition behavior in BH structures is of great importance to the electrochemical community.…”

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confidence: 99%

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Self-Annealing Behavior of Electroplated Cu in Blind-Hole Structures

Yang

Lee

et al. 2019

J. Electrochem. Soc.

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Blind-hole (BH) metallization via Cu electrodeposition is a critical technology for printed circuit boards (PCBs) with high-density interconnections (HDIs) because it provides excellent thermal and electrical conductivity and efficient space utilization. In this study, the self-annealing behavior of electroplated Cu was in-situ characterized via ohmmeter measurements, field-emission scanning electron microscopy (FE-SEM) in combination with electron backscatter diffraction (EBSD) analysis, and time-of-flight secondary ion mass spectrometry (TOF-SIMS). A strong correlation among the electrical property transition, Cu crystallographic transition, and impurity distribution was established that supports the curvature enhanced accelerator coverage (CEAC) mechanism and advances our understanding of the Cu physical/chemical characteristics in BH structures.

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confidence: 99%

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confidence: 99%

Self-Annealing Behavior of Electroplated Cu in Blind-Hole Structures

Yang

Lee

et al. 2019

J. Electrochem. Soc.

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“…Inconsistency of the tensile test results of electroplated copper is also observed in the literature. Miura et al [12] compared electroplated with cold rolled copper thin films ofּ 10ּ μmּ thick.ּ They observed the super plasticity phenomenon in the tensile test results of the electroplated copper thin film with an extremely long nonlinear line of plastics region. They argued that the strain hardening usually found in bulk material was absent due to cooperative grain boundary sliding.…”

Section: Fig 2 Illustration Of Micro-vickers Hardness Testmentioning

confidence: 99%

“…Xiang et al [4] studied the mechanical properties of free standing electroplated copper thin films having thickness varies from 0.9-3.0ּμm.ּTheyּexaminedּtheּdetailedּmicrostructureּ of the electroplated film using Focused Ion Beam microscopy (FIB) and found a slight increase in the stiffness of the copper film due to alterations in the crystallographic texture and the elastic anisotropy of copper. Miura et al [12] studied the fluctuation in mechanical properties of electroplated copper thin films used for threedimensional electronic modules. They compared the copper thin films formed by cold rolling with those created by electroplating using tensile test and nano-indentation.…”

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confidence: 99%

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2023

Jurnal Polimesin

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Thin copper foils are commonly used in arts, crafts, and manufacturing industries. Although copper electroplating processes have been widely studied, most focused on either copper in bulk material form factor or copper in extremely thin film shape. Thin copper foils are considered neither bulk material nor thin film; thus, it is estimated that they will have unique properties. This study aims to investigate the mechanical properties of thin copper foils coated by electroplating processes. The investigations were conducted experimentally by performing electroplating at current densities of 2, 3, and 4 A/dm 2 . The copper foil specimen having a dimension of 10 mm wide, 0.2 mm thick, and 125 mm long were electroplated in a bath of copper sulfate, sulfate acid, chloride acid, and copper brightener mixtures for 60 minutes powered by a 30 A DC power supply. The hardness and tensile test diagrams were studied. The strain, yield stress, and ultimate tensile stress data extracted from the tensile test diagram were compared with other previous studies found in the literature and fitted with linear regression lines. The relationship of those parameters with current density has been successfully obtained. The hardness, strain, and yield stress of the electroplated copper foil increased with larger current densities used in the electroplating process except for the ultimate tensile stress, which was found to be slightly decreased with current densities. The optimum operating condition for obtaining the best results was found at a current density of 3 A/dm 2 .

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Method to determine thermoelastic material properties of constituent and copper-patterned layers of multilayer printed circuit boards

Zanten

Schuerink

Tullemans

et al. 2018

J Mater Sci: Mater Electron

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Due to the ongoing component miniaturization and integration in the electronics industry, there is a need for asymmetric lay-ups for printed circuit boards (PCBs), especially in the case of complex boards that house both analog and digital circuits. This paper focuses on the contribution of the constituent layers that make up the PCB to the board's macroscopic multilayer properties in terms of stiffness and coefficient of thermal expansion (CTE). The thermoelastic material properties for constituents, like cured prepreg and laminate layers, have been determined. Using classical laminate theory, individual layer properties are assembled to the macroscopic level and compared to fabricated multilayer boards. Following this approach, the contribution of various copper features on constituent layers can de deduced. The experiments show that properties of cured prepreg, taking z-direction expansion into account, and laminate layers are dependent on the type of fiberglass reinforcement and the fiber volume fraction. Depending on these properties, the Young's modulus and CTE varies from 11 to 31 GPa and from 10 to 28 ppm/K, respectively. Datasheet values deviate significantly from these results as they do not take the fiber volume fraction into account. By alternating the measurement directions, the experiments have also shown that the fiberglass reinforcement plays a dominant role in determining macroscopic multilayer board properties. The multilayer board follows iso-strain conditions. Therefore, the material properties depend linearly on the copper volume fraction and follow the rule of mixtures independent of the type of copper patterning. Overall, the presented model and method to determine material properties increase the accuracy for predicting multilayer board behavior and offers the possibility to design and predict bow and twist behavior of PCBs with asymmetric lay-ups.

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Fluctuation Mechanism of Mechanical Properties of Electroplated-Copper Thin Films Used for Three Dimensional Electronic Modules

Cited by 13 publications

References 10 publications

Self-Annealing Behavior of Electroplated Cu in Blind-Hole Structures

Self-Annealing Behavior of Electroplated Cu in Blind-Hole Structures

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Method to determine thermoelastic material properties of constituent and copper-patterned layers of multilayer printed circuit boards

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