Phase Stability, Phase Transformations, and Reactive Phase Formation in Electronic Materials XIX: Advanced Electronic Materials
Sponsored by: TMS Functional Materials Division, TMS: Alloy Phases Committee
Program Organizers: Hiroshi Nishikawa, Osaka University; Shi-Kang Lin, National Cheng Kung University; Chao-Hong Wang, National Chung Cheng University; Chih-Ming Chen, National Chung Hsing University; Jaeho Lee, Hongik University; Zhi-Quan Liu, Shenzhen Institutes of Advanced Technology; Ming-Tzer Lin, National Chung Hsing University; Dajian Li, Karlsruhe Institute of Technology; Yu Zhong, Worcester Polytechnic Institute; Yee-wen Yen, National Taiwan University of Science and Technology; Song-Mao Liang, Clausthal University of Technology; A.S.Md Abdul Haseeb, Bangladesh University of Engineering and Technology (BUET); Ligang Zhang, Central South University; Sehoon Yoo, Korea Institute of Industrial Technology
Monday 2:30 PM
February 24, 2020
Room: Marina Ballroom E
Location: Marriott Marquis Hotel
Session Chair: Jaeho Lee, Hongik University; Chih-Ming Chen, National Chung Hsing University
2:30 PM Cancelled
Nanotwinned Copper Composite with High Strength and High Tensile Ductility: Shien Ping Feng1; Yu Ting Huang1; Wei-Ting Wang1; Zeyang Zhang1; Mingyang Zhang1; Wei-Ting Yeh2; 1University of Hong Kong; 2High Performance Solution Co. Ltd.
A special truss copper composite with around 50% nanotwin structure is electroplated by the synergistic effect via our developed additives and electrodeposition parameters (e.g., rotation speed). The Cu composite exhibits a tensile yield strength about 5 times higher than that of conventional coarse-grained Cu, while achieving a high ductility for elongation to failure and uniform deformation at elevated strength. The half nanotwin structure with numerous twin boundaries can effectively block dislocation motion and the other half grained Cu structure leads an excellent elongation property. The simultaneous high strength and ductility produces a very high toughness, which is separated from the general trend with the area under the engineering stress–strain curve. Electroplating a tough nanostructured Cu will offer new opportunities in many applications in the future, including advanced microelectromechanical system and packaging technology in three-dimensional integrated circuitry (3D-IC).
3:00 PM Cancelled
Facile and Scalable Fabrication of Copper Nanoparticles with Superior Antioxidative Properties, Improved Sinterability and their Applications in Electronics: Pengli Zhu1; Gang Li1; Rong Sun1; 1Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences
Cu nanoparticles have received great attention due to its applications in a wide range of electronic devices, such as flexible electronics including radio-frequency identification (RFID) tags, thin-film transistors (TFT), high frequency (UHF) antennas, printed circuit board, power electronic packaging and so on. The corresponding processing temperature in various applications can be reduced to less than 300 ℃ since metallic nanoparticles reveal lower melting points, which allows for more ease of processability for kinds of electronic devices, especially for organic flexible substrate. However, different from the metal nanoparticles such as silver and gold, the key problem that blocked the widespread application of Cu-based nanomaterials is its oxidation and poor sinterability. Bear in mind, herein, kind of Cu nanoparticles with superior self-passivation antioxidation and improved sinterability was prepared via facile and easy to be scalable fabrication procedure, the growth and anoxidation mechanism, applications in various electronics are systematically studied.
3:30 PM
The Effect of the Cu Preferred Orientation on the Adhesion between Cu and LCP in FCCL: Chiahung Lee1; Cheng-Yi Liu1; 1National Central University
In high speed and high frequency generation, traditional polyimide (PI) was not match the need for the fifth generation mobile networks (5G) in flexible copper clad laminate (FCCL). Liquid crystal polymer (LCP) has many advantages to substitute the PI because of its low dielectric constant and low loss tangent. However, the adhesion between Cu and LCP was lower than that between Cu and PI. How to increase the adhesion between Cu and LCP was a big challenge for the 5G. In this study, the electroplating was used to create Cu(111), Cu(200), and Cu(220) preferred orientation on Cu foil. Then, different Cu preferred orientation was used to bond with LCP. We found that Cu(200) preferred orientation had better adhesion with LCP because of the high surface activity of Cu(200). The effect of the Cu preferred orientation on the adhesion between Cu and LCP will be discussed in this study.
3:50 PM
Electroplating of Rhodium using Pulse Current Plating Method: Seo-Hyang Lee1; Jaeho Lee1; 1Hongik University
The electrodeposition of rhodium (Rh) on silicon substrate at different current conditions were investigated. The cracks were found at high current density during the direct current (DC) plating. The pulse current (PC) plating were applied to avoid the formation of cracks on the deposits. Off time in the pulse plating relieved the residual stress of the Rh deposits and consequently the current conditions for the crack-free Rh deposits were obtained. The effects of additives on the surface morphologies were investigated. The heat treatments can make surface cracks due to the difference of CTE between Rh and substrate. Finally crack free Rh electroplating were obtained at elevated temperature.
4:10 PM Break
4:30 PM
4D Characterization of Electromigration-induced Grain Boundary Damage of Cu Interconnects: X-ray Tomography Experiments and Phase-field Simulations: William Farmer1; Amey Luktuke1; Marion Branch Kelly1; Nikhilesh Chawla1; Kumar Ankit1; 1Arizona State University
Electromigration (EM) damage in polycrystalline interconnects, which causes major reliability concerns, typically nucleates at the surface and manifests as slits or hillocks. Although isolated experimental investigations and characterization of EM-defects using TEM have provided a rudimentary understanding, in-depth knowledge of failure mechanisms is warranted for efficient design and implementation of EM-inhibiting strategies. Here, we leverage our expertise in phase-field modeling, 3D X-ray imaging, and diffraction contrast tomography to achieve a fundamental understanding of the diffusional mechanisms accompanying grain boundary (GB) grooving and its subsequent degradation in copper interconnects. An in-depth parametric study sheds light on the dynamics of the intricate interplay between coarsening and GB slit propagation wherein multi-junctions are observed to be more susceptible to damage. Our 4D validation approach, which involves in situ visualization of microstructural degradation during accelerated EM-failure tests and a direct comparison with phase-field simulations, would enable accurate prediction of EM-induced failure in the future.
4:50 PM
Electromigration Effect Upon Single-phase and Two-phase Ag-Cu Alloy: an In-situ Study: Yu-Chen Liu1; Yung-si Yu1; Shih-kang Lin1; Shang-Jui Chiu2; 1National Cheng Kung University; 2National Synchrotron Radiation Research Center
Electromigration (EM) is one of the major failure modes of electronic interconnections. Ag, Cu, and their alloys are most commonly used materials for electronic interconnection. However, the EM effect upon Ag-Cu alloys are not systematically studied. Herein, the Ag-xCu alloys (x = 2.26 and 27.98 at.%) with single and two fcc phases, respectively, were subjected with current stressing for in situ characterizations using scanning electron microscopy and synchrotron radiation-based X-ray diffractometry. The peculiar phenomena and microstructures in the single-phase and two-phase Ag-Cu alloy strips under current stressing, e.g., (1) anomalous grain growth, (2) the formation of submicron cord-like grain with an aspect ratio over 1000, and (3) the formation of asymmetric hillock/voids clusters, are revealed and elaborated based on in situ characterizations. The conclusion can be drawn that the single-phase alloy would have better EM-resistance than multi-phase alloy strips unless the electron flow-induced strains are similar among the phases.
5:10 PM
Revisit the Blech Critical Product: Lattice Strain Induces Electromigration Effect: Kuan-Hsueh Lin1; Yu-chen Liu1; Shih-kang Lin1; Ching-Shun Ku2; Shang-Jui Chiu2; 1National Cheng Kung University; 2National Synchrotron Radiation Research Center
Electromigration (EM) effect is an atomic diffusion induced by electric currents. The “Blech critical product”, which is the product of current density and length, was proposed as the criteria for EM occurrence, with the back stress model as the mechanism. This criterion works well for strips up to 150 microns. However, in this study, we found the critical product failed to predict the EM occurrence when the strips were 5000 microns long or longer. We characterized the lattice strains of Al strips with various lengths in the range of microns to centimeters with in situ current-stressing synchrotron radiation-based X-ray diffraction and first principles calculations. The results showed that beyond the critical lattice strain, hillocks were formed on all Al strips in spite of lengths, suggesting the correlation between the lattice strain and EM occurrence. The mechanism that governs EM occurrence will be proposed and elaborated in the presentation.