Phase Stability, Phase Transformations, and Reactive Phase Formation in Electronic Materials XX: Advanced Electronic Interconnection
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Alloy Phases Committee
Program Organizers: Hiroshi Nishikawa, Osaka University; Shih-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; A.S.Md Abdul Haseeb, Bangladesh University of Engineering and Technology (BUET); Ligang Zhang, Central South University; Sehoon Yoo, Korea Institute of Industrial Technology; Vesa Vuorinen, Aalto University; Yu-Chen Liu, National Cheng Kung University
Wednesday 8:30 AM
March 17, 2021
Room: RM 21
Location: TMS2021 Virtual
Session Chair: Shih-kang Lin, National Cheng Kung University; Yee-Wen Yen, National Taiwan University of Science and Technology
8:30 AM
Introductory Comments: Phase Stability, Phase Transformations, and Reactive Phase Formation in Electronic Materials XX: Sinn-wen Chen1; 1National Tsinghua University
Introductory Comments
8:35 AM Keynote
Interfacial Reactions in the Bi2Te3 Thermoelectric Modules: Sinn-wen Chen1; Ya-Hsiang Hsu1; Hao-wei Shih1; 1National Tsing Hua University
Bi2Te3 and Bi2Te3-based alloys are most important thermoelectric materials. The Ag-Sb eutectic alloy is a promising joining material for mid-temperature applications, and Ni and Cu are frequently encountered barrier layer and electrode materials. There are Cu/Ag-Sb, Ag-Sb/Ni, and Ni/Bi2Te3 interfaces in the modules, and their interfacial reactions are examined. The interfacial reactions in the Ag-41.0at%Sb/Cu couples at 300 and 500℃ are experimentally determined. The phase equilibria isothermal sections of Ag-Cu-Sb at 300 and 500℃ to provide fundamental material information and to illustrate the interfacial reaction in the Ag-Sb/Cu couples. Two reaction phases, Cu2Sb and Ag3Sb, are formed in the Ag-Sb/Cu couples reacted at 300℃. Three reaction phases, Cu2Sb, Cu3Sb and Ag3Sb, are formed in the Ag-Sb/Cu couples reacted at 500℃. The reaction rate at 500℃ is extremely fast. In the Ag-Sb/Ni couples, the reaction phases are NiSb and NiSb2 at 350℃ and are Ni3Sb, Ni5Sb3 and NiSb at 550℃.
9:15 AM Invited
Review of X-ray Microbeam Study of Electromigration: Ping-Chuan Wang1; 1SUNY New Paltz
Synchrotron-based x-ray micro and nanobeam techniques have been developed over the past few decades, allowing structural and elemental probing with impressive accuracy and spatial resolution. Such powerful tools have been proved invaluable in many science and technology communities. One of the applications of great interest to both academia and industry is the fundamental understanding of electromigration, a biased atomic diffusion and degradation mechanism in metal interconnects in integrated circuit. Various x-ray microbeam techniques have been used to characterize the detailed mass transport during electromigration, employing diffraction, fluorescence, topography, etc, to allow spatially resolved mapping of strain, alloy composition and microstructure evolution induced by electromigration. This talk will give an overview of the x-ray microbeam techniques and review the progress in the study of electromigration over the past two decades.
9:45 AM
Effects of Bromide and Adipic Acid on Electrochemical Migration of Tin: A.S.Md Abdul Haseeb1; Ee Lynn Lee1; Yi Sing Goh1; Y. H. Wong1; M. F. M. Sabri1; B. Y. Low2; 1University of Malaya; 2NXP Semiconductor Sdn Bhd
Electrochemical migration (ECM) becomes a serious reliability issue as the pitch size in electronic packages decreases due to miniaturization. ECM is an electrochemical reaction that occurs in the presence of electrolyte and bias voltage. During ECM, metallic components dissolve at the anode and redeposit at the cathode in the form of dendrites leading eventually to short circuit failure. Contaminants originating from manufacturing process steps, flux residue and environment accelerate the process. This work investigates ECM process of tin in the presence of contaminants e.g., bromide and adipic acid. Water drop test (WDT) was conducted in the two-probe semiconductor characterization system under a high-power optical microscope for the in-situ investigation. The products of ECM such as dendrites and precipitates were characterized by SEM/ EDX and XPS. The effects of different contaminants on the mean time to failure and the mechanism of ECM are discussed.
10:05 AM
The Microstructure and Properties Variations of Sn-coated Cu Wires Induced by Electromigration: Liu Hsiao-Chun1; Chien-Lung Liang1; Tsung-Chieh Chiu2; Kwang-Lung Lin1; 1National Cheng Kung University; 2Conquer Electronics
Sn-coated Cu wire was designed as a fuse material in electronic products. A reliable fuse material should be able to sustain a long-term operating environment with electric current stressing before the fusing condition. In this study, Sn-coated Cu wires (145μm/121μm dimeter with/without Sn coating) were investigated for the microstructure and properties variations induced by electromigration. The wires were stressed with direct current at 9.7-14.6 × 103 A/cm2 (1.6-2.4A) for 4-36 h. Electromigration was found to induce significant drops in elongation and toughness, as great as 40% decrement, of the Sn-coated Cu wire. The ultimate tensile strength and electrical resistance properties did not vary prominently with less than 5% variations. The microstructure evolutions of the Cu wire matrix and the intermetallic compounds formed at the Cu/Sn interface under electromigration were investigated using dual-beam focused ion beam and electron backscatter diffraction techniques. The mechanisms involved in the microstructure-properties variations were also disclosed.
10:25 AM
Thermomigration Failure Induced by Surface Diffusion of Sn on Ni/Cu Metallization in Microbumps for 2.5-dimensional Integrated Circuits Packaging: Wei-Dung Tsai1; Chen Wei Lee1; Fan-Yi Ouyang1; 1National Tsing Hua University
The 2.5D-IC packaging can integrate the different Si chips placed horizontally on a Si interposer to achieve heterogeneous integration, and microbumps have been adopted as the vertical interconnects between chips and interposer. The Joule heating from the powered chip may transfer horizontally by interposer to the neighboring un-powered chip, and creates a large temperature gradient.In this study, an electromigration-induced failure was investigated under a current density of 5.4×〖10〗^4 A/〖cm〗^2 at 150°C. However, the micro joints in the neighboring un-powered chip has more serious thermomigration-induced failure because Sn atoms tend to migrate along the surface of Ni/Cu metallization under temperature gradient, and form Ni3Sn4 and Cu3Sn IMCs, respectively. When the Sn diffuses away from solders, necking or significant voids formation occurs in the solder layer of micro bumps, weakening the electrical and mechanical properties. Thus this new thermomigration-induced failure mode will become even significantly in micro joint for 2.5D-IC packaging.
10:45 AM
Synchrotron White Laue Nanodiffraction Characterization of Allotropic Phase Transformation of Hexagonal- into Monoclinic-Cu6Sn5: Pei-Tzu Lee1; Wan-Zhen Hsieh2; Cheng-Yu Lee3; Yu-Hsuan Huang3; Ching-Yu Chiang2; Ching-Shun Ku2; C. Robert Kao1; Cheng-En Ho3; 1National Taiwan University; 2National Synchrotron Radiation Research Center; 3Yuan Ze University
An allotropic phase transformation of Cu6Sn5 from the hexagonal (η) to monoclinic (η’) structure at/below 186 °C exists in the equilibrium Sn-Cu system. As the monoclinic η’-Cu6Sn5 lattice is geometrically pseudosymmetrial with the hexagonal η-Cu6Sn5 phase, the identification of these two phases has been quite difficult by using either electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) or X-ray powder diffraction (XRD). We conduct a characterization of the η-to-η’ allotropic phase transformation and phase distribution by Laue diffraction via synchrotron white X-ray radiation with a 70 nm × 70 nm focused beam. The results showed that allotropic species (η and η’) can be well distinguished and a two-stage phase transformation kinetics is proposed.
11:05 AM
Electroplating of NiP for the Low Residual and High Strength MEMS Probe Tip: Na-Young Kang1; Jaeho Lee1; 1Hongik University
Probe card is one of reliability testing tool in semiconductor system. MEMS technology is used in MEMS probe tip fabrication. Since the reliability of probe is dependent on the physical property of probe tip, the hard and wear resistant material is used. Ni-P is one of the candidate material for this purpose. Ni-P probe tip is fabricated through electroplating method. The physical properties of Ni-P plating is dependent on the contents of P as well as plating property such as grain size and residual stress. In this study the effect of plating bath conditions on the Ni-P electroplating is investigated. The relationship between concentration of P and contents of coating is investigated. The effects of current density on Ni-P electroplating is also investigated. The surface hardness and crystallography of coating is measured and compared. The effects of additive on the properties and contents of the coating is finally optimized.