Phase Stability, Phase Transformations, and Reactive Phase Formation in Electronic Materials XXII: Advanced Electronic Materials
Sponsored by: TMS Functional Materials Division, TMS: Alloy Phases Committee
Program Organizers: Hiroshi Nishikawa, Osaka University; Shih-kang Lin, National Cheng Kung University; Chao-hong Wang, National Chung Chung University; Chih-Ming Chen, National Chung Hsing University; Jae-Ho Lee, Hongik University; Zhi-Quan Liu, Shenzhen Institutes of Advanced Technology; Ming-Tzer Lin, National Chung Hsing University; 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; Ting-Li Yang, National Yang Ming Chiao Tung University
Monday 8:30 AM
March 20, 2023
Room: Sapphire E
Location: Hilton
Session Chair: Jae-Ho Lee, Hongik University; Chih-Ming Chen, National Chung Hsing University
8:30 AM Keynote
Alternative Metal with Lower Resistivity than Cu: A First-principles Study: Tae Gon Ha1; Youngmin Lee2; Jungwoo Choi2; Hyuck Mo Lee2; 1Samsung; 2KAIST
This study finds an alternative metal to replace copper because its resistivity rapidly increases with a decreased feature size of semiconductors. For this purpose, the resistivity of eight different metals with a face-centered cubic structure has been calculated using DFT calculations and the Mayadas-Shatzkes model which quantifies the resistivity size effect. In the case of grain boundary with carbon, the cross-over between copper and rhodium occurs at 6.5nm. For oxygen impurity, the cross-over between two metals takes place at 14.8nm and it is 17.4nm for nitrogen while there is no cross-over for hydrogen. Rhodium seems a good candidate for a sub-6.5nm regime.
9:00 AM
Cu Sintering Process Modified by Adding a Low Temperature Liquid Sintering Step: Bo Rong Huang1; 1National Central University
Thick film technology is currently used to manufacture resistors, dielectric layers or conductive lines. In today's world, thick films are more widely used in high-power applications and passive components with thick film electrodes or substrates, such as low-level cofired ceramics (LTCC) and direct bonding copper (DBC). Therefore, there has a great significance for the industry to study the evolution of microstructure in the sintered thick film and to optimize the procedure of overall manufacturing. In this seminar, I will propose that adding low melting point ceramic powder in the mixed ceramic powder to optimize the process of copper thick film sintering, and how the evolution of the microstructure in the sintering process affects the electrical conductivity of the copper thick film, and finally show the conductivity and hardness of the copper thick film completed by sintering.
9:20 AM
Thermal Stability of Highly (111)-oriented Nanotwinned Ag Thin Film during Annealing Process: Wei-Cheng Chang1; Leh-Ping Chang1; Fan-Yi Ouyang1; 1National Ching Hua University
With the development of semiconductor industry, three-dimensional integrated circuit (3D IC) is a new way to advance Moore’s law. Nanotwinned structure has been introduced in 3D IC to enable low temperature bonding; however, the stability of nanotwinned structure at high temperature is important for reliability of electronic devices. In this work, we investigate the thermal stability of nanotwinned Ag thin films at different temperatures. The results show that some nanotwinned Ag thin films are stable at 450℃, but some samples start to abnormal grain growth from (111) columnar grain to (200) giant grain without nanotwin structure at 250℃. With the help of synchrotron x-ray nanodiffraction, we found that stress and strain in local area would significantly impact the texture transformation of nanotwinned Ag thin films. The mechanism of texture transformation would be discussed in details.
9:40 AM
Multistep Electroplating for the Uniform Composition of Invar Electroplating: Na-Young Kang1; Jaeho Lee1; 1Hongik University
Invar is the Fe-Ni alloy (64Fe36Ni) which has the low coefficient of thermal expansion. Due to this property it has been used in many applications which need tight size restrictions in wide range of temperature. Recently invar has been used as shadow mask in OLED industry. As the resolution of OLED was increased, the thickness of shadow mask was reduced. The limit of extruded invar alloy is 20 micron and it cannot be used in high resolution OLED. Electrodeposition of invar can vary the thickness of film and can solve the problems. However it is not easy to obtain the uniform composition. In this study, invar was electroplated varying of current density as well as the bath composition to obtain uniform composition of electrodeposits. The composition of invar films from front to back of deposits were analyzed with FESEM and EDS. The phase of deposits were investigated using XRD.
10:00 AM Break
10:20 AM
Employment of Diamond-like Carbon and Chromium Carbide Coatings as Diffusion Barrier Layers against Ga-based Thermal Interface Materials (TIMs): Efficacy and Impact on Heat Transfer: Yifan Wu1; Amy Marconnet1; Carol Handwerker1; 1Purdue University
Room temperature liquid metal alloys from gallium have attracted attention as candidates for next-generation thermal interface materials (TIMs) for their high thermal conductivity and intrinsic conformability. However, high reactivity of Ga with metals, i.e. Al embrittlement and corrosion of Cu and Ni, presents a particular challenge that must be addressed for its successful integration into electronics. As a mitigation strategy against Ga corrosion, we tested diamond-like carbon (DLC) and chromium carbide (CrC) coatings for their efficacy as diffusion barriers. Both coating types were proven to offer excellent protection up to 30 days of accelerated aging in contact with Ga at 125℃, showing no interfacial reaction. The impact the barrier layers have on the heat transfer across the interface was measured as a function of both the coating type and the aging time. We demonstrate that a 5μm-thick CrC coating offers sufficient protection, but increases the thermal interface resistance by ~20%.
10:40 AM
Mechanism of Microstructure Evolution between Bi-Sn Layer Deposition and Substrate Elements: Ching Yu Yeh1; 1National Central University
When using E-gun to deposit Bi/Sn film on Ni/Cu metallization layer, it can be found that the structure of Bi/Sn film formed is very special. When Sn is directly deposited on Cu, clusters are formed and react with Cu to form Cu-Sn IMCs with uneven thickness. However, when Sn is deposited on Cu with a Bi layer, a Cu-Sn IMC layer of uniform thickness is formed between the Bi/Cu layers. Under the same Sn depositing time, the thickness of Cu-Sn IMC formed by Sn depositing on Cu with Bi layer is larger than the thickness of IMC formed by Sn depositing directly on Cu, indicating that Bi layer may have a similar effect as a catalyst, helping Sn and Cu can form Cu-Sn IMC with uniform thickness. By understanding the film formation mechanism of Bi/Sn layer depositing on Cu, the low temperature die-attachment structure can be designed.
11:00 AM
Flip-chip Encapsulation with Hybrid Organic Inorganic Passivation of Perovskite Solar Cells: Tse-Lin Lai1; 1National Central University
The oxide/nitride passivation and flip-chip package technology was developed for the perovskite solar cells. The heat resulted from the physical vapor deposition would decompose the active perovskite layer and degrade the efficiency of the perovskite solar cells down by more than 45%. Remarkably, with Si-nitride passivation processed by plasma-enhanced vapor deposition, the efficiency of the perovskite solar cell only decays about 9.1 %. It should be because that the plasma-enhanced vapor deposition causes much less external energy on the perovskite solar cell. Using the exponential efficiency-decay curves of the flip-chip packaged perovskite solar cells, the characteristic time of the reliability-tested solar cell can be calculated to be 145.8 hours, 390.7 hours, and 4864 hours for air ambient, glove chamber, and water ambient tests, respectively. We concluded that the concentration of O2(g) in the reliability test ambient is the root-cause for the efficiency degradation of the perovskite solar cells.