Bruker extended an invite to our team for an event highlighting the latest advances in nanomechanical testing. The event was packed with information and insights into the updated technological capabilities for failure analysis specially well-balanced for academics to understand the scientific fundamentals for the experimental tests while exciting industry partners with the achievable results, analysis, and appropriate definitions for their material characterization. The workshop was over two days on the 27th and 28th with the first day focusing on Exploring Applications of Nanomechanical Technology in Material Research, Advanced Packaging and Semiconductor Failure Analysis and the second day on Exploring Material Testing Applications for Semiconductor and Material Research.

Exploring Applications of Nanomechanical Technology in Material Research, Advanced Packaging and Semiconductor Failure Analysis

Wintech Nano hosted the first day at their newly renovated Singapore office in The Alpha, Singapore Science Park II, where we were very warmly welcomed by their Senior Marketing Manager, Mr. Jason Kam, who gave us a very detailed breakdown into their organization and expansion plans to provide 24/7 world class analytical services–Electrical failure analysis, physical failure analysis, surface & chemical analysis, and technology development.

Dr. Wei Pai-Jen commenced the technical session with a talk on Advancement in nanoscale mechanical characterization. His talk highlighted the various material characteristics obtainable from nanoindentations, which has been traditionally used to retrieve the material hardness and elastic modulus. However, advanced systems for indentation have enabled additional obtainable results, such as the hardness and modulus mapping and depth–properties profiling that can be carefully interpreted to differentiate materials, grain distributions, and coating properties (e.g., adhesion and strength). Mr Jimmy Juan followed up with sharing the capabilities of the nanoindentation systems available at Bruker specifically the Hysitron TI 980 and 990 Triboindenter with in-situ scanning probe microscopy (SPM) capabilities for 3D surface analysis of the samples before and after testing and high-speed indentation capabilities for high through-put large area property mapping that were enabled with the SPM capabilities. One of our favorite highlights was the revisit of the critical load during progressive-loading scratch tests as the measure for assessing the adhesion quality of coatings.

Mr. Juan shared the strong correlations between the critical loads and the elastic modulus through both experimental test results and the fundamental governing equations. Since the modulus was affected by the coating properties (e.g., thickness) and the depth of its evaluation, the critical load result would be severely affected by the coating properties instead of assessing the actual interfacial adhesion. This was where Mr. Juan shared a method to evaluate the effective adhesion work as a function of both the identified critical load and elastic modulus of the coating.

The afternoon was jointly led by Bruker with a live demo of their newly installed Hysitron TI 980 at Wintech Nano and a tour of the lab facilities at Wintech Nano by Mr. Jason Kam. Dr. Wei showcased the ease of using the system fitted with a vacuum chuck to easily mount samples alongside 2 other mechanical and magnetic alternatives. He also showcased the SPM capabilities of the TI 980 with different scanning resolutions to obtain the surface profile of the indentation. Within minutes, we were able to clearly observe the triangular geometry of the Berkovich indentation even with their SPM set at low-resolution. Meanwhile, Mr. Kam showcased us a highly rejuvenating tour of their lab, which has impressively taken a major upgrade since our very first visit to WT in 2019. The labs are specifically designed to ensure security and high efficiency in the failure analysis of semiconductors from storing, surface processing, surface characterization, all the way to atomic-scale cross-sectional visualization.

Exploring Material Testing Applications for Semiconductor and Material Research

Day 2 was hosted at the Institute of Microelectronics (IME) jointly organized by Zeiss and Bruker. Mr Andrew Tan gave a very detailed insight into the developments at Zeiss to integrate the multi-scale targeting and positioning between multiple separate systems for improved user experiences. This would span across X-ray scanning to identify internal target locations, high throughput laser milling followed by precision Ga ion milling polishing, and observation either directly or by lift-out for TEM analysis. While the discussion of this workflow was accommodated more toward defect analysis in semiconductor packagings, the multi-scale workflow can foreseeably improve the post-mortem analysis for other material characterization tasks.

Mr. Jimmy Juan from Bruker made another appearance again to give a detailed presentation on the Bruker nanoindenter and picoindenter capabilities where the benefits of high-throughput mechanical testing, in-situ surface analysis by SPM, and high (up to 1,000 ºC) and low temperature (up to -160 ºC) mechanical testing were discussed. These capabilities are available in the Hysitron TI 980 and the PI 89 SEM picoindenter where the differences lie in the sample size as the PI 89 is designed for installation within the SEM to accommodate smaller sample sizes while the TI 980 is designed for larger samples. Additionally, the latest release TI 990 is specifically designed to accommodate the large-sized semiconductor wafers with sufficient stiffness to provide end-to-end mechanical property measurements.

Dr. Yakai Zhao from IME gave a talk on Application of nanomechanical techniques in hydrogen embrittlement studies of advanced structural alloys taking reference from the results obtained in the article titled A novel methodology to estimate hydrogen diffusivity and its applications in revealing hydrogen effects in CoCrNi medium-entropy alloy versus 316L stainless steel published in International Journal of Plasticity. One of the highlights from the talk were the capabilities of employing nano-indentations to determine the permeation of hydrogen into the additively manufactured alloys and also the outgassing of hydrogen from the immediate surface after natural aging that created vacancies in the host lattice and its consequential reduction in hardness.

In the afternoon, Mr. Jimmy Juan gave further talks on the specific use of the nanoindenters and picoindenters specifically for semiconductor material testing. Meanwhile, Dr. Ronn Goei from Zeiss gave a very brief but insightful introduction to the achieved concept on the controlled electron channeling contrast technique (cECCI) made available on Zeiss systems. With the simple integration of the Euler angles to determine the orientation between the electron beam and the relative lattice structure of the sample, specific configurations between the sample orientation of interest and the electron beam could be achieved to observe specific dislocation and defect activities. This was based on the principle of electron scattering occurring different lattice orientations and defects, such that the specific orientation of the beam relative to these slip planes and defect configurations would be reflected with higher contrast for observation in the detector. The benefits of such as system was the ability to quickly observe larger-area dislocation activities on bulk material surfaces as compared to the traditional time-consuming method of cross-sectioning, lift-out, and small-window observation by TEM. Naturally, the achievable resolution of TEM would still trump that of the cECCI technique, but the high-throughput achievable results from cECCI is expected to garner greater interest in the field of nanomechanics.

These two days have been nothing but greatly insightful with highly professional organization comparable to international conferences. Massive kudos to the organizers at Bruker and special thanks to Mr. Jeffrey Teoh for extending the invitation to us. We have certainly gained significantly much more from this event, especially the very generous availability and spread of food and tea-breaks.

This year, we proposed ME4101 Dissertation Project Topics tailored to our current and future research directions. We are glad to announce that we have 04 students joining our research team.

Ryan Lim Chi Huang
Ryan is a final-year engineering student with a keen interest in the hands-on aspects of engineering. He is passionate about manufacturing and aims to create innovative products with enhanced quality with versatile technological capabilities and know-hows. Outside of academics, he enjoys building and collecting mechanical keyboards, curating vinyl records, and exploring the intricacies of watches. His goal is to leverage his engineering skills to develop products that bridge the gap between functionality and user experience. He will embark on his final year project titled Experimental study on the ductile-to-brittle transition during repeated micro-scratching of brittle materials under the mentorship of Dr. Lionel Lee.

Shannon Tan
Shannon is an undergraduate student majoring in Mechanical Engineering at the National University of Singapore. Prior to his undergraduate studies, he has shown aptitude in his machining operations in his diploma studies. With an interest in design and manufacturing process, he has since read a technical elective on Additive Manufacturing processes while on a local exchange at Nanyang Technological University, which has evoked interest in the area of powder metallurgy. This has led him to pursue a final-year project involving both subtractive and additive manufacturing processes through his dissertation project titled Micro-texturing of biomedical grade additively manufactured metal under the mentorship of Ms. Hoe Lay Min. 

Vaishnavi Harihara Venkatesan
Vaishnavi is a Year 4 undergraduate in the Department of Mechanical Engineering at National University of Singapore. She have worked in AEM holdings as part of my internship and has experience in finite element analysis (FEA) simulations and web development. Outside the classroom, her hobbies include playing the keyboard. For her final year, she will be studying the Investigation of ultra-precision machining of brittle materials under light irradiation under the mentorship of Mr. Guo Yunfa. 

Ye Ximin
Ximin is currently an undergraduate student in the 3+1+1 NUS Partner Chinese Universities Education Framework between Southern University of Science and Technology (SUSTech) and NUS. His interests are focused on atomic and close-to-atomic scale manufacturing and nature-inspired engineering. Since February 2023, he has been leading a project that investigates the machining sciences of ultrasonic-assisted tip-based nanofabrication under the supervision of Prof. Yongbo Wu at SUSTech. Ximin has also co-authored several peer-reviewed journal articles, including publications in the Chinese Journal of Aeronautics and the Lubricants. He has been recognized with several honors, including the Merit Student Scholarship (First Class) and the Outstanding Student Award in SUSTech. Ximin enjoys sports and excels at tennis having secured second place in the men’s team event at the 27th China University Tennis Championship (South China Division). His final year project titled Atomic-scale investigation of enhanced machinability in CaF2 through ion implantation will be studied under the mentorship of Dr. Zhan Jiaming.

We were honored to be given the privilege of giving an invited presentation on our computational research for precision machining at the International Conference on Computational & Experimental Engineering and Sciences (ICCES2024), held at Marina Bay Sands Expo & Convention Centre, Singapore, from 3–6 August. Our specialist in theoretical and computational modeling, Dr. Zhan Jiaming, delivered a talk on Numerical Investigation on the Ductile Machining of Calcium Fluoride Single Crystal Enhanced by Laser Assistance. He highlighted the application of necessary plasticity to enhance machining by covering the reviewing the state-of-the-art for ductile-mode machining, which led to the discussion on the comparisons between localized and global thermal-assisted machining, and our achievements in determining the impact of focused enhancements to plasticity through experimental and numerical thermal-assisted micro-cutting.