Wintech Nano technology Services Pte Ltd.

Singapore, Singapore

Wintech Nano technology Services Pte Ltd.

Singapore, Singapore

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Luo Z.,Nanyang Technological University | Luo Z.,Institute of Chemical and Engineering Sciences, Singapore | Lim S.,Institute of Chemical and Engineering Sciences, Singapore | Tian Z.,Institute of Chemical and Engineering Sciences, Singapore | And 9 more authors.
Journal of Materials Chemistry | Year: 2011

Different C-N bonding configurations in nitrogen (N) doped carbon materials have different electronic structures. Carbon materials doped with only one kind of C-N bonding configuration are an excellent platform for studying doping effects on the electronic structure and physical/chemical properties. Here we report synthesis of single layer graphene doped with pure pyridinic N by thermal chemical vapour deposition of hydrogen and ethylene on Cu foils in the presence of ammonia. By adjusting the flow rate of ammonia, the atomic ratio of N and C can be modulated from 0 to 16%. The domain like distribution of N incorporated in graphene was revealed by the imaging of Raman spectroscopy and time-of-flight secondary ion mass spectrometry. The ultraviolet photoemission spectroscopy investigation demonstrated that the pyridinic N efficiently changed the valence band structure of graphene, including the raising of density of π states near the Fermi level and the reduction of work function. Such pyridinic N doping in carbon materials was generally considered to be responsible for their oxygen reduction reaction (ORR) activity. The 2e reduction mechanism of ORR on our CNx graphene revealed by rotating disk electrode voltammetry indicated that the pyridinic N may not be an effective promoter for ORR activity of carbon materials as previously expected. © 2011 The Royal Society of Chemistry.


Chao F.,WinTech Nano Technology Services Pte. Ltd. | Xiaomin L.,WinTech Nano Technology Services Pte. Ltd. | Kow J.,YXLON International GmbH
Proceedings of the Electronic Packaging Technology Conference, EPTC | Year: 2016

3D packaging with complex multi die and multi component structure has new Failure Analysis challenges in electrical testing, package fault isolation and physical failure analysis. This paper emphasize on new approach using 3D X-Ray other techniques. © 2015 IEEE.


Hua Y.,WinTech Nano Technology Services Pte. Ltd. | Zhou Y.,WinTech Nano Technology Services Pte. Ltd. | Chen Y.,WinTech Nano Technology Services Pte. Ltd. | Fu C.,WinTech Nano Technology Services Pte. Ltd. | Li X.,WinTech Nano Technology Services Pte. Ltd.
Conference Proceedings from the International Symposium for Testing and Failure Analysis | Year: 2014

It is well-known that underetch material, contamination, particle, pinholes and corrosion-induced defects on microchip A1 bondpads will cause non-stick on pads (NSOP) issues. In this paper, the authors will further study NSOP problem and introduce one more NSOP failure mechanism due to Cu diffusion caused by poor Ta barrier metal. Based on our failure analysis results, the NSOP issue was not due to the assembly process, but due to the wafer fabrication. The failure mechanism might be that the barrier metal Ta was with pinholes, which caused Cu diffused out to the top A1 layer, and then formed the "Bump-like" Cu defects and resulted in NSOP on A1 bondpads during assembly process. Copyright © 2014 ASM International® All rights reserved.


Younan H.,WinTech Nano Technology Services Pte. Ltd. | Xiang X.Z.,WinTech Nano Technology Services Pte. Ltd. | Xiaomin L.,WinTech Nano Technology Services Pte. Ltd.
Proceedings of the International Symposium on the Physical and Failure Analysis of Integrated Circuits, IPFA | Year: 2014

In wafer fabrication, Fluorine (F) contamination may cause F-induced corrosion and defects on microchip Al bondpad, resulting in bondpad discoloration or non-stick on pad (NSOP). In the previous paper [1], the authors studied the F-induced corrosion and defects, characterized the composition of the 'flower-like' defects and determined the binding energy of Al fluoride [AlF6]3- using X-ray Photoelectron Spectroscopy (XPS) and Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) techniques. In this paper, we further studied F-induced corrosion and defects, and characterized the composition of the 'crystal-like' defects using XPS. The experimental results showed that the major component of the 'crystal-like' defect was Al fluoride of AlF3. The percentages of the components of the 'crystal-like' defects on the affected bondpad are: Al (22.2%), Al2O3 (5.4%), AlF3(70.0%) and [AlF6]3- (2.4%). During high-resolution fitting, the binding energies of Al (72.8eV)Al2O3 3-(74.5eV), AlF3 (76.3eV) and [AlF6]3- (78.7eV) were used. © 2014 IEEE.


Zhou Y.,WinTech Nano Technology Services Pte. Ltd. | Lee S.L.,WinTech Nano Technology Services Pte. Ltd. | Fu C.,WinTech Nano Technology Services Pte. Ltd. | Hua Y.,WinTech Nano Technology Services Pte. Ltd. | Li X.,WinTech Nano Technology Services Pte. Ltd.
Conference Proceedings from the International Symposium for Testing and Failure Analysis | Year: 2015

In this work, we discussed the fault isolation method for the Thin-Film Transistor (TFT). Many defects in the TFT can be directly observed by optical microscope; however, some defects are not visible in either optical microscope or SEM making the fault isolation effort very challenging. We demonstrated that OBIRCH can be used to find defect locations in TFT failures for leakage and shorts. The TFT is so fragile that the laser power and biasing voltage have to be very carefully controlled to avoid damaging the TFT. After identifying the defect location by OBIRCH hot spot detection, the defect was successfully captured with TEM analysis. Copyright © 2015 ASM International® All rights reserved.


Hua Y.,WinTech Nano Technology Services Pte. Ltd. | Shen Y.,WinTech Nano Technology Services Pte. Ltd. | Chen Y.,WinTech Nano Technology Services Pte. Ltd. | Fu C.,WinTech Nano Technology Services Pte. Ltd. | Li X.,WinTech Nano Technology Services Pte. Ltd.
Conference Proceedings from the International Symposium for Testing and Failure Analysis | Year: 2015

In authors' previous paper, an OSAT [Optical, SEM (Scanning Electron Microscopy), Auger (Auger Electron Spectroscopy) and TEM (Transmission Electron Microscopy)] methodology was developed for qualification of microchip aluminum (Al) bondpads. Using the OSAT methodology, one can qualify microchip Al bondpads. In this paper, we will further study the NSOP (Non-Stick On Pad) problem on microchip Al bondpads. A new qualification methodology, OSSD [(Optical, SEM, and Surface and Depth profiling X-ray Photoelectron Spectroscopy (XPS)] will be proposed, in which XPS surface analysis is used to check the contamination level of fluorine and carbon on bondpad surfaces instead of Auger analysis. XPS depth profiling analysis will also be used to measure Al oxide thickness instead of TEM analysis. By using OSSD, Al bondpads can be qualified with both reduced costs and shortened turnaround times versus OSAT. Copyright © 2015 ASM International® All rights reserved.


Hua Y.,WinTech Nano Technology Services Pte. Ltd. | Chen Y.,WinTech Nano Technology Services Pte. Ltd. | Fu C.,WinTech Nano Technology Services Pte. Ltd. | Li X.,WinTech Nano Technology Services Pte. Ltd.
Conference Proceedings from the International Symposium for Testing and Failure Analysis | Year: 2015

In the authors' previous papers, the failure mechanism and elimination solutions of galvanic corrosion (Al-Cu cell) on microchip Al bondpads in the Al process (0.18un and above) have been studied [1-2]. In this paper, the authors will further study the failure mechanism and root cause of galvanic corrosion (Al-Cu cell) on microchip Al bondpads in the Cu process (0.13um and below) with Ta barrier metal. Based on our results, the root cause of galvanic corrosion (Al-Cu cell) in the Al process is only one way and Al-Cu cell is from Al alloy (Al + 0.5%Cu) on Al bondpads. However, in the Cu process it may be from two ways and Al-Cu cell can be from both Al alloy (Al + 0.5%Cu) on Al bondpads and the Cu metal layer below the barrier metal Ta when Ta has weak points or pinhole. As such, the pinhole defects on Al bondpad caused by galvanic corrosion (Al-Cu cell) in the Cu process might be more serious than that in the Al process. In this paper, TEM is used for root cause identification. Based on the TEM results, galvanic corrosion was due to the weak point/pinhole at the Ta barrier metal layer and Al-Cu diffusion. Copyright © 2015 ASM International® All rights reserved.


Zhou Y.,WinTech Nano Technology Services Pte. Ltd. | Hua Y.,WinTech Nano Technology Services Pte. Ltd. | Li X.,WinTech Nano Technology Services Pte. Ltd.
Conference Proceedings from the International Symposium for Testing and Failure Analysis | Year: 2014

The Rotation Averaged Spectrum of TEM diffraction patterns can be sharpened by a Maximum-Likelihood deconvolution algorithm. The sharpened spectrum will help to improve the precision of TEM diffraction-based techniques, e.g.: phase identification and strain analysis. Copyright © 2014 ASM International® All rights reserved.


Zhou Y.,WinTech Nano Technology Services Pte. Ltd. | Lee S.L.,WinTech Nano Technology Services Pte. Ltd. | Fu C.,WinTech Nano Technology Services Pte. Ltd. | Hua Y.,WinTech Nano Technology Services Pte. Ltd. | Li X.,WinTech Nano Technology Services Pte. Ltd.
Proceedings of the International Symposium on the Physical and Failure Analysis of Integrated Circuits, IPFA | Year: 2015

In this work, we discussed the fault isolation method for Thin-Film Transistor (TFT). Many defects in TFT can be directly observed by optical microscope; however, for some defects, they are not visible in either optical microscope or SEM, which makes the fault isolation very challenging. We demonstrated that OBIRCH can be used to find the defect location in the leakage/short type TFT failure. The TFT is so fragile that the laser power and biasing voltage have to be very carefully controlled to avoid damaging the TFT. After identifying the defect location by OBIRCH hot spot, the following TEM analysis has successfully captured the defect. © 2015 IEEE.


Yang F.,WinTech Nano Technology Services Pte Ltd | Shen Y.,WinTech Nano Technology Services Pte Ltd | Sheng L.H.,WinTech Nano Technology Services Pte Ltd | Chao F.,WinTech Nano Technology Services Pte Ltd
Proceedings of the 2013 IEEE 15th Electronics Packaging Technology Conference, EPTC 2013 | Year: 2013

In this study, die to printed circuit board (PCB) interfacial failure was investigated. Instead of using conventional Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM-EDX) and Fourier Transform Infrared Spectroscopy (FTIR) for bulk material analysis, advanced surface analysis techniques such as X-ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) were employed to analyze the delamination between die and PCB. High percentage of siloxane bond was revealed at the failure interface using XPS. TOF-SIMS was used to further validate that the siloxane bond belongs to Polydimethylsiloxane (PDMS) from blue tape. Combining both XPS and TOF-SIMS analysis techniques, it was shown that the die to PCB delamination was attributed to PDMS contamination. © 2013 IEEE.

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