All Outputs (9)

Self-assembled titanium-based macrostructures with hierarchical (macro-, micro-, and nano) porosities: A fundamental study (2024)
Journal Article
Wadge, M. D., Agyakwa, P. A., Felfel, R. M., Homer, R., Cooper, T. P., Kudrynskyi, Z. R., …Grant, D. M. (2024). Self-assembled titanium-based macrostructures with hierarchical (macro-, micro-, and nano) porosities: A fundamental study. Materials and Design, 240, Article 112835. https://doi.org/10.1016/j.matdes.2024.112835

This study details the novel self-assembly of sodium titanate converted Ti-based microspheres into hierarchical porous 3D constructs, with macro-, micro-, and nanoporosity, for the first time. Ti6Al4V microspheres were suspended into 5 M NaOH (60 °C/... Read More about Self-assembled titanium-based macrostructures with hierarchical (macro-, micro-, and nano) porosities: A fundamental study.

Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling (2024)
Journal Article
Agyakwa, P. A., Robertson, S., Dai, J., Mouawad, B., Zhou, Z., Liu, C., & Johnson, C. M. (2024). Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling. Journal of Electronic Materials, 53, 1374–1398. https://doi.org/10.1007/s11664-023-10870-4

This paper deals with the performance of sintered nano-silver bonds used as wide-bandgap power module die attachment technology. The paper specifically explores the fine-scale microstructures of highly porous sintered attachments under power cycling... Read More about Microstructural Response of Highly Porous Sintered Nano-silver Particle Die Attachments to Thermomechanical Cycling.

Reliability and Characterization of Nanosilver Joints Prepared by a Time-Reduced Sintering Process (2021)
Journal Article
Dai, J., Li, J., Agyakwa, P., Corfield, M., & Johnson, C. M. (2021). Reliability and Characterization of Nanosilver Joints Prepared by a Time-Reduced Sintering Process. IEEE Transactions on Device and Materials Reliability, 21(4), 536-543. https://doi.org/10.1109/TDMR.2021.3118323

This study investigates the power cycling reliability of nanosilver sintered joints formed by a time-reduced sintering process, designed for use on a die bonder. A range of sintering parameters, reflecting different levels of manufacturability, were... Read More about Reliability and Characterization of Nanosilver Joints Prepared by a Time-Reduced Sintering Process.

Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules (2019)
Journal Article
Agyakwa, P., Dai, J., Li, J., Mouawad, B., Yang, L., Corfield, M., & Johnson, C. (2019). Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules. Journal of Microscopy, 277(3), 140-153. https://doi.org/10.1111/jmi.12803

© 2019 The Authors. Journal of Microscopy published by John Wiley & Sons Ltd on behalf of Royal Microscopical Society. A time-lapse study of thermomechanical fatigue damage has been undertaken using three-dimensional X-ray computer tomography. Morp... Read More about Three‐dimensional damage morphologies of thermomechanically deformed sintered nanosilver die attachments for power electronics modules.

Predicting Lifetime of Thick Al Wire Bonds Using Signals Obtained From Ultrasonic Generator (2016)
Journal Article
Arjmand, E., Agyakwa, P., Corfield, M., Li, J., & Johnson, C. M. (2016). Predicting Lifetime of Thick Al Wire Bonds Using Signals Obtained From Ultrasonic Generator. IEEE Transactions on Components, Packaging, and Manufacturing Technology, 6(5), 814-821. https://doi.org/10.1109/TCPMT.2016.2543001

Routine monitoring of the wire bonding process requires real-time evaluation and control of wire bond quality. In this paper, we present a nondestructive technique for detecting bond quality by the application of a semisupervised classification algor... Read More about Predicting Lifetime of Thick Al Wire Bonds Using Signals Obtained From Ultrasonic Generator.

Calibration of a novel microstructural damage model for wire bonds (2014)
Journal Article
Yang, L., Agyakwa, P., & Johnson, C. (2014). Calibration of a novel microstructural damage model for wire bonds. IEEE Transactions on Device and Materials Reliability, 14(4), 989-994. https://doi.org/10.1109/TDMR.2014.2354739

In a previous paper, a new time-domain damage-based physics model was proposed for the lifetime prediction of wire bond interconnects in power electronic modules. Unlike cycle-dependent life prediction methodologies, this model innovatively incorpora... Read More about Calibration of a novel microstructural damage model for wire bonds.

Reliability of thick Al wire: a study of the effects of wire bonding parameters on thermal cycling degradation rate using non-destructive methods (2014)
Journal Article
Arjmand, E., Agyakwa, P. A., & Johnson, C. M. (2014). Reliability of thick Al wire: a study of the effects of wire bonding parameters on thermal cycling degradation rate using non-destructive methods. Microelectronics Reliability, 54(9-10), https://doi.org/10.1016/j.microrel.2014.07.119

The effect of bonding parameters on the reliability of thick Al wire bond is investigated. Samples were prepared with 25 different designs with 5 different bonding parameters such as time, ultrasonic power, begin- force, end-force and touch-down step... Read More about Reliability of thick Al wire: a study of the effects of wire bonding parameters on thermal cycling degradation rate using non-destructive methods.

Interdiffusion coefficients of binary multiphase systems with consideration of variation in Molar volumes (2014)
Journal Article
Li, J., Agyakwa, P., & Johnson, C. M. (2014). Interdiffusion coefficients of binary multiphase systems with consideration of variation in Molar volumes

This communication introduces a modification to the Wagner method to reveal and correct considerable systematic errors existing in the previously established analytical methods used to calculate the interdiffusion coefficients of binary multiphase sy... Read More about Interdiffusion coefficients of binary multiphase systems with consideration of variation in Molar volumes.

Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment (2014)
Journal Article
Li, J., Agyakwa, P., & Johnson, C. (2014). Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment. Journal of Electronic Materials, 43(4), 983-995. https://doi.org/10.1007/s11664-013-2971-7

Real Si insulated gate bipolar transistors with conventional Ni/Ag metallization and dummy Si chips with thickened Ni/Ag metallization have both been bonded, at 250°C for 0 min, 40 min, and 640 min, to Ag foil electroplated with 2.7 μm and 6.8 μm thi... Read More about Suitable Thicknesses of Base Metal and Interlayer, and Evolution of Phases for Ag/Sn/Ag Transient liquid-phase Joints Used for Power Die Attachment.