Prof. Dr. Ahmed Sharif is working has been working as a faculty in the Department of Materials and Metallurgical Engineering, BUET since 1999. Previously he was a core research member of several Group Research projects of City University of Hong Kong (CityU) and Nanyang Technological University (NTU), Singapore. He is an international renowned scientist in joining technology, and has published 40 peer-reviewed (SCI listed) papers in leading international journals in soldering and ferroelectric materials research. A part of his PhD research has led to the award of an international prize the “IEEE CPMT Young Scientist Award” for his paper presentation in an IEEE conference held in Japan in 2004. He has successfully completed a “Ruggedized Electronics” Project of A*Star Science and Engineering Research Council and Nanyang Technological University (NTU), Singapore. He serves as a referee for a large number of international journals on numerous occasions. He served as the Head of the MME Department, BUET from 2014 to 2016. He is working as the Chairman of Self Assessment Committee (SAC) of BSc Eng. program of MME Department from 2015 under IQAC, BUET.
2013 IEEE 63rd Electronic Components and Technology Conference, 2013
ABSTRACT Epoxy type encapsulation does not suffice in High Pressure High Temperature (HPHT) envir... more ABSTRACT Epoxy type encapsulation does not suffice in High Pressure High Temperature (HPHT) environment and hence is not suitable for harsh environment applications. In this work, alternative encapsulation methods exploring the use of thickened lid/base and a novel dome shaped cavity design would be discussed. Results show that such methods are viable and are possible alternatives for similar harsh environment applications.
Proceedings - Electronic Components and Technology Conference, 2009
Abstract 179 Sn8Zn3Bi solder balls with different weight percentages of Sn-Ag-Cu addition were ... more Abstract 179 Sn8Zn3Bi solder balls with different weight percentages of Sn-Ag-Cu addition were bonded to Au/Ni metallized Cu pads, and the effect of multiple reflow and aging on impact reliability was investigated. In the Sn-Ag-Cu content Sn-Zn-Bi solder joints, the AgZn3 ...
2006 Thirty-First IEEE/CPMT International Electronics Manufacturing Technology Symposium, 2006
Abstract The work presented in this paper focuses on the role of 3 wt% Bi in the base Sn-9% Zn so... more Abstract The work presented in this paper focuses on the role of 3 wt% Bi in the base Sn-9% Zn solder on the shear strengths and the interfacial reactions with Au/Ni/Cu pad metallization in ball grid array (BGA) applications. Sn-Zn-Bi solders showed better results ...
2008 33rd IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT), 2008
Abstract In this work, Ag micro-particles content in the range between 04.0 wt.% with Sn-Zn eute... more Abstract In this work, Ag micro-particles content in the range between 04.0 wt.% with Sn-Zn eutectic system, were examined in order to understand the effect of Ag addition on the microstructural and mechanical properties as well as the thermal behavior of the ...
The joint strength and the microstructure of Sn3.5Ag and Sn3.5Ag0.5Cu (wt.%) solders on Cu/Ni/... more The joint strength and the microstructure of Sn3.5Ag and Sn3.5Ag0.5Cu (wt.%) solders on Cu/Ni/Au ball-grid-array (BGA) pad metallization were investigated after high-temperature solid-state aging at 190 °C (around 0.86T m of solder alloys). SnAg solder gave better ...
Nano-sized, nonreacting, noncoarsening SrTiO3 particles have been incorporated into Sn–3.0wt% Ag–... more Nano-sized, nonreacting, noncoarsening SrTiO3 particles have been incorporated into Sn–3.0wt% Ag–0.5wt% Cu solder alloys and the interfacial microstructure and the shear strength on Au/Ni metallized Cu pads ball grid array substrates investigated as a function of the number of reflow cycles and aging time. At their interfaces, a scallop-shaped ternary Sn–Ni–Cu intermetallic compound layer was found in both plain Sn–Ag–Cu solder joints and solder joints containing SrTiO3 nano-particles, and the intermetallic compound layer thickness increased with the number of reflow cycles and aging time. After the addition of SrTiO3 nano-particles, in the solder ball region, a fine microstructure of AuSn4, Ag3Sn, Cu6Sn5 intermetallic compounds appeared in the β-Sn matrix. In addition, the shear strength of solder joints containing SrTiO3 nano-particles exhibited a consistently higher value than that of plain Sn–Ag–Cu solder joints due to a second phase dispersion strengthening mechanism as well as a refinement of the intermetallic compounds. The fracture surface of plain Sn–Ag–Cu solder joints exhibited a brittle fracture mode with a smooth surface while Sn–Ag–Cu solder joints containing SrTiO3 nano-particles showed ductile failure characteristics with rough dimpled surfaces.
An investigation has been carried out to study the dissolution of the Cu pad of the ball-grid-arr... more An investigation has been carried out to study the dissolution of the Cu pad of the ball-grid-array (BGA) substrate into the molten Sn9%In3.5%Ag0.5%Cu, Sn3.5%Ag0.5%Cu and Sn0.7%Cu (wt.%) solder alloys. A fixed volume of BGA solder ball (760 μm dia) was ...
... [13], Xu et al. [14], de Gennes [15], Christensen [16], Greenwood and Johnson [17], and other... more ... [13], Xu et al. [14], de Gennes [15], Christensen [16], Greenwood and Johnson [17], and others. For example, Mangipudi et al. [18] suggested the following relation between G and W: ... Marcel Dekker, New York (1982). 3. VS Mangipudi and M. Tirrell, Rubber Chem. Technol. ...
ABSTRACT A lead-free glass frit paste as a die-attach material for high-temperature microelectron... more ABSTRACT A lead-free glass frit paste as a die-attach material for high-temperature microelectronic application is proposed in this study. The glass paste containing Bi-based powder with a moderate amount of solvent was used for joining Si dice on ceramic substrates without any metallization preparation for either of the bonding surfaces. The die was bonded to a ceramic substrate at 430°C for 10 min. The study focuses on the mechanical and microstructural characterization of the joints with Si dice on two different types of ceramic substrate. Shear strength measurements were carried out at both ambient and 250°C to evaluate room- and high-temperature performance. Furthermore, the effect of aging at 300°C for 500 h on the mechanical properties is presented. The results of the mechanical and microstructural characterization demonstrate that low-temperature glass frit bonding is an effective die-attach method for harsh-environment electronic packaging.
2013 IEEE 63rd Electronic Components and Technology Conference, 2013
ABSTRACT Epoxy type encapsulation does not suffice in High Pressure High Temperature (HPHT) envir... more ABSTRACT Epoxy type encapsulation does not suffice in High Pressure High Temperature (HPHT) environment and hence is not suitable for harsh environment applications. In this work, alternative encapsulation methods exploring the use of thickened lid/base and a novel dome shaped cavity design would be discussed. Results show that such methods are viable and are possible alternatives for similar harsh environment applications.
Proceedings - Electronic Components and Technology Conference, 2009
Abstract 179 Sn8Zn3Bi solder balls with different weight percentages of Sn-Ag-Cu addition were ... more Abstract 179 Sn8Zn3Bi solder balls with different weight percentages of Sn-Ag-Cu addition were bonded to Au/Ni metallized Cu pads, and the effect of multiple reflow and aging on impact reliability was investigated. In the Sn-Ag-Cu content Sn-Zn-Bi solder joints, the AgZn3 ...
2006 Thirty-First IEEE/CPMT International Electronics Manufacturing Technology Symposium, 2006
Abstract The work presented in this paper focuses on the role of 3 wt% Bi in the base Sn-9% Zn so... more Abstract The work presented in this paper focuses on the role of 3 wt% Bi in the base Sn-9% Zn solder on the shear strengths and the interfacial reactions with Au/Ni/Cu pad metallization in ball grid array (BGA) applications. Sn-Zn-Bi solders showed better results ...
2008 33rd IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT), 2008
Abstract In this work, Ag micro-particles content in the range between 04.0 wt.% with Sn-Zn eute... more Abstract In this work, Ag micro-particles content in the range between 04.0 wt.% with Sn-Zn eutectic system, were examined in order to understand the effect of Ag addition on the microstructural and mechanical properties as well as the thermal behavior of the ...
The joint strength and the microstructure of Sn3.5Ag and Sn3.5Ag0.5Cu (wt.%) solders on Cu/Ni/... more The joint strength and the microstructure of Sn3.5Ag and Sn3.5Ag0.5Cu (wt.%) solders on Cu/Ni/Au ball-grid-array (BGA) pad metallization were investigated after high-temperature solid-state aging at 190 °C (around 0.86T m of solder alloys). SnAg solder gave better ...
Nano-sized, nonreacting, noncoarsening SrTiO3 particles have been incorporated into Sn–3.0wt% Ag–... more Nano-sized, nonreacting, noncoarsening SrTiO3 particles have been incorporated into Sn–3.0wt% Ag–0.5wt% Cu solder alloys and the interfacial microstructure and the shear strength on Au/Ni metallized Cu pads ball grid array substrates investigated as a function of the number of reflow cycles and aging time. At their interfaces, a scallop-shaped ternary Sn–Ni–Cu intermetallic compound layer was found in both plain Sn–Ag–Cu solder joints and solder joints containing SrTiO3 nano-particles, and the intermetallic compound layer thickness increased with the number of reflow cycles and aging time. After the addition of SrTiO3 nano-particles, in the solder ball region, a fine microstructure of AuSn4, Ag3Sn, Cu6Sn5 intermetallic compounds appeared in the β-Sn matrix. In addition, the shear strength of solder joints containing SrTiO3 nano-particles exhibited a consistently higher value than that of plain Sn–Ag–Cu solder joints due to a second phase dispersion strengthening mechanism as well as a refinement of the intermetallic compounds. The fracture surface of plain Sn–Ag–Cu solder joints exhibited a brittle fracture mode with a smooth surface while Sn–Ag–Cu solder joints containing SrTiO3 nano-particles showed ductile failure characteristics with rough dimpled surfaces.
An investigation has been carried out to study the dissolution of the Cu pad of the ball-grid-arr... more An investigation has been carried out to study the dissolution of the Cu pad of the ball-grid-array (BGA) substrate into the molten Sn9%In3.5%Ag0.5%Cu, Sn3.5%Ag0.5%Cu and Sn0.7%Cu (wt.%) solder alloys. A fixed volume of BGA solder ball (760 μm dia) was ...
... [13], Xu et al. [14], de Gennes [15], Christensen [16], Greenwood and Johnson [17], and other... more ... [13], Xu et al. [14], de Gennes [15], Christensen [16], Greenwood and Johnson [17], and others. For example, Mangipudi et al. [18] suggested the following relation between G and W: ... Marcel Dekker, New York (1982). 3. VS Mangipudi and M. Tirrell, Rubber Chem. Technol. ...
ABSTRACT A lead-free glass frit paste as a die-attach material for high-temperature microelectron... more ABSTRACT A lead-free glass frit paste as a die-attach material for high-temperature microelectronic application is proposed in this study. The glass paste containing Bi-based powder with a moderate amount of solvent was used for joining Si dice on ceramic substrates without any metallization preparation for either of the bonding surfaces. The die was bonded to a ceramic substrate at 430°C for 10 min. The study focuses on the mechanical and microstructural characterization of the joints with Si dice on two different types of ceramic substrate. Shear strength measurements were carried out at both ambient and 250°C to evaluate room- and high-temperature performance. Furthermore, the effect of aging at 300°C for 500 h on the mechanical properties is presented. The results of the mechanical and microstructural characterization demonstrate that low-temperature glass frit bonding is an effective die-attach method for harsh-environment electronic packaging.
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