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Papers by ahmed sharif

Abu Dhabi International Petroleum Exhibition & Conference

Journal of Applied Polymer Science, Aug 25, 2008

Microelectronic Engineering, 2007

The scope of this paper covers a comprehensive study of the lead-free Sn–Zn–Bi solder system, on ... more The scope of this paper covers a comprehensive study of the lead-free Sn–Zn–Bi solder system, on Cu, electrolytic Ni/Au and electroless Ni(P)/Au surface finishes. This includes a study of the shear properties, intermetallic compounds at the substrate–ball interface and ...

Microelectronics Reliability, 2009

Sn-9Zn solder joints containing Ag nano particles were prepared by mechanically mixing Ag nano pa... more Sn-9Zn solder joints containing Ag nano particles were prepared by mechanically mixing Ag nano particles (0.3, 0.5 and 1 wt%) with Sn-9Zn solder paste. In the monolithic Sn-Zn solder joints, scallop-shaped AuZn 3 intermetallic compound layers were found at their interfaces. However, after the addition of Ag nano particles, an additional uniform AgZn 3 intermetallic compound layer well adhered to the top surface of the AuZn 3 intermetallic compound layer was found. In addition, in the solder ball region, fine spherical-shaped AgZn 3 intermetallic compound particles were observed as well as Zn-rich and b-Sn phases. With the addition of Ag nano particles, the shear strengths consistently increased with an increase in the Ag nano particle content due to the uniform distribution of fine AgZn 3 intermetallic compound particles. The shear strength of monolithic Sn-Zn and 1 wt% Ag nano particle content Sn-Zn solder joints after one reflow cycle were about 42.1 MPa and 48.9 MPa, respectively, while their shear strengths after eight reflow cycles were about 39.0 MPa and 48.4 MPa, respectively. The AgZn 3 IMCs were found to be uniformly distributed in the b-Sn phase for Ag particle doped Sn-9Zn composite solder joints, which result in an increase in the tensile strength, due to a second phase dispersion strengthening mechanism. The fracture surface of monolithic Sn-Zn solder exhibited a brittle fracture mode with a smooth surface while Sn-Zn solder joints containing Ag nano particles showed a typical ductile failure with very rough dimpled surfaces.

Journal of Electronic Packaging, 2005

Sn-based, Pb-free solders with high a Sn content and high melting temperature often cause excessi... more Sn-based, Pb-free solders with high a Sn content and high melting temperature often cause excessive interfacial reactions at interfaces. Sn-3.5Ag solder alloy has been used to identify its interfacial reactions with two-metal layer flexile substrates. In this paper the dissolution kinetics of Sn3.5Ag solder on the electrolytic Ni and electroless NiP layer are investigated. It is found that during 1 min reflow the electrolytic Ni layer dissolves much less than the electroless NiP layer due to the formation of Ni3Sn and Ni3Sn2 intermetallic compounds (IMCs) on the electrolytic Ni layer. The faster nucleation of Ni3Sn4 IMC on the NiP layer is proposed as the main reason for the higher initial dissolution rate of the electroless NiP layer. A P-rich Ni layer is formed underneath the Ni3Sn4 IMC due to the solder-assisted reactions. This P-rich Ni layer acts as a good diffusion barrier layer, which decreases the dissolution rate of the NiP layer as compared to that of the Ni layer, but wea...

SPE Journal, 2000

Summary In recent years, the impact of small-scale permeability structure on hydrocarbon recovery... more Summary In recent years, the impact of small-scale permeability structure on hydrocarbon recovery has been demonstrated, and upscaling procedures, such as the geopseudo method, have been developed to scale-up from the lamina scale using the hierarchy of geological length ...

arquivosdeorl.org.br, 2006

Abu Dhabi International Petroleum Exhibition & Conference

Journal of Applied Polymer Science, Aug 25, 2008

Microelectronic Engineering, 2007

The scope of this paper covers a comprehensive study of the lead-free Sn–Zn–Bi solder system, on ... more The scope of this paper covers a comprehensive study of the lead-free Sn–Zn–Bi solder system, on Cu, electrolytic Ni/Au and electroless Ni(P)/Au surface finishes. This includes a study of the shear properties, intermetallic compounds at the substrate–ball interface and ...

Microelectronics Reliability, 2009

Sn-9Zn solder joints containing Ag nano particles were prepared by mechanically mixing Ag nano pa... more Sn-9Zn solder joints containing Ag nano particles were prepared by mechanically mixing Ag nano particles (0.3, 0.5 and 1 wt%) with Sn-9Zn solder paste. In the monolithic Sn-Zn solder joints, scallop-shaped AuZn 3 intermetallic compound layers were found at their interfaces. However, after the addition of Ag nano particles, an additional uniform AgZn 3 intermetallic compound layer well adhered to the top surface of the AuZn 3 intermetallic compound layer was found. In addition, in the solder ball region, fine spherical-shaped AgZn 3 intermetallic compound particles were observed as well as Zn-rich and b-Sn phases. With the addition of Ag nano particles, the shear strengths consistently increased with an increase in the Ag nano particle content due to the uniform distribution of fine AgZn 3 intermetallic compound particles. The shear strength of monolithic Sn-Zn and 1 wt% Ag nano particle content Sn-Zn solder joints after one reflow cycle were about 42.1 MPa and 48.9 MPa, respectively, while their shear strengths after eight reflow cycles were about 39.0 MPa and 48.4 MPa, respectively. The AgZn 3 IMCs were found to be uniformly distributed in the b-Sn phase for Ag particle doped Sn-9Zn composite solder joints, which result in an increase in the tensile strength, due to a second phase dispersion strengthening mechanism. The fracture surface of monolithic Sn-Zn solder exhibited a brittle fracture mode with a smooth surface while Sn-Zn solder joints containing Ag nano particles showed a typical ductile failure with very rough dimpled surfaces.

Journal of Electronic Packaging, 2005

Sn-based, Pb-free solders with high a Sn content and high melting temperature often cause excessi... more Sn-based, Pb-free solders with high a Sn content and high melting temperature often cause excessive interfacial reactions at interfaces. Sn-3.5Ag solder alloy has been used to identify its interfacial reactions with two-metal layer flexile substrates. In this paper the dissolution kinetics of Sn3.5Ag solder on the electrolytic Ni and electroless NiP layer are investigated. It is found that during 1 min reflow the electrolytic Ni layer dissolves much less than the electroless NiP layer due to the formation of Ni3Sn and Ni3Sn2 intermetallic compounds (IMCs) on the electrolytic Ni layer. The faster nucleation of Ni3Sn4 IMC on the NiP layer is proposed as the main reason for the higher initial dissolution rate of the electroless NiP layer. A P-rich Ni layer is formed underneath the Ni3Sn4 IMC due to the solder-assisted reactions. This P-rich Ni layer acts as a good diffusion barrier layer, which decreases the dissolution rate of the NiP layer as compared to that of the Ni layer, but wea...

SPE Journal, 2000

Summary In recent years, the impact of small-scale permeability structure on hydrocarbon recovery... more Summary In recent years, the impact of small-scale permeability structure on hydrocarbon recovery has been demonstrated, and upscaling procedures, such as the geopseudo method, have been developed to scale-up from the lamina scale using the hierarchy of geological length ...

arquivosdeorl.org.br, 2006

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