2016 IEEE 37th International Electronics Manufacturing Technology (IEMT) & 18th Electronics Materials and Packaging (EMAP) Conference
Sintered silver (Ag) is a porous silver attaching the semiconductor die to the microelectronic su... more Sintered silver (Ag) is a porous silver attaching the semiconductor die to the microelectronic substrates. The market sizes for sintered Ag are explored, and the relevant patents are analyzed at macro and micro-levels. At the macro-level, patenting activity moves to Stage 2 of the technology life-cycle “s-curve”. In stage 2, patenting slows down before the next surge in patenting, likely to be spurred by the wider adoption of wide band-gap semiconductor. The low profitability of sintered Ag also coincides with the available market research reports on the three major market of this technology, i.e., power module, power discrete technology and consumer integrated circuits. However, the patent owners are not abandoning their patents applications. Only eleven entities are co-filing patents related to sintered Ag based on 350 patents and patent applications analyzed here. Such trend suggests the nascent characteristics and continuing investment in this technology. At the micro-level, patenting addresses the following issues. Firstly, pressure assisted sintering is necessary and more reliable than pressureless sintering but the former requires additional process controls and capital investments than the latter. The current state of the art of sintered Ag joint also favours sintering in an ambient environment that oxidizes the substrate. This oxidation poses a delamination risk, and a reliability concern to the microelectronic packages. Lastly, sintered Ag paste favours sintering on the Ag or Au-metallized substrate that represents an additional cost to the customers.
We demonstrated theoretically the wave guiding of elastics waves in a two-dimensional (2D) phonon... more We demonstrated theoretically the wave guiding of elastics waves in a two-dimensional (2D) phononic crystal (PnC) slab. The simulation model based on the Finite Element Method (FEM) was used to calculate the dispersion relation of unit cells that shows a complete band gap between frequency, f=312–412 kHz. The supercell technique to simulate two waveguides size shows filtering frequencies between 365-397 kHz within the band gap. We discuss the frequency shift of the wave guide as a function of the defect size for the possibility of elastic wave filtering application. `
Silver sintering is used for bonding of semiconductor dies to the substrate as part of a power mo... more Silver sintering is used for bonding of semiconductor dies to the substrate as part of a power module/device packaging. Power-module consisting inverters and converters are used to manage the electric drive systems in the hybrids and electric vehicles (HEVs). Many pressure-sintering tools and processes have been patented to produce reliable sintered silver joints for these power applications, and those invented by Siemens, Infineon Technologies, Danfoss, and Valtion (VTT) are analyzed based on the Theory of Inventive Problem Solving (TRIZ) framework. The level of inventiveness for each patent is evaluated, and respective function analysis is conducted to understand the interactions of the components in each sintering tool. This paper is expected to be useful to engineers who are interested in understanding the evolutionary patterns of a technical system especially silver sintering tools
The role of sulfur and its synergistic effects with nitrogen moieties in mediating stem cell prol... more The role of sulfur and its synergistic effects with nitrogen moieties in mediating stem cell proliferation and differentiation has become of interest to the tissue engineering community due to chemical similarities with the glycosaminoglycans found in human tissues and cells. Glycosaminoglycans are biomolecules known to influence stem cell differentiation, but the roles of sulfur with different oxidation states on nitrogen-containing polymers have not been fully understood nor investigated. In this study, we used the plasma polymerization of 1,7-octadiene (ppOD), n-heptylamine (ppHA), ppHA grafted with vinyl-sulfonate via Michael-type addition (ppHA-SO3), thiophene (ppT), and ppT with air plasma treatment (ppT-air) to produce controlled amounts of nitrogen and sulfur moieties having different oxidation states, as confirmed by x-ray photoelectron spectroscopy. Assays of the proliferation and osteogenic activities of Wharton’s jelly mesenchymal stem cells (WJ-MSCs) showed the highest ...
Increase in hydrophilicity of the filtration membrane could attribute to the fouling reduction an... more Increase in hydrophilicity of the filtration membrane could attribute to the fouling reduction and overall filtration performance. In this study, we employ a surface modification on polyamide (PA) membrane by using plasma polymerization with acrylic acid as the precursor by varying the deposition time from 1 to 10 min to induce hydrophilic surface of the membrane without changing the bulk properties of PA membrane. Cross-flow filtration of humic acid using the modified PA membrane was conducted to measure permeates flux and rejection. We calculate the fouling tendencies of each membrane and the result indicates the best performance from sample with 7 min deposition time in terms of permeate flux, rejection and the lowest fouling tendencies. Therefore, this proposed technique could be useful to further improve the commercial filtration membrane; without changing the membrane fabrication process.
In this article, we report the finite element method (FEM) simulation of the suspended double-cla... more In this article, we report the finite element method (FEM) simulation of the suspended double-clamped graphene beam-based NEM switches with standard and perforated beam structures, to analyze the von Mises stress, the contour plot and the electrical field distribution by using FEM simulator provided by IntelliSuite and COMSOL software. This FEM numerical model is used to observe the scaling characteristics of the graphene beam-based NEM switch. The FEM results confirm that the von Mises stress value reduced by ~2–3% for every 0.1 µm increment of the standard graphene beam length. The introduction of perforation in the case of HL = 150 nm, HW = 100 nm and DL = 100 nm, further reduced the von Mises stress at the graphene beam end and the beam center by approximately ~20–35 and ~10–20%, respectively. These low values of von Mises stress along the graphene beam resulted in a lower probability of the device failure. In addition, the strong electrostatic force at the hole’s edges and beam's edges leads to a larger mechanical deflection at the edges compared to the beam center and it is consistent with the analysis of von Mises stress. The results presented here are expected to accelerate developments in the working dimension and parameter of the graphene NEM switch device fabrication for better mechanical reliability operation.
Sintered silver joint is a porous silver that bonds a semiconductor die to the substrate as part ... more Sintered silver joint is a porous silver that bonds a semiconductor die to the substrate as part of the packaging process. Sintered Ag is one of the few possible bonding methods to fulfill the operating conditions of wide band-gap (WBG) power device technologies. We review the current technology development of sintered Ag as a bonding material from the perspective of patents filed by various stakeholders since late 1980s. This review addresses the formulation of sintered pastes (i.e., nano-Ag, hybrid Ag, and micron Ag fillers), innovations in the process and equipment to form this Ag joint. This review will provide the insights and confidence to engineers, scientists from universities and industry as well as investors who are developing and commercializing the sintered Ag as a bonding material for microelectronic packaging.
2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT), 2012
This paper documents the feasibility study of using micrometer-scale Ag paste as a lead-free (Pb-... more This paper documents the feasibility study of using micrometer-scale Ag paste as a lead-free (Pb-free) die attach material for microelectronic packaging. Currently, there is no viable Pb-free die attach in the market which can pass the reliability testing regimen. Sintered Ag was explored as an interconnect material because of its relatively low processing temperature and robust joint after sintered. This report suggests a possible route for using Ag paste as a Pb-free die attach by dispensing as per current production epoxy die attach. This feasibility study reports the mechanical integrity, electrical and reliability testing of a surface mount power package with four types of dispensable Ag pastes. Separate lots of this surface-mount power package with current die attach materials were also evaluated as controls. This paper is expected to be of interest to companies that are exploring alternative Pb-free die attach materials.
2016 IEEE 37th International Electronics Manufacturing Technology (IEMT) & 18th Electronics Materials and Packaging (EMAP) Conference
Sintered silver (Ag) is a porous silver attaching the semiconductor die to the microelectronic su... more Sintered silver (Ag) is a porous silver attaching the semiconductor die to the microelectronic substrates. The market sizes for sintered Ag are explored, and the relevant patents are analyzed at macro and micro-levels. At the macro-level, patenting activity moves to Stage 2 of the technology life-cycle “s-curve”. In stage 2, patenting slows down before the next surge in patenting, likely to be spurred by the wider adoption of wide band-gap semiconductor. The low profitability of sintered Ag also coincides with the available market research reports on the three major market of this technology, i.e., power module, power discrete technology and consumer integrated circuits. However, the patent owners are not abandoning their patents applications. Only eleven entities are co-filing patents related to sintered Ag based on 350 patents and patent applications analyzed here. Such trend suggests the nascent characteristics and continuing investment in this technology. At the micro-level, patenting addresses the following issues. Firstly, pressure assisted sintering is necessary and more reliable than pressureless sintering but the former requires additional process controls and capital investments than the latter. The current state of the art of sintered Ag joint also favours sintering in an ambient environment that oxidizes the substrate. This oxidation poses a delamination risk, and a reliability concern to the microelectronic packages. Lastly, sintered Ag paste favours sintering on the Ag or Au-metallized substrate that represents an additional cost to the customers.
We demonstrated theoretically the wave guiding of elastics waves in a two-dimensional (2D) phonon... more We demonstrated theoretically the wave guiding of elastics waves in a two-dimensional (2D) phononic crystal (PnC) slab. The simulation model based on the Finite Element Method (FEM) was used to calculate the dispersion relation of unit cells that shows a complete band gap between frequency, f=312–412 kHz. The supercell technique to simulate two waveguides size shows filtering frequencies between 365-397 kHz within the band gap. We discuss the frequency shift of the wave guide as a function of the defect size for the possibility of elastic wave filtering application. `
Silver sintering is used for bonding of semiconductor dies to the substrate as part of a power mo... more Silver sintering is used for bonding of semiconductor dies to the substrate as part of a power module/device packaging. Power-module consisting inverters and converters are used to manage the electric drive systems in the hybrids and electric vehicles (HEVs). Many pressure-sintering tools and processes have been patented to produce reliable sintered silver joints for these power applications, and those invented by Siemens, Infineon Technologies, Danfoss, and Valtion (VTT) are analyzed based on the Theory of Inventive Problem Solving (TRIZ) framework. The level of inventiveness for each patent is evaluated, and respective function analysis is conducted to understand the interactions of the components in each sintering tool. This paper is expected to be useful to engineers who are interested in understanding the evolutionary patterns of a technical system especially silver sintering tools
The role of sulfur and its synergistic effects with nitrogen moieties in mediating stem cell prol... more The role of sulfur and its synergistic effects with nitrogen moieties in mediating stem cell proliferation and differentiation has become of interest to the tissue engineering community due to chemical similarities with the glycosaminoglycans found in human tissues and cells. Glycosaminoglycans are biomolecules known to influence stem cell differentiation, but the roles of sulfur with different oxidation states on nitrogen-containing polymers have not been fully understood nor investigated. In this study, we used the plasma polymerization of 1,7-octadiene (ppOD), n-heptylamine (ppHA), ppHA grafted with vinyl-sulfonate via Michael-type addition (ppHA-SO3), thiophene (ppT), and ppT with air plasma treatment (ppT-air) to produce controlled amounts of nitrogen and sulfur moieties having different oxidation states, as confirmed by x-ray photoelectron spectroscopy. Assays of the proliferation and osteogenic activities of Wharton’s jelly mesenchymal stem cells (WJ-MSCs) showed the highest ...
Increase in hydrophilicity of the filtration membrane could attribute to the fouling reduction an... more Increase in hydrophilicity of the filtration membrane could attribute to the fouling reduction and overall filtration performance. In this study, we employ a surface modification on polyamide (PA) membrane by using plasma polymerization with acrylic acid as the precursor by varying the deposition time from 1 to 10 min to induce hydrophilic surface of the membrane without changing the bulk properties of PA membrane. Cross-flow filtration of humic acid using the modified PA membrane was conducted to measure permeates flux and rejection. We calculate the fouling tendencies of each membrane and the result indicates the best performance from sample with 7 min deposition time in terms of permeate flux, rejection and the lowest fouling tendencies. Therefore, this proposed technique could be useful to further improve the commercial filtration membrane; without changing the membrane fabrication process.
In this article, we report the finite element method (FEM) simulation of the suspended double-cla... more In this article, we report the finite element method (FEM) simulation of the suspended double-clamped graphene beam-based NEM switches with standard and perforated beam structures, to analyze the von Mises stress, the contour plot and the electrical field distribution by using FEM simulator provided by IntelliSuite and COMSOL software. This FEM numerical model is used to observe the scaling characteristics of the graphene beam-based NEM switch. The FEM results confirm that the von Mises stress value reduced by ~2–3% for every 0.1 µm increment of the standard graphene beam length. The introduction of perforation in the case of HL = 150 nm, HW = 100 nm and DL = 100 nm, further reduced the von Mises stress at the graphene beam end and the beam center by approximately ~20–35 and ~10–20%, respectively. These low values of von Mises stress along the graphene beam resulted in a lower probability of the device failure. In addition, the strong electrostatic force at the hole’s edges and beam's edges leads to a larger mechanical deflection at the edges compared to the beam center and it is consistent with the analysis of von Mises stress. The results presented here are expected to accelerate developments in the working dimension and parameter of the graphene NEM switch device fabrication for better mechanical reliability operation.
Sintered silver joint is a porous silver that bonds a semiconductor die to the substrate as part ... more Sintered silver joint is a porous silver that bonds a semiconductor die to the substrate as part of the packaging process. Sintered Ag is one of the few possible bonding methods to fulfill the operating conditions of wide band-gap (WBG) power device technologies. We review the current technology development of sintered Ag as a bonding material from the perspective of patents filed by various stakeholders since late 1980s. This review addresses the formulation of sintered pastes (i.e., nano-Ag, hybrid Ag, and micron Ag fillers), innovations in the process and equipment to form this Ag joint. This review will provide the insights and confidence to engineers, scientists from universities and industry as well as investors who are developing and commercializing the sintered Ag as a bonding material for microelectronic packaging.
2012 35th IEEE/CPMT International Electronics Manufacturing Technology Conference (IEMT), 2012
This paper documents the feasibility study of using micrometer-scale Ag paste as a lead-free (Pb-... more This paper documents the feasibility study of using micrometer-scale Ag paste as a lead-free (Pb-free) die attach material for microelectronic packaging. Currently, there is no viable Pb-free die attach in the market which can pass the reliability testing regimen. Sintered Ag was explored as an interconnect material because of its relatively low processing temperature and robust joint after sintered. This report suggests a possible route for using Ag paste as a Pb-free die attach by dispensing as per current production epoxy die attach. This feasibility study reports the mechanical integrity, electrical and reliability testing of a surface mount power package with four types of dispensable Ag pastes. Separate lots of this surface-mount power package with current die attach materials were also evaluated as controls. This paper is expected to be of interest to companies that are exploring alternative Pb-free die attach materials.
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