Vithyacharan Retnasamy

Wire Bond Shear Test Simulation on Sharp Groove Surface Bond Pad

Wire bonding process is first level interconnection technology used in the semiconductor packaging industry. The wire bond shear tests are used in the industry to examine the bond strength and reliability of the bonded wires. Hence, in this study thesimulation on wire bond shear test is performed on a sharp groove surface bond pad. ANSYS ver 11 was used to perform the simulation. The stress response of the bonded wires are investigated.The effects of three wire materials gold(Au), aluminum(Al) and copper(Cu) on the stress response during shear test were examined. The simulation results showed that copper wire bond induces highest stress and gold wire exhibits the least stress response.

FDTD analysis of structured metallic nanohole films for LSPR-based biosensor

We numerically investigated 3-dimensional (3D) sub-wavelength structured metallic nanohole films with various thicknesses using wavelength interrogation technique. The reflectivity and full-width at half maximum (FWHM) of the localized surface plasmon resonance (LSPR) spectra was calculated using finite-difference time domain (FDTD) method. Results showed that a 100nm-thick silver nanohole gave higher reflectivity of 92% at the resonance wavelength of 644nm. Silver, copper and aluminum structured thin films showed only a small difference in the reflectivity spectra for various metallic film thicknesses whereas gold thin films showed a reflectivity decrease as the film thickness was increased. However, all four types of metallic nanohole films exhibited increment in FWHM (broader curve) and the resonance wavelength was red-shifted as the film thicknesses were decreased.

Finite element analysis of thermal distributions of solder ball in flip chip ball grid array using ABAQUS

Purpose – The increased use recently of area‐array technology in electronic packaging has similarly increased the importance of predicting the thermal distribution of area‐array solder interconnection. As the interconnection technology for flip chip package is getting finer and smaller, it is extremely difficult to obtain the accurate values of thermal stresses by direct experimental measurements. Different types of solder bumps used for interconnection would also influence the thermal distribution within the package. Because the solder balls are too small for direct measurement of their stresses, finite element method (FEM) was used for obtaining the stresses instead.Design/methodology/approach – This paper will discuss the results of the thermal stress distribution using numerical method via ABAQUS software. The variation of the thermal stress distribution with the temperature gradient model was evaluated to study the effects of the different material thermal conductivity of solder bumps used. A detaile...

Polymer Core BGA Stress Analysis at Minimal Vertical Loading

Ball grid array is an interconnection method widely used in the electronic packaging industry. The reliability of the solder ball is being improved by introducing new materials for the solder ball. In this study, the stress response of BGA solder ball during minimum vertical loading is analyzed through simulation. The stress response between two types of solder ball, Normal BGA and Micropearl BGA are compared. The Micropearl BGA is a solder ball which contains polymer core. The vertical loading forces used were 1N and 3N. A commercial computational software ANSYS was used for the simulation. The simulation results showed that the Normal BGA exhibited higher stress response.

5mm X 5mm Copper-Diamond Composite Slug Stress Evaluation on LED

Light-emitting diodes (LEDs), have materialized as an innovative light source which features energy saving properties, good optical performance and efficacy which is added advantage over orthodox lighting systems. However, the efficacy of the LED is influenced by heat generated at the junction of the LED. Hence, in this study, the thermal and stress analysis of single chip LED package with copper diamond heat slug with dimension of 5mm x 5mm x 1mm was carried out through simulation under natural convection condition. Input power of 0.1W and 1W were applied to the single chip LED model. Result of the simulation indicates that at input power 1W, junction temperature of 107.02 °C and stress of 104.59 MPa were obtained.

Wire Bond Shear Test Simulation on Hemispherical Surface Bond Pad

Wire bonding process is an interconnection method adopted in the semiconductor packaging manufactory. One of the method used to assess the reliability and bond strength of the bonded wires are wire bond shear test .In this study, simulation on wire bond shear test is done to evaluate the stress response of the bonded wire when sheared on a hemispherical surface bond pad. The contrast between three types of wire material:gold(Au), aluminum(Al) and copper(Cu) were carry out to examine the effects of wire material on the stress response of bonded wire during wire bond shear test. The simulation results showed that copper wire bond induces highest stress and gold wire exhibits the least stress response.

Shear Ram Height Investigation for Gold Wire Bond Shear Test

This paper presents the simulation of gold wire bond shear test. The stress and strain response of the gold ball bond during wire bond shear was examined. The simulation was done using a A 3D non-linear finite element model. The effects of the shear ram height on the stress and strain response of the gold ball bond were investigated. The results of the simulation confirms that shear ram height has a significant effect on the von mises stress and equivalent strain response of the gold ball bond during wire bond shear test.

Solid State Lighting Stress and Junction Temperature Evaluation on Operating Power

LEDs are being utilized as lighting source due to its superior advantages over incandescent lamps in terms of higher efficiency, brighter light emission and longer lifetime. However, the reliability and efficiency of the LED is dependent on the junction temperature of the LED chip. Hence, the heat dissipation of single chip LED package with aluminum heat slug was investigated through simulation in this study .The heat dissipation was evaluated in terms of junction temperature. The single chip LED was powered with input power of 0.1W and 1W. The Von Mises stress of the LED chip at both input power was evaluated. The maximum junction temperature of the LED at steady state is 119.43°C at input power of 1W.

High Power LED Thermal and Stress Simulation on Copper Slug

High power LED are captivating attention due to its cogent impacts on lighting industry in terms of efficacy, low power consumption, long lifetime and miniature physical size. Nonetheless, the efficiency and reliability of the LED is signified by the junction temperature. This work demonstrates the thermal and stress simulation of single chip LED package with 1mm x1mm x 1mm copper heat slug. The simulation was performed using Ansys version 11. The GaN LED chip was powered with input power of 0.1 W and 1 W. The simulation outcome exhibited that at the maximum junction temperature and stress of the LED chip were 115.81°C and 221.56MPa correspondingly for input power of 1W.

Stress and Temperature Simulation Using Copper-Diamond Composite Slug

A revolution to illumination industry, the high power light emitting diodes, LEDs have significant dominance in terms of optical performance, low power consumption and superior reliability over conventional lights. In spite of that the junction temperature of the LED is an imperative aspect which manipulates the consistency of the LED. This study discusses the thermal and stress analysis of single chip LED package with copper diamond heat slug. The simulation was carried out using Ansys version 11. In this simulation, input power of 0.1W and 1W were applied to the LED chip. The key findings of this study exhibited that the max junction temperature of 113.13 °C and stress of 116.36 MPa were gained.