Model of Shear Viscosity for Underfill Flows
نویسندگان
چکیده
To analyze the flow of an underfill encapsulant between the chip and substrate, a shear viscosity model is needed. This paper presents a model of the viscosity for the flow of slurry between two parallel walls, which is a typical situation found in electronic packaging applications. It is postulated that the flow behavior of a dense slurry is governed by the particle-particle and particle-wall interactions. Fluid film lubrication theory is used to find the unit solutions of interaction between two particles. The unit solutions are applied to the simple case of slurry flow densely packed with neutrally buoyant particles. The dependence of the effective viscosity of the slurry on packing parameters is revealed.
منابع مشابه
Calculation of the relativistic bulk tensor and shear tensor of relativistic accretion flows in the Kerr metric.
In this paper, we calculate the relativistic bulk tensor and shear tensor of the relativistic accretion ows in the Kerr metric, overall and without any approximation. We obtain the relations of all components of the relativistic bulk and shear tensor in terms of components of four-velocity and its derivatives, Christoffel symbols and metric components in the BLF. Then, these components are deri...
متن کاملNumerical Simulation of Separation Bubble on Elliptic Cylinders Using Three-equation k-? Turbulence Model
Occurrence of laminar separation bubbles on solid walls of an elliptic cylinder has been simulated using a recently developed transitional model for boundary layer flows. Computational method is based on the solution of the Reynolds averaged Navier-Stokes (RANS) equations and the eddy-viscosity concept. Transitional model tries to simulate streamwise fluctuations, induced by freestream turbulen...
متن کاملDynamic Filling Characteristics of a Capillary Driven Underfill Process in Flip-Chip Packaging
This study investigates the dynamic flow characteristics of capillary-driven underfill flows in a flip chip package. In the present study, we used two different bump arrays using Sn-2.5Ag solder balls with 80 mm and 100 mm diameters on commercially available flip chips, which have different pitches of 150 mm and 180 mm. First, we measured surface tension and viscosity with a rheometer and a ten...
متن کاملDouble-Layer No-Flow Underfill Materials and Process
The no-flow underfill has been invented and practiced in the industry for a few years. However, due to the interfering of silica fillers with solder joint formation, most no-flow underfills are not filled with silica fillers and hence have a high coefficient of thermal expansion (CTE), which is undesirable for high reliability. In a novel invention, a double-layer no-flow underfill is implement...
متن کاملAXIAL FLOW IN A ROTATIONAL COAXIAL RHEOMETER SYSTEM 1. BINGHAM PLASTIC
A mathematical analysis has been carried out for the axial flow of a Bingham plastic fluid, in the Concentric Cylinder Viscometer which consists of a cylindrical sample holder (the cup) and a cylindrical spindle (the bob) coaxial with the cup. The fluid to be tested flows through the annular gap of the cup and the bob system, sheared by the rotation of the inner cylinder, while the outer cy...
متن کامل