Bond Pad Effects on Steady State Thermal Conductivity Measurement Using Suspended Micromachined Test Structures

2007 ◽  
Author(s):  
Leslie M. Phinney ◽  
Edward S. Piekos ◽  
Jaron D. Kuppers
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Joule Heating ◽  
Conductivity Measurement ◽  
Test Element ◽  
Heating Effects ◽  
Temperature Boundary ◽  
Bond Pads ◽  
State Resistance ◽  
Heat Sink Temperature

This study examines the effects of bond pads on the measurement of thermal conductivity for micromachined polycrystalline silicon using suspended test structures and a steady state resistance method. Bond pad heating can invalidate the assumption of constant temperature boundary conditions used for data analysis. Bond pad temperatures above the heat sink temperature arise from conduction out of the bridge test element and Joule heating in the bond pad. Simulations results determined correction factors for the electrical resistance offset, Joule heating effects in the beam, and Joule heating in the bond pads. Fillets at the base of the beam reduce the effect of bond pad heating until they become too large.

Thermal Conductivity Measurements of Thin Aluminum Layers Using Steady State Joule Heating and Electrical Resistance Thermometry in Suspended Bridges

2003 ◽  
Author(s):  
J. Reifenberg ◽  
R. England Voss ◽  
P. Rao ◽  
W. Schmitt ◽  
Y. Yang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Joule Heating ◽  
Electrical Resistance ◽  
Room Temperature ◽  
Aluminum Film ◽  
Thin Metallic Film ◽  
Thin Aluminum ◽  
Film Layer ◽  
Resistance Thermometry

Thin metallic film layers are extensively used as the constituents of the micro-devices. The reliability of these devices, therefore, strongly depends on the thermal behavior of such film layers. Aluminum thin film layers are of particular interest in this respect. The lateral thermal conductivity of the aluminum film layers is measured, using the steady state electrical Joule heating and electrical resistance thermometry technique. Aluminum suspended microbridges of identical thicknesses (500 nm) and variable widths (16 to 18 μm) and/or lengths (200 to 500 μm) are fabricated, using conventional microfabrication processes. The lateral thermal conductivity of the 500 nm thick Aluminum film layer was found to be k = 174 ± 13 Wm−1 K−1, at room temperature (300 K).

Comparative Radial Heat Flow Method for Thermal Conductivity Measurement of Liquids

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Ananth S. Iyengar ◽  
Alexis R. Abramson
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Heat Flow ◽  
Comparative Method ◽  
Conductivity Measurement ◽  
Test Fluid ◽  
Flow Method ◽  
Radial Heat Flow ◽  
Water Glycerol ◽  
Radial Heat

A steady state thermal conductivity measuring setup based on the comparative radial heat flow method is presented. The setup consists of a pair of coaxial cylinders as its main components, with test fluid placed in the annular space between these cylinders with water tight cover plates at the top and bottom of the cylinders. Experiment involves heating the coil at the concentric-center of the inner cylinder; steady state data are acquired for the calculation of the thermal conductivity. Thermal conductivity is calculated by comparing the radial heat flow between the cylinders and the test fluid (comparative method). Thermal conductivity of water, glycerol, and ethylene glycol was measured for varying temperatures and is in good agreement with the published thermal conductivity values in literature.

scholarly journals Measurements of Thermal Conductivity of LWC Cement Composites Using Simplified Laboratory Scale Method

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1351
Author(s):  
Marzena Kurpińska ◽  
Jarosław Karwacki ◽  
Artur Maurin ◽  
Marek Kin
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Foam Glass ◽  
Conductivity Measurement ◽  
Contact Layer ◽  
Material Research ◽  
Cement Composites ◽  
Measuring Device ◽  
Suitable Material ◽  
Transient Methods

The implementation of low-energy construction includes aspects related to technological and material research regarding thermal insulation. New solutions are sought, firstly, to reduce heat losses and, secondly, to improve the environment conditions in isolated rooms. The effective heat resistance of insulating materials is inversely proportional to temperature and humidity. Cement composites filled with lightweight artificial aggregates may be a suitable material. Selecting a proper method for measuring the thermal conductivity of concrete is important to achieve accurate values for calculating the energy consumption of buildings. The steady state and transient methods are considered the two main thermal conductivity measurement approaches. Steady state is a constant heat transfer, whereby the temperature or heat flow is time independent. In the transient method, temperature changes over time. Most researchers have measured the conductivity of cement-based materials based on transient methods. The availability and cost of equipment, time for experimental measurements and measurement ability for moist specimens may be some of the reasons for using this method. However, considering the accuracy of the measurements, the steady state methods are more reliable, especially for testing dry materials. Four types of composites were investigated that differed in filler: natural aggregate, sintered fly ash filler, sintered clay and granular foam glass aggregate. The method of preparing the samples for testing is especially important for the obtained results. The samples, with a specific surface roughness, will show a lower coefficient of thermal conductivity by 20–30%; therefore, the selection of the type of contact layer between the plate of the measuring device and the sample is of particular importance.

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