Analysis of thermal parameters and factors acting on thermal conduction of low‐k films

Abstract

The thermal properties of a silicon oxide‐based low‐k film and a thermally oxidized silicon film were investigated using the 3‐omega and laser thermo‐reflectance (LTR) methods. Thermal conductivity and effusivity were successfully estimated by the 3‐omega and LTR methods, respectively. It was confirmed that the combination of thermal effusivity and conductivity can successfully provide the heat capacity and thermal diffusivity of the films. The thermal parameters thus obtained suggested that the lower thermal conductivity of the examined low‐k film comes mainly from the rather low level of thermal diffusivity. Based on an analysis of the X‐ray diffraction profiles of the films, it was found that the low thermal diffusivity of the low‐k film can be attributed to the discontinuity of the network structure of their clusters. The heat resistance at the interface between the film and Si substrate was also evaluated. We found that the low‐k film exhibited, interestingly, negative interfacial heat resistance, although interfacial heat resistance should have a positive value in general. In order to determine the origin of the negative interfacial heat resistance, the interface state of the films was analyzed in detail on the basis of X‐ray reflectivity (XRR) measurements. The XRR results showed clearly that a thin, high‐density layer was present at the interface of the low‐k films. This high‐density layer presumably promoted heat flow to the substrate, resulting in the apparent negative interfacial heat resistance. Copyright © 2008 John Wiley & Sons, Ltd.

Pore-Confined Polymers Enhance the Thermal Conductivity of Polymer Nanocomposites

“…The total uncertainties are obtained by adding the systematic uncertainties and experimental uncertainties, which are shown as error bars in the figure. The k of the unfilled nanoporous Et-OCS is 0.19 ± 0.02 W/(mK), which is lower than reported values of ∼0.3 W/mK for similar oxycarbosilane materials due to the large porous volume in our sample. , The k of PS-filled Et-OCS nanocomposites is larger than that of the unfilled Et-OCS matrix because of increased density and heat capacity. Moreover, nanocomposites with confined PS fillers show larger k than nanocomposites with bulk-like PS fillers.…”

“…The detailed relationship between R ee and M w of PS can be directly found in Figure 2 oxycarbosilane materials due to the large porous volume in our sample. 23,24 The k of PS-filled Et-OCS nanocomposites is larger than that of the unfilled Et-OCS matrix because of increased density and heat capacity. Moreover, nanocomposites with confined PS fillers show larger k than nanocomposites with bulk-like PS fillers.…”

Dielectric Barrier, Etch Stop, and Metal Capping Materials for State of the Art and beyond Metal Interconnects

“…Bulk Cu has a high reported thermal conductivity of ∼400 W/mK. 223 In comparison, the thermal conductivity of Si 3 N 4 and SiO 2 are typically reported to be lower at 0.5-1.0 W/mK 223,224 and 1.0-1.5 W/mK, [225][226][227][228][229] respectively. Typical low-k ILD a-SiOC:H dielectrics have even lower thermal conductivities of 0.01-0.4 W/mK that similarly scale with decreases in k as with mechanical properties.…”

Probing of Thermal Transport in 50 nm Thick PbTe Nanocrystal Films by Time-Domain Thermoreflectance

“…We have estimated the thermal effusivity of the PbTe NCs and SiO 2 to be ≈1.1 × 10 3 and ≈1.5 × 10 3 J s –1/2 m –2 K –2 , respectively. Thermal silicon dioxide film was reported to be 1.42 × 10 3 J s –1/2 m –2 K –2 , justifying the analytical procedure and the estimated thermal effusivity values. By using density and specific heat values of 8.16 g cm –3 and 156 J kg –1 K –1 , respectively, we have estimated the measured thermal conductivity to be 0.9 W m –1 K –1 at 300 K. It should be noted that the estimated thermal conductivity can have a relatively large total error of ≈30%.…”