Microfabricated sensor platform with through-glass vias for bidirectional 3-omega thermal characterization of solid and liquid samples

TL;DR

This paper introduces a microfabricated, all-electrical platform utilizing through-glass vias and a thin dielectric layer for rapid, accurate thermal property measurements of various solid and liquid samples using the bidirectional 3-omega method.

Contribution

It presents a novel measurement platform combining through-glass vias and atomic layer deposited passivation for versatile, rapid thermal characterization of small-volume samples.

Findings

Accurate thermal conductivity measurements of diverse materials.

Platform works with small sample volumes (~0.02 mm²).

Results align with literature and steady-state methods.

Abstract

A novel microfabricated, all-electrical measurement platform is presented for a direct, accurate and rapid determination of the thermal conductivity and diffusivity of liquid and solid materials. The measurement approach is based on the bidirectional 3-omega method. The platform is composed of glass substrates on which sensor structures and a very thin dielectric nanolaminate passivation layer are fabricated. Using through-glass vias for contacting the sensors from the chip back side leaves the top side of the platform free for deposition, manipulation and optical inspection of the sample during 3-omega measurements. The thin passivation layer, which is deposited by atomic layer deposition on the platform surface, provides superior chemical resistance and allows for the measurement of electrically conductive samples, while maintaining the conditions for a simple thermal analysis. We demonstrate the measurement of thermal conductivities of borosilicate glass, pure water, glycerol, 2-propanol, PDMS, cured epoxy, and heat-sink compounds. The results compare well with both literature values and values obtained with the steady-state divided bar method. Small sample volumes (~0.02 mm$^2$) suffice for accurate measurements using the platform, allowing rapid temperature-dependent measurements of thermal properties, which can be useful for the development, optimization and quality testing of many materials, such as liquids, gels, pastes and solids.