FASTR - Thermal Metrology Instrument

FASTR quantifies thermal conductivity, thermal boundary resistance (TBR), and volumetric heat capacity. These properties are extracted through a hybrid integration of SSTR (steady-state thermoreflectance) and FDTR (frequency-domain thermoreflectance).

FASTR and TDTR are both thermoreflectance techniques, but they handle a core limitation of transient thermoreflectance differently. In TDTR, thermal conductivity and volumetric heat capacity are correlated in the fit, so volumetric heat capacity is typically assumed from literature values. FASTR breaks that correlation. Its SSTR mode measures thermal conductivity at steady state, with no volumetric heat capacity in the analysis. With thermal conductivity fixed, FDTR can then resolve volumetric heat capacity on the same sample, so both properties are measured rather than one being assumed. FASTR also reaches deeper thermal penetration depths for accessing buried layers, and it runs as a turnkey, fully automated platform in place of a manually aligned, expert-run setup.

Yes. It supports film thicknesses from tens of nanometers to bulk (≥1 nm for thermal resistance, and ≥100 nm for thermal conductivity), and is well-suited for characterizing nanolaminates, interface stacks, and embedded layer systems.

FASTR can measure both cross-plane and in-plane thermal conductivity, depending on the sample configuration and measurement conditions.

Overall, FASTR’s directional thermal sensitivity is not fixed; it is determined by sample geometry, thickness, and substrate thermal properties, enabling flexible characterization of heat transport both parallel and perpendicular to the surface when the physics support it.

For example: it runs both modes sequentially for anisotropic materials like AlN: FDTR first for cross-plane conductivity and interface resistance, then SSTR for in-plane conductivity, giving the full directional picture that governs both heat extraction and lateral spreading in the actual device stack.

FASTR determines volumetric heat capacity using its Frequency-Domain Thermoreflectance (FDTR) measurement mode. FDTR applies a sinusoidally modulated laser heat source to the sample and measures the resulting temperature response as a function of modulation frequency.

By fitting the frequency-dependent amplitude and phase data to a heat-diffusion model, SSTR mode fixes thermal conductivity with no heat capacity in the analysis. FDTR mode then resolves volumetric heat capacity and interface resistance against that anchored value.

Yes, in most multilayer and bonded systems. As layers become thinner, thermal boundary resistance often dominates overall heat transport, which makes separating it from intrinsic layer conductivity both more important and more difficult. FASTR combines two modes to do this. FDTR sweeps the heating modulation frequency across several decades, changing the thermal penetration depth so the measurement becomes sensitive to different layers and interfaces at different frequencies. SSTR measures thermal conductivity independently, reducing the number of unknowns in the FDTR fit. Together, they resolve thermal boundary resistance within the stack rather than reporting a composite or “apparent” conductivity. For very thin layers, where a film and its interfaces respond as a single thermal resistance, a thickness series of samples may be needed to separate the two.

Materials with high thermal conductivity generate small temperature rises, which reduces signal sensitivity in conventional bulk steady-state methods such as heat flow meters and guarded hot plates. For thin films, FASTR uses FDTR, adjusting modulation frequency to control heat penetration depth and concentrate sensitivity on the layer of interest. For bulk materials, TOPS uses lock-in infrared thermography.

Compatible materials include metals, ceramics, semiconductors, polymer films, and composites.  Samples must be optically specular, and will be coated with a transducer to facilitate FASTR measurements.

Yes. Most measurements require deposition of a thin metal film as a thermoreflectance transducer. This layer enables accurate detection of surface temperature changes via laser reflectance.

FASTR includes a motorized XY stage with 150 mm × 150 mm max travel, supporting wafers, dies, or sectioned device materials.  Samples do not need to be precision-cut or rectangular; non-uniform or irregularly shaped coupons can be measured directly on the stage as long as they sit flat and fit within the stage travel.

Measurement limits depend on material properties and stack structure, not just thickness alone. Thin films below 10 microns, including bonded layers and thin bondlines, can be characterized when the measurement sensitivity is properly modeled. Unlike bulk steady-state methods that require large temperature gradients, advanced approaches are designed for thin geometries where traditional tools fail to resolve meaningful signals.

Measurement time per spot depends on the FASTR measurement mode. SSTR measurements typically complete in under 1 second per location, while FDTR measurements generally take under 90 seconds per location, depending on the material and its thermal response. For thermal property imaging, it only takes 20 ms per pixel; the total measurement time scales linearly with the number of measurement spots.

Yes. The FASTR platform includes automated batch measurement protocols for up to 30 pre-positioned samples, improving throughput in R&D or QC environments.

Yes. Mapping routines can be scripted via software to define X-Y grids, enabling thermal property mapping with micrometer-level control.

No. FASTR is built for accessibility. It includes automated alignment, laser path optimization, and intuitive software, reducing user variability.

Dynamic repeatability is <0.5%.

Results are checked against well-characterized reference materials (HPFS 7980 fused silica, thermal oxide on Si), with a reference sample built into the stage. The system is regularly used in blind sample validation, customer demos, and third-party verification. Please check this page as well to see our Thermal Conductivity Database for SSTR mode.

LFA measures thermal diffusivity on a bulk, homogeneous sample, then combines it with separately measured density and specific heat to calculate thermal conductivity. It is a well-established method for thick, uniform materials. FASTR takes a different approach suited to layered samples. Its SSTR mode measures thermal conductivity from the steady-state relationship between absorbed laser power and surface temperature rise, and FDTR then resolves thermal boundary resistance and volumetric heat capacity through model fitting. The analysis requires film thickness and substrate thermal conductivity, inputs that are routinely characterized in thin film work. It does not require density or specific heat of the film itself, which are difficult to obtain for thin films, and it does not require a bulk-equivalent sample. For bulk, homogeneous materials, LFA remains a proven method. For thin films, multilayer stacks, and buried interfaces, where LFA’s bulk assumptions no longer hold, FASTR is designed for that territory.

It supports workflows in:

• Semiconductor packaging
• Thin films
• Nanoengineered coatings
• Power electronics
• Low-dimensional or anisotropic materials

Yes. FASTR enables high-throughput testing, making it suitable for formulation screening, layer stack optimization, or interface engineering.

Yes. The system is deployed in university labs, national labs, and industrial R&D teams, particularly those working on thermal metrology, device reliability, and novel materials.

Low. Most users are able to begin productive testing after minimal training. The software includes guided procedures for calibration, alignment, and data analysis.