ElectroStatic Discharge Fault Localization by Laser Probing

This paper deals with the localization of ElectroStatic Discharge (ESD) failure in digital circuits by thermoelastic laser probing. After ESD simulation on a NAND TTL LS circuit, the device was scanned using an interferometric laser probe. In sine wave regime the surface displacement induced by the leakage current was recorded. The heat source acts as a hot spot inducing a thermal expansion in its neighborhood. This expansion, whose magnitude varies from several hundred to a few picometers (10⁻¹²m), allows the localization of the leakage region corresponding to the ESD failure area.     

Comparison of thermoreflectance and scanning thermal microscopy for microelectronic device temperature variation imaging: Calibration and resolution issues

We have studied temperature variations on two submicrometric dissipative structures with two different techniques. On one hand, we have used a thermoreflectance imaging technique which is a well-known non contact optical method to evaluate temperature variations but whose spatial resolution is limited by diffraction. On the other hand, we have used a scanning thermal microscope (SThM) to study the thermal behaviour of these small dissipative structures. We present qualitative results obtained by both methods and we compare their advantages and drawbacks in terms of calibration and spatial resolution for thermal measurements on microelectronic devices. In particular, we show how the thermoreflectance coefficient can become an advantage to enhance the image contrast and favour the spatial resolution.     

Temperature variation mapping of a microelectromechanical system by thermoreflectance imaging

We present in this letter a cost effective noncontact imaging technique well adapted to measure the temperature variations on microelectromechanical systems. The setup is tested on a microheater constituted of a polysilicon resistor deposited on a dielectric membrane. Results concerning the temperature variations of this device are compared on one hand with simulation predictions, and on the other hand with thermoreflectance point measurements. From thermoreflectance images, we also estimate the values of the thermoreflectance coefficients of the polysilicon and of the dielectric.     

Thermoreflectance calibration procedure on a laser diode: application to catastrophic optical facet damage analysis

In this letter, we present a thermoreflectance setup specially designed for the study of the temperature variations of the output facet of a laser diode. Indeed, the temperature of the laser diode is controlled by a Peltier element and the device under test is used as a temperature sensor. We propose a calibration procedure based on electrical measurements combined with optical ones; it leads to the determination of thermoreflectance coefficients and then to absolute temperature variations on a running laser diode. We can hence ensure a proper running of the diode and avoid its catastrophic optical facet damage.     

Laser scanning thermoreflectance imaging system using galvanometric mirrors for temperature measurements of microelectronic devices

We present a thermoreflectance imaging system using a focused laser sweeping the device under test with a scanner made of galvanometric mirrors. We first show that the spatial resolution of this setup is submicrometric, which makes it adapted to microelectronic thermal measurements. Then, we studied qualitative temperature variations on two dissipative structures constituted of thin (0.35 microm) dissipative resistors, the distance between two resistors being equal to 0.8 or 10 microm. This technique combines sensitivity and speed: it is faster than a point classical thermoreflectance technique and, in addition, more sensitive than a charge-coupled device thermoreflectance imaging technique.     

Nonlinearity characterization of temperature sensing systems for integrated circuit testing by intermodulation products monitoring

This work presents an alternative characterization strategy to quantify the nonlinear behavior of temperature sensing systems. The proposed approach relies on measuring the temperature under thermal sinusoidal steady state and observing the intermodulation products that are generated within the sensing system itself due to its nonlinear temperature-output voltage characteristics. From such intermodulation products, second-order interception points can be calculated as a figure of merit of the measuring system nonlinear behavior. In this scenario, the present work first shows a theoretical analysis. Second, it reports the experimental results obtained with three thermal sensing techniques used in integrated circuits.     

Strain energy imaging of a power MOS transistor using speckle interferometry

Mechanical characterization of electronic devices is often quite uneasy; most of the techniques used require a contact with the sample under study. In this paper, we propose an optical noncontact interferometric imaging method to study the thermomechanical behavior of running devices, and in particular, to deduce the corresponding elastic strain energy. This analysis will permit us to localize the zones of fragility of the device. Results obtained on a power MOS transistor to detect the region of maximum elastic strain energy are presented. It is in particular adapted in microelectronics applications to detect stress accumulation due to dilation coefficient mismatches when assembling microchips.