Temperature Stage Microscopy applied to help understand Electronic Packaging and Reliability

The Opto-Mechanics and Physical Reliability Laboratory at SUNY Binghamton is seeking to understand the electronic packaging and reliability using numerical and experimental methods. They use Digital Image Correlation (DIC), a non-contact optical deformation measurement technique which provides full field in plane and out of plane deformation with subpixel accuracy. This enables recognition of distinct features on the test surface based on the grey scale variation in an image and assigns coordinates to these features. The integer values of grey scale in these facets are recorded and the facet centres are tracked, in each successive pair of images, with accuracy of up to one hundredth of a pixel. Local displacements and strains are determined from the movement of the features relative to their initial coordinates.

When combined, the Linkam LTS420 heating/freezing stage and DIC are able to measure the in-plane and out-of-plane deformation at selected temperature ranges. Samples are prepared by applying black and white spray to the specimen. The sample is then placed inside the Linkam LTS420 and the field of view from the two DIC cameras' is made equal to the size of sample to be measured. Heating and cooling profiles are programmed via the T95-LinkPad controller and the sample response to heating or cooling is measured by the DIC cameras through the observation window in the top of the stage.

Speaking about the Linkam LTS420 system, user Charandeep Singh, a graduate student in the department, said: "Compared to the previous chamber we had been using, the Linkam is very efficient. It doesn't vibrate while heating and cooling. It has an impressive ramp rate and high/low maximum temperature range. It is easy to adjust the position of sample without opening the chamber as it is mounted on a glass slide."

The LTS420 is an easy to use, versatile heating and freezing stage. The stage consists of a large area temperature controlled element with a platinum resistor sensor embedded close to the surface for accurate temperature measurements. The sample is simply mounted on a standard microscope slide in direct contact with the heating element and can be manipulated 15mm in X and Y direction. The sample chamber has gas valves to purge with inert gas.