Accelerated Thermal Cycling Lab Report

In this chapter, the accelerated thermal cycling experiment will be demonstrated with detail in terms of the test boards, the thermal chambers and their temperature profiles.

4.0 Thermal Chambers and Boarding Testing
The test boards were tested and provided by Auburn University. With the experiment utilized 4 sets of 9 copper core test boards each containing electronic packages mounted on the front and rear side of the boards. show the various test boards, the identification code shows CCA073-081, CCA010-018, CCA028-036, and CCA019- 027 respectively to each board in Figure 4.1, Figure 4.2, Figure 4.3 and Figure 4.4. The test boards used were 254mm x 190.4mm with various electronic packages on each side. The electronic packages mounted to
Each of the three chambers were to be set up with different temperature profiles, -55°C to 125°C (TC2), 3°C to 100°C (TC3), and -20°C to 60°C (TC4). By make sure the thermal chambers’ profiles were accurate, a thermal profiler was used. Each chamber contained three thermal couples during the Slim KIC-II Thermal Profiler and Software profiling. The KIC software allows the user to watch the temperature vs. time plot over the entire thermal cycle.

4.1 Temperature vs Time Graph Plotting Results
The thermal profile shown in Figure 4.5 has been used for test boards CCA010-018 and CCA 073-081 in order to experimentally determine solder joint reliability in various electronic packages in harsh environments, -55°C to 125°C. This temperature range is used for military and defence companies and is deemed “harsh environment” for electronic packaging. This cycle starts at room temperature (25°C) and has a 30 minutes dwell at the extreme temperatures of -55°C and 125°C and the ramp rate is 3°C/min from the hot extreme to the cold extreme, and 4°C/min. from the cold extreme to the
Several modelling methodologies have been developed and used over the period of time, each having its own merits and demerits. Both 2-D (two dimensional) and 3-D (three dimensional) models have been used for the analysis. Usually 3-D models have been shown to give better accuracy and more realistic results as compared to the 2-D models. Depending upon the geometric and material symmetry of the actual package different configurations of 3-D models like full-scale models 1/4th or 1/8th symmetry models and diagonal slice models [8]. Use of 3-D diagonal slice model configuration is preferred over the other configurations for the fully symmetric packages due to its computational efficiency and ability to capture true boundary conditions. Various other parameters such as material non-linearity, element type, shape and size also affect the simulation