The state of analysis techniques, including defect analysis of joints, adhesion, and assembly parts.

We would like to present the results of strain measurements conducted by attaching strain gauges and thermometers to the surfaces of power modules, both in the mounted state on a circuit board and in the unmounted state. In the mounted module, a slight delay in temperature change was observed, and correspondingly, the change in strain also appeared to be delayed. This is believed to be due to the slower transfer of heat to the module when it is mounted. At Aites, we conduct temperature cycle tests and temperature-humidity cycle tests, during which we can simultaneously measure the strain occurring in the mounted components. Please feel free to consult with us.

We will introduce an example of the analysis of compounds formed at the interface between Sn-Ag-Cu solder and NiP pads. At the interface of NiP pads and Sn-Ag-Cu solder, compounds such as (Ni,Cu)3Sn4 and (Cu,Ni)6Sn5 grow, and surface analysis using EDX shows the distribution of Ni, Cu, and Sn within these compounds. The EBSD method is a technique that analyzes based on the crystallographic information of the sample. By combining it with elemental analysis using EDX, it is possible to estimate the composition, and in some cases, it may be possible to analyze using crystallographic data for Ni3Sn4 and Cu6Sn5 as substitutes.

We would like to introduce an example of cross-sectional observation of mounted components conducted by our company. Using commercially available computer circuit boards, we observed the solder joints of mounted components and the internal structure of the components with a metal microscope. The observation modes of the metal microscope include bright field observation, dark field observation, and polarized light observation, among others. Additionally, there are observations using transmitted light, and the observation mode is selected according to the sample. By conducting cross-sectional observations before and after reliability testing, we can evaluate the reliability of the product. When observing, it is important to select an appropriate "observation mode" to clearly capture the condition of the solder joint interface and defects such as cracks.

We will introduce examples of cross-sectional observations of various components mounted on a board called an organic substrate. Inside various electronic devices around us, there are substrates equipped with electronic components. When observing the mounted substrate, you can see that numerous components are tightly soldered together. It is necessary to verify that these components are properly joined, as they will not function correctly otherwise. Please contact us if you are considering observations before and after reliability testing or cross-sectional observations.