Sugar-assisted transfer printing of K-Type TFTCs onto fiberglass laminate

Sammanfattning

As we have become more modern, we have become more reliant on electronic devices, containing micro- and nanosize components. Coming along with more advanced and complex manufacturing methods have become more advanced, they bear plenty of inconveniences, most commonly the impossibility of printing on surfaces with arbitrary surface curvature. This issue is resolved by the reflow transfer printing method, where the reflow ability of sugar is exploited to adapt to substrates with arbitrary curvature. In the present project, the reflow transfer printing was studied with K-type thin film thermocouples (TFTCs) on fiberglass laminate substrates. Two differently manufactured TFTC samples were studied, where a 5 nm nickel layer was pre-deposited, once in a different and once in the same depositing process. During the experimental phase, several errors with damage and adhesion of the thin films were encountered. It turned out that the samples suffer from mechanical or chemical changes during the coating or baking step. Likely, stress on the thin film due sugar dehydration was the dominant aspect for component deformation and breaking. Additionally, samples respective to separate deposition processes witnessed chemical changes after NiO formation between nickel/nickel alloy interfaces, due to stronger polar bond formation. It is suggested that internal residual stresses have additional contribution on observed delamination of the thin films. Regardless, six transfers were completed with various amounts of components transferred, as the TFTCs were subject to displacement and breaking. Still, the method has proven itself to be a functioning method to transfer alumel-chromel TFTCs onto non-flat composite surfaces, creating a base for a sustainable and innovative component transfer method.