Analysis of mechanical performance of silver inkjet-printed structures

We report the mechanical performance of the structure of sintered silver ink used in inkjet printing, having a particle size of 3-7 nm. Tensile adhesion pull-off testing together with the optimized related ISO and ASTM industrial standards were used. Adhesion testing of samples was performed at room temperature and in 50% relative humidity. Sintered silver ink adhesion patterns were inkjet-printed onto several substrates, i.e. PEN (Polyethylene Naphthalate), PI (Polyimide), and LCP (Liquid Crystal Polymer). To control the ink spreading surface treatment material was used and its effect on adhesion performance was investigated. To determine the effect of various sintering processes on adhesion performance, two different sintering procedures, at 250degC for 30 minutes and at 220degC for 60 minutes, were used. After the results from the initial adhesion tests had been recorded, new adhesion test samples were prepared and placed in the humidity chamber to subject them to moisture, during which the JEDEC Standard JESD22-A101-B Steady State Temperature Humidity Bias Life Test was used with a temperature of 85degC in 85% relative humidity. After this soaking, the mechanical performance of the test samples was investigated by adhesion pull-off testing and the findings noted. In addition, the test samples were subjected to tension tests using a DMA (Dynamic Mechanical Analysis) device in order to analyze the effect of the dynamic mechanical stress on them. The DMA tension tests were performed at a temperature continuously increasing from -60degC to 100degC. This testing was done on various inkjet-printed silver patterns. In this paper, the results of adhesion pull-off and of DMA testing are presented separately and the effect of each parameter on the mechanical performance of the inkjet-printed silver patterns is discussed.