A quantitative view of flexible electronics

Jon Lawson

The latest Olympus application note details how observing in situ mechanical testing of flexible electronic devices with the Olympus LEXT OLS4100 confocal laser scanning microscope is providing valuable quantitative information for optimising interconnect design.

Breaking new ground in the development of flexible electronics, Dr Dario Gastaldi and his research group at the Politecnico di Milano (Milan, Italy), have employed the Olympus LEXT OLS4100 as an alternative to scanning electron microscopy (SEM). As part of their reliability testing system, confocal laser scanning microscopy provides valuable quantitative information, feeding back to optimise interconnect design in terms of both geometry and fabrication. This cutting edge research is available to view in a new online application note from Olympus.

Flexible electronic devices have a wealth of potential applications, from flexible phones to wearable chemical sensors. One design approach allowing such devices to withstand deformation is to overlay electrical components on a deformable substrate. These rigid components are connected via a flexible interconnect, and Dr Gastaldi’s research is looking to optimise interconnect design, employing in situ mechanical reliability testing to analyse device behaviour under strain. This approach requires a high-resolution observation technique, and while SEM was previously employed, it failed to allow precise quantification of out-of-plane deformation.

Replacing SEM with the Olympus LEXT OLS4100 confocal laser scanning microscope, Dr Gastaldi’s group has now benefited from many features, including the quantitative information from the height map and high lateral resolution. The LEXT OLS4100 delivers high precision optical metrology, and the researchers now have quantitative evidence supporting how particular geometries are more resistant to delamination, enhancing the design process through a numerical modelling system. In addition, crack formation can be followed in detail, and it has been shown that plasma treatment of polymers, while increasing adhesion may promote cracking. “I was impressed by the image quality, not to mention the quantitative information,” commented Dr Gastaldi. “The easy management of the LEXT allows us to focus our attention on our research.

Combining Olympus’ digital light microscopy technology with mechanical testing, the Olympus LEXT OLS4100 offers possibilities throughout a vast field of applications across all sectors of material sciences.