MEMS (micro-electro-mechanical systems) are combining a variety of technologies. Due to the new challenges for the connected world the number of MEMS needed for 5G, autonomous driving, Internet of Things, microfluidics and mobile devices will explode over the next years. MEMS are one of the mega trends for the industry. MEMS are produced on wafers with diverse materials ranging from silicon and glass to epoxy and metals. Thus, often they contain non-standard material combinations and are more challenging for process control tools.
Due to the ability of Confovis to measure 3D surfaces independent from the material the WAFERinspect measuring systems are the future process control and metrology tools.
MEMS accomplish higher reliability rates rather than discrete sensors thanks to the elimination of interconnections and wires. MEMS also benefit from simpler physical effects and quick process times.
Nevertheless, MEMS need to get checked for defects (defect inspection) through the entire process. Also, structures need to get measured in 3D and 2D to assure that requirements based on design rules are met and that there are no process excursions leading to failures. The key strength of Confovis over other confocal instruments is the 3D resolution and accuracy. It comes close to AFM tools (Atomic Force Microscopes) but is at least 100 times faster.
The advantage over chromatic confocal or white light interferometric sensors is the ability to measure challenging material combinations, such as copper and passivation layers, chrome on glass, epoxy and gold.
Defect inspection proves to be a challenge and is often cost-intensive on wafers with very different structures and a required resolution of less than 1µ. Thanks to using microscope optics, the optical measurement systems from Confovis are in a position to analyze defects on the entire wafer surface not only as a large image with shading correction, but also „die-by-die“. Cracks in deeper layers, as an example, can be detected in multi-layered structures by searching the 3D-image stack for defects in z-direction.
Due to the integration of defect inspection in combination with the high-resolution metrology tool WAFERinspect defects and dimensional deviations can not only get detected, but once found get measured in nanometer scale. The communication with the host follows SECS/GEM. MEMS manufacturing processes require a variety of handling solutions. Our partner company Mechatronic is experienced in handling glass, thin and high warped wafers.
Confovis is capable to assure an accuracy of 3nm and repeatability of 4nm @ 3 sigma (based on a certified step height of 50 nm). Also, multiple angles in multiple directions can get measured with the 3D confocal unit which is the core strength of Confovis.
