Feasibility study for a high throughput multiprobe Rapid Probe Microscope system

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Production of semiconductor Integrated Circuits (IC), or silicon chips is a £320 billion industry that has delivered exponential scaling in functionality, energy consumption, and cost per function. This market underpins the £3.7 trillion technology sector and enabled introduction of new technologies such as smart phones, 5G networks, and artificial Intelligence. Continued scaling increasingly requires complex three-dimensional integration schemes and associated characterisation techniques.Optical and electron beam technologies currently dominate the £5.2 billion market for IC metrology and inspection but lack the resolution (optical) and 3-dimentional capability required for the next generation of semiconductor processes. Atomic Force Microscopes (AFMs) can overcome these limitations by providing both the resolution and 3-dimensional capability. They are already used in semiconductor R&D and offline failure analysis. However, it takes up to an hour to image multiple sites on a wafer which is too slow for the semiconductor production environment.Infinitesima has developed a novel AFM measurement technique that offers significant advantages when compared to more conventional AFM systems. The Rapid Probe Microscope (RPM) integrates a unique opto-thermal actuation and interferometric detection system that can provide true 3D surface measurements with picometer levels of precision. The RPM is also capable of scanning speeds \>100x faster than is currently available within the market.Infinitesima has identified a potential method of increasing scanning speeds even further by multiplexing the number of scanning probes and associated electronics, optics, and data acquisition systems. Experimental feasibility studies have led to the successful implementation of a proof-of-principal bench top system, demonstrating and de-risking key concepts associated with this approach. The proposed solution for the actuation and measurement of the scanning probe array has been validated and has resulted in a patent filing. Collaboration with an external AFM probe manufacturing company has also led to the successful design and fabrication of multiprobe levers of varying pitch size and aspect ratio. The company is now able to start the transition from the bench top system to full integration within the current RPM wafer cycling platform. One of the significant challenges will be in the miniaturisation and reconfiguration of the optical subsystems in a way that can fit within the limited space envelope available. Infinitesima believes that this project will provide a clear route to integrating the prototype multi-probe system into the current RPM platform, and a viable route to address current and future market requirements.