NSF-DFG: Understanding Rough-surface Humid Adhesion to Enable Precise Manipulation and Positioning of Wafers for Next-generation Semiconductor Device Manufacturing

University Of Pittsburgh, Pittsburgh PA

Investigators

Abstract

This grant supports research that intends to advance fundamental science needed to improve semiconductor microchip manufacturing, an enabling technology for automation, robotics, machine-learning, and other key drivers of the US economy. As microchip components shrink ever-smaller, national reports have identified a key barrier for their technological advancement, which is the robotic manipulation of the chips with near atomic-scale precision. This research seeks to eliminate this barrier by improving the scientific understanding of how microchip materials adhere to the manufacturing equipment in the presence of humidity. Humidity determines how microchips stick because it leads to tiny water bridges between the contacting bodies. These capillary bridges resist stretching and act like a glue keeping the contact together. Insights are generated through advanced experimental measurements on technology-relevant materials, combined with computer simulations, theory, and machine learning. The goal is to predict and control unwanted positional slipping, enabling the creation of the next generation of microchips with greater performance, better reliability, and lower cost. This is a collaboration between modeling by the German team and experiments by the US team. This project bolsters the current manufacturing workforce by (1) making all models and results publicly available using a free-to-use web application; (2) funding The Surface-Topography Challenge, an international open-science effort to better understand surface properties; and (3) training industry leaders via manufacturing-focused Centers at the University of Pittsburgh. It develops the next-generation manufacturing workforce by developing a project-based engineering unit for K-12 students. This project supports research that develops fundamental understanding of how adhesion in semiconductor manufacturing is controlled by a combination of chemistry, mechanical properties, and surface topography of the substrate surfaces. The existing scientific framework for capillary adhesion cannot adequately describe the performance of the wafer-handling equipment, which has complex multi-scale topography that evolves over time during high-volume manufacturing. The central hypothesis of this project is that the formation, deformation, and percolation of capillary bridges determines the adhesive force in humid environments and is controlled by topography at multiple length scales. To test this hypothesis, this research experimentally measures the co-evolution of adhesion and topography (down to the atomic scale) over time during tool use. These experiments are combined with physics-based and data-driven modeling to describe the behavior of the liquid capillaries during adhesion. Scientifically, the goal is to create a new class of humid-adhesion models that account for the complex, multi-scale topography of wafers and manufacturing equipment. Technologically, these experimentally validated, science-guided insights into the attributes of surfaces that control adhesion guide the development of high-performance and long-lifetime equipment for next-generation semiconductor manufacturing. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.