【Frontiers in HaiChuan Chemical Technology】Peking University research team makes new breakthroughs in China’s photoresist field

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Photolithography technology is one of the key drivers behind the continuous miniaturization of integrated circuit chip manufacturing processes. Recently, the team led by Professor Peng Hailin from the School of Chemistry and Molecular Engineering at Peking University, in collaboration with other researchers, used cryo-electron tomography to determine for the first time, in situ, the microscopic three-dimensional structure, interfacial distribution, and entanglement behavior of photoresist molecules in a liquid environment. This discovery has enabled the development of industrial solutions that can significantly reduce photoresist-related defects. A related paper was recently published in Nature Communications. “\"Development\" is one of the key steps in photolithography; it involves using a developing solution to dissolve the exposed areas of the photoresist, thereby transferring the circuit pattern accurately onto the silicon wafer. Resist acts like the pigment used to draw circuits; its movement in the developing solution directly determines the accuracy and quality of the circuits, thereby affecting the yield of chips. For a long time, the microscopic behavior of photoresist in the developing solution has remained a \"black box,\" and process optimization in the industry could only be achieved through trial and error, which has become one of the key bottlenecks restricting the improvement of yield in advanced manufacturing processes of 7 nanometers and below. To overcome this challenge, the research team introduced cryo-electron tomography technology into the semiconductor field for the first time. The researchers ultimately synthesized a microscopic three-dimensional \"panoramic image\" with a resolution better than 5 nanometers, thereby overcoming the three major limitations of traditional technologies: the inability to conduct observations in situ, in three dimensions, and at high resolution. Peng Hailin stated that cryo-electron tomography technology provides a powerful tool for analyzing various liquid-phase interface reactions at the atomic/molecular scale. A thorough understanding of the structure and microscopic behavior of polymers in liquids can help improve defect control and yield in key processes such as lithography, etching, and wet cleaning in advanced manufacturing processes.