New Breakthrough Achieved in China in the Field of Photoresist

According to the Science and Technology Daily, lithography technology is one of the core drivers promoting the continuous miniaturization of integrated circuit chip manufacturing processes. Recently, a team led by Professor Peng Hailin from the College of Chemistry and Molecular Engineering at Peking University, along with collaborators, used cryo-electron tomography to resolve, for the first time in situ, the microscopic three-dimensional structure, interface distribution, and entanglement behavior of photoresist molecules in a liquid environment. This guided the development of an industrial solution that can significantly reduce lithography defects. The related paper was recently published in Nature Communications.

"Development" is one of the core steps in lithography. It involves dissolving the exposed areas of the photoresist using a developer to precisely transfer the circuit pattern onto the silicon wafer. Photoresist acts like the pigment for drawing circuits; its movement in the developer directly determines the accuracy and quality of the circuit pattern, thereby affecting chip yield. For a long time, the microscopic behavior of photoresist in the developer has been a "black box." Process optimization in the industry could only rely on repeated trial and error, which has become a key bottleneck constraining yield improvement for 7-nanometer and more advanced processes.

To solve this problem, the research team introduced cryo-electron tomography into the semiconductor field for the first time. The researchers ultimately synthesized a microscopic 3D "panoramic image" with a resolution better than 5 nanometers, overcoming the three major shortcomings of traditional techniques: the inability to perform in situ, three-dimensional, and high-resolution observation.

Peng Hailin stated that cryo-electron tomography provides a powerful tool for resolving various liquid-phase interface reactions at the atomic/molecular scale. A deeper understanding of the structure and microscopic behavior of polymers in liquids can promote defect control and yield improvement in key processes such as lithography, etching, and wet cleaning in advanced manufacturing.