Photoresist (PR) profiles tend to have deformation and shrinkage with typical transmission electron microscopy (TEM) analysis method using a focused ion beam scanning electron microscope (FIB-SEM) and TEM. The elevated temperatures during sample preparation and TEM analysis are believed to contribute to these issues. This study evaluates the effectiveness of cryogenic workflow in mitigating PR profile shrinkage by employing cryo-focused ion beam (Cryo-FIB) and cryo-transmission electron microscopy (Cryo-TEM). Comparative experiments were conducted at room temperature and cryogenic conditions, demonstrating that full cryogenic workflow reduces the shrinkage of PR, bottom anti-reflective coating (BARC), and line critical dimension (CD). Our findings indicate that both the sample preparation and analysis temperatures influence PR profiles. This study highlights how the full cryogenic workflow significantly minimizes shrinkage, providing more accurate PR profile measurements.

Photoresist (PR) profiles tend to have deformation and shrinkage with typical transmission electron microscopy (TEM) sample preparation methods using a focused ion beam scanning electron microscope (FIB-SEM). As the temperature increases during the TEM sample preparation, it may lead to deformation and shrinkage in PR profiles. In this study, we analyze the impact when performing the sample preparation at a cold temperature using a cryo-FIB to minimize deformation and shrinkage issues. To test this methodology, the TEM sample preparation process was performed under different conditions. From these experiments, the TEM results with full cryo conditions showed that the PR line to space ratio was closest to the target, which is the sample’s real line to space ratio (1:1), and the bottom anti-reflective coating (BARC) shrinkage was minimized.