LithoPhase: in situ phase imaging for real-time monitoring of photolithographic exposure

Photolithography is essential for integrated circuit fabrication, where exposure determines pattern transfer and affects subsequent development and etching. Conventional methods like AFM and SEM are ex situ and cannot isolate exposure dynamics. To overcome these limitations, we introduce LithoPhase, an in situ monitoring system for photolithographic exposure that, to our knowledge, represents the first employment of quantitative phase imaging to track the photolithographic exposure process. Experimental results demonstrate that LithoPhase tracks phase evolution with micron-scale spatial and millisecond temporal resolution. Thus, LithoPhase enables real-time, in situ monitoring of exposure dynamics, offering a viable approach for advanced photolithography.