关键词: 砷化镓, 背孔, 良率, 监控, ICP蚀刻

Abstract: In the fabrication of GaAs back hole process, the through-hole yield affects the subsequent splashing, plating metal layer and front metal interconnection, and there is no effective monitoring method in the key process. In the back hole process, FIB and SEM are used to analyze the chips etched by ICP, which undoubtedly greatly increases the cost of research and development. The chip analysis is only the through-hole yield of the current wafer, and the number of analysis holes is limited, which has its own limitations. In this paper, Si₃N₄ / PI / Si₃N₄ =600 nm/1.6 μm/800 nm is deposited on the front of the wafer by ICP, the etching gas is Cl₂ / BCl₃. Under the OM×20 ratio, the first feature of the wafer front etching through-hole mark and the second through-hole feature whose mark side size is 10 μm larger than the original size can be observed. This monitoring method saves cost and has intuitive statistical yield, timely feedbacks the through-hole yield and monitors the reliability and reproducibility of the product.

Key words: GaAs, Dorsalforamen, Yield, Monitor, ICPetching