Fib delayering endpoint detection by monitoring sputtered materials using rga

A system for milling a sample that includes a first layer formed over a second layer, where the first and second layers are different materials, the system comprising:

• a vacuum chamber;
• a sample support configured to hold a sample within the vacuum chamber during a milling process;
• a focused ion beam (FIB) column configured to generate a focused ion beam ;
• a processor and a memory coupled to the processor, the memory including a plurality of computer-readable instructions that, when executed by the processor, cause the system to:
• mill a region of the sample by scanningthe focused ion beam over the region a plurality of iterations in which, for each iteration, the focused ion beam removes material from the sample generating byproducts from the milled region;
• detect, during the milling, partial pressures of one or more byproducts with a residual gas analyzer positioned to have a direct line of sight to the milled region;
• generate, in real-time, an output detection signal from the residual gas analyzer indicative of an amount of the one or more byproducts detected;
• and
• stop the milling based on the output signal.

A non-transitory computer-readable memory that stores instructions for milling a sample that includes a first layer formed over a second layer, where the first and second layers are different materials, by:

• milling a region of the sample by scanning a focused ion beam over the region a plurality of iterations in which, for each iteration, the focused ion beam removes material from the sample generating byproducts from the milled region;
• detecting, during the milling, partial pressures of one or more byproducts with a residual gas analyzer positioned to have a direct line of sight to the milled region;
• generating, in real-time, an output detection signal from the residual gas analyzer indicative of an amount of the one or more byproducts detected;
• and
• stopping the milling based on the output signal.