Multiple plasma ion source for inline secondary ion mass spectrometry

A non-transitory, computer readable medium having instructions stored thereon that, when executed, cause a method for performing a metrology process on a substrate using an inline secondary ion mass spectrometry (SIMS) process to be performed, the method comprising:

• injecting a premixed gas mixture of two or more gases into a plasma chamber configured to produce sputtering ions for the inline SIMS process which are compatible with downstream substrate fabrication processes, wherein the two or more gases produce only non-metallic ion species for both positive ion detection and negative ion detection;
• ejecting sputtering ions from the plasma chamber into a magnetic field;
• altering an intensity of the magnetic field to select a single species of ions formed from only one of the two or more gases of the premixed gas mixture;
• directing the single species of ions towards a surface of the substrate;
• and
• detecting secondary ions sputtered from the surface of the substrate by the single species of ions.

An apparatus for performing an inline secondary ion mass spectrometry (SIMS) process, comprising:

• a premixed gas mixture source that contains a premixed gas mixture of two or more gases, wherein the two or more gases contain only non-metallic ion species which are compatible with downstream substrate fabrication processes;
• a plasma chamber fluidly connected to the premixed gas mixture source and configured to produce two or more ion species from the two or more gases from the premixed gas mixture source;
• a primary mass filter that is fluidly connected to the plasma chamber and configured to select a sputtering ion species from the two or more ion species by adjusting a magnetic field;
• and
• a controller configured to automatically:
• inject the premixed gas mixture from the premixed gas mixture source into the plasma chamber;
• eject ions formed from the two or more gases from the plasma chamber into the magnetic field of the primary mass filter;
• and
• alter an intensity of the magnetic field to select a single species of ions formed from only one of the two or more gases of the premixed gas mixture,
• wherein the single species of ions is non-metallic for both positive ion detection and negative ion detection.