The Russian's most advanced processor technology used in military products is a 90nm Elbrus2K as used in the Su-57 PAK-FA.
They also use a lot of 250nm processors for other products. This includes space applications. These are basically MIPS processors.
RTI Systems, the company which owns Mikron, is under the sanctions and they fab a lot of those chips. As are other companies in the Rostec group. I don't know if they sanctioned their purchases of photomask and consumables, or parts and maintenance of production line. Probably. If they did this it can impact military semiconductor production. Or production of Mir smart card chips for debit cards. But AFAIK the Chinese are already producing all these items and have alternate suppliers which do fab tool maintenance without having the original parts. None of those Chinese companies are registered in the US. Russia is still stuck on KrF manufacture or i-line.
They might still be buying foreign DAC chips or other miscelaneous semiconductors like network controllers and the like, but those are so, so fricking common they will easily be able to smuggle them somehow.
The embargo will have impact since they basically sanctioned the whole Russian MIC and this includes Rostec. Rostec produces products not just for the military but also for civilian applications. But they will get over it in probably 2-3 years tops and should have stockpiles to last them that long.
I looked deeply into it, and Elbrus2K for civilian applications shouldn't be sanctioned. Since MSCT does not seem to fall under the sanctions list as a join-stock company partly owned by the Moscow Institute of Physics and Technology and even companies like Intel (yes that Intel). Which is not part of the MIC.