totally, it depends on what device you want to fabricate. In my viewpoint, the clean room is essential for better efficiency and lower error rate. Therefore it effects on the device performance. You should provide the laboratory clean as possible as you can.

Good luck

Without any clean room facilities you will have major issues with poor yield. Particles such as dust are macroscopic, they will destroy a large area of your wafer area available for device fabrication. That leads to extremely low (if any) yield and poor statistics.

It is different, however, if you use glove boxes and vacuum equipment with loadlocks, then you can load your (boxed) samples into the loadlock without exposing them to dirty atmosphere. That way you can avoid using clean room facilities. For inspection you could use a (horizontal) laminar flow box. After fabrication there is usually no harm in removing samples from clean conditions to normal lab conditions.