Engineering is not my field so please bear with me. A question...

In the field of nanotechnology, have we reached the point where quantum effects such as the Casimir Effect interferes with nano-construction (engineering tolerances)?

Quantum effects, such as tunneling, have been factors in computer chip design and fabrication for a while now.

So, yes.

Casimir effect, i dont think has been taken into account in any computer chip so far. You almost cant even say if it effects our worlds cause you need identical anti particles to annihilate...so, if silicon and anti silicon are formed.. (which doesn't happen!) it does effect.
And when compared to what Casimir effect is, tunneling is far more "macroscopic" and so out of reach of technology of today.

My bad for not specifying. I was actually thinking more along the line of nano-robots rather than computer micro-chips.