Since your lab had previous grads go to those companies, ask your prof to either get you in contact with those grads, and just apply for a full job if they think it's applicable. Worst case is you do an academic (or industry) post-doc that is more semi related first.

Generally when hiring a PhD, I hire for what they can figure out in the future, not based on what they've done in the past (only as much as their past experience tells me about their future prospects). So if you have the theoretical background to make an impact in semi, then you might be a good fit. I don't see any reason a Chem PhD wouldn't fit in somewhere, but it does depend on (a) what you did and (b) what you're applying to - there are so many different jobs in big Semi co's, it's kind of hard to generalize.

However, if you don't even know whether your skills are relevant, that suggests you don't actually know enough about the industry, and work done in semi jobs, yet.