Hi Jonathan,

There was a recent post on this subject.

You can take the exams in any sequence you choose, so feel free to take a Specialist exam when you feel ready.  You will receive your Specialist level certification once you successfully complete the exam(s), and have achieved your Associate level certification.

So, short answer, to get a Specialist certification you need to get an Associate level certification.

Please let me know if I've answered your question.