The most prominent (and probably the only) Scrum Master certification is the one offered by the Scrum Alliance.
I think there are many opinions about this certification, here are some of them:
- The scrum certification is useless, all that you will learn is common sense.
- The scrum certification is not in demand as the PMP. Just having a Scrum Master experience is enough, no need to get certified.
- The scrum certification will increase your chances of landing a decent job.
- The certification offered by the the Scrum Alliance is not consistent.
- The certification is there just to make some money and promote paid courses.
As you can see from the above, most opinions look at this certification disfavorably (unlike the PMP, where there is a large percentage supporting the certification and thinking that it's great). The thing is Agile (and everything falling under Agile) is not science, and not only that, it's not consistent science.
On the other hand, you have nothing to lose if you do it and make your company pay for it. Who knows, maybe you'll learn something new and/or meet some interesting people who will help your professionally.