I think I know what you're getting at, in that a lot of atheists will defend their points through the use of a scientific method.
But I don't think that atheism has a direct link with science.
People can just reject religion through personal interpretation.
I've seen science work both ways - atheists can learn science and feel comfortable in that it can be used to explain what's happening around us and why it's happening. On the other hand, though, some people could be theists through science because they see how beautiful science is and gather that our natural laws must have been put in place and designed by something of superior intelligence.
As for myself, I have never really believed in a God because I found it all slightly absurd, somewhat silly.
My passion for science came long after I decided against God. So for me, there was no link between the two initially