Kinda-sorta. The answer is "yes" but I don't use a panel by panel, page by page type script that you sometimes see people use. My steps usually go something like:
1.) Bullet point outline of major plot points and events
2.) Go in under each bullet point and write out in a few sentences more about what's happening in detail. This ends up looking like something crossed between a rough draft for a written story and a stream of consciousness. It can be really rough and have a lot of mental notes to myself since it's not intended for anyone else to read (so it's not nearly as clean as like a novel first draft might be). I also, for example, don't tend to outline a whole lot of the dialogue at this point. If there are some really important or key lines or phrases I'll definitely note those, but the majority of the banter is left out. I'll do like 2 or 3 edit passthroughs at this point to make sure that the page count is looking right, everything is flowing okay, and that I trim out unnecessary fat.
3.) Next I go straight to storyboarding. This is probably the closest thing that I do to a "script" script, I sprint through and roughly sketch out every page and add all of the dialogue as I go along.
Then after that it's time for the real pages~