Solder mask or thru-hole mask in PADS Layout 9.5

I'm trying to learn PADS, having been around it for many years but not directly used it before. The last EDA package I used was PCAD in the 90's. I've laid out a 2 layer thru-hole board and want to make the top layer as solid ground plane with copper etched away from the plane only for an annulus around the thru hole pad. The thru hole pad will be plated through so it will appear on both top and bottom. I messed around with defining a CAM layer which I flooded with copper but it was solid copper and would have shorted to the through holes. I want copper relief around the thru hole plate through.

I'm looking for PADS to generate a negative plot which will be mostly black but with dots and shapes which represent the through hole pad areas, plus some clearance (can I spec in some design rule somewhere?). When I expose the plot to make a negative mask, the film should be mostly clear with slightly oversize dots were the pad areas are. I'll also use this mask to make a solder mask by leaving exposed photoresist onthe board.

Would appreciate some guidance.

John

 

Huge thanks Adam. I'm using ver. 9.5 so some of the keystrokes might be a bit different but you put me on the right track and things are working great. I had to click on the "Plane Area" button on the drafting toobar, then right click and choose "rectangle" to select the board area. As soon as I finished the selection, a popup asked me to specify the net association (I'd already done that in Layers but I think this allows for multiple net associations). Then I clicked on the flood button in the toolbar and it did the fill. Gradually getting the hang thanks to your help. Cornwall.....location in one of the greatest movies of all "About Time." .....John/Salt Lake City