Use a Phillips #1 screwdriver to remove the five 5 mm screws from the back of the controller.

The two case screws above the handgrips and the single case screw below the battery bay have a shallow seat. These three screws can be easily removed.

The two case screws adjacent to the ZR and ZL shoulder buttons have a deep seat. Use an extension or a Phillips screwdriver with a longer shaft to reach these screws.