JJ is right, use wonder board/CEMENT BACKER-BOARD.
Just cut (the wonder board) it to fit and screw it throught the laminat in to the wood benight and tile on top of that. If you use 1/2 board and the orginal counter is strudy you should be ok. if t's still flimsy start with 1/2 or so plywood then the wonder board on top to stiffen up.
Pleas see the notes on the sink in previous messages.
If were talking a 50's metel kitchen counter set up, you can't tile it.