You can try using a "bug bomb" to try to get rid of them. I'm not sure if they make a specific bomb for ants alone, but there is surely something. Small ant traps can be used, but I don't think that will handle what you're dealing with. Good luck.

I had severe problem last summer with ants in the house. Tried everything. The county agent told the secret. Spread dry dursban across 6 feet from the house outside foundation and don't wet it in.
It solved it within a week.

everytime I have had carpenter ant problems it was becuase of water leaks causing wood in the walls to rot.They love to nest there! After trying everything including professional exterminators,I located where the critters were coming from,tore the wall apart, located and sprayed the nest with a bee killing insectecide, repaired the leaks and replaced the wood. Never saw an ant again. Your dishwasher could be leaking somewhere.