There have been several threads on this BB about this topic in the past. Good news is you can fix warped chips, BUT you must be careful. When chips are heated they become very soft. Putting them in a vise would cause damage that could not be repaired. There are many methods suggested to flatten out warped chips. One was to put the chip in a microwave oven with one flat piece of glass under and another one over the chip. Heat the oven for a short time, I believe it was about 30 seconds. The chip should soften just enough so that the weight of the glass should flatten it out. After the chip cools, it should be flat again.