How far away from the surface of the range (burner area) does the microwave have to be mounted?

Most installers and Installation Guides state that you need 30" if you have unprotected wood cabinets above the stove. This is to ensure you don't catch it on fire or ruin it with excessive moisture. However, if you have a metal protective shield or a microwave between your stove and the wooden cabinets, then you only need to achieve a comfortable distance between the stove top and the bottom of the cabinets that will allow you to cook comfortably. You should be able to see and reach all the controls and dials. In my case, I have an 18" clearance between my stove and cabinets that still allows me to feel comfortable cooking and doesn't block my sight. Hope this helps.