exit visual studio

I have a VS instance created like that:

Type objType = Type.GetTypeFromProgID("VisualStudio.DTE.10.0");
objDTE = (DTE2)Activator.CreateInstance(objType);

How do I exit VS and make sure the devenv.exe process exited? I am aware of:

objDTE.Quit();

but unfortunately after this line the devenv.exe process is still hanging around - it disappears a few lines down. How do I make sure it disappears immediately (it blocks some files from being deleted)?