Most Samsung microwaves use a bulb and bracket assembly that is meant to be replaced as a unit, not disassembled (see image). If the bulb base was secured using epoxy or some other means, it may not be possible to remove without damaging the bracket.
That said, you can try traditional methods for removing broken light bulb bases. Remember to always unplug the fixture/appliance, or shut off and mark the breaker serving it, before working.
A cut potato or carrot can sometimes be pushed onto the broken glass left in the base, to provide a handle for unscrewing the base. On smaller bulbs, I have successfully used the eraser on the end of a pencil.
If the bulb was really stubborn, I would probably try filling the base with a hot glue gun, then pushing a screwdriver into the soft glue. Once the glue hardens, turning the screwdriver should unscrew the bulb base (if it is at all possible).
As you may have discovered, pliers and the like tend to just break off small pieces of the broken glass bulb.