US Patent 9548130 Non-volatile memory with prior state sensing

A non-volatile memory system comprises a plurality of memory cells arranged in a three dimensional structure and one or more control circuits in communication with the memory cells. The one or more control circuits are configured to program and verify programming for the memory cells. The verifying programming of the plurality of memory cells includes verifying programming for a first data state using a verify operation for a second data state. In one embodiment, the one or more control circuits are also configured to sense whether different memory cells of the plurality of memory cells are in different data states by applying different bit line voltages to the different memory cells.