Patent ID: 7876609
Filing Date: 2011-01-25
Classification: G11C

Abstract:
1. A method of programming data to phase change memory cells in a nonvolatile memory, the nonvolatile memory including N groups of the memory cells, where N is greater than 2, the method comprising: supplying a first state program signal to M memory cells selected from each one of the N groups, where M is greater than 2, and then verify-reading the M memory cells to determine whether the M memory cells are in the first state; supplying a second state program signal different from the first state program signal to L memory cells selected from each one of the N groups, where L is greater than 2, and then verify-reading the L memory cells to determine whether the L memory cells are in the second state, wherein at least one memory cell in each one of the M memory cells and L memory cells is in each one of the N groups.