Memory system and method for controlling nonvolatile memory

A memory system connectable to a host, the memory system comprising:

• a nonvolatile memory including a plurality of dies capable of being operated in parallel or a plurality of planes capable of being operated in parallel, each of the plurality of dies or the plurality of planes including a plurality of blocks each of which is a unit for a data erase operation;
• and
• a controller electrically connected to the nonvolatile memory and configured to control the nonvolatile memory, wherein
• the controller is configured to:
• construct, from the plurality of dies or the plurality of planes, a plurality of block groups each including a plurality of blocks using a first type block group when a difference between the number of defective blocks included in a die or plane having a smallest number of defective blocks among the plurality of dies or the plurality of planes and the number of defective blocks included in a die or plane having a largest number of defective blocks among the plurality of dies or the plurality of planes is equal to or less than one;
• construct the plurality of block groups from the plurality of dies or the plurality of planes using the first type block group and a second type block group different from the first type block group when a difference between the number of the defective blocks included in the die or plane having the smallest number of defective blocks and the number of the defective blocks included in the die or plane having the largest number of defective blocks is equal to or more than two;
• and
• in response to receiving a write command for writing data to one block group among the plurality of block groups from the host, write data associated with the received write command to the one block group, wherein
• the first type block group includes a plurality of non-defective blocks obtained by selecting one or more non-defective blocks in an equal number from each of the plurality of dies or each of the plurality of planes, and wherein
• the second type block group includes a plurality of non-defective blocks selected from part of the plurality of dies or part of the plurality of planes, the number of the non-defective blocks included in the second type block group being equal to the number of the non-defective blocks included in the first type block group, and the number of non-defective blocks per die or per plane included in the second type block group is different between a first die and a second die of the part of the plurality of dies or between a first plane and a second plane of the part of the plurality of planes.

A method of controlling a nonvolatile memory including a plurality of dies operable in parallel or a plurality of planes operable in parallel, each of the plurality of dies or the plurality of planes including a plurality of blocks each of which is a unit for a data erase operation, the method comprising:

• constructing, from the plurality of dies or the plurality of planes, a plurality of block groups each including a plurality of blocks;
• and
• in response to receiving a write command for writing data to one block group among the plurality of block groups from a host, writing data associated with the received write command to the one block group, wherein
• the plurality of block groups includes at least a first block group configured using a first type block group and a second block group configured using a second type block group, wherein
• the first type block group includes a plurality of non-defective blocks obtained by selecting one or more non-defective blocks in an equal number from each of the plurality of dies or each of the plurality of planes, and wherein
• the second type block group includes a plurality of non-defective blocks selected from part of the plurality of dies or part of the plurality of planes, the number of the non-defective blocks included in the second type block group being equal to the number of the non-defective blocks included in the first type block group, and the number of non-defective blocks per die or per plane included in the second type block group is different between a first die and a second die of the part of the plurality of dies or between a first plane and a second plane of the part of the plurality of planes.