Memory Array Comprising Strings of Memory Cells and Method Used in Forming a Memory Array Comprising Strings of Memory Cells

A memory array comprising strings of memory cells, comprising:

• a conductor tier comprising conductor material;
• laterally-spaced memory blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers directly above the conductor tier, channel material strings of memory cells extending through the insulative tiers and the conductive tiers, the channel material of individual of the channel-material strings being directly electrically coupled to the conductor material of the conductor tier;
• and
• individual of the memory blocks comprising a lowest of the conductive tiers having no other of the conductive tiers vertically between the lowest conductive tier and the conductor tier, the lowest conductive tier comprising upper and lower insulative materials having intermediate material of different composition from the upper and lower insulative materials vertically there between;
• the upper insulative material, the lower insulative material, and the intermediate material extending longitudinally along the individual memory blocks proximate each of two laterally outer sides of the individual memory blocks.

A memory array comprising strings of memory cells, comprising:

• a conductor tier comprising conductor material;
• laterally-spaced memory blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers directly above the conductor tier, individual of the memory blocks comprising sub-blocks defined at least in part by a wall that extends through an upper portion of the vertical stack into a lower portion of the vertical stack between two laterally-outer sides of the individual memory blocks, channel material strings of memory cells extending through the upper portion and into the lower portion in the sub-blocks, conducting material in the lower portion directly electrically coupling together the channel material of individual of the channel-material strings and the conductor material of the conductor tier;
• and
• the individual memory blocks in the lower portion comprising upper and lower insulative materials having intermediate material of different composition from the upper and lower insulative materials vertically there-between, the upper and lower insulative materials and the intermediate material extending longitudinally along the individual memory blocks proximate each of the two laterally-outer sides of the individual memory blocks;
• the conducting material being against laterally-inner sides of the upper insulative material, the lower insulative material, and the intermediate material in the individual memory blocks.

A memory array comprising strings of memory cells, comprising:

• a conductor tier comprising conductor material;
• laterally-spaced memory blocks individually comprising a vertical stack comprising alternating insulative tiers and conductive tiers directly above the conductor tier, channel material strings of memory cells extending through the insulative tiers and the conductive tiers, the channel material of individual of the channel-material strings being directly electrically coupled to the conductor material of the conductor tier;
• individual of the memory blocks comprising sub-blocks defined at least in part by a wall that extends through an upper portion of the vertical stack into a lower portion of the vertical stack between two laterally-outer sides of the individual memory blocks;
• and
• a lowest of the conductive tiers having no other of the conductive tiers vertically between the lowest conductive tier and the conductor tier, the wall in a vertical cross-section comprising a core material and an insulative lining laterally outward of two laterally-outer sides of the core material, the insulative lining not extending laterally across a bottom of the core material of the wall in the vertical cross-section.