Three dimensional flash memory element with middle source-drain line and manufacturing method thereof

A three dimensional flash memory element comprising:

• a string including a channel layer extended in one direction and a plurality of electrode layers vertically layered for the channel layer;
• an upper wiring layer placed at the top of the string;
• at least one intermediate wiring layer placed between the plurality of electrode layers in intermediate area of the string;
• and
• a lower wiring layer placed at the bottom of the string;
• wherein each of the upper wiring layer, the at least one intermediate layer, and the lower wiring layer is extended in a direction orthogonal to the direction where the plurality of electrode layers is extended, and
• wherein the upper wiring layer, the at least one intermediate layer, and the lower wiring layer are formed in a stepped form in order that the extended lengths are different from each other.

A manufacturing method of three dimensional flash memory element comprising:

• preparing a plurality of mold structures in which each of strings including a plurality of electrode layers and a plurality of interlayer insulating layers alternately layered and a channel layer extended in one direction to penetrate the plurality of electrode layers and the plurality of interlayer insulating layers is formed,
• layering at least one rest mold structure where an intermediate wiring layer is placed at the bottom of the string among the plurality of mold structures at the top of any one mold structure where a lower wiring layer is placed at the bottom of the string among the plurality of mold structures;
• and
• forming an upper wiring layer at the top of the string on the at least one rest mold structure layered on the any one mold structure,
• wherein each of the upper wiring layer, the at least one intermediate wiring layer, and the lower wiring layer is adaptively used as any one of a drain electrode or a source electrode.

A program operation method of three dimensional flash memory element comprising a string including a channel layer extended in one direction and a plurality of electrode layers vertically layered for the channel layer;

• an upper wiring layer placed at the top of the string;
• at least one intermediate wiring layer placed between the plurality of electrode layers in intermediate area of the string;
• and a lower wiring layer placed at the bottom of the string, wherein the program operation method of three dimensional flash memory element comprises:
• applying 0V voltage or low voltage compared to program voltage to each of the upper wiring layer, the at least one intermediate wiring layer, and the lower wiring layer;
• and
• performing a programming operation of a memory cell by applying program voltage to word line connected to an electrode layer corresponding to the memory to control.

An erase operation method of three dimensional flash memory element comprising a string including a channel layer extended in one direction and a plurality of electrode layers vertically layered for the channel layer;

• an upper wiring layer placed at the top of the string;
• at least one intermediate wiring layer placed between the plurality of electrode layers in intermediate area of the string, and a lower wiring layer placed at the bottom of the string, wherein the erase operation method of three dimensional flash memory element comprises:
• applying erase voltage to at least one wiring layer among the upper wiring layer, the at least one wiring layer, or the lower wiring layer according to memory cell to control;
• and
• performing an erase operation for the memory cell by applying 0V voltage or lower voltage compared to erase voltage to word line connected to an electrode layer corresponding to the memory cell.

A read operation method of three dimensional flash memory element comprising a string including a channel layer extended in one direction and a plurality of electrode layers vertically layered for the channel layer;

• an upper wiring layer placed at the top of the string;
• at least one intermediate wiring layer placed between the plurality of electrode layers in intermediate area of the string;
• and a lower wiring layer placed at the bottom of the string, wherein the read operation method of three dimensional flash memory element comprises:
• selecting two wiring layers corresponding to a first block among the upper wiring layer, the at least one intermediate wiring layer, or the lower wiring layer in the first block of at least two blocks where the plurality of electrode layers is grouped;
• applying free charge voltage to any one wiring layer by using the any one wiring layer of the two wiring layers as a drain electrode;
• sensing at least one memory cell corresponding to at least one electrode layer included in the first block in order;
• selecting two wiring layers corresponding to a second block among the upper wiring layer, the at least one intermediate wiring layer, or the lower wiring layer in the second block of the at least two blocks;
• applying free charge voltage to any one wiring layer by using the any one wiring layer of the two wiring layer as a drain electrode;
• and
• sensing at least one memory cell corresponding to at least one electrode layer included in the second block in order.