Method and apparatus for reducing read disturb in memory

A read method of a plurality of memory cells arranged in series in a semiconductor body, comprising:

• performing a first read with a word line read voltage and a word line pass voltage;
• and
• performing a second read with the word line read voltage and a modified word line pass voltage, wherein the word line pass voltage is larger than the modified word line pass voltage, and
• the first read and the second read are distinguished as different read types by control circuitry of the plurality of memory cells, wherein processing the first read applies the word line pass voltage to a first particular word line and does not apply other pass voltages to the first particular word line and processing the second read applies the modified word line pass voltage to a second particular word line and does not apply other pass voltages to the second particular word line.

A memory, comprising:

• a plurality of memory cells arranged in series in a semiconductor body;
• a plurality of word lines, word lines in the plurality of word lines coupled to memory cells in the plurality of memory cells;
• and
• a control circuit coupled to the plurality of word lines, the control circuit having multiple types of read, including:
• a first read type with a word line read voltage and a word line pass voltage;
• and
• a second read type with the word line read voltage and a modified word line pass voltage,
• wherein the word line pass voltage is larger than the modified word line pass voltage, wherein processing the first read type applies the word line pass voltage to a first particular word line and does not apply other pass voltages to the first particular word line, and processing the second read type applies the modified word line pass voltage to a second particular word line and does not apply other pass voltages to the second particular word line.

A reading method of a plurality of memory cells arranged in series having first ends and second ends in a semiconductor body, comprising:

• using a first read instruction to read a first selected memory cell with first pass voltages applied to multiple word lines of unselected memory cells between the first selected memory cell and the first end of a first series of memory cells;
• and
• using a second read instruction to read a second selected memory cell with second pass voltages applied to multiple word lines of unselected memory cells between the second selected memory cell and the first end of a second series of memory cells,
• wherein the first pass voltages are different from the second pass voltages, wherein processing the first read instruction applies one of the first pass voltages to a first particular word line and does not apply other pass voltages to the first particular word line, and processing the second read instruction applies one of the second pass voltages to a second particular word line and does not apply other pass voltages to the second particular word line.

A read method of a plurality of memory cells arranged in series having first ends and second ends in a semiconductor body, comprising:

• performing a first read of a first selected memory cell with a read voltage, and with first pass voltages applied to multiple word lines of unselected memory cells between the first selected memory cell and the first end of a first series of memory cells;
• and
• performing a second read of a second selected memory cell with the read voltage, and with modified pass voltages applied to multiple word lines of unselected memory cells between the second selected memory cell and the first end of a second series of memory cells,
• wherein the pass voltages are larger than the modified pass voltages, wherein processing the first read applies one of the first pass voltages to a first particular word line and does not apply other pass voltages to the first particular word line, and processing the second read applies one of the modified pass voltage to a second particular word line and does not apply other pass voltages to the second particular word line.