Nonvolatile memory device and program method thereof

Abstract

According to example embodiments of inventive concepts, a nonvolatile memory device includes at least two strings that are vertically stacked on a substrate and share one bit line. A program method of the nonvolatile memory device includes setting a pre-charge condition on the basis of a disturb environment between the at least two cell strings, pre-charging or not pre-charging an unselected cell string among the at least two cell strings in response to the pre-charge condition and programming memory cells in a selected cell string among the at least two cell strings.

1 . A program method of a nonvolatile memory device, the nonvolatile memory device including at least two cell strings that are vertically stacked on a substrate and share one bit line, the program method comprising:
 setting a pre-charge condition on the basis of a disturb environment between the at least two cell strings;   one of
 pre-charging an unselected cell string among the at least two cell strings in response to the pre-charge condition, and 
 not pre-charging the unselected cell string among the at least two cell strings in response to the pre-charge condition; and 
   programming memory cells of a selected cell string among the at least two cell strings.   
     
     
         2 . The program method of  claim 1 , wherein
 the one of pre-charging the unselected cell string and not pre-charging the unselected cell string includes the pre-charging the unselected cell string, and   the pre-charging the unselected cell string includes one of
 adjusting a level of a pre-charge voltage applied to the unselected cell string in response to the pre-charge condition, and 
 adjusting a time of applying the pre-charge voltage to the unselected cell string in response to the pre-charge condition. 
   
     
     
         3 . The program method of  claim 1 , wherein the setting the pre-charge condition includes setting the pre-charge condition in response to a level of a program voltage applied during the programming memory cells of the selected cell string. 
     
     
         4 . The program method of  claim 3 , wherein the one of pre-charging the unselected cell string and not pre-charging the unselected cell string includes the pre-charging the unselected cell string if the level of the program voltage is greater than a reference value. 
     
     
         5 . The program method of  claim 4 , wherein the pre-charging the unselected cell string includes increasing a level of a pre-charge voltage applied to the unselected cell string as the level of the program voltage becomes greater. 
     
     
         6 . The program method of  claim 1 , wherein the setting the pre-charge condition includes setting the pre-charge condition in response to a number of program loops during the programming memory cells of the selected cell string. 
     
     
         7 . The program method of  claim 6 , wherein the one of pre-charging the unselected cell string and not pre-charging the unselected cell string includes the pre-charging the unselected cell string if the number of the program loops is greater than a reference value. 
     
     
         8 . The program method of  claim 7 , wherein the pre-charging the unselected cell string includes increasing a level of a pre-charge voltage applied to the unselected cell string as the number of the program loops becomes larger. 
     
     
         9 . The program method of  claim 1 , wherein the setting the pre-charge condition includes setting the pre-charge condition in response to a program state of data programmed in at least one memory cell of the non-volatile memory device. 
     
     
         10 . The program method of  claim 9 , wherein the one of pre-charging the unselected cell string and not pre-charging the unselected cell string includes the pre-charging the unselected cell string if the program state indicates the data has been programmed in the least one memory cell. 
     
     
         11 . The program method of  claim 1 , further comprising:
 adjusting the pre-charge condition based on a wear environment of the nonvolatile memory.   
     
     
         12 . The program method of  claim 11 , wherein the wear environment includes one of a wear level index, a number of memory cells in the at least two strings having a threshold voltage higher than a reference threshold voltage, and a number of program/erase cycles. 
     
     
         13 . The program method of  claim 1 , further comprising:
 adjusting the pre-charge condition based on a program mode of the nonvolatile memory.   
     
     
         14 .- 15 . (canceled) 
     
     
         16 . A program method of a nonvolatile memory device including a plurality of cell strings on a substrate, the plurality of cell strings including at least two cell strings connected to a bit line in common, the program method comprising:
 determining a parameter corresponding to a program disturb environment between the at least two cell strings connected to the bit line in common;   controlling a pre-charging operation based on whether the parameter is greater than or equal to a threshold value, the controlling the pre-charge operation including one of
 pre-charging an unselected cell string among the at least two cell strings if the parameter is greater than or equal to the threshold value, and 
 not pre-charging the unselected cell string among the at least two cell strings if the parameter is less than the threshold value; and 
   programming a selected cell string among the at least two cell strings.   
     
     
         17 . The program method of  claim 1 , wherein
 the plurality of strings are connected to different string select lines respectively,   each one of the plurality of cell strings include a plurality of memory cells vertically stacked on each other between at least one ground select transistor and at least one string select transistor on the substrate, and   the pre-charging the selected string among the at least two cell strings includes,
 providing a supply voltage to one of the string select lines that is connected to the selected cell string, and 
 providing a pre-charge voltage the bit line connected in common to the at least two cell strings during the providing the supply voltage to the one of the string select lines connected to the selected cell string. 
   
     
     
         18 . The program method of  claim 1 , wherein the determining the parameter includes determining whether a level of a program voltage to be applied during the programming the selected cell string is greater than or equal to the threshold value. 
     
     
         19 . The program method of  claim 1 , wherein the determining the parameter includes determining whether a loop number of the programming the selected cell string is greater than or equal to the threshold value. 
     
     
         20 . The program method of  claim 1 , wherein the determining the parameter includes determining whether a number of erase upper cells in the nonvolatile memory device is greater than or equal to the threshold value.