DATA STORING METHOD, MEMORY CONTROL CIRCUIT UNIT AND MEMORY STORAGE APPARATUS

• US 20150262677A1
• Filed: 05/23/2014
• Published: 09/17/2015
• Est. Priority Date: 03/13/2014
• Status: Active Grant

• Current Assignee: Phison Electronics Corporation
• Original Assignee: Phison Electronics Corporation
• Inventors: Lin, Wei, Lau, Kiang-Giap, Hsu, Yu-Cheng, Lim, Hoe-Hong
• Granted Patent: US 9,257,187 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: G11C 16/08 Address circuits; Decoders; Word-line control circuits
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 7/02 with means for avoiding parasitic signals

Abstract

A data writing method, and a memory control circuit unit and a memory storage apparatus using the method are provided. The method including: programming data to several memory cells on a first word line of the rewritable non-volatile memory module of the memory storage apparatus, and a first predetermined reading voltage is initially configured for the first word line. The data storing method further includes: adjusting the first predetermined reading voltage to obtain a first available reading voltage for the first word line, and applying the first available reading voltage to the first word line to read first page data. The storing method further includes: if the difference value between the first available reading voltage and the first predetermined reading voltage is larger than a predetermined threshold value, performing a protection operation for the first page data.

Claims

1. A data storing method for a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of memory cells, a plurality of word lines and a plurality of bit lines, each of the memory cells electrically connects with one of the word lines and one of the bit lines, each of the memory cells stores a plurality of bit data, and each of the bit data may, according to at least a voltage, be identified as a first state or a second state, the data storing method comprises:

programming data into a plurality of memory cells connecting to a first word line among the word lines, wherein a first predetermined reading voltage is initially configured for the first word line;

adjusting the first predetermined reading voltage to obtain a first available reading voltage for the first word line and applying the first available reading voltage to the first word line to read first page data, wherein the first page data may be corrected by an error checking and correcting circuit correctly; and

when a first difference value between the first available reading voltage and the first predetermined reading voltage is larger than a first predetermined threshold value, programming the first page data into a plurality of memory cells connecting to a second word line among the word lines.

2. The data storing method of claim 1, further comprising:

remapping a first logical sub-unit to a first physical programming unit, wherein the first page data belongs to the first logical sub-unit,

wherein the memory cells connecting to the second word line constitute a plurality of physical programming units and the first physical programming unit is one of the physical programming units.

3. The data storing method of claim 1, wherein the steps of adjusting the first predetermined reading voltage to obtain the first available reading voltage for the first word line and applying the first available reading voltage to the first word line to read the first page data comprising:

performing a retry read operation according to a retry table.

4. The data storing method of claim 3, wherein the step of performing the retry read operation according to the retry table comprising:

after performing the retry read operation at least one time, obtaining a first reading voltage adjustment value according to the retry table; and

adjusting the first predetermined reading voltage according to the first reading voltage adjustment value to obtain the first available reading voltage.

5. The data storing method of claim 4, further comprising:

determining whether the number of times of performing the retry read operation is larger than a first predetermined number and smaller than a second predetermined number; and

if the number of times of performing the retry read operation is larger than the first predetermined number and smaller than the second predetermined number, identifying that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

6. The data storing method of claim 1, further comprising:

applying a plurality of scanning voltages to the first word line to read a plurality of scanned bit data corresponding to each of the scanning voltages from the memory cells connecting to the first word line;

respectively calculating a plurality of first state bit data increments of bit data identified as the first state among the scanned bit data corresponding to the scanning voltages;

obtaining a critical voltage distribution of the memory cells of the first word line according to the first state bit data increments corresponding to the scanning voltages;

searching a peak value in the critical voltage distribution and a valley value adjacent to the peak value;

determining whether a ratio obtained by dividing the valley value with the peak value is larger than a first predetermined ratio; and

if the ratio is larger than the first predetermined ratio, identifying that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

7. The data storing method of claim 1, further comprising:

applying a plurality of scanning voltages to the first word line to read a plurality of scanned bit data respectively corresponding to the scanning voltages from the first word line;

recording a plurality of error bit numbers respectively corresponding to the scanned bit data;

determining whether an error bit number ratio obtaining by dividing a smallest error bit number with a largest error bit number among the error bit numbers is larger than a second predetermined ration; and

when the error bit number ratio is larger than the second predetermined ratio, identifying that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

8. A memory control circuit unit for accessing a rewritable non-volatile memory module, the memory control circuit unit comprising:

a host interface, coupled to a host system;

a memory interface, coupled to the rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of memory cells, a plurality of word lines and a plurality of bit lines, each of the memory cells electrically connects with one of the word lines and one of the bit lines, each of the memory cells stores a plurality of bit data, and each of the bit data may be identified as a first state or a second state; and

a memory management circuit, coupled to the host interface and the memory interface, and is configured to give a first command sequence to the rewritable non-volatile memory module to program data into a plurality of memory cells connecting to a first word line among the word lines, wherein a first predetermined reading voltage is initially configured for the first word line,

wherein the memory management circuit is further configured to adjust the first predetermined reading voltage to obtain a first available reading voltage for the first word line and give a second command sequence to the rewritable non-volatile memory module to apply the first available reading voltage to the first word line to read first page data, wherein the first page data may be corrected by an error checking and correcting circuit correctly,

wherein when a first difference value between the first available reading voltage and the first predetermined reading voltage is larger than a first predetermined threshold value, the memory management circuit is further configured to issue a third command sequence to the rewritable non-volatile memory module to program the first page data into a plurality of memory cells connecting to a second word line among the word lines.

9. The memory control circuit unit of claim 8, wherein the memory management circuit is further configured to remap a first logical sub-unit to the first page data to a first physical programming unit, wherein the first data belongs to the first logical sub-unit,

wherein the memory cells connecting to the second word line constitute a plurality of physical programming units and the first physical programming unit is one of the physical programming units.

10. The memory control circuit unit of claim 8, wherein the memory management circuit is further configured to, give a fourth command sequence to the rewritable non-volatile memory module to perform a retry read operation according to a retry table to read data from the memory cells connecting to the first word line.

11. The memory control circuit unit of claim 10, wherein the memory management circuit, after performing the retry read operation at least one time, obtains a first reading voltage adjustment value according to the retry table,

wherein the memory management circuit, adjusts the first predetermined reading voltage according to the first reading voltage adjustment value to obtain the first available reading voltage.

12. The memory control circuit unit of claim 11, wherein the memory management circuit determines whether the number of times of performing the retry read operation is larger than a first predetermined number and smaller than a second predetermined number,

wherein if the number of times of performing the retry read operation is larger than the first predetermined number and smaller than the second predetermined number, the memory management circuit identifies that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

13. The memory control circuit unit of claim 8, wherein the memory management circuit applies a plurality of scanning voltages to the first word line to read a plurality of scanned bit data corresponding to each of the scanning voltages from the memory cells connecting to the first word line,

wherein the memory management circuit respectively calculates a plurality of first state bit data increments from the bit data identified as the first state among the scanned bit data corresponding to the scanning voltages,

wherein the memory management circuit, obtains a critical voltage distribution of the memory cells of the first word line according to the first state bit data increments corresponding to the scanning voltages,

wherein the memory management circuit searches a peak value in the critical voltage distribution and a valley value adjacent to the peak value,

wherein the memory management circuit determines whether a ratio obtained by dividing the valley value with the peak value is larger than a first predetermined ratio,

wherein if the ratio is larger than the first predetermined ratio, the memory management circuit identifies that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

14. The memory control circuit unit of claim 8,

wherein the memory management circuit applies a plurality of scanning voltages to the first word line to read a plurality of scanned bit data respectively corresponding to the scanning voltages from the first word line,

wherein the memory management circuit records a plurality of error bit numbers respectively corresponding to the scanned bit data,

wherein the memory management circuit determines whether an error bit number ratio obtained by dividing a smallest error bit number with a largest error bit number among the error bit numbers is larger than a second predetermined ratio,

wherein if the ratio is larger than the second predetermined ratio, the memory management circuit identifies that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

15. A memory storage device, comprising:

a connection interface unit, coupled to a host system;

a rewritable non-volatile memory module, wherein the rewritable non-volatile memory module has a plurality of memory cells, a plurality of word lines and a plurality of bit lines, each of the memory cells electrically connects with one of the word lines and one of the bit lines, each of the memory cells stores a plurality of bit data, and each of the bit data may be identified as a first state or a second state; and

a memory control circuit unit, coupled to the connection interface unit and the rewritable non-volatile memory module, and is configured to program data into a plurality of memory cells connecting to a first word line among the word lines, wherein a first predetermined reading voltage is initially configured for the first word line,

wherein the memory control circuit unit is further configured to adjust the first predetermined reading voltage to obtain a first available reading voltage for the first word line and apply the first available reading voltage to the first word line to read first page data, wherein the first page data may be corrected by an error checking and correcting circuit correctly,

wherein when a first difference value between the first available reading voltage and the first predetermined reading voltage is larger than a first predetermined threshold value, the memory control circuit unit is further configured to program the first page data into a plurality of memory cells connecting to a second word line among the word lines.

16. The memory storage apparatus of claim 15, wherein the memory control circuit unit is further configured to remap a first logical sub-unit to a first physical programming unit, wherein the first page data belongs to the first logical sub-unit,

wherein the memory cells connecting the second word line constitute a plurality of physical programming units and the first physical programming unit is one of the physical programming units.

17. The memory storage apparatus of claim 15, wherein the memory control circuit unit is further configured to perform a retry read operation according to a retry table to read data from the memory cells connecting to the first word line.

18. The memory storage apparatus of claim 17, wherein the memory control circuit unit, after performing the retry read operation at least one time, obtains a first reading voltage adjustment value according to the retry table,

wherein the memory control circuit unit, adjusts the first predetermined reading voltage according to the first reading voltage adjustment value to obtain the first available reading voltage.

19. The memory storage apparatus of claim 18, wherein the memory control circuit unit determines whether the number of times of performing the retry read operation is larger than a first predetermined number and smaller than a second predetermined number,

wherein if the number of times of performing the retry read operation is larger than the first predetermined number and smaller than the second predetermined number, the memory control circuit unit identifies that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

20. The memory storage apparatus of claim 15, wherein the memory control circuit unit applies a plurality of scanning voltages to the first word line to read a plurality of scanned bit data corresponding to each of the scanning voltages from the memory cells connecting to the first word line,

wherein the memory control circuit unit respectively calculates a plurality of first state bit data increments from the bit data identified as the first state among the scanned bit data corresponding to the scanning voltages,

wherein the memory control circuit unit obtains a critical voltage distribution of the memory cells of the first word line according to the first state bit data increments corresponding to the scanning voltages,

wherein the memory control circuit unit searches a peak value in the critical voltage distribution and a valley value adjacent to the peak value,

wherein the memory control circuit unit determines whether a ratio obtained by dividing the valley value with the peak value is larger than a first predetermined ratio,

wherein if the ratio is larger than the first predetermined ratio, the memory control circuit unit identifies that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.

21. The memory storage apparatus of claim 15,

wherein the memory control circuit unit applies a plurality of scanning voltages to the first word line to read a plurality of scanned bit data corresponding to the scanning voltages from the first word line,

wherein the memory control circuit unit records a plurality of error bit numbers respectively corresponding to the scanned bit data,

wherein the memory control circuit unit determines whether an error bit number ratio obtained by dividing a smallest error bit number with a largest error bit number among the error bit numbers is larger than a second predetermined ratio,

wherein when the ratio is larger than the second predetermined ratio, the memory control circuit unit identifies that the first difference value between the first available reading voltage and the first predetermined reading voltage is larger than the first predetermined threshold value.