Method, flashing memory controller, memory device for accessing 3D flash memory having multiple memory chips

• US 10,643,733 B2
• Filed: 10/15/2018
• Issued: 05/05/2020
• Est. Priority Date: 04/27/2016
• Status: Active Grant

• Current Assignee: Silicon Motion Incorporated Taiwan (Silicon Motion)
• Original Assignee: Silicon Motion Incorporated Taiwan (Silicon Motion)
• Inventors: Yang, Tsung-Chieh, Hsu, Hong-Jung
• Primary Examiner(s): Nguyen, Vanthu T
• Application Number:
  US16/159,723
• Publication Number:
  US 20190050326A1
• Time in Patent Office: 568 Days
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7209 Validity control, e.g. using flags, time stamps or sequence numbers
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input 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 2211/5641 Multilevel memory having cells with different number of storage levels
• CPC Class Codes: G11C 29/42 using error correcting codes [ECC] or parity check
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents
• CPC Class Codes: G11C 7/1006 Data managing, e.g. manipulating data before writing or reading out, data bus switches or control circuits therefor

Abstract

A method for accessing a flash memory module is provided. The flash memory module is a 3D flash memory module including a plurality of flash memory chips, each flash memory chip includes a plurality of blocks, each block includes a plurality of pages, and the method includes: configuring the flash memory chips to set at least one super block of the flash memory chips; and allocating a buffer memory space to store a plurality of temporary parities generated when data is written into the at least one first super block.

Claims

1. A method for accessing a flash memory module, the flash memory module being a 3D flash memory module including a plurality of flash memory chips, each flash memory chip including a plurality of blocks which include a plurality of multiple-level cell blocks, each block including a plurality of data pages and including a plurality of word lines respectively disposed on a plurality of different planes and a plurality of floating transistors controlled by a plurality of bit lines, floating transistors on each bit line forming at least one page among the plurality of data pages, and the method comprises:

using a first codec to perform encoding upon data to generate at least one set of parity check codes and using a second codec to encode the at least one set of parity check codes to generate at least one set of final parity check codes, wherein the data is to be written into a super block of the flash memory chips and the super block includes one multiple-level cell block of each flash memory chip among the flash memory chips; and

writing the data and the at least one set of final parity check codes into the super block;

wherein each flash memory chip of the 3D flash memory module has a plurality of 3D stacked planes;

all word lines disposed on a same 3D stacked plane are classified into a same word line set;

all word line sets are classified into a group of multiple odd word line sets and a group of multiple even word line sets; and

, the at least one set of parity check codes is generated for data disposed on particular word lines associated with a same order respectively comprised within the multiple odd word line sets or the multiple even word line sets.

2. The method of claim 1, further comprising:

when error(s) occurring due to writing for the data or program fail, directly using the at least one set of parity check codes to correct the error(s) of the data.

3. The method of claim 1, further comprising:

during the data being written into the super block;

reading a portion of the data, which has been written into the super block, from the super block; and

reading at least one portion of parity check codes from the at least one set of parity check codes and using the at least one portion of parity check codes to perform error correction upon the portion of the data when an error occurs and cannot corrected during reading the portion of the data.

4. The method of claim 1, wherein the step of performing encoding upon the data to generate the at least one set of parity check codes comprises:

sequentially performing encoding upon first to N-th data units to generate first to N-th sets of parity check codes; and

the step of writing the data into the super block comprises;

respectively writing the first to N-th data units into first data pages to N-th data pages corresponding to the flash memory chips of the super block; and

wherein the first to N-th sets of parity check codes are written into a buffer memory.

5. The method of claim 4, wherein the at least one set of parity check codes is an at least one set of temporary parity check codes, and the method further comprises:

reading the first to N-th sets of parity check codes from the buffer memory to generate multiple sets of final parity check codes according to the first to N-th sets of parity check codes; and

writing the multiple sets of final parity check codes into the super block.

6. The method of claim 5, wherein multiple word lines positioned on a same plane of each block forms a word line set, and the step of writing the multiple sets of final parity check codes into the super block comprises:

writing the multiple sets of final parity check codes into data pages of a flash memory chip corresponding to last two word line sets of the super block.

7. The method of claim 1, wherein the multiple-level cell blocks are triple-level cell (TLC) blocks or quad-level cell (QLC) blocks.

8. A flash memory controller for accessing a flash memory module, the flash memory module being a 3D flash memory module including a plurality of flash memory chips, each flash memory chip including a plurality of blocks which include a plurality of multiple-level cell blocks, each block including a plurality of data pages and including a plurality of word lines respectively disposed on a plurality of different planes and a plurality of floating transistors controlled by a plurality of bit lines, floating transistors on each bit line forming at least one page among the plurality of data pages, and the flash memory controller comprises:

a memory, configured for storing a program code;

a microprocessor, configured for performing the program code to control access of the flash memory module; and

a first codec, configured for performing encoding upon data to generate at least one set of parity check codes, wherein the data is to be written into a super block of the flash memory chips and the super block includes one multiple-level cell block of each flash memory chip among the flash memory chips;

wherein the microprocessor is arranged for using a second codec to encode the at least one set of parity check codes to generate at least one set of final parity check codes, and writing the data and the at least one set of final parity check codes into the super block;

each flash memory chip of the 3D flash memory module has a plurality of 3D stacked planes;

all word lines disposed on a same 3D stacked plane are classified into a same word line set;

all word line sets are classified into a group of multiple odd word line sets and a group of multiple even word line sets; and

, the at least one set of parity check codes is generated for data disposed on particular word lines associated with a same order respectively comprised within the multiple odd word line sets or the multiple even word line sets.

9. The flash memory controller of claim 8, wherein when error(s) occurring due to writing for the data or program fail, the first codec is arranged for directly using the at least one set of parity check codes to correct the error(s) of the data.

10. The flash memory controller of claim 8, wherein during the data being written into the super block:

the microprocessor is arranged for reading a portion of the data, which has been written into the super block, from the super block, and reading at least one portion of parity check codes the at least one set of parity check codes; and

the first codec is arranged for using the at least one portion of parity check codes to perform error correction upon the portion of the data when an error occurs and cannot corrected during reading the portion of the data.

11. The flash memory controller of claim 8, wherein the first codec is arranged for sequentially performing encoding upon first to N-th data units to generate first to N-th sets of parity check codes, and respectively writing the first to N-th data units into first data pages to N-th data pages corresponding to the flash memory chips of the super block;

and the first to N-th sets of parity check codes are written into a buffer memory.

12. The flash memory controller of claim 11, wherein the at least one set of parity check codes is a at least one set of temporary parity check codes, and the microprocessor is arranged for reading the first to N-th sets of parity check codes to generate multiple sets of final parity check codes according to the first to N-th sets of parity check codes, and writing the multiple sets of final parity check codes into the super block.

13. The flash memory controller of claim 12, wherein multiple word lines positioned on a same plane of each block forms a word line set, and the microprocessor is arranged for writing the multiple sets of final parity check codes into data pages of a flash memory chip corresponding to last two word line sets of the super block.

14. The flash memory controller of claim 8, wherein the multiple-level cell blocks are TLC blocks or QLC blocks.

15. A memory device, comprising:

a flash memory module being a 3D flash memory module including a plurality of flash memory chips, each flash memory chip including a plurality of blocks which include a plurality of multiple-level cell blocks, each block including a plurality of data pages and including a plurality of word lines respectively disposed on a plurality of different planes and a plurality of floating transistors controlled by a plurality of bit lines, floating transistors on each bit line forming at least one page among the plurality of data pages; and

a flash memory controller, configured for accessing the flash memory module;

wherein when receiving a writing instruction from a host device to write data into the flash memory module, the flash memory controller is arranged for;

using a first codec to perform encoding upon data to generate at least one set of parity check codes and using a second codec to encode the at least one set of parity check codes to generate at least one set of final parity check codes, wherein the data is to be written into a super block of the flash memory chips and the super block includes one multiple-level cell block of each flash memory chip among the flash memory chips; and

writing the data and the at least one set of final parity check codes into the super block;

wherein each flash memory chip of the 3D flash memory module has a plurality of 3D stacked planes;

all word lines disposed on a same 3D stacked plane are classified into a same word line set;

all word line sets are classified into a group of multiple odd word line sets and a group of multiple even word line sets; and

, the at least one set of parity check codes is generated for data disposed on particular word lines associated with a same order respectively comprised within the multiple odd word line sets or the multiple even word line sets.