IP Library Granted Patent US 8,976,609
Granted Patent B1
US 8,976,609 · App. 14/311,143 · Granted Mar 10, 2015

Low-test memory stack for non-volatile storage

Inventors: Jack Edward Frayer (Boulder Creek, CA); Vidyabhushan Mohan (San Jose, CA)
Assignee: SanDisk Enterprise IP LLC
G11C29/04H01L22/14G11C2029/0403
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Quick Facts
Patent No.
US 8,976,609
App. No.
14/311,143
Granted
Mar 10, 2015
Kind
B1
Abstract

The various embodiments described herein include systems, methods and/or devices used to packaging non-volatile memory. In one aspect, the method includes, selecting, from a set of non-volatile memory die, a plurality of non-volatile memory die on which predefined die-level and sub-die level tests have been deferred until after packaging, in accordance with predefined criteria and predefined statistical die performance information corresponding to the set of non-volatile memory die. The method further includes packaging the selected plurality of non-volatile memory die into a memory device. After said packaging, the method further includes performing a set of tests on the plurality of non-volatile memory die in the memory device to identify respective units of memory within the non-volatile memory die in the memory device that meet predefined validity criteria, wherein the set of tests performed include the deferred predefined die-level and sub-die level tests.

Claims (26)

1. A method for packaging non-volatile memory, comprising:

selecting, from a set of non-volatile memory die, a plurality of non-volatile memory die on which predefined die-level and sub-die level tests have been deferred until after packaging, in accordance with predefined criteria and predefined statistical die performance information corresponding to the set of non-volatile memory die;

packaging the selected plurality of non-volatile memory die into a memory device; and

after said packaging, performing a set of tests on the plurality of non-volatile memory die in the memory device to identify respective units of memory within the non-volatile memory die in the memory device that meet predefined validity criteria, wherein the set of tests performed include the deferred predefined die-level and sub-die level tests.

2. The method of claim 1 , wherein the selecting includes selecting the plurality of non-volatile memory die in accordance with wafer positions of the plurality of non-volatile memory die.

3. The method of claim 1 , wherein the selecting includes selecting the plurality of non-volatile memory die in accordance with wafer positions of the plurality of non-volatile memory die and statistical die performance information corresponding to the wafer positions.

4. The method of claim 1 , further including:

deferring at least until the selected plurality of non-volatile memory die are packaged into the memory device, or forgoing entirely, performance of at least one of the following tests: a wafer sort test, a memory component test, a known good die test, and a burn-in test.

5. The method of claim 1 , wherein the selecting includes:

in accordance with the predefined statistical die performance information, selecting a number of die so as to over-provision the memory device to guarantee, within a predefined statistical tolerance, a minimum amount of programmable/erasable memory in the memory device.

6. The method of claim 1 , further including:

after packaging the plurality of non-volatile memory die into the memory device, determining an amount of programmable/erasable memory in the memory device.

7. The method of claim 1 , further including:

after packaging the plurality of non-volatile memory die into the memory device, during initialization of the memory device, performing an initialization procedure that includes determining a validity state of one or more units of memory of the plurality of non-volatile memory die, the validity state being one of a valid state or an invalid state; and

using physical-to-physical address remapping to redirect a read/write request addressed to a respective unit of memory having an invalid state to a unit of memory having a valid state.

8. The method of claim 7 , wherein determining a validity state of the one or more units of memory includes:

determining a validity metric of the one or more units of memory; and

comparing the validity metric to a predefined threshold to determine the validity state of the one or more units of memory.

9. The method of claim 8 , wherein the validity metric is a bit error rate (BER) of the one or more units of memory during initialization.

10. The method of claim 8 , further including:

writing to the plurality of non-volatile memory die in accordance with a wear leveling algorithm that accounts for the validity metric determined during initialization.

11. The method of claim 1 , wherein the set of non-volatile memory die comprises flash memory.

12. The method of claim 1 , wherein a median number of program/erase (P/E) cycles performed on units of memory of the plurality of non-volatile memory die prior to the packaging is less than fifty P/E cycles.

13. A storage system, comprising:

an interface for operatively coupling the storage system with a host system; and

a plurality of non-volatile memory die selected, packaged, and tested in accordance with the method of claim 1 .

Assignments (3)
CHANGE OF NAME Recorded May 25, 2016
From: SANDISK TECHNOLOGIES INC
To: SANDISK TECHNOLOGIES LLC
Reel/Frame 038807/0948 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 29, 2016
From: SANDISK ENTERPRISE IP LLC
To: SANDISK TECHNOLOGIES INC.
Reel/Frame 038295/0225 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 24, 2014
From: FRAYER, JACK EDWARD; MOHAN, VIDYABHUSHAN
To: SANDISK ENTERPRISE IP LLC
Reel/Frame 033382/0376 →
Continuity (1)
Provisional Application 62012918 · Jun 16, 2014