Virtual Memory Blocks Using Partial Good Word Line Groups
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Solution Overview
Problem
Conventional memory systems discard entire blocks when both upper and lower decks have defective word line groups (WGRs), reducing memory efficiency and performance.
Innovation Solution
A memory controller combines multiple partial good blocks (PGBs) to form virtual blocks (VBs) even when some WGRs are defective, utilizing configuration data to identify non-defective WGRs and form VBs with a minimum threshold percentage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If entire blocks are discarded when both upper and lower decks have defective word line groups, then reliability is maintained, but memory efficiency and productivity deteriorate
Solution Approach 1:
The patent divides a memory block into multiple word line groups (WGRs) and further segments them into upper and lower decks. This segmentation allows the system to identify and utilize non-defective segments (PGBs) within blocks that would otherwise be discarded, resolving the contradiction by maintaining reliability through selective usage while improving productivity by utilizing previously wasted capacity.
Solution Approach 2:
The patent applies local quality by treating different word line groups within a block differently based on their defect status. Instead of discarding entire blocks uniformly, the system identifies PGBs with sufficient non-defective WGRs and uses them to form virtual blocks, while leaving defective portions unused. This localized approach maintains reliability by avoiding defective areas while improving memory efficiency by utilizing healthy portions.
2Reliability
If memory blocks with defective WGRs are discarded, then data integrity is protected, but available memory space decreases
Solution Approach 1:
The patent changes the parameter threshold for block usability by introducing virtual blocks formed from PGBs that contain a minimum percentage of non-defective WGRs (e.g., at least 30%). This parameter change allows blocks with partial defects to be utilized for data integrity protection, thereby increasing the quantity of available memory space while maintaining acceptable reliability through the threshold requirement.
3Device complexity
If conventional block management is used, then system complexity is low, but memory utilization efficiency deteriorates
Solution Approach 1:
The patent introduces an intermediary layer (virtual blocks and PGB management logic) between the physical memory blocks and the host system. This intermediary handles the complexity of tracking non-defective WGRs, forming PGBs, and managing virtual blocks, thereby enabling high memory utilization efficiency while shielding the host from the underlying complexity through a standardized interface.
Data Source
AI summary
Aspects of the present disclosure configure a system component, such as a memory sub-system controller, to generate virtual or superblocks using multiple partial good blocks. The controller identifies a first partial good block (PGB) in a set of memory components, the first PGB having first subset of word line groups (WGRs) that are categorized as being non-defective. The controller searches for a second PGB in the set of memory components having a second subset of WGRs that are categorized as being non-defective. The controller computes a total quantity of WGRs based on the first quantity of WGRs in the first subset of WGRs and a second quantity of WGRs in the second subset of WGRs and, in response, combines the first PGB and the second PGB to form an individual virtual block.