Sub-Block ECC Pages for Recovering Reflow-Damaged Memory Data

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Solution Overview

Problem

Existing error correction coding (ECC) schemes in memory devices are insufficient to correct errors caused by physical processes like reflow or polishing during the attachment of memory devices to printed circuit boards, leading to data corruption beyond their correction capability.

Innovation Solution

Providing additional ECC data external to the data blocks, specifically corresponding to sub-blocks, to enable correction of errors exceeding the main parity's capability, by using additional parity dedicated to individual sub-blocks, thereby enhancing error correction capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If standard ECC schemes are used for data storage, then data storage density is maintained, but error correction capability is insufficient for errors caused by manufacturing processes like reflow or polishing

Engineering Contradiction:

Improveerror correction capabilityVSAvoiddata storage density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent divides the data block into multiple sub-blocks and applies different ECC strategies to each sub-block. Specifically, it segments the protection mechanism into main ECC data for the entire data block and additional ECC data for individual sub-blocks, allowing targeted error correction where needed while maintaining overall storage efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements local quality by providing enhanced error correction protection specifically for sub-blocks that are more susceptible to manufacturing errors (such as pre-loaded content). The additional ECC data is selectively applied to sub-blocks based on their error susceptibility, rather than uniformly across all data, thus improving reliability where needed while preserving storage density

Inventive Principle:

Principle #3Local quality

2Reliability

If additional ECC data is provided for each sub-block, then error correction capability is enhanced, but memory space is consumed

Engineering Contradiction:

Improveerror correction capabilityVSAvoidmemory space

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies partial action by providing additional ECC data only for specific sub-blocks that require enhanced protection (such as pre-loaded content), rather than for all data blocks. This selective approach ensures that memory space is consumed only where necessary to correct manufacturing errors, balancing reliability enhancement with space conservation

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8806297B2Data recovery using additional error correction coding data

Publication Date: 2014.08.12 SANDISK TECHNOLOGIES LLC

AI summary

A method in a data storage device including a memory and an error correction coding (ECC) engine. A first ECC page including a data block and first main ECC data is stored to the memory. The first main ECC data is usable by the ECC engine to correct errors in the first ECC page. A second ECC page including first additional ECC data is also stored to the memory. The first additional ECC data is usable by the ECC engine to correct errors in a single sub-block of multiple sub-blocks within the data block.