Fusebay Controller with Duplicate-Bit ECC for Reliable Fuse Readout
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Solution Overview
Problem
Current fusebay technologies face challenges in reliable data retrieval and margin testing due to increasing fuse densities and the floating body effect in silicon-on-insulator technologies, leading to sense threshold variations and reduced manufacturing yield.
Innovation Solution
A fusebay controller system incorporating a duplicate bit state machine and error correction code state machine, with selective enablement options, to reconstruct and correct data during retrieval and storage, improving data integrity and programming yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If fuse density is increased to improve storage capacity, then storage capacity is improved, but sense threshold variation increases leading to reduced reliability
Solution Approach 1:
The patent applies preliminary action by generating duplicate bits and ECC syndrome bits during the storage phase before retrieval occurs. This preprocessing allows the system to proactively combat potential sense threshold variations and data corruption that may occur during retrieval, thereby maintaining reliability despite increased fuse density.
Solution Approach 2:
The patent implements feedback mechanisms through ECC syndrome bit generation and interpretation. During retrieval, the system reads stored data, generates syndrome bits, and uses these feedback signals to detect and correct errors caused by sense threshold variation, thus maintaining reliable data retrieval even at high fuse densities.
2Manufacturing precision
If digital sense threshold optimization is used to improve programming robustness, then programming robustness is improved, but manufacturing yield decreases due to margin testing limitations
Solution Approach 1:
The patent applies preliminary action by pre-generating duplicate bits and ECC syndrome bits during the programming phase. This allows margin testing to be performed more effectively since the system can anticipate and compensate for threshold variations before they cause failures, thereby improving both programming precision and manufacturing yield simultaneously.
Solution Approach 2:
The patent implements beforehand cushioning by incorporating redundant duplicate bits and ECC capability during the programming process. This creates a buffer against sense threshold variations and programming uncertainties, allowing the system to maintain high manufacturing precision while improving manufacturing yield through enhanced error tolerance.
3Speed
If SOI technology is used to implement fuse sense circuits, then device performance is improved, but floating body effect causes additional sense threshold variation reducing reliability
Solution Approach 1:
The patent implements feedback by generating ECC syndrome bits during retrieval based on the actual sensed data. This feedback mechanism detects variations caused by the floating body effect in SOI technology and enables correction, thereby maintaining reliable data retrieval despite the inherent threshold instability of SOI-based sense circuits.
Solution Approach 2:
The patent applies copying by creating duplicate bits of the stored data. These copies are generated during programming and retrieved alongside the original data, providing redundant information that can be used to verify and correct errors caused by SOI floating body effects, thus maintaining reliability despite the technology's inherent variations.
4Quantity of substance
If array structures with shared bitlines are used to increase fuse density, then storage capacity is improved, but device leakage and data pattern variations increase causing sense uncertainty
Solution Approach 1:
The patent applies copying by generating duplicate bits for each stored bit. This creates redundant copies that can be compared during retrieval to detect and correct errors caused by device leakage and data pattern variations in array structures with shared bitlines, thereby maintaining sense accuracy despite increased fuse density.
Solution Approach 2:
The patent implements feedback through ECC syndrome bit generation and interpretation. During retrieval, the system uses these feedback signals to detect and correct sense errors caused by leakage and data pattern variations in high-density array structures, maintaining measurement precision despite increased fuse density.
Data Source
AI summary
Error correction is selectively applied to data, such as repair data to be stored in a fusebay for BIST/BISR on an ASIC or other semiconductor device. Duplicate bit correction and error correction code state machines may be included, and selectors, such as multiplexers, may be used to enable one or both types of correction. Each state machine may include an indicator, such as a “sticky bit,” that may be activated when its type of correction is encountered. The indicator(s) may be used to develop quality and yield control criteria during manufacturing test of parts including embodiments of the invention.