Fail Bit Repair via Recursive Redundant Circuit Allocation
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Solution Overview
Problem
Current redundant circuit allocation methods for repairing Fail Bits (FBs) in integrated circuit chips are non-optimal, leading to incomplete repair of FBs and high chip scrap rates due to limited repair ranges and inefficient allocation of Redundant Bit-Lines (RBLs) and Redundant Word-Lines (RWLs.
Innovation Solution
The proposed method involves determining a bank to be repaired, performing initial compression processing to reduce the number of bits, dividing the bank into target repair regions, and using a recursive FB position determination step to identify and repair unrepaired FBs using redundant circuits, optimizing the allocation of RBLs and RWLs for effective FB repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant circuits are allocated using conventional methods, then repair processing can be performed, but the allocation is non-optimal leading to incomplete repair of FBs
Solution Approach 1:
The patent divides the bank to be repaired into multiple target repair regions, and further divides each target repair region into multiple sub-regions. This segmentation allows for systematic identification and repair of FBs in different regions using different allocation modes (first allocation mode for initial repair, second allocation mode for remaining FBs), ensuring complete repair while managing complexity through structured division of the repair task.
Solution Approach 2:
The patent performs preliminary compression processing on the bank to be repaired before dividing it into target repair regions. This preliminary action reduces the data size and simplifies subsequent processing. Additionally, the method determines FB positions in advance through testing before allocating redundant circuits, allowing for optimized repair strategies to be applied systematically.
2Productivity
If conventional FB repair methods are used, then some FBs can be repaired, but chip scrap rates are high due to limited repair ranges
Solution Approach 1:
The patent employs a universal repair framework that can handle different types of FBs through multiple allocation modes. The first allocation mode repairs FBs in specific regions, while the second allocation mode handles remaining FBs, creating a multi-functional repair system that maximizes the utilization of redundant circuits across the entire chip, thereby increasing repair yield without sacrificing effectiveness.
Solution Approach 2:
The patent implements a dynamic repair process where the allocation mode changes based on the repair progress. Initially, the first allocation mode is used to repair FBs in target repair regions, then the second allocation mode is applied to repair remaining FBs. This dynamic adaptation of repair strategies ensures maximum repair effectiveness while systematically addressing all FBs on the chip.
3Reliability
If more redundant circuits are used to repair all FBs, then repair completeness improves, but repair costs increase
Solution Approach 1:
The patent changes the allocation parameters of redundant circuits based on the repair progress and FB distribution. By adjusting which allocation mode is applied to which region, the method optimizes the utilization of available redundant circuits, ensuring complete FB repair while minimizing the consumption of redundant circuit resources through intelligent parameter adjustment rather than simply increasing resource quantity.
Data Source
AI summary
A Fail Bit (FB) repair method and device can be applied to repairing an FB in a chip. The method includes: a bank to be repaired including multiple target repair regions in a chip to be repaired is determined; first repair processing is performed on a first FB in each target repair region by using a redundant circuit; a second FB position determination step is executed to determine a bit position of a second FB, and second repair processing is performed on the second FB; unrepaired FBs in each target repair region is determined, and the second FB position determination step is recursively executed to obtain a test repair position of each unrepaired FB to perform third repair processing on the unrepaired FB according to the test repair position.