Semiconductor Memory Repair with ECC-Guided Redundant Word Lines
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Solution Overview
Problem
As the manufacturing process of volatile memory devices like DRAM becomes more refined, the number of defective memory cells increases, leading to reliability issues that existing repair methods struggle to address effectively.
Innovation Solution
A semiconductor device and method that utilize error correction codes (ECC) to correct errors in memory cell rows, deactivate word lines with excessive errors, and activate redundancy word lines to replace defective cells, reducing the need for physical disconnection or fusing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the manufacturing process is refined to increase integration, then the degree of integration increases, but the number of defective cells increases
Solution Approach 1:
The patent applies preliminary action by providing spare rows and spare columns during the manufacturing process before defects occur. These redundancy resources are prepared in advance and can be activated when defects are detected, allowing the system to maintain functionality despite manufacturing imperfections. The host device detects defective cells and activates corresponding spare rows or columns to replace them, thus resolving the contradiction between high integration and defect occurrence.
2Reliability
If physical disconnection or fusing operations are used to repair defective cells, then defective cells are replaced, but device complexity and power consumption increase
Solution Approach 1:
The patent replaces mechanical repair operations (physical disconnection or fusing) with an electronic/software-based solution. The host device detects defective cells through error correction codes and activates spare rows or columns via control signals, eliminating the need for physical manufacturing operations. This substitution reduces device complexity and avoids additional power consumption associated with fusing operations, while still achieving reliable defect replacement.
3Reliability
If physical disconnection or fusing operations are used to repair defective cells, then defective cells are replaced, but power consumption increases due to power cutoffs
Solution Approach 1:
The patent replaces mechanical repair operations (physical disconnection or fusing) with an electronic/software-based solution. The host device detects defective cells through error correction codes and activates spare rows or columns via control signals, eliminating the need for physical manufacturing operations. This substitution reduces device complexity and avoids additional power consumption associated with fusing operations, while still achieving reliable defect replacement.
4Reliability
If spare rows or columns are provided for repair, then defective cells can be replaced, but device area increases
Solution Approach 1:
The patent applies local quality by providing spare rows and spare columns selectively at specific locations within the memory device structure. Rather than uniformly increasing area throughout the device, the redundancy resources are localized in specific regions, allowing efficient use of space. The host device activates only the specific spare row or column needed for each defective cell, minimizing the impact on overall device area while maintaining repair capability.
Data Source
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AI summary
A semiconductor device includes a host and a memory device including a first memory cell array corresponding to a plurality of word lines and a second memory cell array corresponding to a plurality of redundancy word lines. The host is configured to, based on an occurrence of a first type of error that is correctable through an error correction code (ECC) in a first memory cell row connected to a first word line in the first memory cell array, correct the first type of error through the error correction code. The host is configured to, based on a number of the occurrence of the first type of error in the first memory cell row exceeding a predetermined threshold value, deactivate the first word line and activate a first redundancy word line corresponding to the first word line among the plurality of redundancy word lines.