Semiconductor Memory Multi-Page Read Reliability
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Solution Overview
Problem
Current semiconductor memory devices face challenges in maintaining data reliability due to changes in threshold voltages of memory cells over time, leading to read errors and operational instability, especially in three-dimensional memory cell arrays.
Innovation Solution
The semiconductor memory device employs a multi-page read operation by simultaneously selecting and applying a read voltage to multiple word lines coupled to a page group, ensuring stable data retrieval even when threshold voltages decrease, and utilizes a content addressable memory block to manage operational parameters and retry data, enhancing operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional single-page read operation is performed on three-dimensional memory cells, then the device complexity is low, but the data read reliability deteriorates due to threshold voltage changes over time
Solution Approach 1:
The memory block is divided into multiple page groups, where each page group contains multiple physical pages that share common word lines. This segmentation allows the system to selectively activate multiple pages simultaneously through a unified read operation, improving reliability by reading from multiple threshold voltage profiles while maintaining manageable device complexity through structured organization.
Solution Approach 2:
The patent pre-organizes memory pages into page groups with shared word lines before operation. This preliminary structuring enables the peripheral circuit to perform multi-page reads by simply selecting the appropriate page group and applying a single read voltage to shared word lines, avoiding the complexity of individually managing multiple read operations while ensuring reliable data retrieval across varying threshold voltages.
2Reliability
If multiple word lines are simultaneously selected for multi-page read operation, then the data read reliability improves, but the use of energy increases
Solution Approach 1:
Multiple physical pages that share common word lines are merged into a single page group. When a read operation is performed on this page group, the same read voltage is simultaneously applied to all shared word lines, enabling parallel data retrieval from multiple pages. This merging approach improves data retrieval stability by accessing multiple pages in one operation while minimizing energy consumption by using a unified voltage application rather than separate operations for each page.
3Reliability
If a content addressable memory block is added to manage operational parameters, then the operational reliability improves, but the device complexity increases
Solution Approach 1:
The content addressable memory block serves multiple functions: it stores operational parameters for controlling memory cell operations, maintains retry data for error correction, and provides information for adaptive read voltage adjustment. By consolidating these diverse functions into a single memory structure, the patent improves operational reliability without proportionally increasing device complexity, as the same hardware resource supports multiple critical operations.
Data Source
AI summary
The semiconductor memory device may include a memory cell array and a peripheral circuit. The memory cell array may include a plurality of memory blocks. The peripheral circuit may perform a multi-page read operation on a selected memory block among the plurality of memory blocks. The peripheral circuit may select a first word line and a second word line, which are coupled to the selected memory block, and perform the multi-page read operation on the first and second word lines.