Stacked Memory Remapping for Defect Repair
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Managing defective memory cells in multi-die memory devices is challenging, as existing technologies either reduce storage capacity or increase manufacturing yield by excluding spare cells, but struggle with replacing defective cells post-assembly when no spare cells are available.
Innovation Solution
The solution involves a stacked device architecture where spare cells can be used to replace defective cells, with an interface die that remaps memory address space to organize available cells into addressable and non-addressable portions, allowing for dynamic reconfiguration of memory access to maintain storage capacity and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spare cells are excluded to increase manufacturing yield, then manufacturing yield is improved, but storage capacity is reduced
Solution Approach 1:
The patent implements dynamic remapping capabilities that allow the memory system to adaptively reconfigure address mappings based on which cells are defective. The interface die can dynamically adjust the address space organization to utilize available spare cells, transforming a static memory structure into a dynamic one that can respond to manufacturing variations and maintain both yield and storage capacity.
Solution Approach 2:
The system changes the parameter of address mapping by organizing the address space into addressable and non-addressable portions. By modifying how addresses are mapped to physical cells through remapping operations, the system can exclude defective cells from the addressable space while utilizing spare cells, thereby maintaining storage capacity without sacrificing manufacturing yield.
2Quantity of substance
If spare cells are used to replace defective cells, then storage capacity is maintained, but device complexity increases
Solution Approach 1:
The patent segments the memory device into multiple dice stacked together, with each die containing memory cells and spare cells. The interface die is separated from the memory dice, creating distinct functional segments. This segmentation allows the complexity of spare cell management and remapping operations to be isolated to the interface die, while the memory dice remain relatively simple storage units.
Solution Approach 2:
The interface die acts as an intermediary between the external controller and the stacked memory dice. It handles the complex tasks of address remapping, defective cell detection, and spare cell management, shielding the simpler memory dice from these complexities. The interface die mediates all access operations, translating external addresses into appropriate physical cell addresses while managing the remapping logic.
3Reliability
If defective cells are replaced after assembly, then reliability is improved, but manufacturing yield decreases
Solution Approach 1:
The patent incorporates spare cells into the memory device during manufacturing, before the device is assembled and deployed. These spare cells are prepared in advance and can be used to replace defective cells if they are detected later. By performing the preparation of replacement cells in advance rather than requiring post-assembly intervention, the system maintains manufacturing yield while enabling future reliability improvements.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Various embodiments include apparatus, systems, and methods having multiple dice arranged in a stack in which a defective cell may be replaced by a spare cell on the same die or a different die.