Memory Die Self-Disable via Programmable Chip Enable Circuitry
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Solution Overview
Problem
In semiconductor memory devices, defective memory dies in multi-die packages often exceed redundancy capacity or have failing peripheral circuitry, leading to unusable devices, and existing defect management schemes struggle to effectively handle untrustworthy programmable elements that indicate defects.
Innovation Solution
The implementation of programmable chip enable circuitry that self-disables defective memory dies upon power-on reset by overriding the external chip enable signal if the programmable element cannot be trusted, allowing functional dies to continue operating while preventing defective ones from being used, thereby increasing yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If defective memory dies are rejected from multi-die packages, then reliability of the memory device is improved, but productivity and yield are worsened due to loss of functional dies
Solution Approach 1:
The patent divides the multi-die package into independently controllable segments by implementing individual chip enable circuitry for each memory die. This allows functional dies to be separated and enabled while defective dies are disabled, resolving the contradiction by enabling selective operation of package components rather than treating the package as a single unit.
Solution Approach 2:
The patent applies local quality by implementing defect-specific disabling mechanisms tailored to each memory die's defect profile. Instead of uniformly rejecting entire packages, the system applies localized disablement only to affected dies while preserving functionality of unaffected dies, thereby maintaining reliability without sacrificing yield.
2Reliability
If redundant memory cells are used to replace defective cells, then reliability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the defect management burden from the redundancy mechanism by implementing a separate disablement pathway for defective dies. Instead of relying solely on complex in-place redundancy management, the system extracts defective components from the operational system through disablement, simplifying the overall defect management approach while maintaining reliability.
3Reliability
If entire memory chips are rejected when peripheral circuitry fails, then reliability is improved, but productivity is worsened due to loss of functional memory arrays
Solution Approach 1:
The patent segments the memory package into independently addressable and controllable dies, each with its own enable/disable control. This allows the memory array portion to be separated from the peripheral circuitry, enabling scenarios where functional memory arrays can operate even when associated peripheral circuitry on the same die is defective.
Solution Approach 2:
The patent applies local quality by implementing defect-specific disabling that targets only the affected peripheral circuitry or die while preserving functionality of memory arrays and other components that remain operational. This localized approach maintains productivity by keeping functional components active rather than rejecting entire chips.
Data Source
AI summary
Techniques are disclosed herein for automatically self-disabling a memory die in the event that a programmable element on the memory die for indicating whether the memory die is defective cannot be trusted. Memory die are provided with chip enable circuitry to allow particular memory die to be disabled. If the programmable element can be trusted, the state of the programmable element is provided to the chip enable circuitry to enable/disable the memory die based on the state. However, if the programmable element cannot be trusted, then the chip enable circuitry may automatically disable the memory die. This provides a greater yield for multi-chip memory packages because packages having memory die with a programmable element that cannot be trusted can still be used.