Memory Device Post-Package Repair via Programmable Storage
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Solution Overview
Problem
Conventional memory devices struggle to perform effective repairs after packaging due to limitations in fuse circuits, such as laser fuses, which cannot be programmed post-wafer and lack the ability to address defects discovered after packaging.
Innovation Solution
The implementation of a programmable storage unit, like an E-fuse array circuit or other types of flash memories, within the memory device to store repair information, allowing for the programming of fail addresses and enabling post-package repair operations by entering a repair mode, temporarily storing fail addresses, and programming them into the programmable storage unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If laser fuses are used to store repair information, then the memory device can perform repair operations, but the fuse circuit cannot be programmed after wafer mounting and has limited adaptability to post-package defects
Solution Approach 1:
The patent changes the fundamental parameter of the storage medium from non-programmable laser fuses to programmable memory cells (SRAM, TRAM, PCRAM, MRAM, or NAND flash). This parameter change enables the storage unit to be programmed after packaging, allowing the memory device to adapt to and store repair information for defects discovered post-package, thereby resolving the contradiction between adaptability and reliability.
2Area of stationary object
If conventional fuse circuits are used, then the circuit area is small, but the line pitch is limited and prevents small circuit area designs
Solution Approach 1:
The patent replaces the mechanical/optical fuse system (laser fuses) with an electronic programmable memory system. This substitution eliminates the physical line pitch constraints inherent in fuse-based designs, enabling smaller circuit areas while maintaining or improving programmability through electronic control mechanisms.
3Productivity
If repair information is stored in registers, then the repair operation can be performed quickly, but the repair information is lost when power is supplied and cannot be retained
Solution Approach 1:
The patent merges the functionality of temporary storage (registers) and permanent storage (programmable storage unit) into a hybrid system. The programmable storage unit retains repair information across power cycles, while the system can still perform rapid repair operations by reading from the stored information, thus combining the advantages of both fast access and data retention.
4Adaptability or versatility
If the programmable storage unit is programmed during active operation, then post-package repair is enabled, but the refresh operation cannot be performed concurrently and data may be lost
Solution Approach 1:
The patent implements preliminary action by entering a repair mode before programming the fail address into the programmable storage unit. This mode change prepares the system state in advance, allowing the programming operation to be performed without interrupting normal refresh operations, thus preventing data loss while enabling post-package repair capability.
Data Source
AI summary
An operating method of a memory device includes entering a repair mode, receiving an active command and a fail address, and temporarily storing the received command and address, receiving a write command, and determining whether to perform a program operation, when the program operation is determined to be performed, programming the temporarily-stored fail address into a programmable storage unit, and receiving a precharge command before the programming of the temporarily-stored fail address is completed.