Embedded Memory Device Mask ROM E-Fuse Data Revision
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Solution Overview
Problem
Mask ROMs are inflexible and costly to revise or update due to their non-volatile, fixed data storage, requiring lengthy fabrication processes when errors or updates are needed, which hampers productivity.
Innovation Solution
An embedded memory device combining a mask ROM with an e-fuse memory, where the e-fuse memory can replace faulty data from the mask ROM, using multiplexers to selectively output corrected data, allowing for data updates without re-fabricating the mask ROM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mask ROM is used for data storage, then reliability of information maintenance is high, but ease of repair deteriorates because data cannot be revised
Solution Approach 1:
The patent combines mask ROM and e-fuse memory into a single embedded memory device. The mask ROM provides high reliability for information maintenance, while the e-fuse memory enables data revision capability. Both memory types work together in a unified structure with shared address decoders and data output pathways, allowing the system to simultaneously achieve reliability and ease of repair.
Solution Approach 2:
The patent introduces multiplexers as intermediary components that selectively route data from either the mask ROM or e-fuse memory to the output. This mediator mechanism allows the system to choose which memory source provides the data based on whether revision is needed, thereby enabling both high reliability and ease of repair without compromising either function.
2Duration of action of stationary object
If mask ROM is used for data storage, then non-volatile storage is achieved, but productivity deteriorates due to lengthy fabrication processes when updates are needed
Solution Approach 1:
The patent segments the data storage function into two parts: mask ROM for initial high-reliability data storage and e-fuse memory for subsequent updates. This segmentation allows the system to maintain non-volatile storage while enabling faster updates through the e-fuse memory without requiring lengthy re-fabrication processes.
Solution Approach 2:
The patent performs preliminary action by pre-programming the e-fuse memory with replacement data during the same fabrication process as the mask ROM. This preliminary preparation of update data in the e-fuse memory enables rapid data revision later without requiring time-consuming re-fabrication, thereby improving productivity while maintaining non-volatile storage.
3Ease of repair
If e-fuse memory is added to replace mask ROM limitations, then ease of repair is improved, but device complexity increases
Solution Approach 1:
The patent implements universality by designing the address decoder and data output pathways to serve both mask ROM and e-fuse memory functions. The same address decoding logic and data bus infrastructure are used for both memory types, reducing the need for separate complex control circuits and minimizing overall device complexity despite the dual-memory architecture.
Solution Approach 2:
The multiplexers serve as intermediaries that manage the interaction between mask ROM and e-fuse memory with minimal complexity. By using simple selection logic in the multiplexers rather than complex control circuits, the patent achieves ease of repair through the e-fuse memory while keeping the overall device complexity manageable.
Data Source
AI summary
An embedded memory device includes a mask ROM including a plurality of mask ROM cells and an address decoder configured to decode an address of the plurality of mask ROM cells; and an e-fuse memory configured to replace a part of data stored in the mask ROM with replacement data, the e-fuse memory including, a plurality of e-fuse memory cells configured to store the replacement data, and an e-fuse address selector configured to decode an address of the plurality of e-fuse memory cells and to selectively cause data of one or more of the plurality of e-fuse memory cells to be output based on the decoding result.