Fuse ROM Redundancy Repair for Memory Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increased density and reduced feature size of integrated circuit memories lead to higher failure rates, particularly in fuse farms used for redundancy, resulting in yield reduction and potential customer goodwill issues due to in-field programming failures.
Innovation Solution
A memory repair system utilizing a non-volatile memory component with replacement memory locations and a controller that reads and transfers data to defective memory locations, employing efficient use of fuse ROM redundancy by storing replacement row indexing information and accessing it to maintain memory functionality and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuse ROM is implemented in non-erasable memory technology to store repair information, then security and data integrity are improved, but pre-shipment testing becomes impossible and in-field programming failures increase
Solution Approach 1:
The fuse ROM is divided into multiple bank groups, where each bank group contains multiple banks. This segmentation allows the system to isolate and repair defects at the bank level rather than requiring the entire fuse ROM to be functional, enabling partial operation and improved yield.
Solution Approach 2:
The system performs bank group selection and repair information loading during initialization before the device is put into service. This preliminary action ensures that repair configurations are established in advance, allowing the system to compensate for defects without requiring pre-shipment testing of individual fuse ROM cells.
2Productivity
If spare memory cells are included to replace defective cells, then yield is improved, but die area increases
Solution Approach 1:
The fuse ROM banks serve dual purposes: storing repair information for on-chip memory cells and providing redundancy for themselves. The same physical structure is used for both primary functionality and backup, eliminating the need for separate spare areas.
Solution Approach 2:
When a fuse ROM bank is found to be defective, the system discards that specific bank and recovers functionality by loading repair information from a different bank group during initialization. This allows the system to recover from defects without requiring additional physical space.
3Ease of repair
If fuse ROM stores all repair information, then repair capability is improved, but vulnerability to single point of failure increases
Solution Approach 1:
The fuse ROM is segmented into multiple independent banks organized in bank groups. Each bank can be independently selected and used to store repair information. This segmentation eliminates the single point of failure problem by distributing repair information across multiple isolated storage locations.
Solution Approach 2:
The system changes the operational parameter from using a single fuse ROM bank to selecting from multiple banks based on initialization results. This parameter change allows dynamic adaptation to defects while maintaining comprehensive repair capability.
Data Source
AI summary
A system and method for making efficient use of fuse ROM redundancy to increase yield and security. Some embodiments provide a memory repair system including a non-volatile memory component and a controller coupled to the non-volatile memory component. The non-volatile memory component includes a plurality of memory locations. The plurality of memory locations includes a replacement memory location to replace a faulty memory location and a replacement indicia memory location to store replacement memory location indicia. The controller coupled to the non-volatile memory component reads replacement memory location indicia from the replacement indicia memory location, determines an address for the replacement memory location using the indicia, reads the replacement memory location, and transfers a data value contained in the replacement memory location to a second memory component to repair a defective memory location of the second memory component.