Auto-blow Memory Repair via BIST and Fuse Control
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Solution Overview
Problem
As chip density increases and process technology becomes smaller, memory defects become more common, necessitating an automated method to detect and store repair values to enhance yield and reduce costly automated test equipment (ATE) test time.
Innovation Solution
An integrated circuit method that collects defect information during built-in self-test (BIST) operations, automatically blows fuses, and uses this information to inform built-in self-repair (BISR) operations without software intervention, allowing for the loading of repair values into a register file and subsequent blowing of repair fuses to reconfigure memory blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If automated fuse blowing and defect collection is implemented, then ATE test time is reduced, but device complexity increases
Solution Approach 1:
The integrated circuit device performs self-diagnosis and self-repair through built-in self-test (BIST) and built-in self-repair (BISR) functionality. The defect collection circuit automatically collects defect information from memory blocks during BIST operations, and the fuse controller automatically blows fuses based on collected defects without requiring external software intervention, enabling the device to service itself
Solution Approach 2:
The system performs preliminary defect collection and fuse blowing operations during the ATE test process. By collecting defect information and blowing fuses before final repair operations, the system prepares the device for self-repair, reducing the need for subsequent external intervention and minimizing total test time
2Reliability
If multiple eFuses are used to repair silicon manufacturing defects, then manufacturing yield increases, but device complexity increases
Solution Approach 1:
The device automatically manages the fuse blowing process through integrated defect collection circuits and fuse controllers that operate without external software. This self-service approach simplifies the overall system by eliminating the need for complex external programming equipment while maintaining the ability to use multiple eFuses for repair
Solution Approach 2:
The defect collection circuit and fuse controller are designed to work with multiple memory blocks and numerous eFuses simultaneously. The system can collect defects from any memory block and blow any fuse based on the collected information, providing universal functionality that handles various defect scenarios without requiring separate dedicated circuits for each function
3Ease of repair
If built-in self-repair functionality is incorporated, then ease of repair improves, but device complexity increases
Solution Approach 1:
The BISR functionality enables the device to automatically repair itself by using collected defect information to control fuse blowing operations. The system identifies defects during BIST, collects the defect information, and uses this information to blow fuses that enable automatic repair, making the repair process self-service oriented
Solution Approach 2:
The patent combines defect collection, fuse control, and self-repair functionality into an integrated system. The defect collection circuit, fuse controller, and BISR logic work together as a unified mechanism, merging multiple functions into a cohesive self-repair system that simplifies the overall repair process despite the added complexity of individual components
Data Source
AI summary
In an example embodiment, a method may include collecting, at a controller within an integrated circuit, defect information indicative of defects identified during a built-in self-test (BIST) operation performed on plural memories embedded within the integrated circuit. Fuses within the integrated circuit may be blown based on the defect information collected automatically and without software intervention. The fuses blown may be used to inform a built-in self-repair (BISR) operation performed on the plural memories.