Memory Repair Categorization Tracking for Semiconductor Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Manufacturing-induced defects in semiconductor memory devices, despite the use of redundant memory cells for repair, can lead to reliability concerns, causing manufacturers to hesitate in shipping repaired units for critical applications due to potential susceptibility to failures at customer sites.
Innovation Solution
Implementing a tracking system using a die identification block with pre-defined categories for soft and hard repairs, enabling the use of multi-binning test methods and efuse bits to categorize and track repair categories, allowing for efficient screening and analysis of unreliable parts during Early Failure Rate and High Temperature Operating Life testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If redundant memory cells are used to repair defective memory cells, then device yield and functionality are improved, but reliability concerns increase due to potential failures at customer sites
Solution Approach 1:
The patent segments repaired devices into distinct categories (soft repair, hard repair, mixed repair) based on the type of defects and repair methods used. This segmentation allows manufacturers to track and analyze reliability data by repair category, identifying which repair types maintain acceptable reliability levels for critical applications while still maximizing overall yield through repair of all defect types.
Solution Approach 2:
The patent changes the parameter of defect characterization by introducing multiple defect categories (soft defects, hard defects, stuck-at faults, functional failures) and corresponding repair categories. This parameter change enables differentiated reliability assessment, allowing repaired devices with certain defect types to be shipped for critical applications while others are restricted, thereby resolving the contradiction between yield and reliability.
2Reliability
If all repaired devices are restricted from critical applications, then reliability risk is reduced, but device yield and manufacturing efficiency decrease
Solution Approach 1:
The patent applies local quality by assigning different quality levels (reliability certifications) to different subsets of repaired devices based on their specific defect and repair characteristics. Rather than uniformly restricting all repaired devices, the system identifies specific repair categories that maintain acceptable reliability, allowing those devices to be used in critical applications while restricting only the problematic categories, thus preserving yield while managing risk.
Solution Approach 2:
The patent implements feedback mechanisms through tracking systems that monitor field failure rates by repair category. This feedback loop allows manufacturers to continuously refine which repair categories are approved for critical applications based on actual reliability performance data, enabling dynamic optimization of the balance between yield and reliability risk.
3Measurement precision
If detailed tracking of repair categories is implemented, then reliability analysis and defect identification are improved, but device complexity and manufacturing process complexity increase
Solution Approach 1:
The patent applies preliminary action by categorizing defects and repairs during the manufacturing test phase before devices leave the factory. Repair category information is captured and stored in device metadata or identification structures during initial testing and repair operations. This preliminary categorization enables detailed reliability analysis without adding complexity to field operations, as the classification work is completed upfront during manufacturing.
Solution Approach 2:
The patent introduces intermediary data structures (defect category codes, repair category identifiers, metadata fields) that bridge the gap between complex repair processes and simple tracking requirements. These intermediary elements provide a standardized interface for recording and retrieving repair information, simplifying the overall system by creating a uniform method for handling diverse repair scenarios without requiring complex custom tracking for each device type.
Data Source
AI summary
An integrated circuit includes a set of non-volatile bits that may be programmed during multiprobe testing of the integrated circuit (IC). A defective portion of the IC is identified by testing the IC during multiprobe testing prior to packaging the IC. The IC is scrapped if the defective portion of IC does not meet repair criteria. A defect category is selected that is indicative of the defective portion, wherein the defect category is selected from a set of defect categories. The defective portion is replaced with a standby repair portion by modifying circuitry on the IC. The selected defect category is recorded in a plurality of non-volatile bits on the IC. The non-volatile bits may be read after extended testing or after end-user deployment in order to track failure rate of repaired ICs based on the defect category.