Programmable Reliability Aging Timer for IC Degradation
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Solution Overview
Problem
Semiconductor integrated circuits (ICs) face challenges in ensuring reliability as their lifetime varies based on customer demands, leading to inconsistent performance and reduced productivity due to insufficient reliability margins.
Innovation Solution
A reliability aging timer (RAT) system is implemented to control the IC's operational lifespan by applying stress tests based on customer-defined lifetimes, monitoring degradation, and adjusting operations or replacing IP blocks as necessary to maintain performance expectancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed reliability minimum requirement is applied to all ICs regardless of customer lifetime demands, then reliability testing becomes simplified and standardized, but IC productivity decreases due to insufficient reliability margins for shorter-lifetime applications
Solution Approach 1:
The patent implements dynamic adjustment of reliability aging timer values based on customer-specific lifetime demands. The RAT is configured with different time values corresponding to different IC lifetime requirements, allowing the system to adapt reliability testing parameters to match actual application needs rather than using a fixed standardized approach
Solution Approach 2:
The patent changes the parameter of reliability aging time based on customer lifetime demands. By inputting different lifetime values into the RAT configuration, the system adjusts the reliability testing duration and criteria to match specific application requirements, enabling optimized productivity for each customer segment while maintaining appropriate reliability margins
2Reliability
If reliability testing is performed with extended aging time to ensure long-term reliability, then reliability of long-lifetime ICs improves, but testing time and production cycle increase
Solution Approach 1:
The system dynamically adjusts the reliability aging timer value based on the IC's intended lifetime. For ICs designed for shorter operational lifetimes, the RAT is configured with proportionally shorter aging test durations, while ICs requiring long-term reliability receive extended testing periods, optimizing the balance between reliability assurance and production efficiency
Solution Approach 2:
The patent performs preliminary configuration of the RAT with appropriate time values based on customer lifetime demands before actual reliability testing begins. This preliminary setup allows the system to immediately apply the correct aging duration without adding time overhead during the testing phase
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The RAT system ensures ICs meet reliability standards by continuously operating or suspending functions based on degradation, thereby improving productivity and maintaining performance across varying customer-defined lifetimes.
Implementation Method 1
applying a drain voltage of an N-type metal oxide semiconductor (NMOS) transistor of the IC to a hot carrier injection (HCI) test pattern for the evaluation of characteristics of the NMOS transistor and sensing a drain-source current
Implementation Method 2
applying a gate voltage of a P-type metal oxide semiconductor (PMOS) transistor of the IC to a negative biased temperature instability (NBTI) test pattern for the evaluation of characteristics of the PMOS transistor and sensing a drain-source current
Implementation Method 3
applying a gate voltage of a transistor gate dielectric layer of the IC to a time dependent dielectric breakdown (TDDB) test pattern for the evaluation of characteristics of the transistor gate dielectric layer and sensing a gate current
Implementation Method 4
using a temperature adjustor, the temperature adjustor configured to measure a temperature of the test pattern and adjust the temperature of the test pattern of the RAT to maintain a temperature suitable for the lifetime of the IC according to the stress
Data Source
AI summary
An apparatus and a method which use a programmable reliability aging timer are provided. The apparatus includes a performance circuit configured to perform a function of an integrated circuit (IC), a memory unit configured to store a lifetime of the IC, a controller configured to set an aging target condition according to the lifetime stored in the memory unit, and a reliability aging timer (RAT) configured to apply stress to a test pattern according to the aging target condition and sense a result of the stress to determine the degradation of the IC. The RAT refreshes an operation of the performance circuit if it is determined that the IC degraded before the lifetime of the IC.