Simultaneous TDDB and BTI Testing for Semiconductor Reliability
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Solution Overview
Problem
Current methods for testing integrated circuits require performing time-dependent dielectric breakdown (TDDB) and bias temperature instability (BTI) tests sequentially on different devices, leading to inefficiencies in data cross-referencing and longer testing times, which hampers the learning cycle and process adjustments in semiconductor manufacturing.
Innovation Solution
Performing TDDB and BTI tests simultaneously on the same device using a unified test signal, allowing for the acquisition and analysis of data related to dielectric breakdown and transistor characteristics, enabling cross-correlation of test data for more efficient process adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TDDB and BTI tests are performed sequentially on different devices, then each test can be conducted with dedicated test signals and procedures, but the testing time increases and data cross-referencing becomes inefficient
Solution Approach 1:
The patent combines TDDB and BTI tests into a single unified test structure that can be performed simultaneously on the same device. The test signal is designed to apply both time-dependent dielectric breakdown stress and bias temperature instability conditions through integrated signal paths, allowing both failure mechanisms to be evaluated in one testing sequence rather than requiring separate sequential tests on different devices.
Solution Approach 2:
The test structure and signal design enable a single testing apparatus to perform multiple functions - both TDDB evaluation and BTI characterization - using shared test paths and signal generation circuits. This multi-functional approach allows the same device to be subjected to both types of reliability testing without requiring separate dedicated test structures for each failure mechanism.
2Productivity
If TDDB and BTI tests are performed on the same device simultaneously, then testing time is reduced and data cross-referencing is enhanced, but test signal complexity increases
Solution Approach 1:
The unified test signal is segmented into distinct components that can be independently controlled and adjusted. The signal includes separate stress application paths for TDDB and BTI conditions, with independent voltage ramps and bias configurations that can be activated or modified based on specific testing requirements. This segmentation allows complex simultaneous testing while maintaining controllability through modular signal components.
Solution Approach 2:
The patent introduces intermediary test structures and signal conditioning circuits that facilitate the simultaneous application of TDDB and BTI stress conditions. These intermediary elements act as mediators between the test signal source and the device under test, enabling complex multi-functionality while shielding the control system from excessive complexity through standardized interface circuits.
3Ease of manufacture
If sequential testing on different devices is used, then test setup is simpler, but data correlation between TDDB and BTI results is less effective for process adjustments
Solution Approach 1:
By merging TDDB and BTI measurements into a single simultaneous test on one device, the patent ensures that both failure mechanism data points are obtained under identical process conditions and from the same physical instance. This eliminates variability introduced by device-to-device differences and enables direct correlation between TDDB breakdown voltage and BTI threshold shift for the same transistor, providing richer information for process optimization.
Data Source
AI summary
At least one method and system involves performing a time-dependent dielectric breakdown (TDDB) test and a bias temperature instability (BTI) test on a device. A device having at least one transistor and at least one dielectric layer is provided. A test signal is provided for performing a TDDB test and a BTI test on the device. The TDDB test and the BTI test are performed substantially simultaneously on the device based upon the test signal. The data relating to a breakdown of the dielectric layer and at least one characteristic of the transistor based upon the TDDB test and the BTI test is acquired, stored, and/or transmitted.