TSV Defect Detection in 3D Packaging via Signal Propagation
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Solution Overview
Problem
In 3D integrated circuits, Through Silicon Vias (TSVs) are prone to defects, particularly shorts, which degrade signal quality due to their susceptibility to resistive paths between TSVs and ground, affecting signal fidelity and reliability in high-speed serial links.
Innovation Solution
A system and method for detecting TSV defects using a computer that determines threshold signal voltage and propagation time through test paths, employing multiplexers, edge detectors, delay monitors, and test engines to identify defects by transmitting signals and measuring voltage and propagation time, determining if the signal reaches the threshold within the expected time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If TSVs are used for signal transfer in 3D stacks, then integration density and signal transfer capability are improved, but defect susceptibility and signal fidelity degradation increase
Solution Approach 1:
The patent implements preliminary defect detection by transmitting test signals through TSVs before final product deployment. The system performs signal propagation time measurements and voltage threshold comparisons in advance to identify defective TSVs, enabling early detection and isolation of potential reliability issues while maintaining high integration density.
Solution Approach 2:
The patent introduces test signals as an intermediary mechanism to detect TSV defects. By using dedicated test signal transmission paths and comparison against reference values, the system can identify defective TSVs without directly observing the physical condition, thus maintaining signal fidelity while enabling defect detection in high-density 3D stacks.
2Measurement precision
If signal transmission through TSVs is monitored continuously, then defect detection capability is improved, but system complexity and measurement requirements increase
Solution Approach 1:
The patent implements partial monitoring by selecting specific TSVs for test signal transmission based on predefined criteria rather than continuously monitoring all TSVs. The system transmits test signals through selected test paths and compares results against reference values, achieving adequate defect detection capability while avoiding the complexity of comprehensive continuous monitoring of all TSVs in the 3D stack.
Data Source
AI summary
A computer determines a threshold signal voltage of a semiconductor device. The computer determines a first expected signal propagation time for a signal travelling through a first test path of the semiconductor device. The computer transmits a first signal through the first test path. The computer measures a signal voltage and signal propagation time of the first signal. The computer determines that the signal voltage of the first signal does not reach or exceed the threshold signal voltage within the first expected signal propagation time. The computer determines that the first test path contains a defect.