In-Line Test Structure for E-Beam Estimation of Transistor Leakage
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Solution Overview
Problem
The reduced spacings between gates of transistors in semiconductor integrated circuits lead to increased bridging defects and leakage currents, necessitating a method to efficiently estimate electrical properties before interconnection structures are formed.
Innovation Solution
A test structure is fabricated on a semiconductor substrate using the same processes as the semiconductor device, allowing for in-line estimation of electrical properties through electron beam inspection, which induces secondary electrons and converts them into grayscale images to determine voltage biases and threshold voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spacing between gates of transistors is reduced to increase circuit density, then productivity is improved, but reliability deteriorates due to increased bridging defects and leakage currents
Solution Approach 1:
The patent applies preliminary action by performing electron beam inspection and electrical property estimation on the semiconductor substrate before forming interconnection structures. This early detection approach allows identification of bridging defects and vacancies in the gate spacing regions before they are obscured by subsequent processing steps, enabling preventive quality control while maintaining reduced spacing for high circuit density
2Productivity
If the spacing between gates of transistors is reduced to increase circuit density, then productivity is improved, but manufacturing precision deteriorates due to increased leakage currents through dielectric material
Solution Approach 1:
The patent replaces conventional electrical measurement methods with electron beam inspection technology. The electron beam system can detect electrical properties and estimate threshold voltages of transistors with high precision through non-contact measurement, allowing accurate characterization of leakage currents and other electrical defects even in tightly spaced gates where traditional probes cannot access
Solution Approach 2:
By performing electrical property estimation before interconnection formation, the system establishes a baseline for manufacturing precision that accounts for the actual electrical characteristics of the reduced-spacing transistor array, enabling subsequent process adjustments to compensate for variations in dielectric material performance
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
Enables immediate detection of device defects such as splits or vacancies, providing accurate estimation of electrical properties before interconnection, thereby ensuring quality control and reducing defects in semiconductor devices.
Implementation Method 1
electron beam inspection, which induces secondary electrons and converts them into grayscale images
Data Source
AI summary
A method for estimating at least one electrical property of a semiconductor device is provided. The method includes forming the semiconductor device and at least one testing unit on a substrate, irradiating the testing unit with at least one electron beam, estimating electrons from the testing unit induced by the electron beam, and estimating the electrical property of the semiconductor device according to intensity of the estimated electrons from the testing unit.