Test Key Structure for Non-Destructive Step Height Measurement
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Solution Overview
Problem
Current methods for measuring step height on semiconductor substrates are either destructive, time-consuming, or lack precision, failing to provide a quick and non-destructive solution necessary for steady process control in semiconductor manufacturing.
Innovation Solution
A test key structure comprising a substrate with a pair of test contacts, one on the diffusion region and one on the isolation region, allowing for indirect measurement of step height by calculating the difference in electrical resistances, which are referenced against a database to derive the step height non-destructively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If atomic force microscope is used to measure step height, then measurement precision is improved, but measurement time increases and productivity decreases
Solution Approach 1:
The patent replaces the mechanical scanning system of atomic force microscopy with an electrical measurement system. By measuring electrical resistance through test contacts and correlating it with step height via database lookup, the system achieves rapid measurements without mechanical scanning, thus improving productivity while maintaining measurement capability.
2Productivity
If transmission electron microscopy is used to measure step height, then measurement time is reduced, but the substrate is destroyed
Solution Approach 1:
The patent uses the substrate's own electrical properties (resistance) to measure step height. The test contacts are formed on the substrate itself, and the measurement process utilizes the substrate's inherent electrical characteristics without introducing external damage, enabling non-destructive rapid measurement.
Solution Approach 2:
The patent introduces electrical resistance as an intermediary parameter to indirectly measure step height. Instead of directly imaging the surface like TEM, the system measures electrical resistance through test contacts and uses database correlation to determine step height, avoiding the destructive electron beam exposure while maintaining measurement capability.
3Measurement precision
If conventional measurement methods are used, then measurement capability is achieved, but process control efficiency decreases due to time consumption
Solution Approach 1:
The patent performs preliminary work by forming test contacts during the semiconductor manufacturing process itself. The test contacts are created alongside the actual device structures, so that when measurement is needed, the infrastructure is already in place, eliminating the need for separate sample preparation and enabling immediate rapid measurement.
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 quick, precise, and non-destructive measurement of step height, facilitating improved process control and ensuring the quality and reliability of semiconductor manufacturing by avoiding substrate damage.
Implementation Method 1
The test contact pair includes a first test contact and a second test contact for measuring electrical resistances
Data Source
AI summary
A test key structure for use in measuring step height includes a substrate, and a pair of test contacts. The substrate includes an isolation region and a diffusion region. The test contact pair includes a first test contact and a second test contact for measuring electrical resistances. The first test contact is disposed on the diffusion region and the second test contact is disposed on the isolation region.