Misalignment Measurement Structure Using Segmented Conductive Patterns
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Solution Overview
Problem
Current methods for measuring misalignment of patterns in semiconductor devices often damage the wafer and are inaccurate, as they rely on detecting changes in resistance or light reflection, which can fail to detect misalignment due to changes in contact areas between patterns.
Innovation Solution
The use of two electrically insulated wirings with upper and lower patterns that change resistance in response to misalignment, allowing for precise measurement of misalignment by applying voltages and measuring currents through these wirings, which are formed on a substrate in a scribe lane region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light reflection or resistance change is used for measuring misalignment, then measurement can be performed, but the measurement accuracy is insufficient and may not detect real misalignment
Solution Approach 1:
The measurement structure is divided into multiple independent wiring units (first wiring with first upper/lower patterns, second wiring with second upper/lower patterns). Each wiring independently measures misalignment in different regions, and their resistance changes are compared to detect real misalignment, thereby improving measurement accuracy and reliability.
Solution Approach 2:
The invention measures misalignment by detecting resistance changes in conductive patterns rather than using light reflection. The resistance parameter is changed and monitored to detect misalignment, providing more accurate and reliable measurement compared to optical methods.
2Measurement precision
If misalignment measurement is performed on the actual wafer, then real misalignment data is obtained, but the wafer is damaged during measurement
Solution Approach 1:
The invention uses a test substrate that copies the structure and pattern layout of the actual wafer. Misalignment measurement is performed on this copy rather than the original wafer, allowing real misalignment data to be obtained without damaging the actual production wafer.
3Device complexity
If single wiring structure is used for misalignment measurement, then device complexity is reduced, but measurement reliability is insufficient
Solution Approach 1:
The measurement system is segmented into multiple independent wiring units positioned at different locations. Each wiring unit consists of upper and lower conductive patterns that form independent resistance measurement paths, enabling more reliable misalignment detection through comparison of multiple measurement points.
Solution Approach 2:
Multiple wiring structures are combined in the measurement system, with each wiring contributing to the overall measurement reliability. The first and second wirings are electrically insulated from each other but work together to provide comprehensive misalignment detection, improving reliability while maintaining manageable complexity.
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 accurate detection of misalignment between upper and lower patterns along a specific direction, improving the design rule and stability of semiconductor devices by avoiding damage to the actual wafer during measurement.
Implementation Method 1
The first wiring may have a first resistance which changes according to a first misalignment between the first upper pattern and the first lower pattern in the y-direction. The second wiring may have a second resistance which changes according to a second misalignment between the second upper pattern and the second lower pattern in the y-direction.
Data Source
AI summary
A structure for measuring misalignment of patterns may include a first wiring and a second wiring. The first wiring may include a first lower pattern and a first upper pattern. The first upper pattern may extend in a y-direction, and a first end portion of the first upper pattern that is relatively further toward (proximal to) a negative y-direction may contact the first lower pattern. The second wiring may include a second lower pattern and a second upper pattern. The second upper pattern may extend in the y-direction, a second end portion of the second upper pattern that is relatively further toward (proximal to) a positive y-direction may contact the second lower pattern. The second wiring may be spaced apart from the first wiring along the negative y-direction.