Semiconductor Alignment Measurement Using Diffracted Light Intensity
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Solution Overview
Problem
Conventional methods for measuring and calculating pattern positional displacement in semiconductor devices with three-dimensional structures face challenges due to low alignment accuracy between lower and upper layer patterns, leading to incorrect positional displacement calculations.
Innovation Solution
A measuring and calculating apparatus that includes a measuring unit to measure two-dimensional intensity distributions of diffracted light, an arithmetic unit to calculate positional displacement based on measurement data, and a control unit to control operations, enabling precise calculation of positional displacement by analyzing diffracted light patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used for three-dimensional semiconductor structures, then the measurement process is simple, but the alignment accuracy between lower and upper layer patterns is low
Solution Approach 1:
The patent transitions from conventional two-dimensional alignment measurement to three-dimensional measurement by introducing focus variation technology. The measurement system captures intensity distributions at multiple focal planes (different Z-heights) to accurately measure patterns across multiple layers, thereby achieving high alignment accuracy in three-dimensional semiconductor structures without excessive system complexity
Solution Approach 2:
The patent changes the measurement parameters by using focus variation - adjusting the focal plane position (Z-height) to capture intensity distributions at different depths. This parameter change enables the system to measure patterns at different layer heights and calculate positional displacements accurately in three-dimensional structures
2Manufacturing precision
If conventional alignment measurement methods are used, then the measurement process is fast, but the positional displacement calculation is incorrect
Solution Approach 1:
The patent performs preliminary measurements by capturing intensity distributions at multiple focal planes before calculating positional displacements. This preliminary data collection at different Z-heights provides the necessary information for accurate three-dimensional alignment calculation, preventing incorrect results that would occur with conventional single-plane measurement methods
Solution Approach 2:
The patent replaces complex mechanical alignment adjustment with optical measurement and computational analysis. By using focus variation and intensity distribution analysis, the system calculates positional displacements automatically without requiring mechanical stage adjustments or physical alignment tools, thereby maintaining measurement speed while improving accuracy
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
The apparatus improves calculation accuracy of pattern positional displacement, allowing for precise adjustments during semiconductor device manufacturing and preventing operational failures caused by misalignment.
Implementation Method 1
measuring a first two-dimensional intensity distribution of first diffracted light and a second two-dimensional intensity distribution of second diffracted light
Data Source
AI summary
A measuring and calculating apparatus to measure and calculate a positional displacement amount of a pattern on a surface of a target object. The apparatus includes: a measuring unit to measure a first two-dimensional intensity distribution of a first diffracted light and a second two-dimensional intensity distribution of a second diffracted light; a storage unit to store a first and a second measurement data respectively indicating the first and the second two-dimensional intensity distribution; and an arithmetic unit to execute arithmetic processing using the first and the second measurement data to acquire difference data between the first and the second measurement data, and calculate a positional displacement amount of a difference pattern between the first and second patterns in accordance with the difference data.