Semiconductor Pattern Shape Measurement Using Independent Feedback
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Solution Overview
Problem
Conventional pattern shape measurement techniques, such as CD-SEM and scatterometry, struggle to accurately capture three-dimensional shape information of miniaturized semiconductor patterns, especially contact holes, due to limitations in obtaining feature values from spectral waveforms and the difficulty in distinguishing shape changes, leading to challenges in process control and yield improvement as semiconductor devices continue to miniaturize.
Innovation Solution
A method involving simulation-based waveform calculations, library creation, and database matching, combined with independent measurement apparatus feedback, to select the best-match calculated waveform and obtain accurate shape information, including three-dimensional parameters, for improved process control and yield enhancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods (CD-SEM, scatterometry) are used to measure miniaturized patterns, then the measurement process can be performed, but the measurement precision of three-dimensional shape information deteriorates
Solution Approach 1:
The patent segments the measurement process into multiple independent measurement steps, each targeting specific shape parameters. Instead of attempting to extract all three-dimensional shape information from a single spectral waveform analysis, the method performs sequential measurements using different apparatuses or methods, with each measurement contributing a portion of the complete shape information. This segmentation overcomes the limitation of conventional methods that struggle to extract accurate three-dimensional shape data from miniaturized patterns in a single step.
Solution Approach 2:
The patent transitions from two-dimensional planar measurement to three-dimensional shape measurement by introducing height information as an additional dimension. The measurement system is enhanced to capture not only lateral dimensions (width, length) but also vertical dimension (height, sidewall angle), enabling comprehensive three-dimensional characterization of miniaturized patterns that conventional planar measurement methods cannot provide.
2Productivity
If conventional scatterometry is used for in-line measurement, then productivity is maintained, but the reliability of shape measurement deteriorates due to inability to accurately capture three-dimensional information
Solution Approach 1:
The patent creates a universal measurement system that can perform multiple measurement functions through a single integrated platform. The system combines the capabilities of different measurement apparatuses (scatterometry for rapid spectral measurement, CD-SEM for precise lateral dimension measurement, and height measurement tools) into a unified in-line measurement platform that can extract comprehensive three-dimensional shape information while maintaining high throughput suitable for production environments.
Solution Approach 2:
The patent implements feedback mechanisms where measurement results from one step inform subsequent measurement steps or process adjustments. The multi-step measurement process uses feedback from preliminary measurements to optimize subsequent measurements, ensuring that the most relevant shape parameters are measured with highest precision while maintaining efficient in-line operation that does not bottleneck production flow.
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
This approach enables highly accurate pattern shape measurement and process control, improving yield by providing optimal exposure and etching conditions, even with narrow process margins, and stabilizing semiconductor device manufacturing.
Implementation Method 1
obtaining a detected waveform from reflected light or diffracted light of the irradiated light
Implementation Method 2
obtaining a detected waveform from reflected light or diffracted light of the irradiated light
Data Source
AI summary
A method of measuring a pattern shape of performing a shape measurement of a semiconductor pattern at a high accuracy even when a process margin is narrow with respect to miniaturization of a semiconductor device is provided. In the method of measuring a pattern shape, when a best-match calculated waveform cannot be selected, at least one parameter among shape parameters is set as a fixed value based on information obtained by another measurement apparatus that uses a measurement method independent to the pattern shape measurement, a matching of a library and a detected waveform is performed again, a best-match calculated waveform is selected, and shape information of an object pattern is obtained from the best-match calculated waveform.