Semiconductor Overlay Measurement Using Multi-Wavelength Diffraction
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in accurately monitoring and ensuring the consistency of overlay between layers, leading to potential defects and reduced reliability due to systematic process errors and misalignment.
Innovation Solution
A method involving the use of diffraction-based overlay technology, where multiple wavelengths of light are selected based on an overlay spectrum to measure the consistency between layers, compensating for process errors by calculating overlay deviations and improving measurement reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional overlay measurement methods are used, then the manufacturing process can proceed, but measurement precision and reliability are insufficient due to systematic process errors
Solution Approach 1:
The patent changes the wavelength parameter of light used in overlay measurement. By selecting specific wavelengths from the visible spectrum (400-700nm) based on the overlay spectrum characteristics, the measurement system achieves higher precision and reliability. The wavelength selection is optimized to minimize the effects of systematic process errors such as overlay mark deformation and thickness variations.
Solution Approach 2:
The patent implements a feedback mechanism where the overlay spectrum is analyzed to determine the optimal wavelength for measurement. The measurement results are used to calculate overlay deviations, and this information feeds back into the manufacturing process to compensate for systematic errors. This closed-loop approach continuously improves measurement reliability.
2Manufacturing precision
If single wavelength light is used for overlay measurement, then the process is simple, but measurement accuracy is reduced due to process errors
Solution Approach 1:
The patent employs multiple wavelengths of light instead of a single wavelength for overlay measurement. By analyzing the overlay spectrum and selecting optimal wavelengths in the visible range, the system achieves superior measurement accuracy. The multi-wavelength approach compensates for process errors such as variations in overlay mark geometry and layer thickness that affect single-wavelength measurements.
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 enhances the accuracy of overlay measurements, reduces errors, and improves the reliability of semiconductor device manufacturing by compensating for process-induced deviations, thereby ensuring better interlayer consistency.
Implementation Method 1
radiating a light having a wavelength band onto the semiconductor structure, diffracting the light to generate diffracted light
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a plurality of overlay molds on a semiconductor structure by developing a photoresist material layer of the semiconductor structure, the semiconductor structure including a first layer having a plurality of overlay marks, the plurality of overlay molds at least partially overlapping at least some of the plurality of overlay marks; and measuring one or more overlays by radiating a light having a wavelength band onto the semiconductor structure, each of the one or more overlays indicating an amount of consistency of the first layer and a second layer of the semiconductor structure, the wavelength band being set based on the plurality of overlay marks and the plurality of overlay molds, the second layer being between the first layer and the photoresist material layer.