Semiconductor Stress Mapping via Oblique Monochromatic X-ray Diffraction
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Solution Overview
Problem
Current inspection methods for semiconductor devices, such as Raman spectroscopy and X-ray diffraction, face challenges in accurately measuring stress distribution in semiconductor substrates with complex structures like NAND memory cells, as they struggle to provide high-resolution, non-destructive, and precise stress mapping.
Innovation Solution
An X-ray diffraction inspection apparatus that uses monochromatic X-rays obliquely incident on semiconductor devices, employing a two-dimensional array of photodetection elements to capture X-ray diffraction images, allowing for the identification of maximum intensity images and comparison of conditions to map stress distribution as two-dimensional information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Raman spectroscopy or conventional X-ray diffraction is used for stress inspection, then the inspection can be performed, but the measurement precision and resolution are insufficient for complex semiconductor structures
Solution Approach 1:
The patent transitions from conventional point-by-point or low-resolution X-ray diffraction measurement to a two-dimensional area measurement system. By arranging multiple photodetection elements in a two-dimensional array, the system captures diffraction images across the entire inspection region simultaneously, achieving high-resolution stress mapping without proportionally increasing system complexity
Solution Approach 2:
The inspection region is divided into multiple pixel elements in a two-dimensional array, with each pixel independently detecting diffraction intensity. This segmentation allows parallel measurement across the entire area, significantly improving measurement precision and resolution while maintaining manageable system complexity through modular detection architecture
2Productivity
If conventional X-ray diffraction measurement is used, then stress inspection can be performed, but the inspection time is excessive due to sequential measurement requirements
Solution Approach 1:
The patent implements continuous area measurement by illuminating the entire inspection region with X-rays simultaneously and detecting diffraction signals across all pixel elements at once. This eliminates sequential scanning and achieves continuous, high-speed stress mapping across the semiconductor device while maintaining high spatial resolution through the two-dimensional detection array
Solution Approach 2:
By expanding from one-dimensional or point measurement to two-dimensional area measurement, the system captures the entire stress distribution map in a single measurement cycle. This dimensional expansion enables parallel data acquisition across all spatial positions, dramatically improving inspection speed without sacrificing measurement precision
3Loss of information
If oblique incidence X-ray measurement is used, then stress mapping capability is improved, but the system complexity and measurement conditions become more difficult to control
Solution Approach 1:
The patent employs a two-dimensional photodetection element array that can capture diffraction information from multiple angles and positions simultaneously. This universal detection capability allows the system to extract comprehensive stress distribution information across the entire inspection region while maintaining a relatively simple fixed-geometry measurement configuration, reducing the complexity of controlling multiple measurement conditions
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 high-resolution, non-destructive stress distribution measurement and mapping in semiconductor substrates, effectively identifying variations in diffracted light intensity and peak positions, facilitating the detection of both tensile and compressive stresses.
Implementation Method 1
an X-ray diffraction measurement apparatus that causes monochromatic X-rays to be obliquely incident on an object... a detection unit that detects observed X-rays... an analysis unit that generates X-ray diffraction images obtained by photoelectrically converting the observed X-rays
Implementation Method 2
an analysis unit that generates X-ray diffraction images obtained by photoelectrically converting the observed X-rays
Data Source
AI summary
An apparatus for inspecting a semiconductor device according to an embodiment includes an X-ray irradiation unit configured to make monochromatic X-rays obliquely incident on the semiconductor device, which is an object at a predetermined angle of incidence, a detection unit configured to detect observed X-rays observed from the object using a plurality of two-dimensionally disposed photodetection elements, an analysis apparatus configured to generate X-ray diffraction images obtained by photoelectrically converting the observed X-rays, and a control unit configured to change an angle of incidence and a detection angle of the X-rays, in which the analysis apparatus acquires an X-ray diffraction image every time the angle of incidence is changed, extracts a peak X-ray diffraction image, X-ray intensity of which becomes maximum for each of pixels and compares the peak X-ray diffraction image among the pixels to thereby estimate a stress distribution of the object.