Charged Particle Beam Apparatus Multilayer Contrast Control
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Solution Overview
Problem
Conventional semiconductor inspection methods using electron beams struggle to achieve high pattern contrast, especially in multilayer structures, leading to difficulties in detecting defects such as alignment deficiencies and misalignment due to low electric field intensity distribution and insufficient static charge control.
Innovation Solution
A charged particle beam apparatus that simultaneously irradiates a specimen with light of different wavelength bands to control static charge distribution, enhancing electric field intensity and pattern contrast by making specific layers electrically conductive, allowing for precise defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electron beams are used to irradiate the semiconductor wafer for defect inspection, then secondary electrons are emitted and detected to form images, but static charge control is insufficient leading to low pattern contrast in multilayer structures
Solution Approach 1:
The patent introduces light as an intermediary substance to mediate the charging process. By irradiating the semiconductor wafer with light before or during electron beam inspection, photoelectrons are generated and accumulated to form controlled static charge regions. This light-mediated charging mechanism enables precise control of electric fields in multilayer structures, thereby improving pattern contrast and defect detection sensitivity without direct electron beam charging limitations.
2Measurement precision
If a single wavelength light is used for photoirradiation, then static charge is controlled in one layer, but multiple layers cannot be independently charged to achieve high pattern contrast
Solution Approach 1:
The patent segments the charging function by using multiple light sources with different wavelengths, where each wavelength is selectively absorbed by specific layers of the multilayer semiconductor structure. This allows independent photocharging of different layers, enabling precise control of electric fields in each layer separately. The segmentation of charging control across multiple wavelengths directly addresses the need for layer-specific charge control to achieve high pattern contrast.
Solution Approach 2:
The patent changes the parameter of light wavelength to achieve different charging effects in different layers. By selecting specific wavelengths that correspond to the absorption characteristics of each layer material, the system can independently control the static charge distribution across multiple layers. This parameter change approach enables versatile and adaptive charge control for complex multilayer structures.
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 achieves high precision and sensitivity in defect inspection by stabilizing static charge and improving pattern contrast, enabling effective detection of defects in multilayer structures.
Implementation Method 1
a photoirradiation system capable of simultaneously irradiating an identical region of the specimen placed on the specimen holder with light of a first wavelength band, and light of a second wavelength band, differing in wavelength band from each other
Data Source
AI summary
It has been difficult to obtain pattern contrast required for inspecting a specific layer of a circuit pattern in a charged particle beam apparatus which inspects, by using a charged particle beam, the position and type of a defect on a wafer having a circuit pattern which is in semiconductor manufacturing process. At the time of inspecting the position and type of a defect on a wafer having a circuit pattern which is in semiconductor manufacturing process by using a charged particle beam emitted from a charged particle source (11), the wafer arranged on a holder (20) is irradiated with light in wavelength ranges different from each other from a light irradiation system (9), and at the same time, the wafer is irradiated with a charged particle beam. Thus, contrast of an image is improved and inspection is performed with high sensitivity.