Electron Beam Inspection of Epitaxial Layers Between Inner Spacers
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Solution Overview
Problem
The challenge lies in accurately measuring and inspecting epitaxial layers between inner spacers in semiconductor devices using scanning electron microscopes, as the efficiency of detection is low due to secondary electrons colliding with side walls, and varying acceleration voltages affect image quality, making it difficult to achieve high accuracy and appropriate epitaxial growth management.
Innovation Solution
A processing system and charged particle beam apparatus that calculate distance and brightness values from signal profiles to determine the state of epitaxial layers, allowing for the measurement of epitaxial growth and defect detection in grooves or holes between inner spacers through image analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scanning electron microscope is used to measure epitaxial layers between inner spacers, then pattern images and signal waveforms can be acquired, but the detection efficiency is low due to secondary electrons colliding with side walls
Solution Approach 1:
The patent changes the acceleration voltage parameter to optimize electron beam penetration and secondary electron emission. By adjusting the acceleration voltage, the system achieves better detection of epitaxial layers while accounting for the geometry of inner spacers and groove depths, thereby improving measurement accuracy despite the challenging detection environment.
2Measurement precision
If acceleration voltage is changed to improve epitaxial layer imaging, then detection efficiency may improve, but the SEM image itself varies greatly making consistent measurement difficult
Solution Approach 1:
The patent implements dynamic adjustment of acceleration voltage based on the specific measurement conditions, including inner spacer geometry and groove depth. The system adaptively selects optimal voltage parameters for different measurement scenarios, allowing consistent and accurate epitaxial layer measurement while accounting for variations in device structure.
Solution Approach 2:
The system changes acceleration voltage parameters dynamically according to measurement requirements. By optimizing the acceleration voltage for specific measurement conditions, the patent achieves improved detection efficiency while maintaining image consistency through parameter optimization rather than using fixed voltage settings.
3Reliability
If the epitaxial layer is made excessively thin to reduce capacitance, then response performance improves, but resistance between source and drain becomes large
Solution Approach 1:
The patent replaces physical measurement methods with electron beam-based detection to achieve precise epitaxial layer thickness measurement. By using secondary electron emission characteristics and signal intensity analysis, the system can accurately determine optimal thickness without relying on mechanical measurement techniques, enabling better control of the thickness parameter.
4Manufacturing precision
If the epitaxial layer is made excessively thick to reduce resistance, then on-current improves, but capacitance increases and response performance lowers
Solution Approach 1:
The patent employs electron beam detection and signal intensity analysis to precisely measure epitaxial layer thickness, replacing traditional mechanical measurement methods. This enables accurate control of thickness within the optimal range that balances resistance and capacitance effects, thereby optimizing transistor response performance.
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 precise measurement of epitaxial layer growth and defect determination, improving the accuracy and efficiency of semiconductor device inspection by analyzing brightness and distance data from electron beam-irradiated layers.
Implementation Method 1
since electrons emitted from the epitaxial layer collide with a side wall such as the inner spacer or a dummy gate before the electrons are emitted to the surface of a sample, the efficiency of detection is low
Data Source
AI summary
A processing system and a charged particle beam apparatus for the purpose of determining the degree of growth or the presence or absence of a defect in an epitaxial layer grown in a groove or a hole such as between inner spacers from an image of the groove or the hole are proposed. In a processing system including a computer system, the computer system calculates a distance and a brightness value related to a layer between a plurality of structures from a signal profile in accordance with one direction on a two-dimensional plane related to the layer, which is obtained by irradiating the layer with an electron beam, and determines or outputs a state of the layer based on the distance and the brightness value.