Semiconductor Optical Inspection Using SFG for Threshold Voltage Screening
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Solution Overview
Problem
Existing methods for analyzing semiconductor devices lack effective non-contact inspection techniques to assess interface and surface properties during manufacturing processes, particularly in centrosymmetric materials where second harmonic generation (SHG) is not feasible.
Innovation Solution
An analysis method using a nonlinear optical signal is employed to determine the pass/fail of semiconductor devices by measuring electrical characteristics, such as threshold voltage, and modifying manufacturing conditions based on the analysis results, involving processes like altering material composition, oxygen partial pressure, plasma power, and heat treatment parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If second harmonic generation (SHG) is used for non-contact inspection, then surface and interface properties can be detected, but SHG cannot occur in centrosymmetric materials
Solution Approach 1:
The patent changes the optical parameters by using sum frequency generation (SFG) instead of second harmonic generation (SHG). SFG involves mixing two different frequency lights (ω1 and ω2) to generate a sum frequency signal (ω1+ω2), which provides similar surface sensitivity as SHG but works effectively for centrosymmetric materials, thus resolving the limitation of material adaptability while maintaining measurement precision for interface characteristics
2Reliability
If electrical characteristics are measured to determine pass/fail, then device performance can be assessed, but contact-based measurement may damage the device or require complex probing
Solution Approach 1:
The patent replaces mechanical contact-based electrical measurement with non-contact optical measurement using sum frequency generation. The optical system uses light beams to probe the semiconductor device, and the generated SFG signal provides information about electrical characteristics such as threshold voltage without requiring physical contact, thereby simplifying the measurement system while maintaining reliability in device performance assessment
3Reliability
If manufacturing process conditions are modified based on analysis results, then device performance can be improved, but process changes may affect other device characteristics
Solution Approach 1:
The patent implements a feedback mechanism where the sum frequency generation signal is analyzed to determine device performance, and this information is used to adjust manufacturing process conditions. The system continuously monitors the SFG signal characteristics and feeds this information back to control the deposition process parameters such as oxygen partial pressure and plasma power, enabling real-time optimization while maintaining overall process stability through controlled adjustments
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 method enables quantitative analysis of semiconductor device performance by correlating electrical characteristics with nonlinear signal intensity, improving device performance through process adjustments and subsequent processes.
Implementation Method 1
Second harmonic generation SHG is a nonlinear effect in which light is emitted with a frequency twice that of incident light beam. This process may be considered as coupling two photons of energy E to produce a single photon 2E
Data Source
AI summary
Disclosed in the present invention is an analysis method for a semiconductor device, and an analysis device therefor, the analysis method comprising: manufacturing a semiconductor device; supplying a first optical signal to the semiconductor device; detecting a second optical signal reflected from the semiconductor device; and determining pass or fail for the semiconductor device by analyzing the second optical signal, wherein the determination of the pass or fail for the semiconductor device by analyzing the second optical signal comprises: measuring an electrical characteristic of the semiconductor device; correlating the electrical characteristic with the second optical signal; and determining pass or fail for the semiconductor device from the electrical characteristic, and the electrical characteristic is a threshold voltage of the semiconductor device.