Semiconductor Inspection Using Multi-Frequency OBIRCH Phase Analysis
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Solution Overview
Problem
Conventional methods struggle to analyze the electrical characteristics of semiconductor devices with stacked semiconductor chips, particularly in a non-destructive manner.
Innovation Solution
A semiconductor device inspection method involving power supply, light intensity modulation at multiple frequencies, phase component correction, and normalization to analyze the electrical characteristics of stacked semiconductor structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lock-in OBIRCH method is used to scan semiconductor device with laser, then non-destructive failure analysis is achieved, but inability to analyze electrical characteristics corresponding to stacked structure occurs
Solution Approach 1:
The patent segments the measurement process by using multiple light frequencies (first frequency and second frequency) to probe different depths of the stacked structure. The first frequency corresponds to the first position and the second frequency corresponds to the second position in the optical axis direction, enabling separate analysis of electrical characteristics at each layer level.
Solution Approach 2:
The patent adds the frequency dimension to the conventional single-frequency OBIRCH method. By modulating light intensity at multiple frequencies and analyzing the phase components at these different frequencies, the system can distinguish and analyze electrical characteristics from different vertical positions in the stacked structure.
2Loss of information
If multiple light frequencies are used to probe different positions, then electrical characteristics of stacked structure can be analyzed, but measurement complexity increases
Solution Approach 1:
The patent employs periodic modulation of light intensity at different frequencies to sequentially probe different positions in the stacked structure. By using intensity-modulated light at the first frequency and second frequency in a periodic manner, the system can extract depth-resolved electrical characteristics through phase analysis of the periodic responses.
Solution Approach 2:
The patent uses phase component feedback to distinguish signals from different depths. By measuring the phase components of the characteristic signals at different frequencies and using them to identify which position's electrical characteristics are being reflected, the system can selectively analyze information from specific layers in the stacked structure.
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 accurate analysis of the electrical characteristics corresponding to the stacked structure of semiconductor devices, improving the estimation of layer structures and facilitating failure analysis.
Implementation Method 1
a light source that emits laser light; a signal source that generates a signal for intensity modulation of the laser light
Implementation Method 2
intensity-modulated with a first frequency and light intensity-modulated with a second frequency
Implementation Method 3
Lock-in Optical Beam Induced Resistance Change (OBIRCH) has been known as a method for analyzing the electrical characteristics of a semiconductor device
Implementation Method 4
a lock-in amplifier that lock-in detects a characteristic signal of a plurality of frequency components, while the modulation frequency is changed to a first frequency and a second frequency
Data Source
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AI summary
A semiconductor inspection device 1 includes: a measuring device 7 that supplies power to a semiconductor device S and measures the electrical characteristics of the semiconductor device S according to the supply of the power; an optical scanning device 13 that scans the semiconductor device S with light intensity-modulated with a plurality of frequencies; a lock-in amplifier 15 that acquires a characteristic signal indicating the electrical characteristics of the plurality of frequency components according to the scanning of the light; and an inspection device 19 that processes the characteristic signal. The inspection device 19 corrects a phase component of the characteristic signal at an arbitrary scanning position with a phase component of the characteristic signal at a scanning position reflecting the electrical characteristics of a first layer L1 in the semiconductor device S as a reference, specifies a phase component of the characteristic signal at a scanning position reflecting the electrical characteristics of a second layer L2 in the semiconductor device S, normalizes the phase component of the characteristic signal at the arbitrary scanning position by using the phase component, and outputs a result based on the normalized phase component of the characteristic signal.