Semiconductor Layer Inspection Using Multi-Frequency OBIRCH Phase Correction
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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 scanning with modulated frequencies, and phase correction to estimate electrical characteristics at each layer of the stacked structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional OBIRCH method is used to scan semiconductor device with laser, then failure analysis can be realized in non-destructive manner, but it cannot analyze electrical characteristics corresponding to stacked structure of multiple semiconductor chips
Solution Approach 1:
The patent segments the electrical characteristics measurement into multiple frequency components. By applying light intensity-modulated at different frequencies (first frequency and second frequency higher than the first frequency) and separating the characteristic signals by frequency, the system can distinguish and analyze electrical characteristics from different stacked semiconductor chip layers independently, thus resolving the inability to analyze stacked structure characteristics
Solution Approach 2:
The patent uses periodic light intensity modulation at different frequencies to stimulate different layers of the stacked semiconductor device. The characteristic signals are acquired at these specific frequencies, and phase difference calculations are performed based on periodic signal analysis, enabling depth-resolved electrical characteristic measurement through the stacked structure
2Measurement precision
If light intensity-modulated at single frequency is used for scanning, then measurement process is simple, but cannot distinguish electrical characteristics from different positions in optical axis direction
Solution Approach 1:
The patent employs dynamic light intensity modulation with multiple frequencies instead of static single-frequency modulation. The system dynamically switches between first frequency and second frequency (higher than the first) to modulate light intensity, enabling the differentiation of electrical characteristics from different optical axis positions through frequency-domain separation of the resulting characteristic signals
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 electrical characteristics corresponding to the stacked structure of semiconductor devices, allowing for easy identification of failure locations.
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
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 3
a lock-in amplifier that performs lock-in detection on a characteristic signal indicating changes in the electrical characteristics at a plurality of frequencies
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 calculates a frequency at which the characteristic signal at a scanning position reflecting the electrical characteristics of a first layer L1 in the semiconductor device S and the characteristic signal at a scanning position reflecting the electrical characteristics of a second layer L2 have a predetermined phase difference, corrects a phase component of the characteristic signal at an arbitrary scanning position with a phase component of the characteristic signal at the scanning position reflecting the electrical characteristics of the first layer L1 as a reference, and outputs an in-phase component and a quadrature component of the characteristic signal at the arbitrary scanning position at the calculated frequency.