Semiconductor Fault Analysis via Angled Laser Scanning
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Solution Overview
Problem
Existing fault analysis methods for semiconductor devices struggle to accurately identify defective parts due to similar measured values in wiring areas and defective areas when the scan direction of light irradiation is parallel to the wiring directions, leading to difficulty in specifying the defective parts from differences in measured values.
Innovation Solution
A fault analysis apparatus and method that sets the scan direction of light irradiation to intersect the wiring directions at an angle greater than 0° but smaller than 90°, preferably about 45°, allowing for the creation of a two-dimensional map that facilitates the specification of fault positions by measuring reactions such as current or voltage values, and performing coordinate transformations to enhance fault identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the scan direction of light irradiation is set parallel to the wiring directions, then the measurement process is simple, but it becomes difficult to distinguish defective parts from wiring areas due to similar measured values
Solution Approach 1:
The patent changes the scan direction parameter from being parallel to wiring directions to intersecting at an angle greater than 0° and less than 90°. This parameter change causes the light irradiation to traverse both wiring areas and defective parts in an alternating pattern, creating distinct measured value patterns that enable reliable fault detection while maintaining a single-scan simple measurement process.
2Measurement precision
If multiple scan directions are employed to specify defective parts, then fault detection accuracy is improved, but measurement time increases
Solution Approach 1:
The patent introduces a new dimensional approach by using an intermediate scan direction that is neither parallel nor perpendicular to the wiring directions. This angular dimension allows the measurement to capture spatial variations in both wiring areas and defective parts simultaneously within a single scan, achieving the fault detection accuracy of multiple scans without the time penalty.
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
This approach enables secure specification of defective parts from a single scan direction, simplifying the measurement process and reducing time by distinguishing between measured values in wiring areas and defective parts, and aids in creating clear two-dimensional maps for easier fault localization.
Implementation Method 1
a light source configured to output light for irradiating the semiconductor device; a detector electrically connected to the semiconductor device and configured to measure the reaction of the semiconductor device irradiated with the light
Implementation Method 2
OBIRCH (Optical Beam Induced Resistance Change) measurement which measures a change in resistance value accompanying heat caused by irradiation with laser light
Data Source
AI summary
A fault analysis apparatus is an apparatus for measuring a reaction of a semiconductor device having a wiring extending in two directions orthogonal to each other. The fault analysis apparatus comprises a laser light source that outputs laser light, a control unit that sets a scan direction which is a direction of scanning an irradiation position of the laser light in the semiconductor device, a laser scanner that scans the laser light according to the scan direction, an electric signal detector that measures the reaction of the semiconductor device to the laser light and outputs a measured value, and an image processing unit that creates a two-dimensional map according to the irradiation position and the measured value. The control unit sets the scan direction such that the scan direction intersects the wiring extending directions at an angle greater than 0° but smaller than 90°.