SiC Wafer Laser Control for Polycrystalline Protrusion Removal
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Solution Overview
Problem
Conventional methods for removing polycrystalline protrusions from SiC wafers during epitaxial layer formation are incomplete and can damage the semiconductor substrate, as they rely solely on the difference in absorption coefficients without precise control over laser irradiation.
Innovation Solution
A manufacturing apparatus that includes a stage for the semiconductor component, a laser oscillation device emitting both a first and second laser light, a scattered light detector to identify protrusions, and a laser controller to selectively irradiate protrusions with the second laser light based on detection results, ensuring precise removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser light irradiation is applied to remove protrusions based solely on absorption coefficient differences, then protrusion removal is attempted, but incomplete removal occurs and substrate damage may result
Solution Approach 1:
The patent applies preliminary action by first irradiating the substrate with a first laser light to melt the protrusions before removing them with a second laser light. This preliminary melting step prepares the protrusions for complete removal while preventing substrate damage by controlling the sequence and parameters of laser irradiation.
Solution Approach 2:
The patent utilizes parameter changes by varying the wavelength, power, and irradiation sequence of multiple laser lights. The first laser light operates at parameters that melt the protrusions, while the second laser light uses different parameters to remove the melted material, achieving complete protrusion removal without damaging the substrate.
2Ease of operation
If conventional laser irradiation methods are used without protrusion detection, then the process is simple, but protrusion removal cannot be controlled based on presence or size
Solution Approach 1:
The patent implements feedback by using a scattered light detector to detect protrusions on the substrate surface before laser irradiation. The detection results provide feedback to control the laser irradiation process, allowing the system to selectively apply laser treatment only where protrusions are detected, enabling precise control based on protrusion presence and size while maintaining operational simplicity through automated control.
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 allows for accurate detection and removal of polycrystalline protrusions, preventing substrate damage and ensuring complete removal, thereby enhancing the quality of semiconductor devices.
Implementation Method 1
a scattered light detector to detect scattered light scattered by a polycrystalline protrusion in the first laser light
Implementation Method 2
a laser oscillation device configured to irradiate the second main surface of the semiconductor component disposed on the stage with a first laser light and a second laser light higher in output than the first laser light
Data Source
AI summary
The object is to provide a technology capable of appropriately removing polycrystalline protrusions. A manufacturing apparatus for a semiconductor device includes: a laser oscillation device configured to irradiate a second main surface of a semiconductor component disposed on a stage with a first laser light and a second laser light higher in output than the first laser light; a scattered light detector to detect scattered light scattered by protrusions in the first laser light; and a laser controller to cause the laser oscillation device to irradiate the protrusions with the second laser light, based on a detection result of the scattered light detector.