Laser Wafer Coring for Defect Removal and Material Reuse
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Solution Overview
Problem
Current methods for fabricating power semiconductor devices from semiconductor material boules are costly due to expensive processing equipment and result in significant waste due to defects in the boules or resulting wafers, leading to high scrap rates.
Innovation Solution
A laser-based system is used to core semiconductor workpieces by emitting lasers through their thickness to separate a defective portion from a non-defective portion, allowing the non-defective portion to be further processed into semiconductor devices, with adjustable laser parameters based on workpiece properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional processing equipment is used to fabricate power semiconductor devices, then manufacturing capability is achieved, but manufacturing cost increases and material waste increases
Solution Approach 1:
The patent replaces traditional mechanical cutting methods with a laser-based system that uses optical energy to core semiconductor workpieces. The laser emits through the thickness of the workpiece to separate defective portions from non-defective portions, eliminating the need for expensive mechanical processing equipment and reducing material waste.
Solution Approach 2:
The patent utilizes adjustable laser parameters (wavelength, power, pulse duration) to optimize the coring process for different workpiece properties. By changing these parameters, the system can effectively process various semiconductor materials and defect configurations, achieving high precision material separation while minimizing waste.
2Loss of substance
If defective portions of semiconductor boules are discarded, then product quality is maintained, but material utilization decreases
Solution Approach 1:
The patent extracts and removes only the specific defective portions of the semiconductor workpiece using laser coring, while preserving the non-defective portions for further processing. This selective removal approach minimizes scrap material and maximizes the utilization of usable semiconductor material.
Solution Approach 2:
The patent segments the semiconductor workpiece into defective and non-defective portions through laser-based coring. This segmentation allows the non-defective portions to be separated and processed independently into high-quality semiconductor devices, while only the defective portions are discarded.
3Adaptability or versatility
If laser parameters are fixed, then process simplicity is maintained, but processing adaptability decreases
Solution Approach 1:
The patent implements a control system that dynamically adjusts laser parameters (wavelength, power, pulse duration) based on workpiece properties such as material type, thickness, and defect location. This dynamic adaptation enables the laser system to effectively process various semiconductor workpieces while maintaining precise control through automated feedback mechanisms.
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
Reduces scrap rates and manufacturing costs by enabling the reuse of defective portions as smaller, defect-free wafers, thereby optimizing the use of boule material.
Implementation Method 1
providing emission of one or more lasers through a thickness of the first semiconductor workpiece to remove the first portion of the first semiconductor workpiece from the second portion
Data Source
AI summary
An example method includes providing a first semiconductor workpiece including a first portion and a second portion. The example method includes providing emission of one or more lasers through a thickness of the first semiconductor workpiece to remove the first portion of the first semiconductor workpiece from the second portion. In some implementations, the second portion has a shape corresponding to a second semiconductor workpiece of a different diameter relative to the first semiconductor workpiece.