Carrier-Supported Substrate Separation With Laser-Formed Modified Layers
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Solution Overview
Problem
Conventional methods for producing substrates, such as semiconductor wafers, result in significant material loss and inefficiency, particularly when cutting thick ingots, leading to a need for more efficient substrate production methods that minimize material waste and enhance handling capabilities.
Innovation Solution
A method involving a carrier attached to the workpiece with a modified layer formed inside, allowing for division without cutting, which reduces material loss and facilitates handling by enabling substrates with high thickness uniformity and reduced thickness, using techniques like laser beam application to create the modified layer and subsequent carrier material removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional wire saw cutting is used to produce substrates from thick ingots, then substrates can be obtained, but significant material loss occurs and production efficiency is reduced
Solution Approach 1:
The patent replaces the conventional mechanical wire saw cutting system with a laser-based modified layer formation system. A laser beam is applied to the workpiece to form a modified layer inside the material, which then allows for easy separation. This substitution eliminates the need for mechanical cutting, thereby reducing material loss and improving production efficiency by enabling precise control of the separation depth and reducing the force required for substrate release.
Solution Approach 2:
The patent applies preliminary action by forming a modified layer inside the workpiece before actual substrate separation. The laser modifies the internal structure of the material at the desired separation depth, creating a weakened layer that facilitates subsequent easy separation. This preliminary modification prevents the need for forceful mechanical cutting and minimizes material loss during the separation process.
2Loss of substance
If thick substrates are produced and then ground/polished to reduce thickness, then handling is easier, but substantial workpiece material is removed
Solution Approach 1:
The patent replaces mechanical grinding and polishing systems with a laser-based modified layer formation system. By using laser energy to create a modified layer at the precise desired thickness, the need for subsequent mechanical removal of material through grinding and polishing is eliminated. This substitution dramatically reduces material loss while maintaining ease of handling through controlled thickness uniformity.
Solution Approach 2:
The patent changes the physical and chemical parameters of the workpiece material by applying laser energy to form a modified layer. This modification alters the internal structure and properties of the material at the separation depth, creating a layer that is easier to separate while preserving the desired substrate thickness. This parameter change eliminates the need for extensive material removal and improves both material efficiency and handling characteristics.
3Productivity
If the number of substrates per workpiece is increased, then productivity improves, but handling and processing of thin substrates becomes more difficult
Solution Approach 1:
The patent applies segmentation by dividing the workpiece into multiple thin substrates through the formation of multiple modified layers at different depths. Each modified layer serves as a separation interface, allowing for the extraction of multiple thin substrates from a single workpiece. This segmentation approach increases productivity while the controlled modification process ensures that each substrate maintains sufficient structural integrity for handling.
Solution Approach 2:
The patent replaces mechanical handling systems with a laser-based modified layer formation and separation system. The laser creates controlled modified layers that enable easy separation of multiple thin substrates without requiring forceful mechanical manipulation. This substitution reduces the risk of damage to thin substrates during handling while maximizing the number of substrates that can be obtained from each workpiece.
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 method increases the number of substrates obtainable from a workpiece while minimizing material loss, achieving substrates with excellent electrical characteristics and high uniformity, enabling safe handling and processing of very thin substrates.
Implementation Method 1
applying the laser beam to the SiC ingot to thereby form a separation layer
Data Source
AI summary
The invention relates to a method of producing a substrate. The method comprises providing a workpiece having a first surface and a second surface opposite the first surface, and providing a carrier having a first surface and a second surface opposite the first surface. The method further comprises attaching the carrier to the workpiece, wherein at least a peripheral portion of the first surface of the carrier is attached to the first surface of the workpiece, and forming a modified layer inside the workpiece. Moreover, the method comprises dividing the workpiece along the modified layer, thereby obtaining the substrate, wherein the substrate has the carrier attached thereto, and removing carrier material from the side of the second surface of the carrier in a central portion of the carrier so as to form a recess in the carrier. The invention further relates to a substrate producing system for performing this method.