Holding Table Assembly With Retractable Pins for SiC Ingot Support
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Solution Overview
Problem
The conventional method of slicing SiC wafers using a laser processing apparatus can cause damage to the holding surface of the holding table due to the ingot's corners contacting it, leading to improper laser beam concentration and reduced accuracy.
Innovation Solution
A holding table assembly with support pins that project and retract to support the ingot, using air pressure and suction to prevent direct contact between the ingot and the holding surface, ensuring stable and accurate laser processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the ingot is placed directly on the holding surface, then the holding table structure is simple, but the holding surface may be damaged by corner contact
Solution Approach 1:
The patent introduces support pins as an intermediary element between the ingot and the holding surface. These pins support the ingot during placement and processing, preventing direct contact between the ingot corners and the holding surface, thus protecting the holding surface from damage while maintaining structural simplicity.
Solution Approach 2:
The support pins are positioned in advance to support the ingot before it is fully placed on the holding surface. This preliminary support action prevents the ingot corners from contacting and damaging the holding surface during the placement process.
2Device complexity
If the holding surface is damaged, then the structure remains simple, but the laser beam cannot be concentrated on the desired position
Solution Approach 1:
The support pins serve as a protective intermediary that maintains the integrity of the holding surface. By preventing direct contact between the ingot and holding surface, the pins ensure the holding surface remains smooth and undamaged, which is critical for accurate laser beam concentration and high-precision processing.
3Reliability
If support pins are added to protect the holding surface, then the holding surface is protected, but the device complexity increases
Solution Approach 1:
The support pins are designed to be automatically retracted into the holding surface when not in use, and automatically extend when needed. This self-service mechanism eliminates the need for complex external control systems, reducing overall device complexity while maintaining effective holding surface protection.
Solution Approach 2:
The support pins are made movable rather than fixed, allowing them to extend and retract as needed. This dynamic design provides protection only when necessary, reducing interference during processing while maintaining structural simplicity through the use of straightforward mechanical actuation.
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
Prevents damage to the holding surface by supporting the ingot with retractable pins, allowing precise laser beam concentration and maintaining high-accuracy processing.
Implementation Method 1
the holding surface is inserted into the circular recess of the base, and a laser beam is applied to the ingot from above and concentrated on a predetermined position in the ingot
Implementation Method 2
air is supplied into air pressure chambers defined inside the cylinder sections by the pistons inserted into the cylinder sections, thereby causing the tip ends of the support pins to be positioned at supportable positions projecting from the holding surface
Data Source
AI summary
A holding table assembly has a base that includes three or more cylinder sections spaced apart at regular intervals in a circumferential direction, a circular recess formed at an upper part thereof, and a flow channel communicating with the cylinder sections and the circular recess. A holding table includes a holding surface inserted into the circular recess of the base that holds an ingot under suction. A circular plate has a plurality of minute holes and insertion holes formed at positions corresponding to each of the cylinder sections and spaced apart at regular intervals in the circumferential direction. Pistons are inserted in the cylinder sections, the number of pistons being equal to the number of cylinder sections, and support pins of which base ends abut against the pistons and tip ends are inserted in the insertion holes.