Laser-Ultrasonic Ingot Splitting for Low-Kerf Wafer Production
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Solution Overview
Problem
Existing ingot splitting methods, such as those using diamond wire saws, result in significant material loss due to kerf loss and subsequent polishing losses, making it essential to develop a method that reduces material waste during the ingot splitting process.
Innovation Solution
The ingot splitting method employs a combination of laser scanning and ultrasonic vibration to split ingots. The laser focuses on a plane to be split, weakening the material, while ultrasonic waves are applied to vibrate the ingot, facilitating a clean split with reduced material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a diamond wire saw is used for ingot splitting, then the splitting process can be completed, but significant material loss occurs due to kerf loss and polishing losses
Solution Approach 1:
The patent replaces the traditional mechanical diamond wire saw system with a laser-based system. The laser beam is focused to a small spot size (much smaller than the diamond wire saw width) to create a narrow kerf, minimizing material loss during the splitting process. The laser energy is concentrated at the focal point to achieve precise cutting with minimal material removal.
Solution Approach 2:
The patent changes the physical parameters of the cutting process by using laser energy instead of mechanical abrasion. By adjusting laser parameters such as power, focal length, and scanning speed, the process achieves clean cuts with minimal kerf loss and reduced need for subsequent polishing, thereby reducing overall material loss.
2Loss of substance
If a diamond wire saw with large width is used, then splitting can be performed, but the width causes huge proportion of kerf loss
Solution Approach 1:
The patent replaces the mechanical diamond wire saw with a laser beam that can be focused to a very small spot size. This optical approach allows for precise control of the kerf width, achieving narrow cut widths with high precision without the inherent width limitation of mechanical saw blades.
Solution Approach 2:
The laser energy is concentrated at a specific focal point with a very small spot size, creating localized heating and melting only at the intended cut location. This localized energy delivery ensures precise splitting with minimal material loss and high edge quality, eliminating the need for wide kerfs required by mechanical saws.
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 significantly reduces material loss by minimizing kerf and polishing losses, allowing for the production of more wafers from a single ingot while reducing production costs and increasing efficiency.
Implementation Method 1
A laser provided from a laser source is focused with a focusing lens group on a plane to be split of an ingot
Implementation Method 2
a laser provided from a laser source is focused with a focusing lens group on a plane to be split of an ingot
Implementation Method 3
ultrasonic waves are applied with the ultrasonic source to vibrate the ingot simultaneously
Implementation Method 4
A pulling force is applied to the second side in a direction away from the ingot with the tensioner
Data Source
AI summary
An ingot splitting method and an ingot splitting apparatus are provided. The ingot splitting method includes the following steps. A laser provided from a laser source is focused with a focusing lens group on a plane to be split of an ingot, and a focus point of the laser is used to scan the plane to be split. An opposing first side and second side of the ingot are fixed with a chuck table and an ultrasonic source. The plane to be split is located between the first side and the second side. A pulling force is applied to the second side in a direction away from the ingot with a tensioner, and ultrasonic waves are applied to vibrate the ingot with the ultrasonic source simultaneously, so that the ingot is divided into two parts from the plane to be split.