Laser Wafer Edge Trimming With Dynamic Focus Imaging
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Solution Overview
Problem
Existing edge trimming methods for semiconductor wafers, such as those using grinding tools, often result in chipping and damage due to non-uniform vertical movement of the spindle, and laser-based methods are inefficient in terms of throughput.
Innovation Solution
A substrate processing apparatus and method that forms a modification layer using laser light along the boundary between the peripheral and central portions of the wafer, allowing for precise removal of the peripheral portion without affecting the support substrate, and includes a system with imaging devices for focus adjustment and controlled movement to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If grinding tools are used for edge trimming, then the peripheral portion can be removed, but chipping and damage occur due to non-uniform vertical movement of the spindle
Solution Approach 1:
The patent replaces the mechanical grinding system with a laser-based modification system. The laser radiates light to form a modification layer inside the wafer along the boundary between the peripheral and central portions, eliminating the need for mechanical contact and spindle movement. This substitution of mechanical action with optical action resolves the contradiction by avoiding chipping and damage while maintaining trimming efficiency.
Solution Approach 2:
The patent changes the physical state of the wafer material by creating a modification layer through laser radiation. By controlling the laser parameters (intensity, duration, position), the modification layer is formed precisely at the desired depth and location without mechanical contact. This parameter-based control enables precise removal of the peripheral portion while preserving the quality of the remaining wafer surface.
2Manufacturing precision
If laser-based methods are used for edge trimming, then precision is improved, but throughput is reduced due to inefficient processing
Solution Approach 1:
The patent performs preliminary action by forming a modification layer inside the wafer before actual removal. The laser radiates light to create this modification layer along the boundary between peripheral and central portions in advance. This preliminary modification enables subsequent easy and precise removal of the peripheral portion, improving both precision and efficiency by preparing the material structure beforehand.
Solution Approach 2:
The patent achieves continuous processing by moving the holder and imaging device relatively while the laser forms the modification layer. The controller coordinates the movement of multiple components (holder, imaging device, laser) to maintain continuous laser radiation along the entire boundary. This continuous action eliminates idle time and improves throughput while maintaining precision.
3Measurement precision
If focus adjustment is performed at multiple points, then imaging precision is improved, but processing time increases
Solution Approach 1:
The patent implements dynamic focus adjustment by moving the holder and imaging device relatively during the imaging process. Instead of stopping at multiple discrete points for sequential focus adjustment, the system dynamically adjusts focus while continuously moving. The controller coordinates this dynamic movement to achieve focus adjustment at multiple positions simultaneously, reducing total processing time while maintaining imaging precision.
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
The method enables efficient edge trimming with reduced processing time and prevents damage to the support substrate, improving throughput and precision in wafer processing.
Implementation Method 1
The imaging device images multiple points of the first substrate after performing focus adjustment at plural points of the first substrate
Implementation Method 2
a modifying device configured to form a modification layer by radiating laser light to an inside of the first substrate held by the holder along a boundary between a peripheral portion of the first substrate as a removing target and a central portion thereof
Data Source
AI summary
A substrate processing apparatus includes an imaging device configured to image a first substrate held by a holder; a modifying device configured to form a modification layer by radiating laser light to an inside of the first substrate held by the holder along a boundary between a peripheral portion of the first substrate as a removing target and a central portion thereof; a first moving device configured to move the holder and the imaging device relatively; and a controller configured to control the holder, the imaging device, the modifying device, and the first moving device. The controller controls the holder, the imaging device and the first moving device to perform the focus adjustment of the imaging device and/or the imaging by the imaging device while moving the holder and the imaging device relatively.