Wafer Laser Processing with Rotating Liquid Layer Control
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Solution Overview
Problem
Existing laser processing methods for semiconductor wafers face challenges in efficiently processing workpieces while preventing debris from adhering to the main surface, leading to diffusion and attenuation of the laser beam and exposure of the surface.
Innovation Solution
A laser processing apparatus and method that includes a holder, head, and driver, where the workpiece is rotated around the optical axis of the laser beam, and a liquid is supplied to create a centrifugal force that minimizes beam diffusion, cools, and washes away debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a liquid layer is supplied onto the workpiece surface during laser processing, then debris is washed away and cooling is improved, but the laser beam undergoes diffusion and attenuation
Solution Approach 1:
The liquid layer thickness is made non-uniform across the workpiece surface, being thinner at the irradiation position and thicker at peripheral positions. This local variation in liquid layer quality allows the laser beam to pass through with minimal diffusion and attenuation while still providing adequate debris removal and cooling in different regions of the workpiece.
2Productivity
If the workpiece is rotated during laser processing, then processing efficiency is improved and debris is removed, but the liquid layer thickness distribution becomes unstable
Solution Approach 1:
The system dynamically adjusts the liquid supply amount based on the rotational state of the workpiece. By coordinating the liquid supply rate with the rotation speed and position, the system maintains a stable liquid layer thickness distribution even during rotation, ensuring consistent processing quality while benefiting from improved debris removal and cooling efficiency.
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 apparatus efficiently processes semiconductor wafers by reducing beam diffusion, preventing debris adherence, and maintaining a stable liquid layer thickness, thereby enhancing processing quality and preventing surface exposure.
Implementation Method 1
the revolution of the workpiece exerts a centrifugal force on the liquid layer formed on the main surface by supplying the first liquid onto the main surface
Implementation Method 2
The head is configured to irradiate a first portion of a main surface of the workpiece with a laser beam
Data Source
AI summary
A laser processing apparatus includes a holder configured to hold a workpiece, a head, a first nozzle, and a driver. The head is configured to irradiate a first portion of a main surface of the workpiece with a laser beam. The first nozzle is configured to supply a first liquid to the first portion. The driver is configured to drive the holder in such a manner that the workpiece can revolve around the optical axis of the laser beam at the first portion. Accordingly, the workpiece can be processed, and debris of the workpiece can be prevented from adhering to the main surface of the workpiece.