Laser Processing Liquid Layer Former for Debris Control
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Solution Overview
Problem
Existing laser processing technologies face challenges in preventing debris adhesion to the workpiece surface during processing, which can obstruct the laser beam and lower processing quality, particularly in ablation methods where liquid resin application and removal are inefficient and uneconomical, and immersion in water generates bubbles that obstruct the laser beam.
Innovation Solution
A laser processing apparatus with a holding unit, a laser beam applying unit that includes a condenser and a liquid layer former forming a transparent liquid layer on the workpiece surface, allowing the laser beam to pass through and preventing debris adhesion by continuously flowing liquid to remove bubbles and debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If liquid resin is applied to the front surface of the wafer before laser processing, then debris adhesion to the front surfaces of the devices is prevented, but processing productivity is reduced due to additional steps of applying and removing liquid resin
Solution Approach 1:
A liquid layer (water or other transparent liquid) is introduced as an intermediary medium between the laser beam and the wafer surface. This liquid layer serves multiple functions: it prevents debris from adhering to the device surfaces, it allows the laser beam to pass through effectively, and it can be continuously replenished without requiring complete removal between processing cycles, thus maintaining high productivity while protecting against debris contamination.
Solution Approach 2:
The invention utilizes a liquid delivery system that employs hydraulic principles to supply and maintain a continuous liquid layer on the wafer surface during laser processing. The liquid is delivered through nozzles or channels that use fluid pressure to ensure consistent coverage, allowing the liquid to flow over the surface and carry away debris while maintaining optimal processing conditions throughout the manufacturing cycle.
2Object-affected harmful factors
If the wafer is immersed in water during laser beam application, then debris adhesion is prevented, but minute bubbles are generated that obstruct laser beam propagation
Solution Approach 1:
Instead of using a static immersion method where the wafer is completely submerged in water, the invention employs a dynamic liquid delivery system that continuously supplies fresh liquid to the processing area. This dynamic approach ensures that bubbles generated during processing are immediately carried away by the flowing liquid, preventing them from accumulating and obstructing the laser beam path, while still maintaining effective debris removal.
Solution Approach 2:
The liquid is supplied to the wafer surface before and during laser processing in advance, creating a protective liquid layer that prevents debris adhesion from the outset. This preliminary establishment of the liquid barrier ensures that debris is prevented from adhering to the surface before it can interfere with processing, while the continuous supply prevents bubble formation from disrupting laser beam propagation.
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 ensures uninterrupted laser beam application and prevents debris adhesion to the workpiece surface, maintaining processing quality without the need for liquid resin application or water immersion, thereby enhancing productivity and economic efficiency.
Implementation Method 1
a laser oscillator adapted to emit a laser beam
Implementation Method 2
a condenser adapted to focus the laser beam emitted from the laser oscillator
Implementation Method 3
a transparent section that is formed at the bottom wall adjacently to the jet port and that permits transmission of the laser beam therethrough, and the laser beam is applied to the workpiece through the transparent section and the layer of the liquid
Data Source
AI summary
A laser beam applying unit of a laser processing apparatus includes a laser oscillator adapted to emit a laser beam, a condenser adapted to focus the laser beam emitted from the laser oscillator and to thereby apply the laser beam to the workpiece held by a holding unit, and a liquid layer former disposed at a lower end portion of the condenser and adapted to form a layer of a liquid on an upper surface of the workpiece. The liquid layer former includes a casing having a bottom wall that forms a gap between itself and the upper surface of the workpiece, a liquid supply section adapted to supply the liquid to the casing, and a transparent section that is formed at the bottom wall adjacently to the jet port and that permits transmission of the laser beam therethrough.