Laser Processing Gas Flow Rectification for Uniform Irradiation
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Solution Overview
Problem
Conventional laser processing apparatuses face issues with turbulent gas flows around the laser beam irradiation area, leading to non-uniform laser intensity and difficulties in discharging substances like vapor or fine particles from the optical path, due to external gas flow disturbances during substrate movement.
Innovation Solution
The apparatus incorporates a gas discharge unit with a rectifying surface featuring multiple gas ports, including a first gas discharge port, a second gas discharge port, and a gas suction port, arranged to stabilize the gas flow and prevent turbulent flow by discharging gases in specific directions and angles, ensuring a uniform atmosphere around the laser beam irradiation area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas is injected toward the substrate along the laser beam axis at the irradiation position, then a local gas atmosphere is formed to eliminate the influence of outside air, but turbulent flow occurs around the laser beam irradiation position
Solution Approach 1:
The gas discharge unit is divided into multiple independent gas discharge ports (first, second, and third ports) positioned at different locations and orientations. This segmentation allows each port to contribute to different aspects of flow control, collectively achieving stable laminar flow while maintaining effective gas atmosphere formation around the irradiation area.
Solution Approach 2:
Gas is discharged at specific locations (center and side portions of the irradiation area) with specific orientations (parallel to substrate surface) to create localized flow patterns. This local quality approach ensures that gas is supplied where needed to maintain atmosphere stability without causing turbulent flow throughout the entire processing area.
2Stability of the object's composition
If gas flow velocity is reduced to stabilize turbulent flow, then flow stability improves, but it becomes difficult to form a uniform atmosphere
Solution Approach 1:
The gas discharge ports are oriented to discharge gas parallel to the substrate surface rather than perpendicular to it. This dimensional change in discharge orientation creates a flow pattern that stabilizes the gas atmosphere without causing turbulence, allowing uniform atmosphere formation while maintaining flow stability.
3Adaptability or versatility
If turbulent flow occurs, then gas pressure or temperature fluctuation occurs, but this results in change in optical refractive index and non-uniform laser intensity
Solution Approach 1:
The gas discharge parameters (flow rate, discharge orientation, discharge location) are optimized to maintain laminar flow conditions. By controlling these parameters, the system prevents pressure and temperature fluctuations that would otherwise change the optical refractive index and cause non-uniform laser intensity distribution.
4Stability of the object's composition
If turbulent flow occurs or flow velocity is extremely low, then it becomes difficult to discharge substances such as vapor or fine particles from the optical path of the laser
Solution Approach 1:
The gas discharge system is designed to maintain dynamic laminar flow that continuously moves through the irradiation area. This dynamic flow effectively transports vapor and fine particles away from the optical path while maintaining flow stability, preventing particle accumulation without causing turbulence.
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 configuration effectively prevents turbulent gas flows, maintains a stable atmosphere, and ensures uniform laser processing by stabilizing the gas flow and efficiently removing substances from the optical path, thereby improving processing quality and productivity.
Implementation Method 1
an improvement has been made to change the injecting gas flow into laminar flow
Implementation Method 2
when a gas flow is injected to the laser beam irradiation position, a turbulent flow occurs around the laser beam irradiation position
Implementation Method 3
the gas discharge unit has a rectifying surface at a position facing the workpiece during laser beam irradiation, and the rectifying surface is provided with a first gas discharge port through which the first gas is discharged
Implementation Method 4
gas pressure or temperature fluctuation occurs. As a result, a change in optical refractive index with respect to the laser occurs, resulting in a non-uniform laser intensity at the laser beam irradiation position
Implementation Method 5
vapor or fine particles of a constituent element (for example, Si) generated from a semiconductor film (for example, Si film) by irradiation with a laser beam changes the refractive index of the laser beam on the optical path or blocks the laser
Implementation Method 6
one or both of a second gas discharge port and a gas front-back suction port, the second gas discharge port discharging a second gas to the workpiece during laser beam irradiation on both outer sides of the first gas discharge port at least in the scanning direction
Data Source
AI summary
A laser processing apparatus includes: a scan moving unit which moves one or both of a workpiece and a laser beam; a laser beam irradiation unit which irradiates the workpiece with the laser beam; and a gas discharge unit which discharges at least a first gas to an irradiation area irradiated with the laser beam in the workpiece. The gas discharge unit has a rectifying surface at a position facing the workpiece during laser beam irradiation. The rectifying surface is provided with a first gas discharge port through which the first gas is discharged; and one or both of a second gas discharge port and a gas front-back suction port. The second gas discharge port discharges a second gas to the workpiece during laser beam irradiation on both outer sides of the first gas discharge port at least in the scanning direction.