Correction Lens Stabilizes Laser Irradiation Position
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Solution Overview
Problem
The use of a beam expander optical system in laser light irradiation for semiconductor film crystallization leads to unstable laser light paths due to environmental changes, causing significant errors in the irradiation position of the laser light on the semiconductor substrate, resulting in non-uniform crystallinity and film quality issues.
Innovation Solution
Incorporating a correction lens between the laser oscillator and the beam expander optical system, which includes a concave or convex lens, to stabilize the optical path and maintain the incidence position of the laser light, thereby reducing the displacement of the irradiation position on the substrate. The correction lens is positioned to ensure that the second conjugate point aligns with the focal point of the beam expander lens, optimizing the beam expansion and focusing to minimize positional errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a beam expander optical system is used to uniform the spatial intensity distribution of laser light, then the energy distribution uniformity is improved, but the irradiation position displacement error increases due to optical path changes from environmental factors
Solution Approach 1:
A correction lens is introduced as an intermediary optical element between the laser oscillator and the beam expander optical system. This correction lens compensates for optical path changes caused by environmental factors, thereby reducing the displacement error of the irradiation position while maintaining the beam expansion function for uniform energy distribution
Solution Approach 2:
The invention adjusts the positional parameters of the correction lens relative to the laser oscillator and beam expander to optimize the optical path. By changing the distance parameters (a, b, c) in the optical system configuration, the system achieves compensation for environmental variations while maintaining stable beam expansion
2Reliability
If the distance between the laser oscillator and beam expander optical system is increased to reduce incidence error, then the irradiation position stability is improved, but the device complexity and space requirement increase
Solution Approach 1:
The correction lens serves as a mediator that enables stable irradiation positioning without requiring large distances between components. It optically compensates for incidence errors, allowing the system to achieve high reliability with compact configuration
3Measurement precision
If a correction lens is added to stabilize the optical path, then the irradiation position accuracy is improved, but the device complexity increases
Solution Approach 1:
A single correction lens is introduced as a minimal intermediary component to achieve optical path stabilization. This simple addition compensates for environmental variations and improves irradiation accuracy without significantly increasing system complexity
4Manufacturing precision
If the magnification ratio of the beam expander is increased to expand the beam area, then the energy distribution uniformity is improved, but the displacement error of the irradiation position is amplified
Solution Approach 1:
The correction lens performs preliminary compensation for optical path changes before the light enters the beam expander. By counteracting environmental variations upstream in the optical path, it prevents the amplification of displacement errors that would otherwise occur with high magnification beam expansion
Solution Approach 2:
The correction lens acts as an intermediary between the laser oscillator and beam expander, stabilizing the incident beam parameters before expansion. This ensures that high magnification does not amplify positional errors, maintaining both uniformity and accuracy
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 significantly reduces the displacement of the laser light irradiation position on the substrate, ensuring more uniform energy distribution and improved crystallinity of the semiconductor film, even under varying environmental conditions.
Implementation Method 1
a correction lens disposed between the laser oscillator and the beam expander optical system
Implementation Method 2
a beam expander optical system which laser light oscillated from the laser oscillator enters
Implementation Method 3
when a semiconductor film is crystallized in order to form a TFT using a polycrystalline semiconductor film over a glass substrate, a method for crystallizing a semiconductor film by being irradiated with a laser beam is often used
Implementation Method 4
crystallization of a semiconductor film by laser light
Data Source
AI summary
Laser light is emitted from a laser oscillator, and the laser light is made to enter a beam expander optical system including a concave lens through a correction lens. The laser oscillator, the correction lens and the concave lens are disposed so that, when an emission point of the laser oscillator is a first conjugate point, a point at which an image at the first conjugate point is formed through the correction lens is a second conjugate point, a distance between the correction lens and the second conjugate point is b, a focal length of the concave lens is f, and a distance between the correction lens and the concave lens is X, the X satisfies b−3|f|≦X≦b+|f|.