Wedge-Shaped Light-Cutting Plates for Laser Annealing Interference
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Solution Overview
Problem
The existing excimer laser annealing process for producing polycrystalline silicon thin films in AMOLED backplanes often results in interference mura, leading to decreased product quality and pass rate due to beam interference between the ingoing and reflected laser beams, which affects the crystallization process.
Innovation Solution
A laser annealing device with wedge-shaped light-cutting plates is introduced, where the light-cutting end face is designed with a wedge-shaped structure to increase the included angle between the reflected and ingoing beams, reducing interference and enhancing the quality of the polycrystalline silicon thin film, and the contact area between the light-cutting plate and annealing window is minimized to reduce abrasion and extend the annealing window's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If light-cutting plates with flat end faces are used to block and reflect laser beams, then the laser beam can be effectively cut and directed, but interference mura occurs on the polycrystalline silicon thin film due to beam interference between ingoing and reflected beams
Solution Approach 1:
The light-cutting plate's end face is designed with an asymmetric wedge shape rather than a flat symmetric surface. This asymmetric geometry causes the reflected laser beam to diverge at a specific angle (e.g., 10-20 degrees) relative to the incident beam, preventing the reflected beam from interfering with the ingoing beam that forms the polycrystalline silicon thin film, thereby eliminating interference mura while maintaining effective beam cutting and direction control
2Manufacturing precision
If light-cutting plates are positioned close to the annealing window to effectively block laser beams, then beam cutting precision is improved, but abrasion of the annealing window increases due to contact between the light-cutting plate and annealing window
Solution Approach 1:
The light-cutting plate is designed with a wedge shape extending in the depth dimension (perpendicular to the annealing window surface). This three-dimensional wedge structure allows the plate to be positioned at an angle such that its end face effectively blocks and reflects the laser beam while the tapered geometry prevents direct contact between the plate body and the annealing window, thereby maintaining beam cutting precision while eliminating abrasion and extending the annealing window's service life
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 wedge-shaped light-cutting plates effectively reduce interference mura on the polycrystalline silicon thin films, improving their quality and increasing the production pass rate, while also extending the life of the annealing window and reducing maintenance costs.
Implementation Method 1
the incident beam 41 arriving at the light-cutting plates 1 is reflected by the light-cutting plates 1, so that reflected beams 42 are formed
Implementation Method 2
irradiates an amorphous silicon film on a substrate with an excimer laser beam for a short time to produce a polycrystalline silicon film by the recrystallization of the amorphous silicon film
Implementation Method 3
produce a polycrystalline silicon film by the recrystallization of the amorphous silicon film
Data Source
Figure 1~3
AI summary
The invention relates to the field of laser annealing, and discloses a laser annealing device, a production process of a polycrystalline silicon thin film, and a polycrystalline silicon thin film produced by the same. The laser annealing device comprises an annealing chamber, in which a laser generator is provided, wherein an annealing window, through which the laser passes, and two light-cutting plates oppositely provided above the annealing window are also provided in the annealing chamber, wherein the light-cutting end face of each of the light-cutting plates is a wedge-shaped end face. In technical solutions of the invention, since the light-cutting end face is a wedge-shaped end face, the included angle formed by the reflected beam, which is formed by the reflection of the incident beam arriving at the light-cutting end face, and the ingoing beam, which passes through the annealing window, is relatively large, and the vibrating directions of them differ relatively greatly. Hence, the phenomenon of interference will hardly occur, and thus the interference mura generated on the polycrystalline silicon thin film due to the interference is reduced, the quality of the polycrystalline silicon thin film is improved, and the percent of pass of the product is also increased.