Laser Crystallizing Stage with Vacuum Grooves for Thin Substrates
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Solution Overview
Problem
The existing laser crystallizing apparatuses face challenges in maintaining proper substrate loading and unloading due to air trapping and surface resistance, leading to potential hole marks and loss of laser focus, especially as substrate thickness decreases, which affects grain growth during the crystallization process.
Innovation Solution
A stage with groove lines and control holes, where each control hole is connected to a vacuum or purge line to apply negative or positive pressure, ensuring secure substrate attachment and release, and a buffer tank is used to manage pressure and prevent hole marks, allowing for independent pressure control across multiple areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum holes or purge holes are provided on the stage to stabilize substrate loading and unloading, then substrate loading reliability is improved, but hole marks are created on the substrate surface
Solution Approach 1:
The stage surface is divided into different functional zones: groove lines with control holes for loading/unloading operations, and flat mark-free areas for laser processing. This local differentiation allows the substrate to be securely held during transfer while providing pristine surfaces for crystallization without hole marks.
Solution Approach 2:
The stage surface is segmented into multiple groove lines, each with its own control holes, allowing distributed substrate support and release points. This segmentation prevents concentrated stress and hole marks while maintaining reliable substrate handling.
2Productivity
If substrate thickness is decreased to reduce processing time, then productivity is improved, but substrate stability during laser crystallization deteriorates
Solution Approach 1:
The substrate is preliminarily secured to the stage using vacuum pressure through control holes before laser crystallization begins. This preliminary fixation ensures that even thin substrates remain stable during the laser processing operation, preventing displacement or deformation.
3Reliability
If groove lines with control holes are used for substrate handling, then substrate loading and unloading reliability is improved, but laser focus precision deteriorates due to hole marks
Solution Approach 1:
The stage design creates distinct functional zones: groove lines with control holes for reliable substrate handling, and adjacent flat mark-free areas that provide optimal surfaces for laser focus and crystallization processing.
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 solution prevents substrate bending and hole marking, maintains laser focus, and enhances the uniformity of crystallization, increasing operational efficiency and reducing processing time without the need for additional flattening devices.
Implementation Method 1
Each control hole is provided with a negative pressure to hold the substrate to a surface of the stage
Implementation Method 2
or a positive pressure to release the substrate from the surface of the stage
Implementation Method 3
a laser generator generating a laser beam
Implementation Method 4
crystallizes an amorphous silicon thin film into a polycrystalline silicon thin film
Data Source
AI summary
A laser crystallizing apparatus includes a stage configured to receive a substrate, the stage including a plurality of groove lines each having a predetermined depth and width, and a plurality of control holes, each arranged in a respective groove line. Each control hole is provided with a negative pressure to hold the substrate to a surface of the stage or a positive pressure to release the substrate from the surface of the stage.