Laser Annealing Beam Drift Correction via Mirror Control
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Solution Overview
Problem
Conventional laser annealing apparatuses experience irradiation unevenness due to beam position and angle deviations, leading to varying crystal quality and transistor characteristics, and existing drift correction methods increase production costs and affect beam propagation characteristics.
Innovation Solution
A laser annealing apparatus with a position deviation detector and an angle deviation detector, coupled with a deflection mirror and mirror controller, detects and corrects beam deviations before the beam shaping optical system, eliminating the need for additional beam shaping units and maintaining beam propagation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a beam shaping unit and orientation control mechanism are added to correct beam drift, then beam positioning accuracy is improved, but device complexity and production cost increase
Solution Approach 1:
The patent employs a feedback control mechanism where a line sensor detects the actual beam center position, compares it with the reference position, and generates correction signals to adjust the mirror orientation. This closed-loop feedback system automatically compensates for beam drift without requiring complex mechanical repositioning mechanisms, thereby improving positioning accuracy while controlling device complexity.
Solution Approach 2:
The patent introduces a line sensor as an intermediary detection device that measures beam position deviations. This intermediary component provides precise measurement data that enables the control system to make accurate corrections, achieving high positioning precision without directly manipulating the beam path with complex optical elements.
2Manufacturing precision
If the orientation of reflection mirrors in the optical resonator is changed to eliminate beam deviation, then beam positioning accuracy is improved, but laser output stability deteriorates
Solution Approach 1:
The patent places the line sensor and control mechanism as intermediaries between the laser resonator and the beam shaping optical system. This allows orientation correction to be applied after the beam exits the resonator, preventing any feedback from the correction process from affecting the resonator's internal beam propagation and laser output stability.
Solution Approach 2:
The patent segments the laser system into distinct functional modules: the laser resonator (which maintains stable output), the beam shaping optical system, and the separate orientation control mechanism with line sensor. This segmentation isolates the correction function from the resonator, allowing independent optimization of both laser output stability and beam positioning 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 approach effectively reduces irradiation unevenness caused by beam drift in the short-axis direction without increasing production costs or affecting beam propagation, ensuring consistent crystal quality and transistor performance.
Implementation Method 1
a laser beam emitted from a laser is shaped into a beam with a linear cross section through a beam shaping optical system. This linear beam scans a substrate, which is an object to be irradiated
Implementation Method 2
laser annealing apparatus and method for performing an annealing process on an object to be processed by irradiating the object with a linear beam
Implementation Method 3
a laser beam emitted from a laser is shaped into a beam with a linear cross section through a beam shaping optical system
Implementation Method 4
a pair of reflection mirrors 43 and 44 which forms an optical resonator
Implementation Method 5
a beam center position detection device (a line sensor 45 and a profile position calculation device 46) for detecting a center position in a width direction of the beam
Data Source
AI summary
The irradiation unevenness caused by drift occurring in a beam short-axis direction is reduced without adding a new beam shaping unit and affecting the propagation characteristic of a beam in an optical resonator. A position deviation detector for detecting a position deviation of a laser beam before passing through a beam shaping optical system, an angle deviation detector for detecting an angle deviation of the laser beam before passing through the beam shaping optical system, a deflection mirror for deflecting the laser beam, which is disposed in an optical path between a laser and an object (substrate), and a mirror controller for controlling orientation of the deflection mirror, based on detection data obtained using the position deviation detector and the angle deviation detector so as to eliminate the position deviation from a reference irradiation position in the short-axis direction of a linear beam on a surface to be irradiated.