Wafer Frame Irradiation Using Position Detection and Zone Attenuation
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Solution Overview
Problem
Existing methods for uniformly irradiating semiconductor substrates during thermal processing face challenges such as inadequate energy density, damage to fragile edges, and complexity in synchronizing scanning stages and optical systems, leading to inefficient and inaccurate irradiation.
Innovation Solution
A method and system that utilize a detecting unit to determine the initial position of the substrate, a scanning unit to emit an irradiation beam uniformly covering each frame while attenuating it in intermediate zones by more than 80%, and a control unit to synchronize the movement of the substrate and scanning unit, ensuring precise and uniform irradiation without damaging edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a full wafer irradiation system is used to cover the entire wafer at the same time, then the irradiation uniformity is improved, but the energy density becomes insufficient and the system cannot deliver sufficient energy to cover the entire wafer uniformly
Solution Approach 1:
The patent divides the wafer into multiple frames and irradiates each frame individually with a smaller, more focused beam. This segmentation allows the system to concentrate energy on smaller areas (achieving high energy density) while systematically covering the entire wafer (achieving uniform irradiation across all frames). The beam is scanned across different frame positions rather than attempting to illuminate the entire wafer simultaneously.
2Manufacturing precision
If a smaller irradiation beam with scanning stage is used to achieve uniform irradiation, then the irradiation precision is improved, but the device complexity increases due to heavy scanning stage and complex synchronization requirements
Solution Approach 1:
The patent replaces the heavy mechanical scanning stage with a stationary or minimally moving platform. Instead of mechanically moving the entire scanning stage across the wafer, the system uses a fixed beam delivery system that can be rapidly positioned or scanned using lighter, faster optical components. This substitution reduces mechanical inertia, simplifies synchronization, and enables faster scanning while maintaining irradiation precision.
3Area of stationary object
If conventional scanning system is used to move the wafer or irradiation beam, then the irradiation coverage is improved, but the scanning speed becomes slow due to heavy scanning stage
Solution Approach 1:
The patent employs dynamic beam scanning techniques where the irradiation beam is rapidly directed across different frames using fast-steering mirrors or acousto-optic deflectors. This dynamic approach allows the system to cover the entire wafer area quickly without the inertia limitations of heavy mechanical stages. The beam can be repositioned in microseconds between frames, achieving high scanning speeds while maintaining complete coverage.
4Area of stationary object
If full wafer irradiation is applied, then the irradiation coverage is improved, but the edges of the wafer are damaged due to fragile edge areas
Solution Approach 1:
The patent applies different irradiation characteristics to different regions of the wafer. The smaller, scanned beam allows precise control over which areas receive irradiation. By adjusting the beam scan pattern and intensity, the system can fully irradiate the frame areas while avoiding or reducing irradiation at the fragile edge regions. This local quality approach ensures that each region receives the appropriate amount of energy based on its specific requirements and vulnerability.
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 solution enables precise and uniform irradiation of semiconductor substrate frames, avoiding damage to edges and intermediate zones, while achieving efficient energy distribution, thus improving the annealing process and reducing the complexity of synchronization.
Implementation Method 1
determining an initial position of said processed substrate using a detecting unit
Implementation Method 2
irradiating said first frame of the processed substrate by an irradiation beam emitted by a source unit and scanned by a scanning unit
Implementation Method 3
said irradiation beam being adapted to cover uniformly the whole first frame
Data Source
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AI summary
A method for uniformly irradiating a frame of a processed substrate (1), said processed substrate comprising a plurality of frames, two consecutive frames being separated by an intermediate zone, said method comprises steps of: - determining an initial position of said processed substrate using a detecting unit (80), - comparing said detected initial position with a first predetermined position associated with a first frame of the processed substrate, - irradiating said first frame of the processed substrate by an irradiation beam (105) emitted by a source unit (30) and scanned by a scanning unit (40) based on the first predetermined position, said irradiation beam being adapted to cover uniformly the whole first frame. A system for uniformly irradiating a frame of a processed substrate is also described.