Ion Beam Angle Correction and Wafer Tilt for Crystal Alignment
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Solution Overview
Problem
In ion implantation processes for semiconductor manufacturing, the misalignment between the ion beam trajectory and the crystal axis of wafers due to manufacturing errors and beamline deviations leads to inefficiencies, as existing methods do not adequately account for discrepancies between actual and ideal ion beam trajectories, resulting in complex control configurations that can interfere with precise ion beam transport.
Innovation Solution
An ion implanter equipped with an angle measurement apparatus to measure ion beam angles in orthogonal directions, an angle corrector to adjust the ion beam trajectory, a tilt device to rotate the wafer, and a controller to align the ion beam with the crystal axis information, allowing for precise correction of ion beam angles and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ion beam trajectory is adjusted to account for manufacturing errors and beamline deviations, then the alignment accuracy with the crystal axis is improved, but the control configuration becomes more complex
Solution Approach 1:
The system performs preliminary measurement of the ion beam trajectory using the angle measurement apparatus before the ion implantation process. The measured trajectory information is stored and used to calculate correction values in advance, which are then applied during the actual implantation process. This preliminary action separates the complex measurement and calculation tasks from the execution phase, improving alignment accuracy without significantly increasing the complexity of the control configuration during operation.
Solution Approach 2:
The control device acts as an intermediary that receives trajectory information from the angle measurement apparatus, calculates the necessary correction values, and translates these into control signals for the beamline adjustment mechanisms. This intermediary processing layer simplifies the overall control configuration by centralizing the complex calculations and decision-making logic in a dedicated control unit, rather than distributing complexity across multiple components.
2Manufacturing precision
If the wafer rotation is used to correct ion beam angle deviations, then the alignment precision is improved, but the burden on the wafer drive unit increases
Solution Approach 1:
The system uses the wafer rotation mechanism only for correcting angle deviations in one direction (azimuthal alignment), while the beamline adjustment mechanisms handle the other direction (elevation angle). This partial use of wafer rotation avoids overburdening the wafer drive unit by distributing the correction tasks between multiple subsystems, each handling a specific aspect of the alignment correction.
Solution Approach 2:
The alignment correction function is segmented into two independent correction mechanisms: beamline adjustment for correcting elevation angle deviations and wafer rotation for correcting azimuthal angle deviations. This segmentation allows each subsystem to operate within its optimal performance range and reduces the burden on any single component, particularly the wafer drive unit which only needs to handle rotational alignment rather than the full three-dimensional correction task.
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 enables precise alignment of the ion beam with the crystal axis, improving the accuracy of ion implantation by simplifying the control configuration and reducing the burden on the wafer drive unit, thus enhancing the precision of ion implantation processes without compromising ion beam transport.
Implementation Method 1
an angle measurement apparatus that measures a first angle of an ion beam in a first direction and a second angle of the ion beam in a second direction
Implementation Method 2
an angle corrector that is located in a beamline of the ion beam and corrects an angle of the ion beam in the first direction
Data Source
AI summary
An ion implanter includes an angle measurement apparatus that measures a first angle of an ion beam in a first direction and a second angle of the ion beam in a second direction, the first direction and the second direction being mutually orthogonal to a traveling direction of the ion beam, an angle corrector that is located in a beamline of the ion beam and corrects an angle of the ion beam in the first direction based on the first angle, a wafer holder that holds a wafer in a process chamber, a tilt device that is connected to the wafer holder and that rotates the wafer around a rotation axis parallel to the first direction, and a controller that controls the tilt device based on the second angle, crystal axis information of the wafer, and implantation recipe information.