Wider Ion Beam for Lower Dose Rate Implantation
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Solution Overview
Problem
Conventional ion implantation processes at high dose rates cause significant damage to semiconductor devices, and simply increasing scan speed is insufficient to reduce device damage to an acceptable level.
Innovation Solution
The use of a wider ion beam generated by positioning the extraction manipulator at a gap distance from the ion source that differs by at least 10% from the optimal gap distance, combined with applying potentials to specific electrodes and a magnetic field, to reduce beam density and minimize device damage during ion implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ion beam is optimized to maximize beam density, then dose rate is maximized and throughput is improved, but device damage increases significantly
Solution Approach 1:
The patent changes the gap distance parameter between the extraction manipulator and ion source exit aperture from its conventional optimized value to a non-optimal value that is at least 10% different. This parameter change transforms the narrow high-density beam into a wider lower-density beam, reducing device damage while maintaining acceptable throughput through the modified beam characteristics
Solution Approach 2:
Instead of optimizing the extraction manipulator position to maximize beam current (conventional approach), the patent intentionally positions it at a non-optimal gap distance that produces a wider, less dense beam. This inverted approach prioritizes device protection over maximum throughput, accepting lower beam density to prevent damage
2Object-affected harmful factors
If the scan speed of the work piece is increased to reduce dose rate, then device damage is reduced, but scan speed adjustment alone is insufficient to achieve acceptable damage levels
Solution Approach 1:
The patent changes the fundamental beam parameter (width/density) by modifying the extraction manipulator position, rather than relying solely on scan speed adjustments. This creates a wider beam with lower linear density, achieving dose rate reduction that scan speed alone cannot accomplish while maintaining productive throughput
3Quantity of substance
If the extraction manipulator is positioned at the optimal gap distance to maximize ion beam current, then beam density is maximized, but beam width is narrow causing high dose rates
Solution Approach 1:
The patent deliberately changes the gap distance parameter from its current optimized value by at least 10%, transforming the beam from narrow and dense to wider and less dense. This parameter modification redistributes the ion beam current over a larger area, reducing the dose rate while maintaining sufficient total current for productive implantation
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 lowers the dose rate and reduces device damage by spreading the ion beam current over a larger area, improving beam uniformity and reducing the risk of device damage during semiconductor fabrication.
Implementation Method 1
an ion beam may be extracted from an ion source and filtered by mass, charge, and energy through a magnetic analyzer
Implementation Method 2
filtered by mass, charge, and energy through a magnetic analyzer
Implementation Method 3
A first potential may be applied to a first set of electrodes. The x-dimension of the ion beam may increase as the ion beam passes through the first set of electrodes
Data Source
AI summary
In an exemplary process for lower dose rate ion implantation of a work piece, an ion beam may be generated using an ion source and an extraction manipulator. The extraction manipulator may be positioned at a gap distance from an exit aperture of the ion source. A current of the ion beam exiting the extraction manipulator may be maximized when the extraction manipulator is positioned at an optimal gap distance from the exit aperture. The gap distance at which the extraction manipulator is positioned from the exit aperture may differ from the optimal gap distance by at least 10 percent. A first potential may be applied to a first set of electrodes. An x-dimension of the ion beam may increase as the ion beam passes through the first set of electrodes. The work piece may be positioned in the ion beam to implant ions into the work piece.