Ribbon Beam Uniformity via Two-Stage Corrector Bar Assemblies
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Solution Overview
Problem
Ribbon beams in ion implantation suffer from intrinsic non-uniformity issues, lacking both dose and angle uniformity, which are essential for precise semiconductor manufacturing, with existing solutions failing to meet stringent requirements of less than 1% dose variation and 0.5° angle variation.
Innovation Solution
The use of a two-stage corrector-bar assembly system with individually excitable coils and magnetic core members to deflect and redistribute beamlets, achieving desired spatial spread and angle uniformity, allowing for independent control over dose and angle uniformity through a controller that adjusts coil excitations and measures beam changes to optimize ion distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a ribbon beam is used for ion implantation, then scanning complexity is reduced and productivity is improved, but dose uniformity and angle uniformity deteriorate due to intrinsic beam non-uniformity
Solution Approach 1:
The ribbon beam is segmented into multiple individual beamlets that can be independently controlled. Each beamlet is deflected by individually excitable coils, allowing separate adjustment of spatial position and angle for each beamlet to achieve uniform dose and angle distribution across the wafer.
Solution Approach 2:
Different regions of the ribbon beam are given different local properties through selective coil excitation. Each beamlet can be independently deflected to compensate for local non-uniformities, creating a customized beam profile that achieves uniform dose and angle distribution across the entire wafer surface.
2Ease of manufacture
If beamlets within a ribbon beam are allowed to have different directions and angle spreads, then beam formation is simplified, but angle uniformity deteriorates causing different locations to experience different ion incident angles
Solution Approach 1:
The angle and direction parameters of each beamlet are independently adjusted through controlled coil excitation. By changing the excitation parameters of individual coils, each beamlet's angle can be precisely controlled to achieve uniform incident angles across the entire ribbon beam, while maintaining the simplified ribbon structure.
3Ease of manufacture
If beamlets are not evenly spaced within the ribbon beam, then beam generation is easier, but dose uniformity deteriorates causing non-uniform ion dose distribution
Solution Approach 1:
The spatial distribution of beamlets is made dynamically adjustable through individual coil excitation. Even though beamlets may be unevenly spaced initially, the independent deflection capability allows real-time adjustment of each beamlet's position to achieve uniform dose distribution, transforming a static non-uniform structure into a dynamically controllable uniform beam.
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 significantly improves dose and angle uniformity of ribbon beams, ensuring that the ion dose and angle variations are within the required limits, enhancing the precision and effectiveness of ion implantation processes.
Implementation Method 1
a first plurality of coils distributed along the first set of magnetic core members... each of the first plurality of coils may be individually excited to deflect at least one beamlet in the ribbon beam
Implementation Method 2
individually excited to deflect at least one beamlet in the ribbon beam, thereby causing the plurality of beamlets to arrive at the second corrector-bar assembly in a desired spatial spread
Data Source
AI summary
A technique for improving uniformity of a ribbon beam is disclosed. In one particular exemplary embodiment, an apparatus may comprise a first corrector-bar assembly and a second corrector-bar assembly, wherein the second corrector-bar assembly is located at a predetermined distance from the first corrector-bar assembly. Each of a first plurality of coils in the first corrector-bar assembly may be individually excited to deflect at least one beamlet in the ribbon beam, thereby causing the beamlets to arrive at the second corrector-bar assembly in a desired spatial spread. Each of a second plurality of coils in the second corrector-bar assembly may be individually excited to further deflect one or more beamlets in the ribbon beam, thereby causing the beamlets to exit the second corrector-bar assembly at desired angles.