Curved Ion Beam Deceleration Stage for Energy Contamination Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ion implanters face energy contamination issues due to energetic neutrals that are not properly decelerated and strike the substrate at higher energies than intended, especially when using straight deceleration stages, leading to inefficiencies in low-energy high-current ion beam transport and potential damage to substrates.
Innovation Solution
Incorporating a deceleration stage with a deflection assembly and a hydrogen source to create a partial pressure of hydrogen gas, which deflects and decelerates the ion beam, reducing energy contamination by minimizing scattering and space charge effects, while maintaining optimal beam control and trajectory alteration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a straight deceleration stage is used to decelerate the ion beam, then the ion beam can be transported efficiently, but energetic neutrals strike the substrate at higher energies causing energy contamination
Solution Approach 1:
The deceleration stage is designed with a curved or bent geometry instead of a straight path. This curvature causes energetic neutrals that are not decelerated to miss the substrate, while the ion beam follows the curved path and is properly decelerated by the electric fields within the stage. The curved design physically separates the trajectories of neutrals and ions, eliminating energy contamination while maintaining transport efficiency.
2Manufacturing precision
If the ion beam is decelerated to low energy before substrate impact, then precise energy delivery is achieved, but space charge forces cause the ions to repel each other limiting transport distance
Solution Approach 1:
The deceleration process is divided into multiple stages rather than a single deceleration step. The ion beam is decelerated in increments through multiple electrode pairs along the curved path, allowing gradual reduction of energy while maintaining beam coherence. This segmented approach reduces space charge effects at any given point while achieving the target low energy at the substrate.
Solution Approach 2:
The curved deceleration path allows the ion beam to be transported and decelerated simultaneously along a bent trajectory. This geometry enables the beam to maintain lower energy over a longer effective path length, compensating for space charge repulsion by distributing the deceleration process over multiple electrode sections along the curve.
3Object-affected harmful factors
If a bend is introduced in the deceleration stage to screen neutrals, then energy contamination is reduced, but the design complexity increases
Solution Approach 1:
The curved deceleration stage performs multiple functions simultaneously: it decelerates the ion beam through electric fields, screens energetic neutrals from the substrate through its geometry, and maintains beam focus along the curved path. By combining these functions in a single integrated structure rather than separate components, the design achieves neutral screening without proportionally increasing overall system complexity.
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 effectively reduces energy contamination and improves ion beam transport at lower energies by deflecting and decelerating ions, ensuring that energetic neutrals are not scattered towards the substrate, thereby maintaining precise energy delivery and reducing the risk of substrate damage.
Implementation Method 1
a deceleration assembly to decelerate the ion beam
Implementation Method 2
a deflection assembly to deflect the ion beam, where the deflection assembly includes a second plurality of electrodes disposed within the housing
Implementation Method 3
directing hydrogen gas into the deceleration stage during the decelerating
Implementation Method 4
minimizing scattering and space charge effects
Data Source
AI summary
An ion implantation system may include an ion source to generate an ion beam, a substrate stage disposed downstream of the ion source; and a deceleration stage including a component to deflect the ion beam, where the deceleration stage is disposed between the ion source and substrate stage. The ion implantation system may further include a hydrogen source to provide hydrogen gas to the deceleration stage, wherein energetic neutrals generated from the ion beam are not scattered to the substrate stage.