Beam Collimator for High-Energy Ion Implanter
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Solution Overview
Problem
High-energy ion implanters face challenges in achieving precise ion implantation due to implantation angle deviations and dose uniformity issues, particularly in high-aspect-ratio structures and high-energy ion implantation processes, where existing systems like parallel magnets suffer from beam non-uniformity and increased size and power consumption.
Innovation Solution
A high-energy ion implanter with a beam collimator system using electric field collimating lenses and an Angular Energy Filter (AEF) to collimate and filter the ion beam, ensuring precise angle and dose uniformity, and a U-shaped folded beamline layout to reduce installation area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If parallel magnets are used for beam collimation, then beam uniformity is improved, but device size and power consumption increase
Solution Approach 1:
The patent replaces the magnetic field-based parallel magnet system with an electric field-based lens system. Specifically, electrostatic lenses (including condenser lenses and field lenses) are used to collimate and focus the ion beam, substituting electromagnetic mechanisms with electrostatic ones. This reduces power consumption while achieving comparable or superior beam uniformity through precise electric field control.
Solution Approach 2:
The patent changes the fundamental parameter from magnetic field strength to electric field potential distribution. By controlling voltages on various electrode elements (segmented electrodes, ring electrodes), the system achieves beam collimation and focusing without the high power consumption associated with generating strong magnetic fields. The electric field parameters can be dynamically adjusted to optimize beam uniformity.
2Length of moving object
If high-energy ion implantation is performed, then implantation depth is improved, but implantation angle precision deteriorates
Solution Approach 1:
The patent implements preliminary beam collimation and angle correction before the high-energy ions reach the wafer. Electric field lenses are positioned upstream in the beam path to pre-align the beam trajectory. The Angular Energy Filter (AEF) is also positioned before the implantation region to correct angle deviations that may develop during acceleration, ensuring precise angle control is maintained even at high energies.
Solution Approach 2:
The patent introduces electric field lenses and the Angular Energy Filter as intermediary elements between the ion source and the wafer. These intermediaries actively shape and correct the beam trajectory during its path, compensating for angle deviations that would otherwise accumulate over the long acceleration and transport path required for high-energy implantation.
3Manufacturing precision
If beam collimation is enhanced, then dose uniformity is improved, but device complexity increases
Solution Approach 1:
The patent divides the beam collimation function into multiple segmented electrode elements rather than using a single complex magnetic system. The collimation is achieved through a sequence of simpler electrostatic lenses (condenser lenses, field lenses) with segmented electrodes that can be independently controlled. This modular approach achieves superior dose uniformity while reducing overall system complexity compared to high-field parallel magnets.
Solution Approach 2:
The electric field lens system performs multiple functions simultaneously: collimation, focusing, and angle correction. The same electrostatic lens elements that collimate the beam also serve to focus it onto the wafer surface, eliminating the need for separate dedicated components and reducing overall device complexity despite enhanced collimation capability.
4Area of stationary object
If U-shaped folded beamline layout is used, then installation area is reduced, but beam path length increases
Solution Approach 1:
The patent employs a U-shaped folded beamline layout that transitions the beam path from a linear arrangement to a three-dimensional folded configuration. The beamline bends back on itself in a U-shape, utilizing vertical and lateral spatial dimensions to fold the path within a compact footprint. This dimensional reorganization reduces the horizontal installation area while the increased path length is compensated by enhanced collimation and focusing capabilities at strategic points along the folded path.
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 highly precise ion implantation with improved dose uniformity and reduced power consumption, while also simplifying installation and maintenance by minimizing the apparatus' footprint and optimizing work space.
Implementation Method 1
an angle of a beam traveling direction with respect to the reference trajectory is changed by an electric field generated in the bow-shaped curved gap
Implementation Method 2
a plurality of acceleration and/or deceleration lens units that are arranged along a reference trajectory so that a beam collimated to the reference trajectory comes out from an exit of the beam collimator
Implementation Method 3
Angular Energy Filter (AEF) to collimate and filter the ion beam
Data Source
AI summary
A beam collimator includes a plurality of lens units that are arranged along a reference trajectory so that a beam collimated to the reference trajectory comes out from an exit of the beam collimator. Each of the plurality of lens units forms a bow-shaped curved gap and is formed such that an angle of a beam traveling direction with respect to the reference trajectory is changed by an electric field generated in the bow-shaped curved gap. A vacant space is provided between one lens unit of the plurality of lens units and a lens unit that is adjacent to the lens unit. The vacant space is directed in a transverse direction of the collimated beam in a cross section that is perpendicular to the reference trajectory. An inner field containing the reference trajectory is connected to an outer field of the plurality of lens units through the vacant space.