Ion Beam Scanning System Corrects Divergence Angle Deviations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ion implantation systems face challenges in achieving high accuracy and productivity, particularly in high-current ion implantation processes, due to issues like beam divergence angle deviations, implantation angle inaccuracies, and contamination, which affect the uniformity and precision of ion distribution on semiconductor wafers.
Innovation Solution
The implementation of a beam generation and transportation system comprising a mass analysis device, a vertically and horizontally focusing quadrupole electromagnet system, a scanner, an acceleration/deceleration device, and an energy filtering system, which corrects beam divergence angle and size deviations, ensuring precise and uniform ion implantation by transforming the beam into an elliptical or oval cross-section for improved scanning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a batch ion implantation system is used to maintain high productivity, then the throughput remains high, but the implantation angle accuracy deteriorates due to rocking motion of wafers and beam center axis deviation
Solution Approach 1:
The patent replaces the mechanical rotation system with offset angles with an electromagnetic beam scanning system. The beam is scanned across the wafer surface using electromagnetic deflectors, eliminating the need for mechanical wafer rotation and associated rocking motions. This substitution maintains high productivity through rapid electronic scanning while achieving superior implantation angle accuracy by eliminating mechanical instability.
Solution Approach 2:
The patent introduces dynamic beam scanning that adapts to wafer position and orientation in real-time. The beam scanning parameters are dynamically adjusted during the implantation process to compensate for any deviations, ensuring consistent implantation angle accuracy across all wafer positions while maintaining high throughput through continuous scanning operation.
2Manufacturing precision
If the beam divergence angle is reduced to improve implantation angle accuracy, then the lateral distribution of dopants improves, but the beam current decreases
Solution Approach 1:
The patent segments the ion beam into multiple scanned sub-beams that collectively cover the entire wafer surface. Each sub-beam maintains a narrow divergence angle for precise implantation, while the rapid scanning across multiple positions delivers the required total dopant quantity. This segmentation allows simultaneous achievement of high beam current and narrow divergence through temporal multiplexing.
Solution Approach 2:
The patent employs periodic beam scanning across the wafer surface, delivering ions in rapid successive pulses to different locations. This periodic action allows each pulse to maintain narrow beam divergence for precise implantation while the cumulative effect of many pulses delivers the required total beam current and dopant quantity throughout the wafer.
3Manufacturing precision
If mechanical scanning is used to cover the entire wafer surface, then the beam can be distributed uniformly, but the scanning accuracy decreases and productivity is reduced
Solution Approach 1:
The patent replaces mechanical scanning systems with electromagnetic beam scanning. The beam is deflected electronically across the wafer surface using electromagnetic deflectors, eliminating mechanical inertia and friction limitations. This enables much faster scanning speeds for high productivity while maintaining precise beam positioning and uniform dose distribution through electronic control.
4Manufacturing precision
If the beam energy is reduced to achieve low energy implantation, then the implantation precision improves, but the beam current decreases and productivity is affected
Solution Approach 1:
The patent uses periodic pulsed beam delivery at low energy, where short high-current pulses are delivered rapidly to different wafer positions through scanning. Each pulse maintains low energy for precise implantation while the high repetition rate and scanning coverage deliver sufficient total beam current and productivity. The periodic pulsed operation allows low energy precision with compensated beam current through temporal multiplexing.
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 configuration enables high-accuracy, high-productivity ion implantation with improved dose uniformity and implantation angle precision, even at low energies, by correcting beam trajectory deviations and reducing contamination, thus enhancing the quality of semiconductor devices.
Implementation Method 1
a beam generation and transportation system comprising a mass analysis device, a vertically and horizontally focusing quadrupole electromagnet system
Implementation Method 2
vertically and horizontally focusing quadrupole electromagnet system, which corrects beam divergence angle and size deviations
Implementation Method 3
a mass analysis device
Implementation Method 4
an acceleration/deceleration device
Implementation Method 5
an energy filtering system
Data Source
AI summary
The present invention is a method to enhance accuracy of irradiation with beam for an irradiation system with a beam. The irradiation system comprises a beam generation source, a mass analysis device, a beam transformer, a scanner which swings the beam reciprocally with high speed, a beam parallelizing device, an acceleration/deceleration device, an energy filtering device, and beam monitors. The beam transformer comprises a vertically focusing synchronized quadrupole electromagnet syQD and a horizontally focusing synchronized quadrupole electromagnet syQF. Consequently, it is possible to correct at least one of a deviation in beam divergence angle and a deviation in beam size within a range between a center trajectory and an outer trajectory after swinging of the beam by the scanner.