Ion Implantation Angular Uniformity via Beamlet Segmentation
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Solution Overview
Problem
Current ion implantation methods face challenges in achieving angular uniformity of the implanted workpiece due to limitations in beam transport optics and divergent beam characteristics, which affect the electrical characteristics of semiconductor devices.
Innovation Solution
An ion implantation method involving the use of multiple beamlets with specific incident angles, mapped to an imaginary planar coordinate system, where the workpiece is rotated in increments around a perpendicular axis to ensure each beamlet contributes equally to the ion beam intensity from two directions, repeated until a total rotation of 360 degrees is achieved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a divergent ion beam is used for implantation, then the beam can cover a larger area of the workpiece, but the angular uniformity of implantation deteriorates
Solution Approach 1:
The ion beam is divided into multiple beamlets (first beamlet, second beamlet, third beamlet, etc.) that strike the workpiece at different incident angles. Each beamlet is independently controlled to contribute to the overall ion beam intensity, allowing the system to maintain angular uniformity while covering a larger area through the collective action of multiple segmented beam components.
2Manufacturing precision
If the workpiece is rotated during implantation to achieve dose uniformity, then the angular uniformity improves, but the processing time increases
Solution Approach 1:
The workpiece orientation is pre-adjusted to a specific angle before implantation begins. This preliminary positioning allows multiple beamlets to strike the workpiece at different incident angles simultaneously, achieving both dose uniformity and angular uniformity without requiring continuous rotation during the implantation process, thereby reducing processing time.
3Manufacturing precision
If multiple beamlets with different incident angles are used, then the angular uniformity improves, but the system complexity increases
Solution Approach 1:
The system utilizes the natural divergent characteristics of the ion beam source to generate multiple beamlets with different incident angles. Rather than requiring complex external steering mechanisms for each beamlet, the system allows the beamlets to self-organize and strike the workpiece at different angles, with the workpiece orientation being the primary control parameter, thereby reducing 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
This method ensures angular uniformity and dose uniformity across the workpiece, enhancing the electrical characteristics of semiconductor devices by optimizing the ion beam's intensity distribution.
Implementation Method 1
Ion implantation is a material engineering process by which ions of a material can be implanted into another solid, thereby changing the physical properties of the solid
Data Source
AI summary
An ion implantation method for achieving angular uniformity throughout a workpiece and application thereof are provided. The ion beam has at least one beamlet striking the workpiece surface with corresponding incident angles. The workpiece is mapped to an imaginary planar coordinate system. The incident angle of a center beamlet of the ion beam has a projection on the coordinate system forming a projection angle with an axis thereof. A workpiece orientation of the workpiece is adjusted based on the projection angle such that the contribution of each beamlet to the overall ion beam intensity upon striking the workpiece surface is rendered substantially the same from respective directions of each of the coordinate axes.