Ion Beam Angle Spread Control for Doping Uniformity
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Solution Overview
Problem
Ion beam angle variations in semiconductor fabrication lead to performance inconsistencies and process repeatability issues due to uncontrolled incident angles and spreads, affecting doping profiles and device performance, especially in conformal doping and complex substrate topologies.
Innovation Solution
Implementing a technique to control ion beam angle spreads by directing ion beams at multiple incident angles, achieved through magnetic or electrostatic field deflection, substrate tilting, or rotation, allowing for a controlled distribution of ion beam angles during scanning, which can be continuous or incremental.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ion beam is directed at substrate with fixed incident angle, then setup is simple, but angle spread causes doping non-uniformity and performance variations
Solution Approach 1:
The patent applies dynamics by making the ion beam incident angle variable rather than fixed. The beam angle is dynamically adjusted during the implantation process to scan across a range of angles, transforming the static beam configuration into a dynamic one that actively compensates for angle spread effects and achieves uniform doping profiles.
Solution Approach 2:
The patent employs periodic action by implementing a scanning mechanism that periodically varies the ion beam incident angle across the substrate. This periodic angular modulation allows the beam to systematically cover different angle ranges, averaging out the effects of intrinsic angle spread and achieving conformal doping uniformity across the substrate surface.
2Manufacturing precision
If thermal diffusion is used for conformal doping, then doping can be achieved, but thermal budget limitations restrict process flexibility
Solution Approach 1:
The patent replaces the thermal diffusion mechanism with a mechanical/physical approach using ion beam implantation with angular scanning. Instead of relying on thermal energy to drive dopant diffusion, the invention uses controlled ion beam incidence at varying angles to physically deposit dopants conformally, thereby eliminating thermal budget constraints and enabling doping processes that are independent of high-temperature requirements.
3Reliability
If ion beam angle spread is not controlled, then process is simple, but wafer-to-wafer and within-wafer angle variations cause performance inconsistencies
Solution Approach 1:
The patent implements feedback by using angle sensors to detect the actual incident angle of the ion beam and using this information to adjust the beam angle in real-time. This closed-loop feedback system compensates for angle variations and drift, ensuring consistent doping profiles across wafers and within wafers, thereby improving process repeatability and reliability.
Solution Approach 2:
The patent replaces manual or open-loop mechanical angle adjustment with an automated control system that uses electronic feedback signals to precisely regulate the ion beam incident angle. This substitution of mechanical control with electronically controlled feedback mechanisms enables more accurate and repeatable angle management, reducing variability and improving process reliability.
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 reduces angle errors, enhances doping uniformity, and improves process repeatability by ensuring a controlled ion beam angle spread, resulting in more symmetric dopant profiles and improved device performance, even on irregular substrates, while avoiding thermal budget limitations.
Implementation Method 1
directing ion beams at multiple incident angles, achieved through magnetic or electrostatic field deflection
Implementation Method 2
directing ion beams at multiple incident angles, achieved through magnetic or electrostatic field deflection
Implementation Method 3
Ion implantation is a process of depositing chemical species into a substrate by direct bombardment of the substrate with energized ions
Data Source
AI summary
A technique for ion beam angle spread control is disclosed. In one particular exemplary embodiment, the technique may be realized as a method for ion beam angle spread control. The method may comprise directing one or more ion beams at a substrate surface at two or more different incident angles, thereby exposing the substrate surface to a controlled spread of ion beam incident angles.