Ion Beam Doping Profile Control via Dynamic Energy Modulation
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Solution Overview
Problem
Current semiconductor manufacturing methods face limitations in achieving precise doping profiles, particularly in forming smooth and uniform vertical dopant profiles due to constraints in thermal budget and end-of-range peaks during ion implantation, which affects the performance of semiconductor devices.
Innovation Solution
The method involves changing the ion acceleration energy of an ion beam while simultaneously moving it relative to the semiconductor substrate, allowing for a closed-loop control of the ion beam current density to achieve a desired doping concentration profile with a Full Width at Half Maximum (FWHM) of at least 5 μm, enabling precise doping without the need for multiple implant recipes or extensive thermal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ion implantation is used to form doping profiles, then precise monitoring of total dose and dose rate is achieved, but end-of-range peaks and limited thermal budget constrain the ability to form smooth box-like or triangular doping profiles
Solution Approach 1:
The patent applies dynamics by continuously changing the ion beam acceleration energy during the implantation process rather than using fixed energy levels. This dynamic adjustment allows the ion beam to deposit dopants at varying depths, creating smooth transition regions and eliminating the sharp end-of-range peaks that occur with static energy implantation. The acceleration energy is modulated in real-time to achieve desired doping profiles such as box-like or triangular shapes.
Solution Approach 2:
The patent employs parameter changes by varying the acceleration energy of the ion beam during implantation. Instead of maintaining a constant energy level, the system dynamically adjusts this critical parameter to control the depth and distribution of dopant deposition. This parameter modulation enables precise shaping of doping profiles while maintaining smooth transitions and avoiding concentration peaks.
2Manufacturing precision
If multiple implant recipes or extensive thermal processing is used to achieve desired doping profiles, then doping precision is improved, but process complexity and thermal budget increase
Solution Approach 1:
The patent implements continuity of useful action by performing the entire doping profile formation in a single continuous ion implantation step. The acceleration energy is continuously modulated throughout the process to achieve the desired doping concentration profile, eliminating the need for multiple discrete implantation steps or subsequent thermal processing stages. This continuous approach maintains precision while simplifying the overall process.
Solution Approach 2:
The patent applies preliminary action by pre-programming the acceleration energy modulation profile before implantation begins. The desired doping concentration profile is calculated and translated into a specific time-dependent acceleration energy pattern, which is then executed during a single implantation step. This preliminary planning enables precise doping control without requiring multiple iterative steps or post-implantation thermal processing.
3Manufacturing precision
If ion beam acceleration energy is changed during implantation, then smooth doping profiles with FWHM > 5 μm are achieved, but process control complexity increases
Solution Approach 1:
The patent employs feedback by implementing a closed-loop control system that monitors the ion beam current density in real-time and adjusts the acceleration energy accordingly. The system measures the actual beam parameters and uses this information to maintain the desired doping concentration profile, ensuring uniformity and smooth transitions. This feedback mechanism simplifies the control of what would otherwise be a complex dynamic process.
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 enables the creation of semiconductor devices with improved doping profiles, reducing thermal budget requirements and allowing for higher voltage classes of semiconductor devices, such as 1700 V IGBTs, while simplifying the ion implantation process and reducing costs by achieving target doping concentrations in a single ion implantation step.
Implementation Method 1
Ion implantation allows for precisely monitoring both total dose and dose rate. Ion implantation typically leads to a Gaussian-like distribution of the dopants around an end-of-range-peak
Implementation Method 2
ion acceleration energy of the implanted ions. Formation of doping profiles having a small degree of undulation
Data Source
AI summary
A method of manufacturing a semiconductor device includes reducing a thickness of a semiconductor substrate and/or forming a doped region in the semiconductor substrate. The method further includes changing an ion acceleration energy of an ion beam while effecting a relative movement between the semiconductor substrate and the ion beam impinging on the semiconductor substrate.