Ion Beam Angle Control via Wafer Resistance Feedback
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Solution Overview
Problem
Existing ion implantation technologies face challenges in precisely controlling the implant angle distribution of ion beams, which affects the carrier concentration distribution in semiconductor wafers, due to difficulties in directly measuring the angle distribution of ion beams and the occurrence of channeling phenomena.
Innovation Solution
The method involves irradiating wafers with predetermined channeling conditions and measuring their resistance to adjust the implant angle distribution of the ion beam in both the x and y directions using a combination of electric and magnetic fields, allowing for precise control of the ion beam's angle distribution through the use of lens devices and a controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the angle distribution of ion beam is not precisely controlled, then the ion implantation process is simpler to perform, but the carrier concentration distribution in the wafer cannot be precisely controlled
Solution Approach 1:
The patent employs a feedback mechanism where the actual implant angle distribution is measured using a test wafer and resistance measurement, then this information is fed back to adjust the lens device parameters. This closed-loop control system continuously optimizes the beam angle distribution to achieve precise carrier concentration control without requiring overly complex predictive models.
Solution Approach 2:
The patent replaces direct mechanical measurement of beam angle with an indirect electrical measurement method. Instead of using complex mechanical angle sensors on the ion beam, the system uses electrical resistance measurement of a test wafer to infer beam angle distribution, substituting a simpler electrical measurement system for a complex mechanical one.
2Measurement precision
If lens devices are used to adjust implant angle distribution, then beam angle precision is improved, but the device complexity increases
Solution Approach 1:
The patent adjusts the implant angle distribution by changing the electrical parameters (voltage, current) of the lens devices rather than physically reconfiguring their mechanical structure. This allows precise control of beam angle while maintaining a fixed, simpler mechanical configuration, reducing device complexity.
3Loss of information
If resistance measurement is used to determine implant angle distribution, then measurement capability is improved, but the measurement process becomes more complex
Solution Approach 1:
The patent uses a test wafer as an intermediary medium to convert the difficult-to-measure beam angle distribution into an easily measurable electrical resistance signal. The test wafer absorbs the ion beam and translates angular distribution information into resistance variations that can be measured with simple electrical equipment, avoiding complex direct angle measurement systems.
4Measurement precision
If channeling conditions are utilized for measurement, then measurement sensitivity is improved, but the risk of channeling phenomena affecting results increases
Solution Approach 1:
The patent converts the harmful channeling phenomenon into a beneficial measurement tool. By deliberately orienting the test wafer to create controlled channeling conditions, the system amplifies the relationship between beam angle and resistance measurement, making the measurement more sensitive. The channeling effect, normally a source of error, becomes an enhancement of measurement capability.
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 a highly precise ion implantation process, ensuring a desired carrier concentration distribution by accurately adjusting the implant angle distribution, thereby improving the precision and effectiveness of the ion implantation process.
Implementation Method 1
two or more lens devices that converge or diverge an ion beam by applying at least one of an electric field and a magnetic field
Implementation Method 2
two or more lens devices that converge or diverge an ion beam by applying at least one of an electric field and a magnetic field
Implementation Method 3
the process of implanting a semiconductor wafer with ions (hereinafter, also referred to as 'ion implantation process')
Implementation Method 4
forming an ion beam by accelerating the generated ions
Data Source
AI summary
An ion implantation method for scanning an ion beam reciprocally in an x direction and moving a wafer reciprocally in a y direction to implant ions into the wafer is provided. The method includes: irradiating a first wafer arranged to meet a predetermined plane channeling condition with the ion beam and measuring resistance of the first wafer irradiated with the ion beam; irradiating a second wafer arranged to meet a predetermined axial channeling condition with the ion beam and measuring resistance of the second wafer irradiated with the ion beam; and adjusting an implant angle distribution of the ion beam by using results of measuring the resistance of the first and second wafers.