Ion Implant Grid Assembly for Solar Cell Doping
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Solution Overview
Problem
Traditional beamline implantation for solar cells is inefficient due to high power consumption, limited productivity, and substrate overheating, as it provides a single beamlet and requires extensive power in a small area, leading to low productivity and potential damage to the wafer.
Innovation Solution
A plasma grid implantation system comprising multiple grid plates with adjustable positions, allowing for both homogeneous and selective ion implantation across a substrate, utilizing a plasma source to accelerate ions through apertures in positively and negatively biased grid plates, and a substrate holder for precise ion implantation, enabling efficient and controlled doping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional beamline implantation is used, then high power density is achieved, but substrate temperature increases excessively and productivity decreases
Solution Approach 1:
The ion beam is divided into multiple beamlets by using a grid structure with multiple apertures instead of a single beamline. This distributes the power density across multiple locations on the substrate, preventing excessive heating at any single point while maintaining overall doping efficiency
Solution Approach 2:
The system transitions from a single-point beamline implantation to a distributed grid pattern across the substrate surface. By adding spatial distribution in multiple dimensions, the power is spread out, reducing localized temperature rise while maintaining total ion flux
2Power
If traditional beamline implantation is used, then high power density is achieved, but productivity is low
Solution Approach 1:
Multiple beamlets operate simultaneously across the substrate, allowing parallel processing of different regions. This increases the effective processing area and throughput while maintaining the power density needed for efficient ion implantation
Solution Approach 2:
Multiple beamlets are combined into a grid pattern that covers a larger substrate area. The merging of multiple ion streams enables simultaneous doping of multiple regions, significantly improving productivity compared to sequential single-beamline processing
3Manufacturing precision
If traditional beamline implantation is used, then ion implantation is achieved, but dopant placement precision is limited
Solution Approach 1:
Each aperture in the grid can be independently controlled to deliver ions with precise energy and angle to specific locations. This local control enables precise dopant placement while the overall grid structure maintains simplicity through standardized aperture patterns
Solution Approach 2:
The system allows dynamic adjustment of beam parameters for each aperture, enabling precise control of ion implantation characteristics. This dynamic control achieves high manufacturing precision without requiring complex mechanical positioning systems
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
The system achieves high productivity with multiple wafers per hour, maintains substrate temperature below 100°C, and allows for precise dopant placement, avoiding the formation of 'dead layers' and enabling efficient solar cell performance by optimizing doping levels and resistivity.
Implementation Method 1
a plasma source configured to provide plasma
Implementation Method 2
the first grid plate is configured to be positively biased, either continuously in DC mode or in pulsed mode, by a power supply
Implementation Method 3
the second grid plate is configured to be negatively biased, either continuously in DC mode or in pulsed mode, by a power supply
Implementation Method 4
a substrate holder configured to support a substrate in a position where the substrate is implanted with the ions subsequent to the ions passing through the second grid plate
Data Source
AI summary
An ion implantation system having a grid assembly. The system includes a plasma source configured to provide plasma in a plasma region; a first grid plate having a plurality of apertures configured to allow ions from the plasma region to pass therethrough, wherein the first grid plate is configured to be biased by a power supply; a second grid plate having a plurality of apertures configured to allow the ions to pass therethrough subsequent to the ions passing through the first grid plate, wherein the second grid plate is configured to be biased by a power supply; and a substrate holder configured to support a substrate in a position where the substrate is implanted with the ions subsequent to the ions passing through the second grid plate.