Non-contact Dopant Measurement via Infrared Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for in-line measurement of dopant content in semiconductor devices, particularly in photovoltaic (PV) cell fabrication, are limited by their inability to provide continuous, robust, and cost-effective monitoring of dopant concentration and distribution, leading to inefficiencies in the manufacturing process.
Innovation Solution
A non-contact system using infrared radiation to measure dopant content by analyzing the absorption and reflection characteristics of wafers, allowing for flexible and configurable measurement across various points in the manufacturing line, including selective emitter and IBC cell structures, with the ability to vary scanning intensity and compensate for environmental factors like light and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If contact-based measurement methods are used to measure dopant content, then measurement can be performed, but the measurement process is slow and disrupts continuous manufacturing flow
Solution Approach 1:
The patent replaces contact-based mechanical measurement systems with a non-contact optical measurement system using infrared radiation. The system uses an infrared light source and detector to measure dopant content through optical absorption without physically touching the wafer, enabling continuous measurement during manufacturing while maintaining measurement accuracy
Solution Approach 2:
The patent introduces infrared radiation as an intermediary medium to transfer measurement information from the dopant to the detector without direct contact. The infrared radiation interacts with the dopant atoms through absorption, providing a non-intrusive measurement path that maintains continuous manufacturing flow
2Reliability
If traditional measurement systems are installed in fabrication lines, then dopant monitoring is possible, but the system complexity and cost increase significantly
Solution Approach 1:
The patent extracts the measurement function from complex contact-based sensor systems and implements it using a simple infrared optical path. By removing unnecessary mechanical components and using direct infrared absorption measurement, the system achieves reliable dopant monitoring with minimal added complexity to the fabrication line
Solution Approach 2:
The patent changes the measurement parameter from electrical or mechanical contact properties to optical absorption characteristics in the infrared range. This parameter change enables simpler system architecture while maintaining measurement reliability, as optical absorption directly correlates with dopant concentration without requiring complex intermediate measurements
3Productivity
If measurement points are fixed in the fabrication line, then continuous monitoring is achieved, but flexibility to measure at various process stages is lost
Solution Approach 1:
The patent implements a dynamic measurement system where the infrared source and detector can be positioned at various locations along the fabrication line. The system can adapt to measure wafers at different process stages (after doping, after diffusion, etc.) by adjusting the measurement point location, maintaining continuous monitoring capability while providing measurement flexibility
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
Enables precise, continuous, and cost-effective measurement of dopant content and distribution across semiconductor wafers, improving yield and process control in PV cell manufacturing by providing accurate data on dopant concentration and distribution.
Implementation Method 1
A non-contact system using infrared radiation to measure dopant content by analyzing the absorption and reflection characteristics of wafers
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A system and method of non-contact measurement of the dopant content of semiconductor material by reflecting infrared (IR) radiation off of the material and splitting the radiation into two beams, passing each beam through pass band filters of differing wavelength ranges, comparing the level of energy passed through each filter and calculating the dopant content by referencing a correlation curve made up of known wafer dopant content for that system.