Continuous CdTe Thin Film Deposition System
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Solution Overview
Problem
Current thin film deposition processes for CdTe photovoltaic modules are inefficient for large-scale production due to non-uniformity, material waste, and the need for batch processing, which increases costs and reduces energy conversion efficiency.
Innovation Solution
A continuous vapor deposition system where substrates are conveyed through a vacuum chamber at a controlled speed, with post-heating and cooling sections to maintain a uniform temperature profile and prevent thermal damage, allowing for continuous material supply and uniform film deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch processing is used in CSS deposition, then material can be deposited on substrates, but production efficiency is low and material waste increases due to periodic interruptions
Solution Approach 1:
The patent implements a continuous deposition process where substrates are conveyed through the deposition chamber without periodic interruptions. The source material is continuously replenished during substrate conveyance, eliminating batch processing interruptions and maintaining continuous useful action throughout the deposition process, thereby improving productivity and reducing material waste
Solution Approach 2:
The patent performs preliminary replenishment of source material before substrates reach the deposition zone. The source material is loaded into the chamber in advance during substrate conveyance, ensuring material availability before deposition begins, which prevents interruptions and maintains continuous production flow
2Ease of manufacture
If substrates are indexed into and out of the deposition chamber, then batch processing is enabled, but significant material waste occurs during indexing and positioning steps
Solution Approach 1:
The continuous conveyance system eliminates indexing operations by maintaining constant substrate movement through the chamber. Substrates are fed continuously from a magazine and conveyed through the deposition zone without stopping, eliminating material waste associated with indexing and positioning operations while maintaining ease of manufacture through automated continuous processing
Solution Approach 2:
The patent replaces the mechanical indexing system with a continuous conveyance mechanism. Instead of periodically moving substrates in and out of the chamber using indexing operations, the system uses continuous conveyance through the entire chamber, substituting the batch mechanical system with a continuous flow system that eliminates waste during positioning
3Productivity
If continuous conveyance is used, then productivity increases and material waste reduces, but uniform temperature profile control becomes more difficult
Solution Approach 1:
The patent applies different heating zones along the conveyance path to maintain uniform temperature profile. The chamber includes multiple heating elements positioned at different locations (source region, deposition region, downstream region) that can be independently controlled to compensate for temperature variations caused by continuous substrate movement, ensuring each zone maintains optimal temperature for its specific function
Solution Approach 2:
The system dynamically adjusts heating parameters along the conveyance path to maintain uniform temperature profile during continuous operation. Different regions of the chamber are heated to different temperatures based on their specific requirements, and the heating parameters are modified to account for the continuous movement of substrates, ensuring consistent deposition conditions throughout the 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 efficient, large-scale production of CdTe photovoltaic modules with reduced material waste and improved energy conversion efficiency by ensuring uniform film deposition and controlled thermal processing.
Implementation Method 1
a thin film of a sublimed source material is deposited onto an upper surface of the substrates
Implementation Method 2
vapor deposition apparatus configured for depositing a thin film of a sublimed source material
Data Source
AI summary
A system and associated process for vapor deposition of a thin film layer on a photovoltaic (PV) module substrate is includes establishing a vacuum chamber and introducing the substrates individually into the vacuum chamber. A conveyor system is operably disposed within the vacuum chamber and is configured for conveying the substrates in a serial arrangement through a vapor deposition apparatus within the vacuum chamber at a controlled constant linear speed. A post-heat section is disposed within the vacuum chamber immediately downstream of the vapor deposition apparatus in the conveyance direction of the substrates. The post-heat section is configured to maintain the substrates conveyed from the vapor deposition apparatus in a desired heated temperature profile until the entire substrate has exited the vapor deposition apparatus.