Roll-to-Roll Vapor Deposition with Segmented Heating for Uniform CIGS Coating
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Solution Overview
Problem
The challenge in thermal vapor deposition lies in regulating the thickness distribution and composition of material layers on large substrates, managing spatial and energy constraints within vacuum chambers, minimizing material and energy consumption, preventing droplet deposition, and addressing particle fallout during long cycles.
Innovation Solution
The roll-to-roll vapor deposition system employs a compact evaporation source with multiple heating elements and inclined nozzles to independently regulate flux, reduce energy consumption, and prevent spitting, featuring a crucible design with heat shields and a 'hot lip' mechanism to maintain uniform deposition and adapt to changing material levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple adjacent evaporation sources operate at different regulated temperatures to deposit material with desired distribution and thickness, then deposition precision is improved, but device complexity increases
Solution Approach 1:
The evaporation source is segmented into multiple independently temperature-controlled zones along its length. Each zone can be regulated to different temperatures to achieve desired material flux distribution across the substrate width, resolving the contradiction by enabling precision control without requiring multiple separate source units
Solution Approach 2:
Different regions of the evaporation source are assigned different temperature characteristics to produce localized variations in material flux. This allows precise control of deposition thickness distribution across the substrate by tailoring the temperature profile to specific deposition requirements at different locations
2Volume of stationary object
If a compact evaporation source design is used to reduce vacuum chamber volume, then space utilization is improved, but heat management capability deteriorates
Solution Approach 1:
The heating elements are nested within or integrated into the evaporation source structure, with temperature sensors positioned inside the source. This compact nested arrangement enables effective heat management and temperature control within a minimized vacuum chamber volume
Solution Approach 2:
Temperature control is achieved through integrated electrical heating elements and sensors rather than external mechanical heating systems. This substitution enables precise thermal management in a compact configuration, reducing the energy required for heating while maintaining control capability
3Productivity
If evaporation sources are positioned close to the substrate for efficient deposition, then productivity is improved, but harmful factors increase due to droplet deposition
Solution Approach 1:
A controlled atmosphere or flux management mechanism acts as an intermediary between the evaporation source and substrate. This intermediary controls the material flux to prevent droplet formation while maintaining high deposition rates, resolving the contradiction between productivity and harmful droplet deposition
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 solution enables precise, energy-efficient, and uniform material deposition on large substrates, reducing energy costs and assembly complexity while preventing unwanted material deposition, thereby enhancing the reliability and efficiency of the vapor deposition process.
Implementation Method 1
Coating of objects using thermal evaporation requires a crucible to heat up and vaporize material that deposits itself onto a substrate
Implementation Method 2
at least one electrical heating element to direct the vaporized material flux onto the nearby moving web substrate
Data Source
Figure 1A~1C
Figure 1D~1E
Figure 2A~2E
AI summary
A roll-to roll vapor deposition system (800) suited for the deposition of thin CIGS films on a thin web (830) comprising a vacuum deposition chamber (810) enclosing at least three sets (822, 823, 824) of evaporation sources, each set comprising at least three evaporation source apparatuses, whereby web (830), for example made of polymer or metal foil, departs a pay-off roll (841) and gets coated by said evaporation sources sets (822, 823, 824) as it travels between tensioning rolls (851, 852, 853, 854) until it gets rolled-up by take-up roll (842), and whereby said at least three evaporation source apparatuses are long high-temperature high-output linear evaporation source apparatuses (200) for atomic vapor deposition of metal atoms suited for the production of CIGS thin films. This enables to achieve a more even spatial distribution of the deposited material with less energy expense and the possibility to regulate an evaporation profile.