Deposition Drum Heating Zones to Prevent Substrate Wrinkles
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Solution Overview
Problem
Thermal expansion during substrate processing in battery manufacturing leads to wrinkles in flexible substrates, which deteriorate the quality of the deposited layers in thermal evaporation processes.
Innovation Solution
A material deposition apparatus and method that includes a processing drum with temperature control, a roller, and heater assemblies to control substrate temperature, with a speed-dependent heating system to minimize thermal expansion and wrinkles, ensuring consistent substrate temperature during deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If substrate temperature is increased to improve deposition rate, then deposition rate increases, but substrate thermal expansion causes wrinkles that deteriorate layer quality
Solution Approach 1:
The substrate temperature control is divided into multiple independent heating zones (first heating zone before processing drum, second heating zone on processing drum, third heating zone after processing drum). Each zone can be independently controlled to maintain different temperatures, allowing the substrate to be heated to high temperatures for rapid deposition while preventing uncontrolled thermal expansion and wrinkles through localized temperature management.
Solution Approach 2:
Different regions of the substrate are maintained at different temperatures according to their specific requirements. The deposition zone experiences high temperature for rapid material deposition, while other zones are controlled at lower temperatures to prevent thermal expansion. This localized temperature control allows high deposition rates without compromising layer quality.
2Manufacturing precision
If substrate temperature is controlled to prevent wrinkles, then layer quality improves, but deposition rate decreases
Solution Approach 1:
The temperature control system is segmented into multiple independent zones that can operate at different temperatures simultaneously. The deposition zone maintains high temperature for rapid deposition, while transport and cooling zones maintain lower temperatures to prevent wrinkles, thereby achieving both high layer quality and high deposition rate.
Solution Approach 2:
The substrate is pre-heated in the first heating zone before entering the deposition area, and then rapidly heated to deposition temperature in the second heating zone on the processing drum. This preliminary heating prepares the substrate for high-rate deposition while the controlled heating rate prevents excessive thermal expansion and wrinkles.
3Manufacturing precision
If substrate heating is applied to control thermal expansion, then wrinkles are reduced, but energy consumption increases
Solution Approach 1:
The heating system is divided into three zones that can be independently controlled. Energy is applied selectively only where and when needed: the first zone pre-heats the substrate, the second zone provides rapid heating during deposition, and the third zone performs controlled cooling. This segmented approach minimizes overall energy consumption compared to uniform heating of the entire substrate.
Solution Approach 2:
The substrate undergoes periodic heating and cooling cycles as it moves through different zones. The substrate is heated to deposition temperature, maintained during deposition, then cooled in the third zone. This periodic thermal treatment controls thermal expansion to prevent wrinkles while minimizing total energy input by limiting heating to necessary periods and zones.
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 solution effectively reduces substrate wrinkles and enhances the quality of thin film deposition by maintaining controlled temperature zones and speed-dependent heating, resulting in improved deposition rates and layer quality.
Implementation Method 1
Thermal expansion during the substrate processing may result in wrinkles in the substrate
Implementation Method 2
a second heater assembly positioned to heat the substrate while being supported on the processing drum
Implementation Method 3
For deposition at high deposition rates, thermal evaporation may be used as a PVD process. For thermal evaporation, a source material is heated up to produce a vapor that may be deposited
Implementation Method 4
a processing drum having a cooler configured to control a substrate temperature during processing of a substrate on the processing drum
Data Source
AI summary
A material deposition apparatus for depositing an evaporated material onto a substrate is provided. The material deposition apparatus includes a processing drum having a cooler configured to control a substrate temperature during processing of a substrate on the processing drum; a roller guiding the substrate towards the processing drum; a first heater assembly positioned to heat the substrate in a free-span area between the roller and the processing drum; a second heater assembly positioned to heat the substrate while being supported on the processing drum; at least one deposition source provided along a substrate transport path downstream of the second heater assembly; a substrate speed sensor providing a speed signal correlating with a substrate transportation speed; and a controller having an input for the speed signal configured to control at least the first heater assembly.