Evaporation Filter Insert for Uniform Thin Film Deposition
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Solution Overview
Problem
Existing vapor phase material deposition methods face challenges with clogging and non-uniformity due to condensation and splashing of materials at low evaporation temperatures, particularly in the deposition of materials like magnesium for OLED screens, leading to unstable and defective thin layer formation.
Innovation Solution
An evaporation device with a filter insert comprising a conical opening and multiple plates and grids that selectively filters out solid and liquid materials while allowing vapor phase material to pass through, thermally decouples the upper and lower parts of the effusion cell, and includes a cover to prevent heat loss and condensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an insert with an opening is placed on the open end of the crucible to control material dispersion and limit splashes, then the uniformity and quality of film deposition is improved, but heat loss through the opening causes condensation and clogging of the insert
Solution Approach 1:
A cover is introduced as an intermediary component between the heating zone and the insert opening. This cover acts as a thermal barrier that prevents direct heat loss through the insert opening, thereby reducing condensation and clogging while maintaining the insert's function of controlling material dispersion and limiting splashes.
Solution Approach 2:
The temperature distribution in the effusion cell is modified by introducing the cover. The cover creates a thermal gradient that maintains higher temperatures in the region of the insert opening, preventing condensation of evaporated material while allowing the insert to continue its function of controlling material flow and dispersion.
2Quantity of substance
If the crucible temperature is kept low (e.g., 400°C for magnesium deposition) to enable deposition of materials with low vapor pressure, then the deposition of materials like magnesium for OLED screens becomes feasible, but heat loss through the insert opening accelerates condensation on the insert walls
Solution Approach 1:
The cover serves as a thermal intermediary that compensates for heat loss at the insert opening. This allows the crucible to maintain low temperature (400°C for magnesium) necessary for depositing low vapor pressure materials, while the cover prevents excessive heat loss that would otherwise cause condensation and process instability.
Solution Approach 2:
The cover is positioned in advance to prevent heat loss and condensation before they can occur. By providing thermal insulation at the critical opening region, the cover preemptively counteracts the condensation tendency that would otherwise arise from heat loss during low-temperature deposition of materials like magnesium.
3Loss of energy
If the insert opening is blocked to prevent condensation and clogging, then heat loss is reduced, but the flow of material deposition becomes unstable
Solution Approach 1:
The cover acts as a thermal intermediary that reduces heat loss without physically blocking the insert opening. This allows vapor phase material to continue flowing through the opening while the cover compensates for thermal energy loss, thereby maintaining stable material flow while reducing heat loss and condensation.
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 enhances the uniformity and homogeneity of thin layer deposition, prevents material projections and contamination, and maintains a stable deposition process even at low temperatures, ensuring reproducible and defect-free thin film formation.
Implementation Method 1
heating means suitable for heating the crucible containing the load and generating a flow of material in the vapor phase by evaporation or sublimation of the material of the load
Implementation Method 2
heating means suitable for heating the crucible containing the load and generating a flow of material in the vapor phase by evaporation or sublimation of the material of the load
Implementation Method 3
Heat loss through the opening of the insert cools the insert and results in partial condensation of the vapor phase material on the walls of the insert
Implementation Method 4
Heat loss through the opening of the insert cools the insert and results in partial condensation of the vapor phase material on the walls of the insert
Data Source
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AI summary
The invention relates to an evaporation device comprising an evaporation cell with heating means and a crucible having an open top and a closed bottom for receiving a charge. The device is adapted to generate a vapor-phase flow of material by evaporation or sublimation of the charge material. According to the invention, the evaporation device includes a filter insert comprising an upper portion (20) having a conical opening (11) for placement at the open end of the crucible, and a lower portion (21) comprising, from top to bottom, a plate (13) having at least one opening (130) and a grid (14). The lower portion (21) is for placement in the crucible between the upper portion (20) and the charge. An apparatus and a method for depositing a film of material onto a substrate are also provided.