Evaporation Source Baffle and Cooling Gas for Thin Film Uniformity
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Solution Overview
Problem
Existing evaporation sources for thin film deposition often result in non-uniform film thickness due to particle coalescence and excessive heat radiation, requiring large processing chambers that can deform substrates and necessitate oversized equipment.
Innovation Solution
An evaporation source with a baffle-equipped crucible and a shower head nozzle structure that minimizes particle coalescence and distributes heat effectively, combined with a movable design to reduce processing chamber size and substrate deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional spray nozzle is used to apply evaporated deposition material, then deposition material can be applied onto substrate, but excess heat is radiated into processing chamber causing substrate deformation
Solution Approach 1:
The patent introduces a cooling gas flow as an intermediary medium between the spray nozzle and substrate. This cooling gas absorbs excess heat from the evaporated deposition material before it reaches the substrate, preventing thermal deformation while enabling continuous deposition material application.
Solution Approach 2:
The patent changes the temperature parameter of the deposition material by introducing cooling gas. The cooling gas reduces the temperature of evaporated particles from high-temperature state to a controlled temperature range, eliminating harmful thermal effects on the substrate while maintaining deposition functionality.
2Productivity
If evaporation source uses conventional heating method, then deposition material can be evaporated, but particles coalesce and form clusters resulting in non-uniform film thickness
Solution Approach 1:
The cooling gas acts as an intermediary that interferes with particle coalescence. By introducing this gas medium, the patent prevents direct contact and aggregation of evaporated particles, maintaining their dispersion and enabling uniform film formation.
Solution Approach 2:
The patent employs periodic or continuous cooling gas flow to intermittently cool and disperse evaporated particles. This periodic action prevents continuous coalescence by repeatedly disrupting particle aggregation, resulting in uniform deposition.
3Adaptability or versatility
If large processing chamber is used to accommodate substrate movement, then rotatable substrate can be processed, but chamber size increases and equipment becomes oversized
Solution Approach 1:
Instead of moving the substrate through a large chamber, the patent inverts the approach by moving the evaporation source relative to a stationary substrate. This inversion eliminates the need for large chamber space while maintaining processing capability.
Solution Approach 2:
The patent introduces dynamic movement of the evaporation source rather than requiring substrate rotation. The movable evaporation source can dynamically adjust its position and trajectory, providing versatility without requiring large chamber volume for substrate movement mechanisms.
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 achieves uniform thin film deposition with reduced heat transfer, enabling smaller processing chambers and stable substrate handling, ensuring consistent film thickness and reduced substrate deformation.
Implementation Method 1
a heating unit to heat the crucible and evaporate the deposition material
Implementation Method 2
introduction of a cooling gas flow into the processing chamber during the application of the evaporated deposition material onto the substrate
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
An evaporation source for depositing a thin film includes a crucible having a space for a deposition material and at least one baffle, the baffle being positioned inside the crucible and to divide the crucible into a plurality of channels.