Shadow Mask Gravity Compensation Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shadow-mask deposition techniques face limitations in achieving high-resolution, dense patterns due to gravity-induced sag, leading to increased feathering and poor deposition uniformity, which restricts the minimum feature size and pattern density, especially in applications like OLED displays and organic solar cells.
Innovation Solution
The introduction of a compensation layer with compressive stress on the shadow-mask membrane, which counteracts the effect of gravity, maintaining a substantially flat shadow mask and reducing feathering, is implemented. This compensation layer is strategically positioned on the inner or outer surface of the structural layer, with specific thickness and residual stress properties to balance the gravitational force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin shadow mask membrane is used to achieve high-resolution patterns, then the minimum feature size and pattern density are improved, but gravity-induced sag increases causing feathering and poor deposition uniformity
Solution Approach 1:
A compensation layer with compressive stress is deposited on the shadow mask membrane to counterbalance the gravitational force acting on the thin structure. This stress compensation prevents sagging and maintains the mask's flatness, enabling high-resolution patterning without feathering effects.
Solution Approach 2:
The residual stress parameter of the shadow mask membrane is modified by adding a compensation layer with specific compressive stress characteristics. This changes the overall stress state of the membrane structure to counteract gravity-induced deformation while maintaining the thin profile needed for high resolution.
2Manufacturing precision
If the shadow mask is positioned closer to the substrate to reduce feathering, then the deposition precision is improved, but gravity-induced sag increases due to the unsupported span
Solution Approach 1:
The compensation layer provides stress-based support to counteract gravity, allowing the shadow mask to be positioned closer to the substrate without sagging. This enables reduced feathering while maintaining structural integrity through internal stress balancing rather than mechanical support.
3Strength
If a thicker shadow mask is used to maintain structural integrity, then the shadow mask strength is improved, but the minimum feature size and pattern density are reduced
Solution Approach 1:
The shadow mask structure is made composite by depositing a compensation layer on the thin membrane. This composite structure provides the necessary structural integrity and stress resistance without increasing the overall thickness that would limit pattern density, combining the benefits of thin profiles with structural strength.
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 the direct patterning of dense, small-feature arrangements without shadowing, enhancing the minimum feature size and pattern density, while maintaining deposition uniformity across large areas, effectively mitigating the issues of gravity-induced sag and feathering.
Implementation Method 1
A compensation layer is disposed on the inner surface of the membrane, where the compensation layer comprises a material characterized by compressive stress
Implementation Method 2
the compensation layer induces a bending moment in the combined layer structure that manifests as a restoring force on the structural layer directed normal to the membrane surface and outward from the substrate. The thickness and residual stress of the compensation layer are selected to compensate for the effect of gravity on the structural layer
Data Source
AI summary
A shadow mask that includes compensation layer operative for at least partially correcting gravity-induced sag of a shadow-mask membrane is disclosed. The compensation layer is formed on a surface of the shadow-mask membrane such that the compensation layer is characterized by a residual stress that gives rise to a first bending moment in the membrane, where the first bending moment is directed in the opposite direction to a second bending moment in the membrane that is induced by the effect of gravity.