Shadow Mask Support Structure for OLED Deposition
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Solution Overview
Problem
In semiconductor manufacturing, shadow masks used in material deposition processes tend to sag due to thermal expansion and material accumulation, leading to poor precision and quality in deposited regions, especially in OLED production where precise edges are crucial.
Innovation Solution
A support structure is positioned on the same side as the deposition side of the substrate, with the shadow mask sandwiched between the support structure and the substrate, ensuring it remains flat and securely held, using a thin, thermally stable material like Invar™, and optionally incorporating magnetic elements for enhanced support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the shadow mask is made thin to reduce weight and cost, then the shadow mask becomes more prone to sagging under its own weight and thermal expansion, but using a thicker shadow mask increases weight and cost while still suffering from sagging
Solution Approach 1:
A support structure is introduced as an intermediary component between the substrate and the shadow mask. This support structure provides mechanical reinforcement to the shadow mask, preventing it from sagging under its own weight or due to thermal expansion, while allowing the shadow mask to remain thin and lightweight. The support structure acts as a mediator that transfers the load-bearing function away from the shadow mask itself.
Solution Approach 2:
The system combines the shadow mask with a support structure to create a composite assembly. The support structure is made of a material with high strength-to-weight ratio and low thermal expansion coefficient, complementing the thin shadow mask. This composite approach allows the shadow mask to maintain its thin profile while the support structure provides the necessary mechanical and thermal stability.
2Ease of operation
If the shadow mask is held in a horizontal position to simplify deposition, then the shadow mask and substrate tend to sag under their own weight, but holding them vertically prevents sagging while allowing foreign particles to adhere to the substrate
Solution Approach 1:
The support structure serves as an intermediary that enables the shadow mask to be held in a horizontal position without sagging. By providing mechanical reinforcement, the support structure allows the system to maintain the simpler horizontal configuration while achieving the precision normally associated with vertical positioning.
Solution Approach 2:
The introduction of the support structure changes the mechanical parameters of the shadow mask assembly, increasing its rigidity and resistance to sagging. This parameter change allows the system to maintain horizontal positioning without the usual drawbacks, effectively decoupling the position stability from the orientation constraint.
3Reliability
If clamps are used to hold the shadow mask to prevent sagging, then the shadow mask can be securely held, but the clamps may interfere with material deposition or require additional removal steps
Solution Approach 1:
The holding function is extracted from the shadow mask itself and transferred to a separate support structure. This allows the shadow mask to be secured without direct clamping, as the support structure provides the necessary retention mechanism. The clamps or holding elements are removed from the shadow mask interface, eliminating interference with material deposition.
Solution Approach 2:
The support structure acts as an intermediary that provides the holding function without direct contact between clamps and the shadow mask. This intermediary approach allows secure retention of the shadow mask while avoiding the interference and complexity issues associated with direct clamping 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
This arrangement maintains precise material deposition with sharply defined edges, reduces thermal expansion issues, and allows for the use of thin, lightweight shadow masks, resulting in high-quality semiconductor devices with reduced production costs.
Implementation Method 1
a support structure holding means for holding the support structure and/or a substrate holding means for holding the substrate
Implementation Method 2
a shadow mask comprising a number of deposition openings... the shadow mask is positioned between the substrate and the support structure
Implementation Method 3
These are heated in some suitable manner, for example electrically, so that the material vaporizes
Implementation Method 4
a vapour deposition step is necessary in order to deposit matter - organic or inorganic - on a substrate
Data Source
Figure 1a~1b
Figure 2~3a
Figure 3b
AI summary
The invention describes an arrangement (1) for holding a substrate (10) in a material deposition apparatus (50), which substrate (10) has a deposition side (10a) upon which material (M) is to be deposited, and which arrangement (1) comprises a shadow mask (20) comprising a number of deposition openings (D1); a support structure (30) comprising a number of surround openings (S1); and a support structure holding means (6) for holding the support structure (30) and/or a substrate holding means (5) for holding the substrate (10), such that the support structure k (30) is on the same side as the deposition side (10a) of the substrate (10), and the shadow mask (20) is positioned between the substrate (10) and the support structure (30) such that at least one deposition opening (D1) of the shadow mask (10) lies within a corresponding surround opening (S1) of the support structure (30). The invention further describes a material deposition apparatus (50) comprising an arrangement (1) for holding a substrate (10). The invention also describes a method of arranging a substrate (10), a shadow mask (10) and a support structure (30) in a material deposition apparatus (50).