Shadow Mask Standoffs for OLED Direct Deposition
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Solution Overview
Problem
Existing shadow-mask deposition techniques face challenges in achieving high-resolution, high-density patterns due to 'feathering' issues and irreversible adhesion between the shadow mask and substrate, which limits feature size and pattern density, especially in sensitive material applications like OLED displays.
Innovation Solution
The use of standoffs to establish and maintain a controlled, uniform separation between the shadow mask and substrate during deposition, reducing contact area and mitigating stiction, while allowing for precise alignment and uniform feature formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shadow mask is positioned close to substrate for high-resolution patterning, then feature resolution is improved, but irreversible adhesion (stiction) occurs between mask and substrate
Solution Approach 1:
A release layer is deposited between the shadow mask and substrate to act as an intermediary that prevents irreversible adhesion. This release layer allows the mask to be positioned close to the substrate for high-resolution patterning while preventing direct contact that would cause stiction, enabling the mask to be released after deposition.
Solution Approach 2:
The deposition process uses controlled parameter changes including varying deposition rates and using pulsed deposition sequences. These parameter changes control the material flow and adhesion characteristics, allowing precise pattern formation while managing the adhesion between mask and substrate to prevent irreversible bonding.
2Manufacturing precision
If shadow mask is positioned close to substrate to reduce feathering, then pattern precision is improved, but contact area increases causing irreversible adhesion
Solution Approach 1:
The release layer serves as a mediator that enables close mask-to-substrate positioning for reduced feathering while preventing direct contact. This intermediary layer allows the system to achieve high pattern precision without the harmful stiction effect that would otherwise occur at such close spacing.
Solution Approach 2:
The solution moves the problem from the lateral dimension (mask-substrate spacing) to the vertical dimension (release layer thickness). By controlling the thickness and properties of the release layer in the vertical dimension, the system achieves close lateral spacing for precision while maintaining separation to prevent adhesion.
3Productivity
If material vapor flows directly from source to substrate through shadow mask, then direct patterning is achieved, but feathering occurs at feature edges
Solution Approach 1:
The deposition parameters are controlled including vapor flow rate, deposition speed, and mask-to-substrate spacing. By optimizing these parameters, the system achieves direct patterning efficiency while minimizing feathering through controlled material condensation dynamics on the substrate surface.
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 approach enables better control over feature shape and separation, reducing feathering and irreversible adhesion, thus enabling the formation of high-resolution, high-density patterns on sensitive materials without the need for harsh chemicals, suitable for applications like OLED displays.
Implementation Method 1
Vapor molecules of the material are generated via any of a variety of processes, such as thermal evaporation, sputtering, and the like
Implementation Method 2
shadow-mask deposition, which is analogous to stencil-based printing techniques
Data Source
AI summary
The present disclosure enables high-resolution direct patterning of a material on a substrate by establishing and maintaining a separation between a shadow mask and a substrate based on the thickness of a plurality of standoffs. The standoffs function as a physical reference that, when in contact between the substrate and shadow mask determine the separation between them. Embodiments are described in which the standoffs are affixed to an element selected from the shadow mask, the substrate, the mask chuck, and the substrate chuck.