Rotating Substrate Shadow Mask for Thin Film Thickness Gradient Control
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Solution Overview
Problem
Existing methods for manufacturing thin films with varying thicknesses are complex and costly, making them unsuitable for mass production, with issues in controlling gradients and material distribution during coating.
Innovation Solution
A method involving a shadow mask with radial lines and arcuate openings, where a substrate is rotated relative to the mask to control exposure times, allowing for the formation of thin films with varying thicknesses suitable for mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional shadow mask reciprocation method is used, then thin film with varying thickness can be formed, but device complexity increases due to complicated reciprocating movement mechanism
Solution Approach 1:
Instead of moving the shadow mask reciprocatingly as in conventional methods, this invention inverts the approach by keeping the shadow mask stationary and rotating the substrate carrier. The substrate rotates underneath the fixed shadow mask, achieving the same varying thickness effect through rotational exposure time control rather than mask movement.
Solution Approach 2:
The invention introduces rotational dynamics by rotating the substrate carrier at controlled speeds. By varying the rotation speed, the exposure time of different substrate regions to the coating material changes, enabling precise control of film thickness gradient without complex reciprocating mechanisms.
2Productivity
If multiple shadow mask wafers are used for coating multiple films, then multiple films can be formed, but manufacturing precision decreases due to uneven distribution of coating material
Solution Approach 1:
The invention implements feedback control by using sensors to detect the actual film thickness in real-time during the coating process. The system adjusts the rotation speed or exposure parameters based on detected thickness variations, ensuring uniform gradient control across multiple films even when using multiple shadow masks simultaneously.
3Manufacturing precision
If photolithography and etching processes are used to create varying thickness film, then film can be formed, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention extracts and eliminates the complex photolithography and etching steps from the manufacturing process. By directly depositing material with controlled varying thickness through rotational exposure, the method achieves the desired film structure in a single coating step, removing the need for separate patterning and material removal processes.
4Manufacturing precision
If conventional coating method with stationary shadow mask is used, then coating can be applied, but productivity decreases when multiple films need to be coated
Solution Approach 1:
The invention merges multiple coating operations into a single rotational process. By arranging multiple substrates or multiple shadow masks in the rotational system, multiple films can be coated simultaneously or sequentially in one continuous operation, significantly improving productivity while maintaining precision through unified control.
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 method enables easy control of film gradients and reduces production costs, making it suitable for mass production of thin films with varying thicknesses.
Implementation Method 1
a shadow mask defining at least one radial line to a central point thereof, and having at least one opening
Implementation Method 2
rotating the carrier plate relative to the shadow mask about the rotation axis to permit the first zones of the substrate to be swept and exposed from the arcuate portions of the opening per each turn by a plurality of predetermined exposure times
Implementation Method 3
coating a material on the substrate through the opening of the shadow mask whilst implementing step d) to form on the substrate, a first thin film with a varying thickness
Data Source
AI summary
A method of fabricating a thin film with a varying thickness includes the steps of providing a shadow mask with an opening, providing a carrier plate, arranging a substrate on the carrier plate, and coating the substrate through the opening whilst rotating the carrier plate relative to the shadow mask. A plurality of zones of the substrates is swept and exposed from arcuate portions of the opening per each turn by a plurality of predetermined exposure times, respectively. The varying thickness of the thin film corresponds to variation of the predetermined exposure times.