Mask Assembly with Detachable Test Sheets for Film Thickness Monitoring
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Solution Overview
Problem
During the evaporation process for patterned transparent conductive oxide layers, the deposited material on masks can reach excessive thickness, leading to contamination in the process chamber due to peeling off, which is not effectively addressed by existing technologies.
Innovation Solution
A mask assembly with detachable test sheets made of transparent material is used, where the evaporation material is deposited on the test sheets during the process, allowing for detection of film thickness and triggering an alarm when it exceeds a predetermined value, thereby preventing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask is used during the evaporation process, then a patterned transparent conductive oxide layer can be prepared, but the deposited material on the mask reaches excessive thickness leading to contamination in the process chamber
Solution Approach 1:
The mask surface is segmented into functional areas: patterned regions for deposition and separate test sheet regions for monitoring. The test sheets are detachable components that can be independently removed and measured, allowing the main mask to continue functioning while contamination is monitored on separate test elements.
Solution Approach 2:
Test sheets serve as intermediary elements between the evaporation source and the main mask. These separate test sheets absorb excess deposited material that would otherwise accumulate on the main mask and cause contamination. The test sheets act as sacrificial monitoring elements that protect the primary functional mask.
2Object-affected harmful factors
If the mask is cleaned frequently to prevent contamination, then contamination is reduced, but productivity decreases due to frequent interruptions
Solution Approach 1:
Test sheets are pre-installed on the mask before the evaporation process begins. These test sheets are positioned to receive deposited material in advance, serving as early warning indicators. By having the monitoring mechanism in place before deposition starts, the system can detect excessive thickness early and trigger cleaning only when necessary, rather than requiring frequent preventive cleaning.
Solution Approach 2:
The system implements feedback through detachable test sheets that can be removed and measured to detect film thickness. This feedback mechanism allows real-time monitoring of deposition levels on the mask. When test sheets show excessive material accumulation, the system can trigger alerts or automatic cleaning procedures, optimizing the cleaning frequency based on actual contamination levels rather than following a fixed schedule.
3Measurement precision
If test sheets are provided on the mask, then film thickness can be detected, but device complexity increases
Solution Approach 1:
The test sheets are designed as simple, inexpensive, detachable components that can be easily replaced. Rather than integrating complex permanent monitoring systems into the mask, the invention uses simple test sheets that serve their monitoring purpose and can be discarded or replaced when needed. This approach achieves measurement functionality while minimizing added complexity and cost.
Solution Approach 2:
The testing function is extracted from the main mask structure and implemented as separate, detachable test sheets. This separation allows the test sheets to be independently handled, removed, and measured without affecting the main mask assembly. The extraction of the monitoring function into separate components simplifies the overall system architecture while maintaining measurement capability.
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 method effectively prevents contamination in the process chamber by allowing for timely cleaning of the mask based on the detected film thickness on the test sheets, improving product yield and process efficiency.
Implementation Method 1
the film-thickness detector is configured to detect a light transmittance of the test sheet, and generates the signal corresponding to the film thickness of the evaporation material deposited on the test sheet in accordance with the light transmittance of the test sheet
Implementation Method 2
an evaporation material can be deposited on the test sheet when an evaporation process is performed by using the mask assembly
Implementation Method 3
Generally, a patterned transparent conductive oxide layer is prepared by an evaporation process
Data Source
AI summary
The disclosure provides a mask assembly comprising a mask which comprises a first surface facing towards an evaporation source and a second surface facing towards an article to be deposited, and pattern openings are formed in the mask, wherein the mask assembly further comprises at least one test sheet which is detachably provided on the mask. The test sheet is provided at a region on the mask where no pattern opening is provided, and is configured such that an evaporation material can be deposited on the test sheet when an evaporation process is performed by using the mask assembly. The disclosure further provides an apparatus and a method for detecting a film thickness of the evaporation material on the mask assembly. With the apparatus, the film thickness of the evaporation material deposited on the mask assembly can be easily detected.