Pellicle Frame Edge Rounding for Pseudo Contamination Control
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Solution Overview
Problem
In the manufacturing of semiconductor devices and liquid crystal display boards, dust particles on the exposure original plate or mask for lithography can cause pattern deformation, rough edges, and quality issues. As the design rule for LSI moves towards sub-quarter micron patterns, the size of dust particles to be prevented from contaminating is minimized, necessitating stringent control over the pellicle frame's edges and chamfers to prevent pseudo foreign matter contamination.
Innovation Solution
The pellicle frame's edges where the inner wall meets the upper or lower end faces are designed to form a virtual curve, effectively making these edges virtually rounded. This design includes primary chamfering and can include secondary chamfering, with angles greater than 135°, and complete rounding or further chamfering of edges between chamfer faces. The pellicle frame is also coated with an anodic oxidation or acrylic-based electrodeposition layer to reduce scratches and protrusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chamfers are formed on the pellicle frame edges to prevent particle generation, then dust particle prevention is improved, but scratches and protrusions occur at the boundary edges between chamfer faces and other surfaces
Solution Approach 1:
The patent applies curvature by rounding the boundary edges between chamfer faces and other surfaces (inner wall, outer wall, upper end face, lower end face) of the pellicle frame. This rounding eliminates sharp corners where scratches and protrusions would form, while maintaining the chamfer structure for dust particle prevention. The curved transition surfaces prevent stress concentration and material defects at the boundaries.
2Manufacturing precision
If the pellicle frame edges are completely rounded to prevent scratches, then surface integrity is improved, but dust particle prevention capability is reduced
Solution Approach 1:
The patent merges two opposing structural approaches by combining chamfered edges (for dust particle prevention) with rounded boundary edges (for surface integrity). The pellicle frame simultaneously features chamfer faces on the main edges and rounded transitions at the boundaries between these chamfers and other surfaces, integrating both functional requirements into a single structure.
3Object-affected harmful factors
If string ent control is applied to the pellicle frame, then dust particle prevention is improved, but pseudo foreign matter is generated at the boundary edges
Solution Approach 1:
The patent eliminates pseudo foreign matter generation by rounding the boundary edges where scratches and protrusions would occur during machining and coating processes. The curved surfaces prevent stress concentration and material defects that would otherwise be misidentified as foreign particles during inspection, thereby maintaining stringent foreign particle control without generating false positives.
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 design significantly reduces the occurrence of scratches and protrusions at the boundary edges of the pellicle frame, minimizing the risk of pseudo foreign matter contamination during inspection. As a result, highly accurate dust particle control is achieved, enhancing the precision and quality of semiconductor and liquid crystal display manufacturing processes.
Implementation Method 1
The pellicle frame is also coated with an anodic oxidation or acrylic-based electrodeposition layer to reduce scratches and protrusions.
Implementation Method 2
The pellicle frame is also coated with an anodic oxidation or acrylic-based electrodeposition layer to reduce scratches and protrusions.
Data Source
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AI summary
There is provided a pellicle wherein each edge area where the inner wall of the pellicle frame meets the upper end face or the lower end face, respectively, of the pellicle frame consists not only of the conventional single chamfer face but also of additional attempt(s) to make the edge area virtually rounded, such as additional chamfering(s) or rounding, whereby the edge area is devoid of cracking and scars.