Photomask Cleaning via Gravity-Assisted Rotation
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Solution Overview
Problem
Conventional mask structures used in semiconductor integrated circuits are prone to defects, leading to manufacturing failures and reliability issues due to limitations in process technology and material constraints, which hinder the miniaturization and complexity of integrated circuits.
Innovation Solution
A method involving a partially completed mask structure with a substrate and patterned photoresist layer is supported to face gravitational force and rotated annularly, with a cleaning fluid applied to remove particles, preventing reattachment and enabling an etching process on the light blocking layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mask structures are used for photolithography, then manufacturing process can be maintained, but defects occur leading to low device yields
Solution Approach 1:
The patent applies preliminary action by performing a specialized cleaning process on the mask structure before the photolithography step. The cleaning process includes rotating the mask structure while applying cleaning fluid to remove particles from the photoresist layer surface, preventing defects before they can affect device fabrication. This preliminary cleaning action ensures high device yield by eliminating potential defect sources in advance.
2Manufacturing precision
If mask structures are cleaned using conventional methods, then processing time is reduced, but particles remain on the photoresist layer surface
Solution Approach 1:
The patent applies dynamics by introducing rotational motion to the mask structure during the cleaning process. The mask structure rotates while cleaning fluid is applied, creating dynamic relative motion between the cleaning fluid and the photoresist layer surface. This rotational movement enhances particle removal effectiveness by preventing particles from reattaching and improving fluid circulation, while the process remains integrated into existing equipment.
3Manufacturing precision
If the photoresist layer is cleaned by applying cleaning fluid while the mask structure is rotated, then particles are removed effectively, but the mask structure must be supported in a specific orientation
Solution Approach 1:
The patent applies equipotentiality by positioning the mask structure face-down so that the photoresist layer surface is parallel to the gravitational force direction. This orientation creates a stable, gravity-assisted cleaning environment where cleaning fluid can effectively reach and remove particles from the surface. The gravitational alignment simplifies the cleaning operation by eliminating the need for complex positioning adjustments during the cleaning process.
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 enhances device yields, reduces defects in photolithography masks, and supports smaller design rules without requiring substantial modifications to existing equipment or processes, resulting in improved integration and reliability.
Implementation Method 1
accelerating the one or more particles away from the surface of the patterned photoresist layer via the gravitational force
Data Source
AI summary
A method for processing a photomask for semiconductor devices. The method includes providing a partially completed mask structure, which has a backside and a face. The face includes a substrate material, a light blocking layer overlying the substrate material, and an overlying patterned photoresist layer overlying the light blocking layer. The method includes supporting the backside of the mask structure to maintain the mask structure in place and maintaining the face of the patterned photoresist layer in a direction parallel to a gravitational force and toward the gravitational force. The method includes rotating the mask structure in an annular manner as the patterned photoresist layer of the mask structure is being maintained in the direction parallel to the gravitational force and toward the gravitational force. Additionally, the method includes applying cleaning fluid on the patterned photoresist layer as the patterned photoresist layer of the mask structure is being maintained in the direction parallel to gravity, is facing the gravitational force, and is being rotated to remove one or more particles from the patterned surface. Preferably, the method includes accelerating the one or more particles away from the surface of the patterned photoresist layer, whereupon the one or more particles are prevented from attaching themselves back to the patterned photoresist layer via the gravitational force.