Pellicle Frame Recesses for Adhesive Removal
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Solution Overview
Problem
The existing adhesive used in pellicle frames for photo masks degrades over time, becoming denser and difficult to remove, leading to contamination and defects in the photo mask production process, which requires costly and time-consuming cleaning and replacement procedures.
Innovation Solution
A photo mask assembly design featuring a pellicle frame with recesses to accommodate the adhesive, maintaining its thickness and preventing deformation, along with a second adhesive layer supporting the pellicle, allows for easy removal of the degraded adhesive without damaging the photo mask, reducing contamination risks and simplifying the replacement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to mount pellicle frame on photo mask, then pellicle can be securely fixed, but adhesive becomes dense and difficult to remove after long-term use due to degradation and outgassing
Solution Approach 1:
The pellicle frame is divided into a frame body and a separate mounting structure that interfaces with the photo mask. This segmentation allows the mounting structure to be designed specifically for easy removal while maintaining strong bonding during use, resolving the contradiction between secure fixation and ease of removal.
Solution Approach 2:
The adhesive properties are modified by changing its chemical composition and physical parameters. The adhesive is formulated to undergo controlled degradation under specific conditions (such as exposure to certain solvents or temperature changes), transforming from a strong bond state to an easily removable state, thus resolving the contradiction between initial bonding strength and subsequent removal ease.
2Productivity
If adhesive is not removed completely, then cleaning process is faster, but adhesive residue causes killing defects and damages pattern on photo mask
Solution Approach 1:
The mounting structure is designed to be completely extractable from the photo mask surface without leaving residue. This is achieved through a mechanical mounting mechanism or a specially formulated adhesive that removes cleanly, allowing fast cleaning while ensuring no residue remains to cause defects or damage the pattern.
Solution Approach 2:
The mounting structure is designed as a disposable or easily replaceable component. After a certain period or number of uses, the entire mounting structure is removed and replaced rather than attempting to clean the adhesive thoroughly. This approach ensures photo mask quality while maintaining productivity, as the replacement process is faster and more reliable than extensive cleaning.
3Reliability
If pellicle is replaced frequently, then defect control is improved, but time and cost for cleaning and replacement increases
Solution Approach 1:
The pellicle assembly is segmented into the pellicle itself and the mounting structure, which can be independently replaced. This allows for rapid replacement of just the pellicle or the entire assembly as a unit, reducing replacement time while maintaining defect control through regular replacement schedules.
Solution Approach 2:
The mounting structure is pre-designed with features that facilitate rapid replacement, such as pre-cut adhesive regions, mechanical interlocks, or alignment features. This preliminary design enables quick removal and installation of the pellicle assembly, reducing replacement time while ensuring proper positioning and maintaining defect control.
Data Source
AI summary
A photo mask assembly including a photo mask, a first adhesive layer adhered with the photo mask, a pellicle frame and a pellicle is provided. The pellicle frame includes a plurality of recesses for accommodating the first adhesive layer. The pellicle frame is adhered with the photo mask through the first adhesive layer accommodated in the plurality of recesses. The pellicle is disposed on the pellicle frame. The pellicle frame is between the pellicle and the first adhesive layer. An optical apparatus including the above-mentioned photo mask assembly is also provided.