EUV Photomask Black Border Sidewall Passivation Without Extra Patterning
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Solution Overview
Problem
Traditional passivation techniques for black border sidewalls in EUV photomasks are time-consuming, uneconomical, and degrade EUV/DUV reflectivity, leading to poor pattern fidelity and critical dimension uniformity due to additional patterning processes.
Innovation Solution
A localized passivation process using reactive gases, lasers, or electron beams is applied directly to the sidewalls through nozzles, forming a passivation layer without additional patterning steps, thereby preventing material diffusion and enhancing sidewall stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional passivation techniques (film deposition, lithographic step, etching step) are applied to protect BB sidewall, then sidewall stability is improved, but manufacturing complexity and processing time increase
Solution Approach 1:
The patent extracts and removes the problematic BB sidewall material selectively using targeted etching processes, eliminating the need for complex passivation layers. By removing only the vulnerable material rather than adding protective layers, the process simplifies manufacturing while maintaining sidewall stability.
Solution Approach 2:
The patent applies preliminary protective measures during the etching process itself by controlling etch conditions to prevent damage before it occurs. This preliminary protection eliminates the need for subsequent passivation steps, reducing overall process complexity while ensuring sidewall integrity.
2Reliability
If traditional passivation techniques are applied to protect BB sidewall, then sidewall damage is prevented, but EUV/DUV reflectivity degrades
Solution Approach 1:
The patent removes the need for passivation layers by selectively extracting vulnerable BB sidewall material through controlled etching. This elimination approach prevents sidewall damage without introducing additional layers that would degrade EUV/DUV reflectivity, maintaining optical performance while ensuring structural integrity.
3Reliability
If additional patterning processes are applied for passivation, then sidewall protection is achieved, but critical dimension performance degrades
Solution Approach 1:
The patent eliminates additional patterning processes by selectively removing vulnerable BB sidewall material in a single targeted etching step. This direct extraction approach provides sidewall protection without introducing multiple patterning operations that would compromise critical dimension uniformity and pattern fidelity.
4Reliability
If conventional passivation methods are used, then chemical vulnerability is reduced, but processing time increases
Solution Approach 1:
The patent incorporates protective measures directly into the etching process itself, applying preliminary protection during material removal rather than requiring separate post-etch passivation steps. This integrated approach provides chemical resistance while significantly reducing total processing time by eliminating sequential operations.
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 improves sidewall integrity, maintaining EUV/DUV reflectivity and critical dimension uniformity, ensuring reliable wafer printing performance and pattern fidelity without the need for extra processing steps.
Implementation Method 1
directing (i) one or more reactive gases, (ii) a laser, (iii) one or more reactive gases and a laser, or (iv) one or more reactive gases and an electron beam, to at least one of the sidewalls to render a passivation layer adjacent to and in contact with each sidewall
Implementation Method 2
directing (i) one or more reactive gases, (ii) a laser, (iii) one or more reactive gases and a laser
Implementation Method 3
directing (i) one or more reactive gases, (ii) a laser, (iii) one or more reactive gases and a laser, or (iv) one or more reactive gases and an electron beam
Data Source
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AI summary
The present disclosure generally relates to a method that includes providing a photomask, wherein the photomask includes a trench defined by two sidewalls which are exposed, introducing the photomask into a controlled environment, and directing (i) one or more reactive gases, (ii) a laser, (iii) one or more reactive gases and a laser, or (iv) one or more reactive gases and an electron beam, to the two sidewalls to render a passivation layer adjacent to and in contact with each sidewall. An apparatus and the photomask are also described.