Chromium Oxygen Carbon Etching Stopper Film for Mask Blank
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Solution Overview
Problem
In the manufacturing of semiconductor devices, the miniaturization of mask patterns and the use of short-wavelength exposure light sources pose challenges in achieving high pattern accuracy and preventing pattern collapse due to side etching during dry etching processes, particularly with chromium-based etching stopper films when using chlorine-based gases and oxygen.
Innovation Solution
A mask blank structure with an etching stopper film made of chromium, oxygen, and carbon, where the chromium content is 50 atomic % or more, and a pattern-forming thin film made of silicon or tantalum, optimized to reduce side etching by controlling the chemical bonding state and using specific etching gases and bias conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a chromium-based etching stopper film is used with chlorine-based gases and oxygen in dry etching, then etching performance is improved, but side etching increases causing pattern collapse
Solution Approach 1:
The patent changes the chemical composition parameters of the etching stopper film by incorporating carbon alongside chromium and oxygen. This compositional parameter change modifies the film's chemical reactivity with chlorine-based etching gases, reducing unwanted side etching while preserving vertical etching performance. The specific atomic ratios of Cr:O:C are optimized to achieve the desired etching characteristics.
Solution Approach 2:
The patent creates a composite etching stopper film material consisting of chromium, oxygen, and carbon in specific combinations. This composite material approach allows the film to exhibit improved etching selectivity and reduced side etching compared to conventional chromium-based films, while maintaining compatibility with the dry etching process using chlorine-based gases.
2Area of moving object
If mask patterns are miniaturized for high-density semiconductor devices, then device density is improved, but pattern collapse due to side etching worsens
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching stopper film to reduce its reactivity with chlorine-based etching gases. By adjusting the Cr:O:C ratios, the film's etching characteristics are optimized to minimize side etching, which is critical for maintaining pattern integrity during the miniaturization process.
Solution Approach 2:
The patent applies the etching stopper film with specific local chemical properties at the pattern sidewalls. The carbon-containing chromium oxide film provides localized protection against side etching at the pattern edges, while allowing controlled etching in the vertical direction. This local quality enhancement is crucial for preventing pattern collapse in miniaturized structures.
3Manufacturing precision
If short-wavelength exposure light sources are used for fine pattern formation, then pattern resolution is improved, but etching selectivity between films becomes more difficult to assure
Solution Approach 1:
The patent changes the chemical composition parameters of the etching stopper film to achieve better etching selectivity. The carbon-containing chromium oxide film provides improved chemical stability and selectivity with chlorine-based etching gases, making the multi-layer etching process more controllable and less complex despite the use of short-wavelength exposure light sources.
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 configuration effectively suppresses side etching and ensures accurate formation of fine patterns, preventing pattern collapse and enabling high-accuracy transfer masks and semiconductor devices.
Implementation Method 1
an etching stopper film made of a material containing chromium, oxygen, and carbon... optimized to reduce side etching by controlling the chemical bonding state
Data Source
AI summary
In the present invention, an etching stopper film (2), a light-blocking film (3) comprising a material containing one or more elements selected from among silicon and tantalum, and a hard mask film (4) are laminated in that order on a translucent substrate (1). The etching stopper film is made of a material containing chromium, oxygen and carbon, the chromium content is 50 atom % or more, the maximum peak in a N1s narrow spectrum obtained by means of analysis using X-Ray photoelectron spectroscopy is below the detection limit, and a Cr2p narrow spectrum obtained by means of analysis using X-Ray photoelectron spectroscopy has a maximum peak at a bond energy of 574 eV or less.