Benzyltrialkylammonium Hydroxide Developer for Lithography
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Solution Overview
Problem
In the context of microelectronic device manufacturing, particularly in electron beam (EB) and extreme ultraviolet (EUV) lithography, there is a challenge in achieving minimal edge roughness and preventing pattern collapse or bridge defects during the development process, as existing developers like tetramethylammonium hydroxide (TMAH) aqueous solutions are insufficient for forming patterns with feature sizes of 16 nm or less, and the sensitivity of resist films is compromised due to increased accelerating voltages and acid diffusion issues.
Innovation Solution
An aqueous solution containing 0.1 to 20% by weight of benzyltrialkylammonium hydroxide is used as a developer, which accelerates alkaline dissolution in chemically amplified positive resist compositions, minimizing edge roughness and preventing pattern collapse by suppressing swell and bridge defects, along with the addition of acetylene alcohol for defoaming and surface activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tetramethylammonium hydroxide (TMAH) aqueous solution is used as developer, then the development process is simple and cost-effective, but edge roughness increases and pattern collapse occurs at feature sizes of 16 nm or less
Solution Approach 1:
The patent uses a composite developer system combining TMAH with benzyltrialkylammonium hydroxide. This composite approach leverages the basic dissolution capability of TMAH while the benzyltrialkylammonium hydroxide component suppresses resist swell and reduces edge roughness, achieving fine pattern fidelity without excessive complexity
Solution Approach 2:
The patent modifies the developer composition by introducing benzyltrialkylammonium hydroxide at specific concentrations (0.1-20% by weight). This parameter change in the developer's chemical composition directly addresses the edge roughness and pattern collapse issues while maintaining processability
2Manufacturing precision
If accelerating voltage is increased to improve resolution and reduce forward scattering, then image contrast improves, but resist film sensitivity decreases
Solution Approach 1:
The patent employs chemically amplified resist compositions with modified chemical parameters that enhance sensitivity. The developer composition is specifically designed to work with these resists, accelerating dissolution rates and compensating for the sensitivity loss caused by high accelerating voltages, thereby maintaining throughput while achieving high resolution
3Manufacturing precision
If resist film thickness is reduced to improve resolution and prevent pattern collapse, then resolution improves, but dry etch resistance decreases
Solution Approach 1:
The patent modifies the resist composition's chemical parameters by incorporating polymers with enhanced etch resistance and optimizing the cross-section composition. Simultaneously, the developer composition is adjusted to provide adequate dissolution contrast, enabling thin films to maintain both resolution and sufficient etch resistance through optimized chemical parameters rather than increasing thickness
4Area of moving object
If feature size is reduced to increase integration density, then integration density improves, but pattern collapse and bridge defects increase
Solution Approach 1:
The patent optimizes the developer's chemical composition parameters by incorporating benzyltrialkylammonium hydroxide, which suppresses resist swell during development. This parameter change in the developer chemistry enables the formation of high-aspect-ratio and sub-16nm patterns without pattern collapse or bridge defects, maintaining pattern integrity at reduced feature sizes
Solution Approach 2:
The benzyltrialkylammonium hydroxide acts as an intermediary substance in the developer that mediates between the resist film and the development process. It suppresses excessive swelling and provides controlled dissolution, preventing pattern collapse and bridge defects while enabling the formation of fine, high-aspect-ratio patterns
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 use of benzyltrialkylammonium hydroxide as a developer effectively reduces edge roughness and prevents pattern collapse, enabling the formation of resist patterns with minimal defects and improved sensitivity, even at smaller feature sizes, while maintaining the resist film's dry etch resistance and resolution.
Implementation Method 1
a developer for photosensitive resist materials comprising an aqueous solution containing 0.1 to 20% by weight of a substituted or unsubstituted benzyltrialkylammonium hydroxide
Implementation Method 2
along with the addition of acetylene alcohol for defoaming and surface activation
Data Source
AI summary
An aqueous solution containing 0.1-20 wt % of a benzyltrialkylammonium hydroxide is a useful developer for photosensitive resist materials. When an exposed resist film is developed in the developer, any swell of the resist film during development is suppressed. A resist pattern with minimal edge roughness can be formed while preventing pattern collapse or bridge defect formation.