Negative Tone Resist Composition for High Resolution Patterning
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Solution Overview
Problem
Current photolithography techniques face challenges in achieving high resolution and fine patterning due to limitations in wavelength reduction, edge roughness, and dissolution contrast during organic solvent development, particularly for negative tone patterns.
Innovation Solution
A pattern forming process using a resist composition that includes a polymer capable of forming a lactone ring under acidic conditions, combined with an acid generator and organic solvent, to enhance dissolution contrast between unexposed and exposed regions during organic solvent development.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography with organic solvent development is used, then the process is simple and widely applicable, but the dissolution contrast between unexposed and exposed regions is insufficient, leading to poor pattern definition
Solution Approach 1:
The patent employs a composite resist composition comprising a carboxyl-containing polymer and a polymerizable ester compound. The carboxyl-containing polymer provides acid sensitivity for exposure, while the polymerizable ester compound reacts with the acid to form crosslinked structures that enhance dissolution contrast. This composite approach allows both components to contribute their specific functions, achieving superior pattern definition without excessive complexity.
Solution Approach 2:
The patent utilizes chemical parameter changes during the exposure and development process. The polymerizable ester compound undergoes chemical transformation when exposed to acid generated during photolithography exposure, changing its reactivity and solubility parameters. This parameter change creates the high dissolution contrast needed for precise patterning while maintaining process simplicity.
2Manufacturing precision
If the wavelength of exposure light is reduced to achieve finer patterning, then the resolution improves, but the equipment cost and complexity increase significantly
Solution Approach 1:
The patent changes the chemical parameters of the resist system to achieve better patterning definition using existing ArF excimer laser equipment. By modifying the resist composition to include the polymerizable ester compound that forms crosslinked structures upon acid exposure, the system achieves enhanced resolution without requiring wavelength reduction or equipment upgrades.
3Manufacturing precision
If ArF lithography is used for 90-nm node and below, then the patterning resolution improves, but the etch resistance of resist decreases and development becomes more difficult
Solution Approach 1:
The patent modifies the chemical parameters of the resist composition by incorporating the polymerizable ester compound that forms crosslinked structures upon acid exposure. This crosslinking enhances the etch resistance of the exposed regions during development, allowing ArF lithography to achieve both high resolution and adequate etch resistance at 90-nm node and below.
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 process achieves high dissolution contrast and enables the formation of negative tone patterns with improved resolution and adhesion, overcoming limitations in existing technologies.
Implementation Method 1
an acid generator, and an organic solvent onto a substrate, prebaking the composition to form a resist film, exposing the resist film to high-energy radiation
Implementation Method 2
a polymer adapted to form a lactone ring under the action of an acid so that the polymer may reduce its solubility in an organic solvent developer
Implementation Method 3
developing the exposed film in an organic solvent-based developer to form a negative pattern wherein the unexposed region of film is dissolved and the exposed region of film is not dissolved
Data Source
AI summary
A negative pattern is formed by applying a resist composition onto a substrate, prebaking, exposing to high-energy radiation, baking (PEB), and developing the exposed resist film in an organic solvent developer to dissolve the unexposed region of resist film. The resist composition comprising a polymer adapted to form a lactone ring under the action of an acid so that the polymer may reduce its solubility in an organic solvent developer, an acid generator, and an organic solvent displays a high dissolution contrast between the unexposed region of promoted dissolution and the exposed region of inhibited dissolution.