Dual Organic Polymer Layer Pattern Formation
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Solution Overview
Problem
Conventional photolithography techniques face challenges in forming photoresist patterns with narrow critical dimensions and dense structures, leading to reduced defocus margin and inadequate etching masks, especially when using short-wavelength light, resulting in reduced contact area and potential separation of non-photosensitive organic patterns from underlying layers.
Innovation Solution
A method involving a dual organic polymer layer system, where a thick first organic polymer layer serves as an etching mask and a thin photosensitive second organic polymer layer is used, with a silicon-containing polymer layer that is oxidized and etched to form an anisotropic pattern, enhancing the defocus margin and etching capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin photoresist layer is used to improve defocus margin, then the defocus margin increases, but the etching mask capability deteriorates
Solution Approach 1:
The patent divides the photoresist layer into two distinct layers: a thin first photoresist layer (50-200 nm) that provides excellent defocus margin for pattern formation, and a thick second photoresist layer (500-2000 nm) that serves as a robust etching mask. This segmentation allows each layer to optimize its thickness for its specific function, resolving the contradiction between thin-layer defocus advantage and thick-layer etching protection.
Solution Approach 2:
The patent transitions from a single-layer photoresist structure to a multi-layer vertical structure. By adding the second photoresist layer above the first layer, the system gains an additional dimensional layer that专门 handles the etching mask function, while the first layer handles the pattern formation function. This vertical dimensionality change allows simultaneous optimization of both defocus margin and etching mask capability.
2Measurement precision
If short-wavelength light is used for high-resolution exposure, then the resolution improves, but the defocus margin decreases
Solution Approach 1:
The thin first photoresist layer (50-200 nm) is specifically designed to work with short-wavelength light (193 nm or 248 nm) for high-resolution pattern formation. Its reduced thickness minimizes the depth of focus requirements, allowing the system to achieve both high resolution and adequate defocus margin when using short-wavelength exposure light.
3Measurement precision
If the opening width decreases to improve resolution, then the exposure precision improves, but the contact area between pattern and underlying layer reduces
Solution Approach 1:
The thick second photoresist layer compensates for the reduced contact area at the opening level by providing extensive lateral coverage and vertical height. Even when openings are narrow for high resolution, the second layer's thickness ensures sufficient material volume and structural integrity, preventing pattern separation during etching while maintaining the narrow opening geometry for high exposure precision.
4Device complexity
If a non-photosensitive organic layer is used to form patterns, then the pattern structure simplifies, but the pattern separation risk increases
Solution Approach 1:
The patent uses a composite photoresist structure where the first photoresist layer (50-200 nm) provides strong adhesion to the underlying layer and excellent pattern formation, while the second photoresist layer (500-2000 nm) provides robust mechanical support and etching mask functionality. This composite structure combines the advantages of both thin and thick photoresist layers, achieving both simplified processing and enhanced pattern separation resistance.
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 approach maintains a consistent defocus margin and provides a superior etching mask, allowing for precise pattern formation and effective etching of underlying layers with improved contact area and reduced risk of pattern separation.
Implementation Method 1
the silicon-containing polymer layer is oxidized and simultaneously the second organic polymer layer and the first organic polymer layer are ashed by oxygen plasma
Implementation Method 2
the silicon-containing polymer layer is oxidized and simultaneously the second organic polymer layer and the first organic polymer layer are ashed by oxygen plasma
Data Source
AI summary
Disclosed is a method of forming a pattern. A first organic polymer layer is formed on a substrate on which an underlying layer, and then a second organic polymer layer, which has an opening partially exposing the first organic polymer layer, is formed on the first organic polymer layer. Next, a silicon-containing polymer layer is formed on the second organic polymer layer to cover the opening. The silicon-containing polymer layer is oxidized and simultaneously the second organic polymer layer and the first organic polymer layer are ashed by oxygen plasma to form a pattern having an anisotropy-shape. The underlying layer is etched using the silicon-containing polymer layer and the first organic polymer layer as an etching mask to form a pattern.