Double Patterning Photoresist Process for Variable Dense Patterns
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Solution Overview
Problem
Conventional double patterning techniques in semiconductor device fabrication face challenges in achieving reduced pitch and accurate pattern profiles, particularly when dealing with varying densities, leading to uneven or inaccurate results.
Innovation Solution
A method involving a photoresist layer exposed to multiple light sources through different masks, using a combination of positive and negative tone developers to achieve higher resolution and flexible line/space ratios, allowing for the creation of variable dense patterns with dissimilar dimensions and spacings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional double patterning techniques are used, then pitch reduction is achieved, but pattern profile accuracy deteriorates leading to uneven or inaccurate results
Solution Approach 1:
The patent segments the patterning process into multiple distinct stages: first applying a positive photoresist and exposing through a first mask to form initial patterns, then applying a negative photoresist and exposing through a second mask to form additional patterns. This segmentation allows each layer to be optimized independently, achieving both pitch reduction and pattern profile accuracy that cannot be achieved with conventional single-layer double patterning.
2Adaptability or versatility
If conventional double patterning techniques are used, then pattern density variation is handled, but manufacturing uniformity deteriorates resulting in uneven patterns
Solution Approach 1:
The patent applies different photoresist materials and exposure parameters to different regions of the substrate based on local pattern density requirements. Areas with high density variations receive tailored exposure doses and developer treatments, while uniform areas use standard parameters. This local quality approach maintains manufacturing uniformity across the entire wafer while accommodating varying pattern densities in different regions.
3Device complexity
If single developer type is used in double patterning, then process simplicity is maintained, but pattern resolution deteriorates
Solution Approach 1:
The patent deliberately introduces asymmetry into the development process by using a positive tone developer for the first photoresist layer and a negative tone developer for the second layer. This asymmetric approach exploits the complementary solubility characteristics of positive and negative photoresists, enabling each layer to be developed with optimal contrast and resolution. The asymmetric developer selection resolves the contradiction by accepting increased process complexity in exchange for significantly improved pattern resolution.
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 enables the fabrication of semiconductor devices with improved resolution and accurate pattern profiles, overcoming the limitations of conventional double patterning methods by allowing for reduced pitch and precise control over pattern design.
Implementation Method 1
The premise behind photolithography is the change in solubility of the positive photoresist in a positive tone developer throughout certain regions of the photoresist that have been exposed to light
Implementation Method 2
Exposed regions of a positive photoresist become more soluble in the PTD
Implementation Method 3
exposed regions of the positive photoresist become less soluble in a negative tone developer
Data Source
AI summary
A method of manufacturing using a double patterning method is provided. The double patterning method uses a first developer and a second developer that are different. For example, the first developer may be a positive tone developer for a positive photoresist while the second developer may be a negative tone developer for the positive photoresist. Photoresists having a photoactive compound are also provided that may be useful in double patterning methods. The resulting double patterning results, wherein a dimension of a variable first dense pattern is larger than a dimension of a variable second dense pattern.