Alignment Mark Guide Pattern Segmentation for DSA
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Solution Overview
Problem
In the pattern formation method using directed self-assembly technology, irregular phase-separation of block copolymers in alignment marks leads to loss of function due to irregular light and dark contrast, making it difficult for image recognition to accurately grasp the position and shape of the alignment mark.
Innovation Solution
The alignment mark is designed with a plurality of guide pattern features and a self-assembled film formed by microphase-separating block copolymers, where the self-assembled film is structured with alternating line pattern features between guide pattern features, ensuring uniform contrast and visibility for accurate image recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If block copolymer is applied to the alignment mark region in directed self-assembly process, then fine pattern formation is enabled, but irregular phase-separation occurs causing loss of alignment mark function
Solution Approach 1:
The alignment mark region is segmented into multiple sub-regions (first alignment mark region and second alignment mark region) with different guide pattern configurations. This segmentation allows different portions of the block copolymer to phase-separate in controlled, regular patterns rather than irregularly, maintaining alignment mark functionality while enabling fine pattern formation.
Solution Approach 2:
Different local structures are introduced in different regions of the alignment mark. The first alignment mark region has guide patterns with a first pitch while the second alignment mark region has guide patterns with a second pitch. This local quality variation ensures regular phase-separation throughout the entire alignment mark region, preventing the irregular contrast that would cause function loss.
2Illumination intensity
If alignment mark area is increased 100-1000 times for improved visibility, then image recognition visibility is improved, but block copolymer phase-separation irregularity becomes more pronounced
Solution Approach 1:
The large-area alignment mark is segmented into multiple smaller regions with identical or different guide pattern pitches. Each segment independently maintains regular phase-separation, ensuring that the overall large-area mark remains uniform in composition and contrast, preventing the irregularity that would otherwise occur in such a large continuous region.
Solution Approach 2:
By introducing multiple local guide pattern configurations (different pitches in different regions), the patent ensures that each local area maintains stable and regular phase-separation. This local quality control across the entire large area prevents the composition instability that would otherwise be pronounced in expanded alignment marks.
3Stability of the object's composition
If guide pattern pitch is varied in different regions, then regular phase-separation is achieved throughout, but device pattern pitch must be carefully coordinated
Solution Approach 1:
The patent changes the pitch parameter of guide patterns in different regions (first pitch in first region, second pitch in second region) to control phase-separation behavior. By carefully selecting these pitch values to be integer multiples or simple ratios, the complexity of coordinating with device patterns is managed while achieving regular phase-separation throughout the alignment mark region.
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 allows for high-accuracy alignment and suppression of misalignment between the photomask and wafer substrate by maintaining uniform contrast and visibility, enhancing the reliability of image recognition in the wafer process without increasing the number of manufacturing processes.
Implementation Method 1
a block copolymer is microphase-separated along a guide pattern to form a fine pattern
Implementation Method 2
pattern formation method using directed self-assembly (DSA) technology
Data Source
AI summary
According to one embodiment, an alignment mark provided on an underlayer includes a plurality of first guide pattern features, and a first self-assembled film. The first guide pattern features extend in a first direction and are aligned in a second direction crossing the first direction. The first self-assembled film is provided between adjacent ones of the first guide pattern features and includes a plurality of first line pattern features and a second line pattern feature. The first line pattern features extends in the first direction, is aligned in the second direction, and has a pitch in the second direction narrower than a pitch in the second direction of the first guide pattern features. The second line pattern feature is provided between adjacent ones of the first line pattern features and extends in the first direction.