Staggered Blanker Aperture Array for Complementary E-Beam Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithographic technologies face challenges in scaling via features to smaller sizes due to limitations in overlay control, critical dimension resolution, and line width roughness, especially as via pitches decrease, leading to increased fabrication costs and potential inability to print via openings with conventional scanners.
Innovation Solution
Complementary e-beam lithography (CEBL) is used in conjunction with optical lithography to pattern unidirectional lines and divide pitch, employing techniques like spacer-based-patterning and staggered blanker aperture arrays to improve line density and enable precise cutting of metal lines and via formation, enhancing throughput and precision in high-volume manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lithographic processes are used to pattern smaller via features, then manufacturing cost is reduced, but manufacturing precision deteriorates due to overlay control limitations and critical dimension resolution constraints
Solution Approach 1:
The patent divides the patterning process into two separate lithographic steps: first patterning the mandrel features, then using those mandrels as masks to pattern the via features. This segmentation allows each step to operate at relaxed dimensions while achieving the required final precision, resolving the contradiction between using conventional lithography and maintaining manufacturing precision.
Solution Approach 2:
The patent performs preliminary patterning of mandrel features before the actual via feature patterning. These pre-patterned mandrels serve as self-aligned masks that define the precise locations of via features, enabling conventional lithography to achieve high precision through the preliminary structural preparation.
2Productivity
If via pitch is decreased to increase density, then productivity is improved, but manufacturing precision deteriorates due to overlay control and critical dimension limitations
Solution Approach 1:
By segmenting the patterning into mandrel formation and via formation steps, the patent enables independent optimization of each step. The mandrels can be spaced at larger, more controllable pitches while the via features achieve the required small pitch through the self-aligned mask process, thus increasing density without sacrificing pitch control precision.
Solution Approach 2:
The mandrel structures serve as intermediary elements that mediate between the lithographic capabilities and the desired via pitch. These intermediaries allow the system to achieve finer effective pitch than would be possible with direct lithographic patterning, enabling increased productivity while maintaining precision.
3Manufacturing precision
If multiple lithographic masks are used to pattern extremely small via pitches, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent uses a single lithographic mask design that serves multiple functions: it patterns both the mandrel features and serves as the alignment reference for the second patterning step. This multi-functionality reduces the need for multiple specialized masks and alignment procedures, decreasing process complexity while maintaining precision.
Solution Approach 2:
The mandrel structures self-align the via features through their geometric relationship with the first patterned layer. The via features automatically inherit precise positioning from the mandrels without requiring additional active alignment steps or complex mask designs, enabling high precision with reduced process complexity.
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
CEBL effectively extends the capabilities of current optical lithography, allowing for cost-effective patterning at advanced technology nodes by improving line density and precision, enabling the fabrication of smaller via features and reducing fabrication costs.
Implementation Method 1
Complementary e-beam lithography (CEBL) is used in conjunction with optical lithography to pattern unidirectional lines and divide pitch
Data Source
AI summary
Lithographic apparatuses suitable for, and methodologies involving, complementary e-beam lithography (CEBL) are described. In an example, a blanker aperture array (BAA) for an e-beam tool includes a first column of openings along a first direction and having a pitch. The BAA also includes a second column of openings along the first direction and staggered from the first column of openings. The second column of openings has the pitch. A scan direction of the BAA is along a second direction, orthogonal to the first direction.