Integrated Circuit Fabrication Using Reticle Jog Structures
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Solution Overview
Problem
Conventional photolithographic processes face limitations in printing small feature sizes and pitches due to physical constraints, such as wavelength and aperture limitations, leading to bottlenecks in ultra-deep submicron technology, where current lithography technologies struggle to efficiently create complex patterns required for advanced integrated circuits.
Innovation Solution
The method employs jog structures in reticles to increase the distance between adjacent features, allowing them to be printed in a single exposure process instead of requiring multiple patterning processes, thereby simplifying the fabrication process and reducing the number of reticles needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithographic processes are used, then manufacturing simplicity is maintained, but feature size and pitch are limited by physical constraints
Solution Approach 1:
The layout is divided into multiple pattern sets that can be printed separately and then combined. Each pattern set contains features that are spaced apart by jog structures, allowing each set to be printed within the pitch limitations of conventional photolithography while achieving an overall smaller effective pitch through self-aligned merging of the patterns.
Solution Approach 2:
The patent introduces jog structures that extend features in additional spatial dimensions (beyond the primary pattern direction). These jogs create overlapping regions in the layout that, when printed separately and merged, produce features with effective pitches smaller than what can be printed in a single exposure, thus overcoming the pitch limitation by utilizing dimensional overlap.
2Manufacturing precision
If multiple patterning processes are used, then smaller pitch is achieved, but manufacturing complexity increases
Solution Approach 1:
The complex pattern is segmented into multiple manageable pattern sets, each printable with conventional photolithography. The segmentation is designed so that features in different sets are spatially separated by jog structures, allowing independent printing followed by self-aligned merging, thus achieving small effective pitch without requiring complex multiple patterning processes.
Solution Approach 2:
The jog structures serve dual purposes: they provide the necessary spacing for separate pattern printing while simultaneously defining the locations where patterns will self-align and merge. This self-service functionality of the jogs eliminates the need for additional alignment steps and complex process control, simplifying the overall manufacturing process despite achieving small pitch.
3Ease of manufacture
If jog structures are introduced, then distance between features is enlarged for single exposure, but layout complexity increases
Solution Approach 1:
The jog structures are extracted as separate, dedicated geometric elements from the functional circuit features. By giving the spacing function a distinct structural form (the jogs), the functional features can be simplified while the jogs handle the complexity of providing necessary spacing and alignment information for single-exposure printing.
Solution Approach 2:
The jog structures perform multiple functions simultaneously: they provide spacing between features for single-exposure printing, define alignment references for pattern merging, and can serve as part of the functional circuit layout. This multi-functionality reduces overall layout complexity by consolidating multiple requirements into a single structural element.
Data Source
AI summary
A method of fabricating an integrated circuit includes the following steps. A first reticle is used to form a first pattern, wherein the first pattern includes a first feature and a first jog part protruding from and orthogonal to the first feature. A second reticle is used to form a second pattern, wherein the second pattern includes a second feature, and the first feature is between the second feature and the first jog part. A third reticle is used to form a third pattern, wherein the third pattern includes a third-one feature overlapping the first jog part and a third-two feature overlapping the second feature.