Interconnection Structure Patterning for Hybrid-Height Metal Lines
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Solution Overview
Problem
Current direct metal etch approaches are unable to efficiently and reliably form interconnection levels with hybrid-height metal lines, where metal lines of different heights need to be combined in the same interconnection level.
Innovation Solution
A method involving the formation of multiple dielectric and metal layers, followed by planarization and masking, allows for the etching of metal features of varying heights by using a mask pattern to transfer different sub-patterns into the metal layers, resulting in hybrid-height metal features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If direct metal etch approaches are used, then manufacturing simplicity is improved, but the ability to form hybrid-height metal lines deteriorates
Solution Approach 1:
The patent segments the metal layer formation process into multiple sequential steps: forming a first metal layer pattern, then forming a second metal layer pattern on top of it. This segmentation allows different portions of the metal interconnection structure to be formed at different heights, enabling hybrid-height metal lines while maintaining a systematic and manufacturable process approach.
Solution Approach 2:
The patent introduces vertical dimensionality by forming metal layers at different heights (first metal layer pattern at a lower height, second metal layer pattern at a higher height). This multi-level vertical arrangement enables the formation of hybrid-height metal lines, transforming a two-dimensional planar etching process into a three-dimensional structured process.
2Adaptability or versatility
If multiple metal layers are formed sequentially, then hybrid-height metal features are enabled, but process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the first metal layer pattern and its associated dielectric layer pattern before forming the second metal layer pattern. This sequential preliminary preparation ensures that each metal layer is properly supported and isolated, reducing defects and rework while enabling the complex hybrid-height structure through systematic step-by-step construction.
3Adaptability or versatility
If mask patterns with multiple sub-patterns are used, then different metal feature heights are achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies local quality by using a mask pattern with different sub-patterns (first sub-pattern, second sub-pattern, third sub-pattern) that are selectively positioned over different regions of the metal layers. Each sub-pattern transfers a specific pattern into the underlying metal at a specific height, allowing precise local control over metal feature heights while managing overall manufacturing precision through region-specific patterning.
Data Source
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AI summary
The disclosure relates to a method for forming an interconnection structure, comprising: forming a first dielectric layer pattern over a substrate; covering the first dielectric layer pattern with metal and planarizing the metal to expose an upper surface of the first dielectric layer pattern and form a first metal layer pattern; forming a second dielectric layer pattern over the first dielectric layer pattern and the first metal layer pattern; covering the second dielectric layer pattern with metal and planarizing the metal to expose an upper surface of the second dielectric layer pattern and form a second metal layer pattern; forming a mask pattern of a mask material over the second dielectric layer pattern and the second metal layer pattern; and in an etching process comprising using the mask pattern as an etch mask, transferring: a first, second and third sub-pattern of the mask pattern into a first portion of the first metal layer pattern to form a set of lower metal features, a second sub-pattern of the mask pattern into a first portion of the second metal layer pattern and a second portion of the first metal layer pattern to form a set of stacked metal features, and a third sub-pattern of the mask pattern into a second portion of the second metal layer pattern to form a set of upper metal features.