Alternating Mandrel Lines for Tight-Pitch Interconnection Structures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional circuit fabrication methods face challenges in forming tight-pitch conductive lines due to edge placement errors and the complexity of patterning techniques, making it difficult to achieve precise and reliable line cuts without affecting adjacent lines.
Innovation Solution
A method involving the formation of alternating patterns of mandrel lines made from different materials, which are used as etch masks to selectively cut and pattern conductive lines directly in the conductive layer, reducing sensitivity to edge placement errors and eliminating the need for tone inversion techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dual damascene process with trench blocking techniques is used to form cut conductive lines, then conductive lines can be formed in insulating layers, but edge placement errors increase and manufacturing precision deteriorates when forming tight-pitch patterns
Solution Approach 1:
The patent segments the mandrel lines into two distinct sets: first mandrel lines (continuous) and second mandrel lines (interrupted with gaps). This segmentation allows selective etching of different line types through material differentiation, enabling precise control over which lines are cut and which remain continuous, thereby improving manufacturing precision for tight-pitch patterns
Solution Approach 2:
Different materials are assigned to different mandrel lines based on their desired final state. First mandrel lines use a first material that is etched selectively, while second mandrel lines use a second material that is resistant to the same etch. This local quality differentiation enables reliable and precise pattern formation by tailoring each line's etch response to its functional requirements
2Manufacturing precision
If multiple patterning techniques like SADP are used to achieve sub-lithographic critical dimensions, then tighter line pitches can be formed, but device complexity and process difficulty increase significantly
Solution Approach 1:
The patent performs preliminary patterning actions by forming mandrel lines with predetermined continuity characteristics before the final conductive line formation. The first mandrel lines are intentionally made continuous while second mandrel lines are made interrupted, allowing the etch process to automatically produce the desired line cut patterns without requiring complex multi-step patterning techniques
Solution Approach 2:
The patent changes the material parameter of mandrel lines to control etch selectivity. By assigning different materials (with different etch resistance properties) to different mandrel lines, the process achieves precise pattern control through material property differentiation rather than through complex geometric patterning steps
3Manufacturing precision
If tone inversion techniques are used to form precise line cuts, then manufacturing precision improves, but process time and productivity decrease
Solution Approach 1:
The mandrel lines are designed to be self-descriptive of their final state: continuous mandrel lines naturally produce continuous conductive lines, while interrupted mandrel lines with gaps automatically produce cut conductive lines. This self-service approach eliminates the need for tone inversion techniques and associated process steps, thereby improving productivity while maintaining precision
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 formation of tight-pitch conductive line patterns with improved precision and reliability, reducing the complexity of the patterning process and enhancing the yield by directly printing conductive lines in the conductive layer.
Implementation Method 1
cutting at least a first mandrel line of the second set of mandrel lines into two line segments separated by a gap by etching said first mandrel line of the second set of mandrel lines selectively to the set of spacer lines and the first set of mandrel lines
Data Source
AI summary
A method for forming an interconnection structure for a semiconductor device is provided. The method includes: (i) forming a conductive layer on an insulating layer; (ii) forming above the conductive layer a first set of mandrel lines of a first material; (iii) forming a set of spacer lines of a second material different from the first material, wherein the spacer lines of the second material are formed on sidewalls of the first set of mandrel lines; (iv) forming a second set of mandrel lines of a third material different from the first and second materials, wherein the second set of mandrel lines fill gaps between spacer lines of the set of spacer lines; (v) cutting at least a first mandrel line of the second set of mandrel lines into two line segments separated by a gap by etching said first mandrel line of the second set of mandrel lines selectively to the set of spacer lines and the first set of mandrel lines, cutting at least a first mandrel line of the first set of mandrel lines into two line segments separated by a gap by etching said first mandrel line of the first set of mandrel lines selectively to the set of spacer lines and the second set of mandrel lines; (vi) removing the set of spacer lines, selectively to the first and second sets of mandrel lines, thereby forming an alternating pattern of mandrel lines of the first set of mandrel lines and mandrel lines of the second set of mandrel lines; and (vii) patterning the conductive layer to form a set of conductive lines, wherein the patterning comprises etching while using the alternating pattern of mandrel lines of the first and second sets of mandrel lines as an etch mask.