Bottom Via Spacer Interconnect Structure for Via Misalignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In advanced semiconductor technology, misalignments between metal lines and vias in interconnect structures become more critical as feature sizes decrease, leading to issues like shorts and reliability problems due to the limitations of current lithography processes and dual damascene techniques.
Innovation Solution
The implementation of a dielectric spacer layer formed using atomic layer deposition between the vias and conductive elements, which helps in reducing misalignment and enhancing the reliability of interconnect structures by providing additional spacing and improving the integrity of the dielectric interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dual damascene techniques are used to form interconnect structures, then manufacturing capability is maintained, but misalignment between metal lines and vias increases leading to shorts and reliability problems
Solution Approach 1:
The patent applies preliminary action by forming a spacer layer on the conductive element surfaces before forming the via holes. This spacer layer is deposited in advance to establish precise spacing relationships, ensuring that subsequent via formation maintains proper alignment with the conductive elements. The preliminary deposition of the spacer layer prevents misalignment issues that would otherwise occur during the dual damascene process.
Solution Approach 2:
The spacer layer acts as an intermediary element between the conductive elements and the via holes. This intermediate layer provides a controlled interface that mediates the spatial relationship between these components, ensuring proper alignment and preventing direct contact that could lead to shorts. The spacer layer translates the dimensional requirements into precise physical spacing.
2Area of moving object
If feature sizes are decreased to advance semiconductor technology, then device density increases, but misalignment issues and tiger tooth problems become more critical
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical parameters of the spacer layer deposition process. By controlling deposition temperature, pressure, and material composition, the process achieves precise thickness control of the spacer layer at reduced feature sizes. This parameter optimization ensures that the spacer layer maintains appropriate dimensions even as overall feature sizes decrease, preventing pattern replication errors and tiger tooth formation.
Solution Approach 2:
The patent transitions from two-dimensional planar patterning to three-dimensional spacer-based patterning. Instead of relying solely on lithographic pattern transfer in the planar domain, the solution introduces vertical dimensionality through conformal spacer deposition. This dimensional transition provides an additional degree of freedom for controlling feature dimensions and alignment, enabling precise pattern replication at smaller feature sizes.
3Device complexity
If conventional interconnect structures are used without spacers, then device complexity is reduced, but electron migration and time-dependent dielectric breakdown risk increase
Solution Approach 1:
The spacer layer serves as a protective intermediary between adjacent conductive elements and between conductive elements and via holes. This intermediate barrier prevents direct electrical contact that could lead to electron migration and dielectric breakdown. The spacer material acts as a physical mediator that isolates conductive components, reducing electromagnetic field interactions and preventing harmful current paths while maintaining structural integrity.
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 effectively addresses the misalignment and 'tiger tooth' issues, enhancing the reliability of interconnects and reducing the risk of electron migration and time-dependent dielectric breakdown, while allowing for more precise pattern replication and improved device performance.
Implementation Method 1
A dielectric spacer layer is conformally formed using atomic layer deposition
Data Source
AI summary
A method includes providing a semiconductor structure including a dielectric layer having an opening exposing a top surface of a metal layer. A bottom via is selectively deposited in the opening and over the metal layer. A barrier layer is deposited over the bottom via and in contact with the dielectric layer at a sidewall of the opening. A top via is formed in the opening, in contact with the barrier layer, and over the bottom via. The top via is separated from the dielectric layer by the barrier layer.