Superconductor Interconnect Preclean for Oxide-Free Dielectric Deposition
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Solution Overview
Problem
Existing superconducting circuit fabrication methods face issues with oxidization of conductive contacts and lines due to chemical mechanical polishing and exposure to oxygen, leading to degraded performance and inconsistent fabrication in mass production.
Innovation Solution
A plasma preclean process using nitrogen trifluoride (NF3) gas is integrated into a single dielectric deposition chamber to remove surface oxides from superconducting interconnect elements and interlayer dielectric surfaces before dielectric deposition, preventing further oxidation during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If chemical mechanical polishing (CMP) process is used to polish superconducting interconnect elements, then surface flatness is improved, but oxidization of the conductive contacts and lines occurs leading to degraded performance
Solution Approach 1:
The patent applies preliminary action by performing in-situ dielectric deposition immediately after CMP polishing while the substrate is still in the deposition chamber. This eliminates the need to transfer the substrate to another chamber, preventing oxidization of the freshly polished superconducting surfaces before they are encapsulated by the dielectric layer.
2Adaptability or versatility
If substrate is transferred between chambers for sequential processing, then process flexibility is improved, but exposure to oxygen during transfer causes oxidization
Solution Approach 1:
The patent merges the CMP polishing process and dielectric deposition process into a single chamber system. The substrate remains in the same chamber for both operations, eliminating transfers and the associated oxidization risk. The chamber is configured to perform both mechanical polishing and vapor phase dielectric deposition sequentially without substrate removal.
3Manufacturing precision
If multiple processing steps are performed in separate chambers, then each process can be optimized independently, but fabrication time and complexity increase
Solution Approach 1:
The patent implements a multi-functional chamber that can perform both CMP polishing and dielectric deposition operations. The chamber is equipped with both mechanical polishing apparatus and vapor phase deposition systems, allowing it to execute multiple processing steps that were traditionally required in separate specialized chambers.
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 method ensures a smooth, clean surface for metal interconnects and dielectric layers, enhancing the performance and consistency of superconducting circuits by eliminating oxidized layers that reduce critical current and yield, and minimizing loss tangent.
Implementation Method 1
performing a cleaning process on a top surface of the first interconnect layer in the dielectric deposition chamber to remove oxidization from a top surface of the first interconnect layer
Implementation Method 2
The CMP process and any exposure to oxygen prior to deposition of the next dielectric layer can result in oxidization of the conductive contacts and lines
Implementation Method 3
depositing a second dielectric layer over the first interconnect layer in the dielectric deposition chamber
Data Source
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AI summary
A method is provided of forming a superconductor device interconnect structure. The method comprises forming a first dielectric layer overlying a substrate and forming a superconducting interconnect element in the first dielectric layer. The superconducting interconnect element includes a top surface aligned with a top surface of the first dielectric layer to form a first interconnect layer. The superconductor device interconnect structure is moved into a dielectric deposition chamber. The method further comprises performing a cleaning process on a top surface of the first interconnect layer in the dielectric deposition chamber to remove oxidization from a top surface of the first interconnect layer, and depositing a second dielectric layer over the first interconnect layer in the dielectric deposition chamber.