Air Spacer Protection Ring Layout to Prevent Barrier Layer Oxidation
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Solution Overview
Problem
In the formation of air spacers in integrated circuit devices, existing methods fail to effectively prevent oxidation and damage to the bottom portions of barrier layers, leading to increased resistance and degradation in circuit performance due to the exposure of these layers to chemicals during the removal of sacrificial and protection layers.
Innovation Solution
A method involving the deposition of a sacrificial layer followed by an anisotropic etching process to form a sacrificial ring, followed by the deposition and anisotropic etching of a protection layer to form a protection ring that physically contacts the underlying feature, preventing oxidation of the barrier layer when the sacrificial ring is removed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sacrificial and protection layers are etched together in a single process, then the process complexity is reduced, but the protection layer cannot effectively prevent oxidation of the barrier layer bottom portion
Solution Approach 1:
The patent divides the etching process into two separate steps: first etching the sacrificial layer to form a sacrificial ring, then etching the protection layer to form a protection ring. This segmentation allows each layer to be processed independently, ensuring the protection ring can effectively shield the barrier layer bottom portion from oxidation while maintaining manageable process complexity through systematic sequencing.
Solution Approach 2:
The sacrificial layer is etched first to create the sacrificial ring structure before the protection layer is etched. This preliminary action establishes the foundational structure that enables the subsequent protection layer etching to properly position the protection ring for effective oxidation prevention of the barrier layer.
2Quantity of substance
If air spacers are formed by removing dielectric material and re-depositing, then the k value is reduced to 1.0, but the barrier layer bottom portion is exposed to chemicals causing oxidation
Solution Approach 1:
The protection ring acts as an intermediary barrier between the chemicals used in the air spacer formation process and the barrier layer bottom portion. By depositing the protection layer conformally and etching it to form a protection ring that physically contacts the barrier layer, the patent creates a protective mediator that prevents direct chemical exposure while allowing the air spacer formation to proceed.
Solution Approach 2:
The protection layer is deposited and etched to form the protection ring before the sacrificial ring removal step that creates the air spacer. This preliminary anti-action establishes the protective barrier in advance, preventing the oxidation damage that would otherwise occur during the subsequent sacrificial ring removal and air spacer formation processes.
3Manufacturing precision
If the protection layer is etched after the sacrificial layer, then the protection ring can form properly, but the barrier layer bottom portion is exposed to oxidation during sacrificial ring removal
Solution Approach 1:
The protection ring serves as a protective intermediary that remains in place during the sacrificial ring removal process. By maintaining the protection layer structure throughout the sacrificial ring etching and removal steps, the patent ensures the barrier layer bottom portion is shielded from oxidation even though the protection layer was etched after the sacrificial layer.
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 reduces parasitic capacitance between conductive features and prevents oxidation of the barrier layer, enhancing the performance and reliability of the integrated circuit devices by ensuring the protection ring fully encircles the conductive features, thereby protecting them from chemical damage.
Implementation Method 1
performing a first anisotropic etching process to etch the sacrificial spacer layer, wherein a first bottom portion of the sacrificial spacer layer at a bottom of the opening is removed
Implementation Method 2
depositing a sacrificial spacer layer extending into the opening
Data Source
AI summary
A structure includes a first conductive feature, a first etch stop layer over the first conductive feature, a dielectric layer over the first etch stop layer, and a second conductive feature in the dielectric layer and the first etch stop layer. The second conductive feature is over and contacting the first conductive feature. An air spacer encircles the second conductive feature, and sidewalls of the second conductive feature are exposed to the air spacer. A protection ring further encircles the second conductive feature, and the protection ring fully separates the second conductive feature from the air spacer.