Conductive Line Tip Definition Using a Dielectric Cut-First Plug
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Solution Overview
Problem
As line pitch decreases in integrated chip fabrication, controlling the placement of line tips becomes challenging, leading to increased risks of shorts and dielectric damage during the formation of conductive interconnects.
Innovation Solution
A method involving the formation of a dielectric plug before trench etching, using a selective anisotropic etch to create end-to-end trenches, which reduces the risk of shorts and dielectric damage by providing well-defined tip locations and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional trench etching is used to form conductive lines, then manufacturing simplicity is maintained, but control over line tip placement deteriorates and short risk increases
Solution Approach 1:
The patent applies preliminary action by forming the dielectric plug in the cut region before performing the trench etching process. This pre-positioned plug serves as a template that defines where the trench should stop, ensuring precise line tip placement is achieved before the actual conductive line formation begins. The plug is formed at an earlier stage to guide subsequent processing steps.
Solution Approach 2:
The dielectric plug acts as an intermediary element between the trench etching process and the desired line tip placement. By introducing this intermediate structure, the patent enables precise control over where trenches terminate without requiring direct control mechanisms during the etching process itself. The plug mediates the interaction between the etch process and the final line geometry.
2Productivity
If line pitch is decreased to increase density, then productivity is improved, but control over line tip placement deteriorates and short risk increases
Solution Approach 1:
The patent applies segmentation by dividing the continuous dielectric layer into discrete regions using the dielectric plug. This segmentation creates clearly defined boundaries for trench formation, allowing precise control over line tip placement even when lines are closely spaced. The plug segments the etching process into controlled regions, preventing unwanted interactions between adjacent lines.
Solution Approach 2:
By pre-forming the dielectric plug before trench etching, the patent establishes predetermined stop points for the etch process. This preliminary action ensures that even at reduced pitch, the line tips will be precisely positioned where intended, maintaining manufacturing precision despite increased density requirements.
3Productivity
If aggressive etching is used to maintain productivity, then manufacturing speed is maintained, but dielectric damage increases
Solution Approach 1:
The patent applies preliminary anti-action by using the dielectric plug to pre-defin e the trench boundaries before etching begins. This allows the use of aggressive etching conditions to maintain productivity, while the plug prevents over-etching and subsequent dielectric damage. The plug acts in advance to counteract the potential harmful effects of aggressive etching.
Solution Approach 2:
The dielectric plug serves as an intermediary that protects the surrounding dielectric material from damage during aggressive etching. By introducing this intermediate structure, the patent enables faster etching rates while the plug absorbs or prevents the harmful effects from reaching the main dielectric layer, maintaining both productivity and material 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 enhances control over line tip placement, reduces the risk of shorts, and maintains the low dielectric constant of the material, thereby improving the reliability and performance of conductive interconnects in integrated chips.
Implementation Method 1
Material from the first dielectric layer in the trench regions is etched away, using a selective anisotropic etch that leaves the second dielectric plug in place, to form trenches in the first dielectric layer
Data Source
AI summary
Semiconductor devices and methods of forming conductive lines in the same include forming a cut region in a first dielectric layer, the cut region having a first width. A second dielectric plug is formed in the cut region. A mask is formed, over the first dielectric layer, that defines at least one trench region that crosses the second dielectric plug, with the at least one trench region having a second width that is smaller than the first width. Material from the first dielectric layer in the trench regions is etched away, using a selective anisotropic etch that leaves the second dielectric plug in place, to form trenches in the first dielectric layer. Conductive material is deposited in the trenches to form conductive lines that are separated by the second dielectric plug.