Semiconductor Wiring Air Gaps Preventing Collapse and RC Delay
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Solution Overview
Problem
The increasing demand for high-speed and low-power semiconductor devices with high integration leads to reliability concerns, as existing technologies struggle to maintain device integrity and prevent issues like wire collapse and RC delay.
Innovation Solution
A semiconductor device fabrication method involving a sacrificial layer, insulating layers, and spacer formation to create air gaps between wiring structures, using materials like silicon carbon nitride and tungsten, which enhances reliability by preventing wire collapse and reducing RC delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wiring structures are formed in highly integrated semiconductor devices, then device functionality is improved, but wire collapse and RC delay occur reducing reliability
Solution Approach 1:
The patent segments the continuous wiring structure by introducing air gaps at regular intervals along the wiring. This divides the long continuous wire into shorter segments, reducing the overall RC delay by breaking up the resistive path and reducing capacitance accumulation. The air gaps act as insulating barriers that prevent charge accumulation and reduce electromagnetic interference between adjacent wiring segments.
Solution Approach 2:
The patent introduces an intermediary material (air gap filled with low-k dielectric material) between adjacent wiring structures and between the wiring and substrate. This intermediary layer reduces parasitic capacitance and prevents direct electrical interaction that would cause RC delay. The low-k material serves as a mediator that maintains electrical isolation while allowing mechanical support.
2Reliability
If sacrificial layers are used for air gap formation, then wire collapse is prevented improving reliability, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming sacrificial layers (first and second sacrificial layers with different etch selectivities) before the final wiring structure is complete. These sacrificial layers are strategically positioned to provide mechanical support during subsequent processing steps. The first sacrificial layer is formed earlier in the process to establish initial support, while the second sacrificial layer is added later to provide additional support during spacer formation and wiring deposition.
Solution Approach 2:
The sacrificial layers serve as temporary intermediary structures that facilitate the formation of the final wiring structure. They act as placeholders and mechanical supports during the manufacturing process, enabling the formation of air gaps and spacers without causing wire collapse. After serving their protective function, these intermediary layers are selectively removed through etching to create the desired air gap structure.
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
The method achieves high reliability by preventing wire collapse and reducing RC delay, optimizing semiconductor device integrity through the use of air gaps and specific material combinations.
Implementation Method 1
vaporizing the first sacrificial patterns
Implementation Method 2
the vaporizing of the first sacrificial patterns comprises vaporizing using heat energy or optical energy
Data Source
AI summary
In a method of fabricating a semiconductor device, a first sacrificial layer, a first insulating layer, and a second sacrificial layer are successively provided on a substrate. The second sacrificial layer, the first insulating layer, and the first sacrificial layer are patterned to define an opening exposing a portion of the substrate and successively forming second sacrificial patterns, capping patterns, and first sacrificial patterns on the substrate. A second insulating layer is conformally formed at inner sidewalls and a bottom of the opening. The second insulating layer and the second sacrificial patterns are etched to form spacers on sidewalls of the first sacrificial patterns and to remove the second sacrificial patterns. A wiring pattern is provided to fill the opening in which the spacers are formed. The first sacrificial patterns are then vaporized.