Semiconductor Device Structure with Dielectric Gaps for RC Delay Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices become smaller and more complex, the challenge of forming reliable devices at increasingly smaller sizes complicates the fabrication process, particularly due to increased resistance-capacitance (RC) delay in circuit performance.
Innovation Solution
The method involves forming a dielectric layer with varying dielectric constants and carbon concentrations, modifying specific portions to change these properties, and using etching processes to create gaps between conductive features, which reduces parasitic capacitance and RC delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple distinct stages: forming openings in the dielectric layer, depositing conductive material, removing portions of the dielectric layer, and filling gaps with additional conductive material. This segmentation allows each step to be optimized independently, managing the overall process complexity while achieving continued scaling
Solution Approach 2:
Portions of the dielectric layer are removed before final conductive feature formation, creating gaps that simplify subsequent material deposition. This preliminary action reduces the complexity of forming tightly spaced conductive features by pre-establishing the spatial relationships and reducing parasitic interactions
2Productivity
If feature sizes continue to decrease, then functional density increases, but RC delay increases and device reliability decreases
Solution Approach 1:
Portions of the dielectric layer are selectively removed to create gaps between conductive features. This extraction eliminates the parasitic capacitance that would otherwise exist between closely spaced conductive elements, directly addressing the RC delay issue while maintaining high functional density
Solution Approach 2:
The dielectric layer has different properties in different regions: intact dielectric material provides mechanical support and insulation, while removed portions create low-capacitance gaps. This local differentiation optimizes both electrical performance (reduced RC delay) and structural integrity
3Reliability
If gaps are created between conductive features to reduce parasitic capacitance, then RC delay decreases, but mechanical strength of the dielectric layer may be compromised
Solution Approach 1:
The dielectric layer maintains its full thickness and mechanical strength in regions where gaps are not created, while only local portions are removed to form gaps between specific conductive features. This localized modification preserves overall structural integrity while achieving the electrical performance benefits of reduced parasitic capacitance
Solution Approach 2:
The dielectric layer is effectively segmented into intact regions (providing mechanical strength) and gap regions (providing electrical isolation). This segmentation allows the structure to simultaneously satisfy mechanical strength requirements and electrical performance requirements
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 mitigates RC delay and enhances device performance and reliability by creating controlled gaps that support conductive features while maintaining mechanical strength of the dielectric layer.
Implementation Method 1
removing portions of the first and second portions by performing an etching process
Implementation Method 2
modifying portions of the dielectric layer to change the dielectric constant and carbon concentration of the portions
Data Source
AI summary
Structures and formation methods of a semiconductor device structure are provided. The semiconductor device structure includes a dielectric layer over a semiconductor substrate. The semiconductor device structure also includes a first conductive feature in the dielectric layer. A portion of the dielectric layer has a top surface that is provided on a different level in relation to a top surface of the first conductive feature. The semiconductor device structure further includes a second conductive feature in the dielectric layer and extending from a bottom surface of the first conductive feature. The portion of the dielectric layer is separated from the second conductive feature by a gap. A distance between the portion of the dielectric layer and the second conductive feature becomes smaller along a direction from the top surface of the first conductive feature towards the bottom surface of the first conductive feature.