CPODE Air-Gap Structure for Lower Parasitic Capacitance
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Solution Overview
Problem
As integrated circuit technologies progress towards smaller technology nodes, parasitic capacitance between active device regions becomes a significant issue, leading to lower device speed due to increased RC delays, and existing methods for reducing parasitic capacitance are not entirely satisfactory.
Innovation Solution
The method involves forming a Continuous Poly on Diffusion Edge (CPODE) structure with lowered dielectric constants by replacing dummy gate stacks with a dielectric structure and introducing an air gap, which reduces parasitic capacitance between active device regions, thereby improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If separation distance between active device regions is reduced to meet design requirements of smaller technology nodes, then functional density increases, but parasitic capacitance increases leading to lower device speed
Solution Approach 1:
A dielectric structure with lowered dielectric constant is introduced as an intermediary between active device regions. This mediator reduces the parasitic capacitance formed between closely spaced device regions, enabling high functional density while maintaining acceptable device speed performance.
Solution Approach 2:
The dielectric constant parameter of the material between active device regions is changed from a higher value to a lowered value. This parameter change directly reduces parasitic capacitance (C = εA/d), allowing devices to operate at higher speeds even when separation distances are reduced for increased functional density.
2Ease of manufacture
If conventional dielectric materials are used between active device regions, then manufacturing is simpler, but parasitic capacitance is high reducing device performance
Solution Approach 1:
The dielectric constant parameter is changed by selecting materials with inherently lower dielectric constants or by modifying existing dielectric materials. This parameter change reduces parasitic capacitance and improves device performance while remaining compatible with existing manufacturing processes.
Solution Approach 2:
Composite dielectric structures are employed, combining multiple materials with different properties. These composite materials achieve lowered effective dielectric constants while maintaining manufacturability through established deposition and processing techniques.
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 reduces parasitic capacitance, enhancing the processing speed and overall performance of semiconductor devices by incorporating a CPODE structure with an air gap, specifically designed for advanced technology nodes.
Implementation Method 1
parasitic capacitance of dielectric components disposed between active device regions may have serious bearings on the overall performance of an IC device
Implementation Method 2
CPODE structure with lowered dielectric constants
Data Source
AI summary
A semiconductor structure includes semiconductor layers disposed over a substrate and oriented lengthwise in a first direction, a metal gate stack disposed over the semiconductor layers and oriented lengthwise in a second direction perpendicular to the first direction, where the metal gate stack includes a top portion and a bottom portion that is interleaved with the semiconductor layers, source/drain features disposed in the semiconductor layers and adjacent to the metal gate stack, and an isolation structure protruding from the substrate, where the isolation structure is oriented lengthwise along the second direction and spaced from the metal gate stack along the first direction, and where the isolation structure includes a dielectric layer and an air gap.