Semiconductor Spacer With Air Gap Reduces Parasitic Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor devices become highly integrated, the reduced space between patterns and contact plugs leads to increased parasitic capacitance, which deteriorates performance by reducing operating speed.
Innovation Solution
Incorporating an air gap between the line pattern and the spacer, and a metal silicide layer in the contact plug, with a spacer structure having a first portion and a second portion with different lateral surface roughness, and a metal-containing pattern to reduce parasitic capacitance and prevent open fails during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the space between patterns and contact plugs is reduced to achieve high integration, then integration density is improved, but parasitic capacitance increases causing performance deterioration
Solution Approach 1:
An air gap is introduced as an intermediary element between the line pattern and contact plug. This air gap acts as a mediator that reduces parasitic capacitance while maintaining the reduced physical spacing required for high integration density. The air gap serves as a dielectric intermediary that optimizes the electrical characteristics without compromising the compact layout.
Solution Approach 2:
The dielectric constant parameter is changed by introducing an air gap (which has a lower dielectric constant than solid materials) between the line pattern and contact plug. This parameter change reduces parasitic capacitance while maintaining the physical proximity needed for high integration, thereby resolving the contradiction between integration density and performance.
2Productivity
If the space between patterns and contact plugs is reduced to achieve high integration, then integration density is improved, but manufacturing failures such as open fails increase
Solution Approach 1:
The air gap serves as a manufacturing buffer zone that provides a margin of error during fabrication processes. By introducing this intermediary space, the structure becomes more tolerant to variations in etching depth, deposition uniformity, and other manufacturing parameters, thereby reducing open fails while maintaining high integration density.
Solution Approach 2:
The air gap is designed in advance as a cushioning space that compensates for potential manufacturing variations. This pre-planned buffer zone prevents open fails by ensuring that even if manufacturing dimensions vary within acceptable tolerances, the electrical connection remains intact, thus improving manufacturing reliability without sacrificing integration density.
3Ease of manufacture
If a uniform spacer structure is used, then manufacturing simplicity is maintained, but parasitic capacitance reduction effectiveness is limited
Solution Approach 1:
The spacer structure transitions from uniform to non-uniform, with different thicknesses at different locations. The first spacer portion has a greater thickness than the second spacer portion, creating local quality variations that optimize parasitic capacitance reduction in critical areas while maintaining manufacturability through a relatively simple two-region design.
Solution Approach 2:
The spacer is designed with asymmetric thickness distribution, where the first portion has a greater thickness than the second portion. This asymmetric design optimizes the parasitic capacitance reduction by providing enhanced insulation where needed most, while still maintaining a relatively simple manufacturing process that can accommodate the asymmetric geometry.
Data Source
AI summary
A spacer covering a sidewall of a contact plug includes a relatively more damaged first portion and a relatively less damaged second portion. An interface of the first and second portions of the spacer is spaced apart from a metal silicide layer of the contact plug. Thus reliability of the semiconductor device may be improved. Related fabrication methods are also described.