Semiconductor Device Air Spacer Stability and Contact Resistance
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Solution Overview
Problem
In high-integration semiconductor devices, the proximity of interconnection lines and contact plugs leads to increased load capacitance, contact resistance, and defects, and the anisotropic etching process often fails to form a stable air spacer due to exposure of sacrificial layers.
Innovation Solution
The semiconductor device incorporates a structure with conductive patterns and insulating films where the first insulating film protrudes towards the air spacer, and the conductive pattern extends into the substrate to contact active regions, reducing contact resistance and stabilizing the air spacer formation by protecting the sacrificial layer during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If interconnection lines and contact plugs are placed closer to increase integration density, then device integration is improved, but load capacitance increases
Solution Approach 1:
An air spacer is introduced as an intermediary structure between the interconnection line and contact plug. This air spacer acts as a mediator that provides electrical isolation and reduces parasitic capacitance coupling between adjacent conductive elements, thereby reducing load capacitance while allowing closer placement for higher integration density
Solution Approach 2:
The air spacer creates a localized region with different dielectric properties (air instead of solid insulator) between specific conductive elements. This local modification of dielectric quality reduces capacitance in critical areas where interconnection lines and contact plugs are in close proximity, without affecting other parts of the device
2Ease of manufacture
If conventional anisotropic etching is used to form air spacers, then manufacturing simplicity is maintained, but air spacer stability deteriorates due to sacrificial layer exposure
Solution Approach 1:
The protruding portion of the insulating film is formed in advance before the air spacer formation process. This preliminary structural preparation ensures that the sacrificial layer remains covered and protected during subsequent anisotropic etching operations, preventing exposure and maintaining air spacer stability throughout the manufacturing process
Solution Approach 2:
The protruding insulating film structure serves as a protective cushion or barrier that prevents the sacrificial layer from being exposed during etching. This beforehand protection measures anticipates and prevents potential failures in air spacer formation, ensuring process robustness without complicating manufacturing
3Reliability
If contact resistance is reduced by extending conductive patterns into the substrate, then contact performance is improved, but device complexity increases
Solution Approach 1:
The conductive pattern is extended from a planar (2D) configuration into the vertical dimension (3D) by extending it downward into the substrate. This dimensional transition allows the conductive pattern to reach and contact the active region at a deeper level, reducing contact resistance while the extension follows a straightforward vertical path that minimizes structural complexity
Data Source
AI summary
A semiconductor device includes a substrate having a plurality of active regions defined by a device isolation region, a plurality of conductive patterns on the plurality of active regions, each of the conductive patterns having side walls, a conductive line that faces the side walls of the conductive patterns with an air spacer therebetween on the active regions, the conductive line extending in a first direction, and a first insulating film covering the side walls of the conductive patterns between the air spacer and the conductive pattern. A lower portion of the first insulating film that is near the substrate protrudes toward the air spacer.