Backside Power Rail Layout With Air Spacer Insulation
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Solution Overview
Problem
Existing IC devices face challenges in achieving high integration density while maintaining efficient power distribution and preventing leakage currents and shorts between power rails.
Innovation Solution
The integration of a backside power rail structure with air spacers and insulating liners in the IC device, which includes a backside power rail passing through the substrate, connected to a via power rail via an air spacer, to enhance insulation and reduce the thickness of the insulating layer, thereby increasing integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power rail structure is integrated through the substrate to enhance power distribution, then power distribution efficiency is improved, but leakage currents and shorts between power rails may occur
Solution Approach 1:
An air spacer is introduced as an intermediary insulating structure between the front surface power rail and the back surface power rail. This air spacer physically separates the two power rails and prevents direct electrical contact, thereby eliminating leakage currents and short circuits while maintaining the through-substrate power distribution architecture for efficient power delivery.
Solution Approach 2:
The power rail structure transitions from a planar configuration to a three-dimensional configuration by extending power rails through the substrate thickness. Front surface power rails and back surface power rails are positioned at different vertical levels (z-dimension), enabling efficient power distribution while the air spacer provides insulation in the vertical dimension to prevent shorts.
2Productivity
If integration density is increased to achieve miniaturization, then device capacity is improved, but insulation between power structures becomes more difficult to maintain
Solution Approach 1:
The air spacer utilizes the vertical dimension (z-axis) through the substrate to provide insulation between power rails. By positioning the air spacer in the vertical direction rather than requiring lateral separation, the design achieves high integration density in the planar direction while maintaining effective insulation in the vertical direction, thus resolving the conflict between miniaturization and insulation effectiveness.
Solution Approach 2:
The air spacer structure is replicated multiple times between adjacent power rail pairs across the substrate. This copying of the insulating structure ensures consistent insulation effectiveness throughout the high-density integrated circuit while maintaining a compact footprint.
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An integrated circuit device (100) includes: a substrate (102) having a backside surface (102B); a pair of fin-type active regions (F1) protruding from the substrate (102) and defining a trench region (T1) in the substrate (102); a pair of source/drain regions (130) disposed, one-by-one, on the pair of fin-type active regions (F1), respectively; a device isolation film (112) covering a sidewall of each of the pair of fin-type active regions (F1) and disposed in the trench region (T1); a via power rail (VPR) disposed between the pair of fin-type active regions (F1) and between the pair of source/drain regions (130), wherein the via power rail (VPR) passes through the device isolation film (112) in a vertical direction; a backside power rail (BPW) passing through the substrate (102) in the vertical direction and disposed at a position overlapping the via power rail (VPR), wherein the backside power rail (BPW) is connected to the via power rail (VPR); and an air spacer (AG1) disposed between the substrate (102) and the backside power rail (BPW).