Backside Power Network Contacts for Dense IC Power Rail Integration
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Solution Overview
Problem
Current integrated circuit device fabrication methods for backside power distribution networks (BSPDN) face challenges in increasing integration density and simplifying the middle-of-line (MOL) and back-end-of-line (BEOL) portions, particularly in forming efficient power contacts and rails that effectively connect source/drain regions and power rails.
Innovation Solution
A method involving the formation of a sacrificial layer in a substrate, followed by replacing it with a power contact that contacts the source/drain region and forming a power rail that connects to the power contact, thereby simplifying the fabrication process and enhancing integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional front-side power distribution networks are used, then power delivery is achieved, but integration density is limited and MOL/BEOL fabrication complexity increases
Solution Approach 1:
The patent moves the power distribution network from the traditional front-side (planar dimension) to the backside of the substrate, utilizing the third dimension (vertical stacking). This allows power rails and contacts to be formed on the backside of the substrate, enabling simultaneous formation with transistor structures on the front-side, thereby simplifying MOL/BEOL processes and increasing integration density.
Solution Approach 2:
The power distribution network is segmented into distinct components: backside power rails, power contacts connecting to source/drain regions, and embedded power regions. This segmentation allows each component to be optimized independently and formed through specialized processes, reducing overall fabrication complexity while maintaining high integration density.
2Reliability
If power contacts are formed to connect source/drain regions and power rails, then electrical connectivity is achieved, but fabrication process complexity increases
Solution Approach 1:
Sacrificial layers are formed in advance at the interfaces where power contacts will eventually connect to source/drain regions. These sacrificial layers are strategically positioned and then replaced with conductive material to form the power contacts. This preliminary action simplifies the overall fabrication process by pre-establishing connection pathways before final power rail formation.
Solution Approach 2:
Sacrificial layers serve as intermediary structures during fabrication. These temporary structures are formed, processed, and then replaced with the final power contact material. The intermediary sacrificial layers enable precise positioning and formation of power contacts without directly complicating the final structure, as they are removed and replaced in the process.
3Area of stationary object
If source/drain regions are positioned close to power contacts, then area is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The sacrificial layers are formed self-aligned with the source/drain regions, meaning their positions are automatically determined by the source/drain region geometry rather than requiring separate alignment steps. This self-service approach ensures precise positioning of power contacts relative to source/drain regions without increasing manufacturing precision requirements, as the alignment is inherent to the process sequence.
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 allows for improved electrical connectivity between source/drain regions and power rails, enhancing the integration density and simplifying the fabrication process for integrated circuit devices with BSPDN structures.
Implementation Method 1
forming a sacrificial layer in a preliminary substrate by adding an element into the preliminary substrate
Data Source
AI summary
Integrated circuit devices and methods of forming the same are provided. The methods may include forming a sacrificial layer in a preliminary substrate by adding an element into the preliminary substrate, forming a transistor structure on the preliminary substrate, the transistor structure including a source/drain region, replacing the sacrificial layer with a power contact that comprises an upper surface contacting the source/drain region, and forming a power rail that contacts a lower surface of the power contact.