Backside Power Network Structure With Self-Aligned Power Contacts
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Solution Overview
Problem
Existing integrated circuit devices face challenges in increasing integration density and simplifying the middle-of-line (MOL) and back-end-of-line (BEOL) portions of device fabrication, particularly in forming a backside power distribution network (BSPDN) structure.
Innovation Solution
A method of forming an integrated circuit device that includes self-aligned power contacts with a backside insulator, where the power contact is aligned with the source/drain region without the need for a placeholder, and a BSPDN structure is formed on the power contact, simplifying the MOL and BEOL portions of fabrication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional placeholder methods are used for power contact alignment, then alignment can be achieved, but device complexity and fabrication steps increase
Solution Approach 1:
The source/drain region itself serves as the alignment reference for the power contact, eliminating the need for external placeholder structures. The power contact is self-aligned to the source/drain region through the formation sequence, where the source/drain region is formed first and then used as the reference for subsequent power contact formation.
Solution Approach 2:
The source/drain region is formed in advance before the power contact, creating a pre-established reference structure that guides the subsequent power contact formation. This preliminary formation of the source/drain region enables automatic alignment without requiring additional placeholder structures.
2Quantity of substance
If more fabrication steps are added for BSPDN formation, then integration density can be enhanced, but manufacturing time and complexity increase
Solution Approach 1:
The power contact formation process is merged with the source/drain region formation process, where both structures are created in a coordinated sequence using shared process steps. This merging eliminates the need for separate placeholder formation and removal steps, reducing overall fabrication time while achieving precise alignment.
Solution Approach 2:
The unnecessary placeholder structure is extracted and removed from the fabrication process entirely. By eliminating this intermediate structure that serves no functional purpose, the process steps associated with placeholder formation, alignment, and removal are also eliminated, improving manufacturing efficiency.
3Manufacturing precision
If placeholder structures are used for power contact alignment, then alignment precision can be maintained, but material waste and process steps increase
Solution Approach 1:
The source/drain region serves its dual function as both the electrical connection element and the alignment reference for the power contact. This self-service approach eliminates the need for separate placeholder materials, preventing material waste while maintaining precise alignment.
Solution Approach 2:
The placeholder structure, which would be formed and then discarded, is completely eliminated from the process. By using the functional source/drain region as the reference instead, no sacrificial or placeholder materials are consumed and subsequently discarded, reducing material waste.
Data Source
AI summary
Integrated circuit devices and methods of forming the same are provided. The methods may include providing a substrate structure including a substrate, a bottom insulator and a semiconductor region between the substrate and the bottom insulator, the semiconductor region extending in a first direction; forming first and second preliminary transistor structures on the bottom insulator, wherein and the bottom insulator may include first and second portions that the first and second preliminary transistor structures respectively overlap, and a third portion between the first and second portions; replacing the third portion of the bottom insulator with a bottom semiconductor layer; forming a source/drain region between the first and second preliminary transistor structures; replacing the substrate and the semiconductor region with a backside insulator; forming a power contact in the backside insulator, wherein the source/drain region may overlap the power contact; and forming a power rail.