FinFET Contact Liner Structure for Low-Resistance Isolation
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Solution Overview
Problem
The challenge of forming reliable semiconductor devices with increasingly smaller sizes is exacerbated by the complexity of fabrication processes as feature sizes continue to decrease, making it difficult to maintain device performance and reduce manufacturing costs.
Innovation Solution
A method involving the formation of gate structures, epitaxy features, and dielectric layers through advanced patterning and replacement processes, including the use of sacrificial layers, spacers, and multi-patterning techniques to create FinFETs, with a dielectric liner protecting conductive structures to prevent undesirable electrical connections and enhance contact integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency is improved and costs are lowered, but fabrication processes become more difficult to perform and device reliability deteriorates
Solution Approach 1:
The fabrication process is divided into multiple patterning steps (e.g., self-aligned double patterning, self-aligned triple patterning) where each step creates a portion of the final pattern. This segmentation allows each individual patterning step to work at relaxed dimensions while achieving ultra-fine final feature sizes, thereby maintaining reliability during fabrication.
Solution Approach 2:
Sacrificial layers are formed and precisely patterned before the actual device features are created. These preliminary structures serve as templates that guide subsequent material deposition and pattern transfer, ensuring that critical dimensions are accurately defined before the main fabrication challenges arise.
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency is improved and costs are lowered, but fabrication process complexity increases
Solution Approach 1:
Multiple patterning steps are merged through self-alignment mechanisms where structures formed in one step automatically serve as alignment references for subsequent steps. This merging of alignment functions into the patterning process itself eliminates the need for separate alignment operations, reducing overall process complexity despite multiple patterning steps.
Solution Approach 2:
The fabricated structures themselves provide the alignment and positioning information needed for subsequent fabrication steps. For example, previously formed fins or trenches serve as self-aligned masks or templates for next-step material deposition, making the structures self-servicing rather than requiring external alignment systems.
3Ease of manufacture
If conventional patterning processes are used at smaller feature sizes, then manufacturing simplicity is maintained, but manufacturing precision deteriorates
Solution Approach 1:
The patterning process transitions from two-dimensional planar patterning to three-dimensional vertical structuring with fins, trenches, and multi-layer patterns. This dimensional transition allows precision to be achieved through vertical material deposition and etching controlled by thin-film thickness rather than relying solely on lithographic resolution, thereby maintaining manufacturing simplicity while achieving superior precision.
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, a gate structure, a source/drain contact, a conductive structure, and a dielectric liner. The semiconductor substrate has a channel region and a source/drain region. The gate structure is over the channel region. The source/drain contact is over the source/drain region. The conductive structure is over a top surface of the source/drain contact. The dielectric liner surrounds the conductive structure and contacts a gate spacer disposed on a sidewall surface of the gate structure.