T-Shaped Single Diffusion Barrier via Single-Mask Process
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current T-shaped single diffusion break (SDB) designs for fin-type field effect transistor (FinFET) devices face defects due to leakage paths and require costly additional masks and process steps, particularly with the use of shallow trench isolation (STI) layers and multiple masks in the process flow.
Innovation Solution
A single-mask process flow is implemented to form a T-shaped SDB, involving the creation of silicon substrate regions, hard mask layers, recesses, spacers, and oxide filling to form a T-shaped STI region, with specific etching and masking steps using reticles and negative tone developers to reduce complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a standard STI layer is used at the same height as other structure locations, then the process is simple, but leakage paths occur between fins causing defects
Solution Approach 1:
The patent applies local quality by creating a T-shaped SDB structure with different heights and shapes at specific locations between fins, while maintaining standard STI at other locations. The T-shaped SDB extends deeper into the substrate locally to block leakage paths, while the rest of the STI structure remains uniform and simple to manufacture.
2Manufacturing precision
If two masks are used to form a T-shaped SDB with higher oxide STI under the SDB, then the SDB structure is achieved, but the process cost increases
Solution Approach 1:
The patent merges the formation of the T-shaped SDB structure into a single etching process step. By using a specifically designed mask pattern and etching conditions, the complex T-shaped structure is created in one step rather than requiring separate deposition and etching steps with multiple masks, thereby reducing process complexity while maintaining manufacturing precision.
3Manufacturing precision
If additional oxide deposition and etch process steps are used, then the T-shaped SDB is formed, but the process flow becomes costly and complex
Solution Approach 1:
The patent uses preliminary action by forming a mandrel structure before the final SDB formation. This mandrel serves as a template that guides the single etching step to create the precise T-shaped profile. The preliminary mandrel formation simplifies the subsequent etching process, eliminating the need for multiple deposition and etching steps, thereby improving productivity while maintaining manufacturing precision.
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 reduces defects and costs by simplifying the process flow to a single-mask method, enhancing the formation of T-shaped SDBs while maintaining high aspect ratio and precision in FinFET devices.
Implementation Method 1
forming a recess in the silicon substrate through the opening
Implementation Method 2
filling the trench and the recess with an oxide layer, forming a T-shaped third STI region
Implementation Method 3
removing the spacers; removing the first hard mask layer
Data Source
AI summary
Methods of forming a T-shaped SBD using a single-mask process flow are disclosed. Embodiments include providing a substrate having STI regions; forming a hard mask layer over the substrate and the STI regions, the hard mask having an opening laterally separated from the STI regions; forming a recess in the substrate through the opening, the recess having a first width; forming spacers on sidewalls of the recess, with a gap therebetween; forming a trench in the substrate through the gap, the trench having a second width less than the first; removing the spacers; removing the hard mask layer; filling the trench and the recess with an oxide layer, forming a T-shaped STI region; forming another hard mask layer on a portion of the T-shaped STI region; and revealing a Fin by removing portions of the STI regions and the T-shaped STI region.