FinFET Etch Stop Layer Structure for Lower RC Delay
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Solution Overview
Problem
The challenge in semiconductor manufacturing is to form reliable FinFETs as feature sizes continue to decrease, making fabrication processes more difficult and affecting the reliability of semiconductor devices.
Innovation Solution
The process involves forming a fin structure over a semiconductor substrate, patterning gate structures over the fin, and depositing an etch stop layer made of silicon nitride using atomic layer deposition, which exposes spacer elements and prevents oxidation of source/drain portions, thereby improving device reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but fabrication process difficulty increases and device reliability deteriorates
Solution Approach 1:
An etch stop layer is introduced as an intermediary component between the source/drain portions and the surrounding environment. This layer acts as a protective barrier that prevents oxidation of the source/drain portions during subsequent fabrication processes, thereby maintaining device reliability even as feature sizes decrease and fabrication processes become more challenging.
Solution Approach 2:
The etch stop layer is deposited in advance before oxidation-prone processes are performed. By establishing this protective layer beforehand, the source/drain portions are pre-protected from oxidation, allowing fabrication processes to proceed without compromising device reliability despite reduced feature dimensions.
2Device complexity
If conventional fabrication processes are used without etch stop layer, then process simplicity is maintained, but source/drain oxidation occurs and device quality deteriorates
Solution Approach 1:
The etch stop layer serves as a protective intermediary that prevents direct exposure of the source/drain portions to oxidizing environments. This simple addition of a protective barrier layer effectively prevents oxidation without requiring complex process modifications, thereby maintaining process simplicity while significantly improving device quality.
3Productivity
If no etch stop layer is deposited, then manufacturing steps are reduced and productivity is improved, but source/drain portions oxidize and yield decreases
Solution Approach 1:
The etch stop layer is deposited as a preliminary protective measure before oxidation-prone fabrication steps. This pre-protection approach ensures that source/drain portions remain oxidation-free throughout subsequent processes, thereby maintaining high manufacturing yield without significantly impacting production throughput.
Solution Approach 2:
The etch stop layer acts as a protective intermediary that prevents oxidation of source/drain portions during fabrication. This simple protective barrier maintains manufacturing yield by preventing oxidation-related defects, while the deposition process is sufficiently fast to minimize impact on overall manufacturing productivity.
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 enhances the manufacturing yield and quality of semiconductor devices by preventing source/drain oxidation and reducing RC delay, ultimately improving the performance of semiconductor device structures.
Implementation Method 1
depositing an etch stop layer made of silicon nitride using atomic layer deposition, which exposes spacer elements and prevents oxidation of source/drain portions
Implementation Method 2
depositing an etch stop layer made of silicon nitride using atomic layer deposition
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes a substrate and a gate structure over the substrate. The semiconductor device structure also includes a spacer element covering a first sidewall of the gate structure. The semiconductor device structure further includes a source/drain portion in the substrate, and the spacer element is between the source/drain portion and the gate structure. In addition, the semiconductor device structure includes an etch stop layer covering the source/drain portion. The etch stop layer includes a first nitride layer covering the source/drain portion and having a second sidewall, and the second sidewall is in direct contact with the spacer element. The etch stop layer also includes a first silicon layer covering the first nitride layer and having a third sidewall, and the third sidewall is in direct contact with the spacer element.