Semiconductor Active-Pattern Dam Structure for Simpler Gate Etching
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Solution Overview
Problem
The challenge in semiconductor device development is to reduce capacitance and ensure electrical stability as pitch sizes decrease, particularly in regions where active patterns are closely spaced, complicating the etching process for forming gate electrodes.
Innovation Solution
A dam is formed on a field insulating layer between active patterns in regions with a small pitch, avoiding the need to etch these areas during gate electrode formation, thereby simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a dam is formed on the field insulating layer between active patterns in regions with small pitch, then the etching complexity is reduced and manufacturing ease is improved, but the device structure becomes more complex
Solution Approach 1:
The gate electrode formation process is segmented into multiple etching steps: a first etching step forms gate electrodes in regions without dams, and a second etching step forms gate electrodes in regions with dams. This segmentation allows each step to be optimized independently, reducing the overall etching complexity while managing structural complexity through systematic division of the fabrication process
Solution Approach 2:
The dam structure acts as an intermediary element between active patterns in small pitch regions. By introducing this intermediate structure on the field insulating layer, the patent simplifies the etching process for gate electrode formation in densely packed regions, as the dam provides a physical barrier and reference structure that eliminates the need for complex etching masks and alignment procedures
2Productivity
If the pitch between active patterns is reduced for high integration, then the integration density is improved, but the capacitance between contacts increases and electrical stability deteriorates
Solution Approach 1:
Different regions of the semiconductor device are given different structural characteristics: small pitch regions have dams formed on the field insulating layer to simplify etching, while larger pitch regions do not have dams. This local differentiation allows the device to achieve high integration density in critical areas while maintaining electrical stability through region-specific structural optimization
Solution Approach 2:
The dam structure adds a vertical dimension to the field insulating layer in small pitch regions. By raising the field insulating layer to form a dam structure, the patent creates additional vertical space that helps maintain electrical isolation and stability between closely spaced active patterns, effectively using the vertical dimension to compensate for the reduced horizontal pitch
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes a substrate, a first active pattern, which extends in a first direction on the substrate, a second active pattern, which extends in the first direction on the substrate and is spaced apart from the first active pattern by a first pitch in a second direction different from the first horizontal direction, a third active pattern, which extends in the first direction on the substrate and is spaced apart from the second active pattern by a second pitch greater than the first pitch in the second direction, a field insulating layer, which borders side walls of each of the first to third active patterns, a dam, which is between the first active pattern and the second active pattern on the field insulating layer, the region between the second active pattern and the third active pattern being free of the dam, a gate electrode, which extends in the second direction, and has a first portion on the first active pattern, a second portion on the second active pattern, and a third portion on the third active pattern, a first work function layer between the first portion of the gate electrode and the dam, and a second work function layer between the second portion of the gate electrode and the dam.