Semiconductor Gate Stack Protection Element Design
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Solution Overview
Problem
The challenge in the semiconductor industry is to form reliable semiconductor devices at increasingly smaller sizes due to the complexity and difficulty of fabrication processes as feature sizes decrease, affecting production efficiency and costs.
Innovation Solution
A semiconductor device structure is formed with a protection element having a wider upper portion over a gate stack, which protects the metal gate stack during conductive contact formation, preventing short circuits and improving device reliability and performance.
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 complexity and difficulty increase
Solution Approach 1:
A protection element is formed over the gate stack before conductive contacts are created. This preliminary protective structure prevents damage to the metal gate stack during subsequent contact formation processes, addressing the increased fabrication difficulty associated with smaller feature sizes
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency and cost are improved, but device reliability becomes more difficult to maintain
Solution Approach 1:
The protection element is formed in advance over the gate stack to prevent damage during contact formation. This preliminary protective measure ensures device reliability is maintained even as feature sizes decrease and fabrication becomes more challenging
Solution Approach 2:
The protection element acts as a cushioning structure that absorbs or prevents damage during the contact formation process. By providing this protective barrier beforehand, the device maintains reliability despite the increased difficulty of fabrication at smaller scales
3Reliability
If a protection element with wider upper portion is formed over the gate stack, then device reliability is improved by preventing damage during contact formation, but device structure complexity increases
Solution Approach 1:
The protection element has a non-uniform structure with a wider upper portion and narrower lower portion. This local variation in geometry provides enhanced protection where needed (over the gate stack) while minimizing overall structural complexity and material usage
Data Source
AI summary
One or more formation methods of a semiconductor device structure are provided. The method includes forming a dummy gate stack over a semiconductor substrate and forming spacer elements over sidewalls of the dummy gate stack. The method also includes removing the dummy gate stack to form a recess between the spacer elements. The method further includes partially removing the spacer elements such that an upper portion of the recess becomes wider. In addition, the method includes forming a metal gate stack in the recess and forming a protection element over the metal gate stack to fill the recess.