Interconnection Structure Sidewall Protection Layer
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Solution Overview
Problem
The dual damascene process faces challenges in achieving precise dimensional control and preventing over-etching in the formation of interconnection structures for semiconductor devices, particularly as feature sizes decrease, which can lead to electrical connectivity issues and device performance degradation.
Innovation Solution
The process involves forming a liner layer, dielectric structures, and conductive structures through a series of etching and deposition steps, including the use of etch stop layers and protective layers to prevent over-etching and ensure accurate formation of via and trench openings, with specific materials and techniques like CVD, HDP CVD, and ALD to maintain precise control over the interconnection structure dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching processes are used in dual damascene, then manufacturing simplicity is maintained, but manufacturing precision deteriorates due to over-etching and poor dimensional control
Solution Approach 1:
A protective layer is deposited on the sidewalls of the first dielectric structure before the second dielectric structure is etched. This preliminary protective action prevents over-etching and ensures precise dimensional control of the via opening, as the protective layer acts as a barrier during the etching process.
Solution Approach 2:
The etching process is segmented into multiple stages: first etching the second dielectric structure to form the trench, then etching through the first dielectric structure to form the via opening. The protective layer is applied between these stages to prevent harmful interactions, allowing each etching step to be controlled independently for better precision.
2Area of moving object
If feature sizes are reduced for higher integration, then device density increases, but manufacturing precision deteriorates due to increased sensitivity to over-etching
Solution Approach 1:
The protective layer is deposited in advance on the sidewalls before the etching of smaller features. This preliminary protection is especially critical for reduced feature sizes where over-etching can easily compromise dimensional control. The protective layer ensures that even as features shrink, the precision required for high-density integration is maintained.
3Reliability
If etching depth is increased to ensure connectivity, then electrical connectivity improves, but manufacturing precision deteriorates due to over-etching risks
Solution Approach 1:
The protective layer is applied before the deep etching process to ensure that even when etching to greater depths for connectivity, the sidewalls are protected from over-etching. This allows the etch to proceed to the necessary depth for reliable electrical connection without compromising the dimensional control of the via opening.
Solution Approach 2:
The protective layer acts as an intermediary barrier between the etching process and the first dielectric structure. It mediates the etching process, allowing deep etching for connectivity while preventing direct harmful interaction that would cause over-etching and dimensional control issues.
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 precision and reliability of interconnection structure formation, preventing over-etching and ensuring accurate dimensions, thereby improving the electrical connectivity and performance of semiconductor devices.
Implementation Method 1
the protective layer has a weaker adhesion to the byproduct than that of the first dielectric structure, so that adhesion of the byproduct to the sidewall of the via opening is prevented
Implementation Method 2
etching the first dielectric structure to form a via opening
Implementation Method 3
with specific materials and techniques like CVD, HDP CVD, and ALD
Implementation Method 4
with specific materials and techniques like CVD, HDP CVD, and ALD
Data Source
AI summary
An interconnection structure comprises a first metal structure, a first dielectric layer, a second dielectric layer, a second metal structure, a first protective layer, and a second protective layer. The first dielectric layer is over the first metal structure. The second dielectric layer is over the first dielectric layer. The second metal structure has an upper portion extending through the second dielectric layer, and a lower portion extending through the first dielectric layer. The upper portion has a width greater than a width of the lower portion. The first protective layer spaces the first dielectric layer apart from the lower portion of the second metal structure. The second protective layer spaces the second dielectric layer apart from the upper portion of the second metal structure, and has a top width greater than a top width of the first protective layer.