Dummy Plug Anchoring for Semiconductor Pattern Stability
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Solution Overview
Problem
In high-integration semiconductor devices, the formation of steps between pattern dense and loose regions due to differences in film thickness leads to defects like lifting or detachment of dummy patterns, which cannot be adequately addressed by reducing the size of the dummy pattern, resulting in deteriorated device characteristics.
Innovation Solution
A semiconductor device with a dummy pattern and a method for fabricating it, where a dummy plug with a smaller or larger hole size and depth than the contact plug is used to support the dummy pattern, preventing defects such as lifting or detachment by fixing the dummy pattern on the interlayer dielectric film, and ensuring the dummy pattern is made of the same material as the semiconductor layer pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the dummy pattern is decreased to prevent lifting or detachment defects, then the reliability of the dummy pattern is improved, but the ability to reduce the step between regions deteriorates
Solution Approach 1:
The dummy pattern structure is segmented into two functional parts: the dummy pattern itself (for step reduction) and the dummy plug (for structural support and adhesion). This segmentation allows each part to optimize its function independently - the dummy pattern maintains adequate size for step reduction while the dummy plug provides anchoring to prevent lifting defects
Solution Approach 2:
The dummy plug acts as an intermediary element between the dummy pattern and the interlayer dielectric film. It provides a transition zone that enhances adhesion and mechanical support, allowing the dummy pattern to maintain its size for effective step reduction without suffering from lifting defects
2Manufacturing precision
If a dummy pattern is introduced into the pattern dense region, then the step between regions is reduced, but the complexity of the fabrication process increases
Solution Approach 1:
The formation of the dummy plug is merged with the existing contact hole formation process. The same photoresist patterning and etching steps that create contact holes are used to create dummy contact holes, and the same conductive material deposition fills both contact holes and dummy contact holes. This merging eliminates separate fabrication steps and reduces overall process complexity
Solution Approach 2:
The dummy plug structure serves multiple functions: it provides adhesion support for the dummy pattern, acts as a placeholder for future via connections, and maintains planarity in the interlayer dielectric film. This multi-functionality reduces the need for additional specialized structures or processes
Data Source
AI summary
A method for fabricating a semiconductor device includes forming an interlayer dielectric film on a semiconductor substrate including a pattern region and a dummy region, forming a photoresist pattern on the interlayer dielectric film such that the pattern region and the dummy region are partially exposed, etching the interlayer dielectric film exposed through the photoresist pattern as an etching mask to form a contact hole and a dummy contact hole, filling the contact hole and the dummy contact hole with a conductive material to form a contact plug and a dummy plug, depositing a semiconductor layer on the contact plug and the dummy plug, and subjecting the semiconductor layer to patterning to form a semiconductor layer pattern and a dummy pattern.