Multi-Stage Trench Patterning to Mitigate Pattern Collapse
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Solution Overview
Problem
Deep trenches in semiconductor fabrication often collapse during the fabrication process, leading to pattern collapse issues.
Innovation Solution
The use of extreme low-k dielectric regions and multiple stages of patterning with controlled trench aspect ratios, along with barrier layers formed by atomic layer deposition, helps mitigate pattern collapse by stabilizing the trench etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If trenches are etched deeper to accommodate metal lines, then the metal line capacity is improved, but the trench stability deteriorates leading to pattern collapse
Solution Approach 1:
The patent divides the single deep trench etching process into multiple stage patterning steps, creating intermediate structures that support the final deep trench. This segmentation allows the trench to be formed deeper without collapsing by building structural support incrementally through multiple patterning cycles.
Solution Approach 2:
The patent applies preliminary actions by forming mandrel structures and performing initial patterning steps before the final deep trench etching. These preliminary structures provide mechanical support and define the trench geometry in advance, preventing collapse during the deep etching process.
2Stability of the object's composition
If multiple stages of patterning are used to control trench aspect ratio, then the trench stability is improved, but the fabrication process complexity increases
Solution Approach 1:
The patent employs mandrel structures that serve multiple functions: they act as etch masks, provide mechanical support during deep trench formation, and define the final trench geometry. This multi-functionality reduces the need for separate support structures, simplifying the overall process despite multiple patterning stages.
Solution Approach 2:
The patent uses nested patterning where intermediate structures are formed within and around the final trench geometry. Each patterning stage creates structures that are nested within the previous stage's structures, efficiently utilizing space and reducing the number of separate fabrication steps needed.
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 effectively prevents trench collapse by maintaining a stable aspect ratio and ensuring that trenches are not etched too deeply, thereby maintaining structural integrity during semiconductor fabrication.
Implementation Method 1
barrier layers formed by atomic layer deposition
Data Source
AI summary
One or more techniques or systems for mitigating pattern collapse are provided herein. For example, a semiconductor structure for mitigating pattern collapse is formed. In some embodiments, the semiconductor structure includes an extreme low-k (ELK) dielectric region associated with a via or a metal line. For example, a first metal line portion and a second metal line portion are associated with a first lateral location and a second lateral location, respectively. In some embodiments, the first portion is formed based on a first stage of patterning and the second portion is formed based on a second stage of patterning. In this manner, pattern collapse associated with the semiconductor structure is mitigated, for example.