Dielectric Gap Fill Using ALD Conversion for Void-Free STI Trenches
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Solution Overview
Problem
Existing methods struggle to fill narrow gaps in semiconductor structures, such as trenches between fins, without leaving seams or voids, which can lead to issues like fin bending and reduced structural integrity.
Innovation Solution
A method involving atomic layer deposition (ALD) of a conformal dielectric material followed by conversion to a converted dielectric material using oxygen-containing processes, such as annealing, gas soak, or UV treatment, to expand and fill the gaps without seams, combined with a flowable chemical vapor deposition (FCVD) for wider gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional deposition methods are used to fill narrow gaps, then the process is simpler and faster, but seams or voids form in the dielectric material
Solution Approach 1:
The filling process is divided into multiple sequential steps: first forming a conformal dielectric layer, then converting it to an expansive dielectric material, and finally performing a second conversion to the final dielectric material. This segmentation allows each step to optimize for its specific function, achieving complete gap filling without voids while maintaining process control
Solution Approach 2:
The conformal dielectric material is deposited first as a preliminary layer before the actual gap filling occurs. This preliminary layer serves as a precursor that will be converted to the expansive dielectric material, ensuring uniform coverage and preventing void formation before the expansion step
2Manufacturing precision
If the dielectric material is made more expansive to fill gaps completely, then voids are eliminated, but fin bending increases
Solution Approach 1:
The dielectric material undergoes controlled parameter changes through sequential conversions. First, it is converted to an expansive state to fill gaps completely, then subsequently converted to the final dielectric material with optimized properties. This two-stage parameter change allows the material to achieve both complete gap filling and minimal fin bending by adjusting its physical and chemical properties at different stages
3Manufacturing precision
If multiple conversion steps are performed to optimize dielectric material properties, then filling quality improves, but processing time increases
Solution Approach 1:
The multiple conversion steps are merged into a coordinated sequence where the first conversion to expansive dielectric material and the second conversion to final dielectric material are performed in an integrated process flow. This merging allows the conversions to be optimized together, achieving high-quality gap filling while minimizing total processing time through efficient process integration
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
The method ensures seamless filling of gaps, reducing fin bending and enhancing structural integrity by using a porous structure that allows efficient conversion and expansion of the dielectric material, achieving a lower k-value and improved density.
Implementation Method 1
A first dielectric material is conformally deposited in a trench using an atomic layer deposition (ALD) process
Implementation Method 2
the first dielectric material is converted to a second dielectric material through processes like anneal, gas soak, plasma treatment, or UV treatment in an oxygen-containing ambient
Implementation Method 3
the first dielectric material is converted to a second dielectric material through processes like anneal, gas soak, plasma treatment, or UV treatment in an oxygen-containing ambient
Implementation Method 4
the first dielectric material is converted to a second dielectric material through processes like anneal, gas soak, plasma treatment, or UV treatment in an oxygen-containing ambient
Data Source
AI summary
Generally, examples are provided relating to filling gaps with a dielectric material, such as filling trenches between fins for Shallow Trench Isolations (STIs). In an embodiment, a first dielectric material is conformally deposited in a trench using an atomic layer deposition (ALD) process. After conformally depositing the first dielectric material, the first dielectric material is converted to a second dielectric material. In further examples, the first dielectric material can be conformally deposited in another trench, and a fill dielectric material can be flowed into the other trench and converted.