Flowable Low-k Gap Fill With Plasma Densification for Narrow Trenches
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Solution Overview
Problem
Current atomic layer deposition (ALD) methods for filling narrow trenches in microelectronics devices with low-k dielectric materials fail to achieve the necessary low dielectric constant and introduce seams that cause delamination and early breakdown of the device.
Innovation Solution
A processing method involving the deposition of a flowable low-k dielectric layer on a substrate, followed by densification using plasma treatment, and selective etching to precisely place the film within the desired area, ensuring a seamless and close to bottom-up fill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If atomic layer deposition (ALD) is used to fill narrow trenches with low-k dielectric materials, then the trenches can be filled, but the dielectric constant is not sufficiently low and seams are introduced causing delamination and early breakdown
Solution Approach 1:
The patent changes the deposition parameters by using flowable chemical vapor deposition (FCVD) instead of atomic layer deposition (ALD), and modifies the dielectric material composition to achieve a lower dielectric constant (k < 2.5). The process parameters including temperature, pressure, and precursor flow rates are optimized to enable seamless filling without delamination issues
Solution Approach 2:
The patent employs composite dielectric materials combining low-k dielectric compounds with specific organic precursors to achieve both low dielectric constant and seamless film formation. The composite approach allows tuning of material properties to simultaneously satisfy low-k requirement and defect-free filling requirement
2Object-generated harmful factors
If the dielectric constant is reduced to reduce leakage, then leakage decreases, but the film quality deteriorates with seams and delamination
Solution Approach 1:
The patent achieves low dielectric constant (k < 2.5) by changing the material composition parameters and deposition conditions. The FCVD process parameters are specifically tuned to enable conformal deposition at low k-values without forming seams, resolving the trade-off between low leakage and high film quality
3Reliability
If narrow trenches with high aspect ratios are filled, then isolation is improved, but voids and seams are formed reducing fill quality
Solution Approach 1:
The patent utilizes the flowable nature of the FCVD-deposited dielectric layer, allowing the material to flow and self-level within the high aspect ratio trenches. This fluid-like deposition behavior enables complete filling of narrow trenches without voids or seams, achieving both good isolation and high fill quality
4Quantity of substance
If traditional ALD processes are used, then deposition is achieved, but the process time and complexity increase without achieving desired performance
Solution Approach 1:
The patent replaces the step-by-step ALD process with a continuous flowable chemical vapor deposition process. This substitution eliminates the need for repeated deposition and etch cycles, reducing process time and complexity while achieving the same or better deposition quality in a single continuous operation
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 achieves a seamless, high-quality film that effectively fills high aspect ratio trenches without voids, providing improved electrostatic coupling and reduced parasitic capacitance and leakage, thus enhancing the performance and reliability of microelectronics devices.
Implementation Method 1
densifying the flowable low-k dielectric layer
Data Source
AI summary
Provided are methods of depositing a film in high aspect ratio (AR) structures with small dimensions. The method provides flowable deposition for seamless gap-fill, film densification by low temperature inductively coupled plasma (ICP) treatment (<600° C.), optional film curing, and etch back to form a low-k dielectric film having a dielectric constant, k-value less than 3.