Interfacial Layer for Flowable Dielectric Delamination Control
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Solution Overview
Problem
Conventional dielectric growth processes, such as chemical vapor deposition (CVD), struggle to fill high aspect ratio gaps in integrated circuit devices, often resulting in voids due to 'pinching off' near the tops of the gaps, which can lead to structural integrity issues.
Innovation Solution
A hydrophobic gap-filling dielectric is formed using a flowable CVD process, and an interfacial layer with a hydrophilic surface is introduced to enhance the adhesion of an interlayer dielectric, ensuring complete gap fill and structural integrity by using materials like silicon nitride or oxygen-rich silicon oxycarbide, which provide a hydrophilic surface for better adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CVD processes are used to fill gaps, then the process is simple and well-established, but voids form near the tops of high aspect ratio gaps leading to structural integrity issues
Solution Approach 1:
The patent changes the physical state and flow characteristics of the dielectric material by using a flowable CVD process instead of conventional CVD. The dielectric is deposited as a flowable liquid that can completely fill high aspect ratio gaps without pinching off, then cured to form a solid void-free structure, resolving the gap fill completeness issue while maintaining structural integrity
Solution Approach 2:
The patent introduces an interfacial layer with a hydrophilic surface as an intermediary between the hydrophobic gap-filling dielectric and the interlayer dielectric. This interfacial layer improves adhesion and prevents delamination, addressing the structural integrity issue that would otherwise result from poor bonding between the hydrophobic dielectric and surrounding structures
2Manufacturing precision
If flowable CVD process is used to fill high aspect ratio gaps, then complete gap fill without voids is achieved, but the dielectric becomes hydrophobic leading to poor adhesion of interlayer dielectric
Solution Approach 1:
The patent introduces an interfacial layer with a hydrophilic surface as an intermediary between the hydrophobic gap-filling dielectric and the interlayer dielectric. This interfacial layer improves adhesion and prevents delamination, addressing the structural integrity issue that would otherwise result from poor bonding between the hydrophobic dielectric and surrounding structures
Solution Approach 2:
The patent applies different surface properties to different parts of the dielectric structure. The gap-filling dielectric maintains its hydrophobic nature for complete gap fill, while the interfacial layer provides a hydrophilic surface specifically at the bonding interface to ensure strong adhesion of the interlayer dielectric
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 solution effectively fills high aspect ratio gaps without voids, ensuring structural integrity and improving the adhesion of interlayer dielectrics to hydrophobic gap-filling dielectrics, thereby enhancing the reliability of integrated circuit devices.
Implementation Method 1
Flowable CVD processes have been developed to address these issues. Flowable CVD processes form a liquid on the chip surface that flows to fill high aspect ratio gaps.
Implementation Method 2
A cure process solidifies the liquid to produce a gap-filling dielectric that is substantially free of voids.
Implementation Method 3
an interfacial layer is disposed between the interlayer dielectric and the hydrophobic gap-filling dielectric
Data Source
AI summary
An interfacial layer is provided that binds a hydrophilic interlayer dielectric to a hydrophobic gap-filling dielectric. The hydrophobic gap-filling dielectric extends over and fill gaps between devices in an array of devices disposed between two metal interconnect layers over a semiconductor substrate and is the product of a flowable CVD process. The interfacial layer provides a hydrophilic upper surface to which the interlayer dielectric adheres. Optionally, the interfacial layer is also the product of a flowable CVD process. Alternatively, the interfacial layer may be silicon nitride or another dielectric that is hydrophilic. The interfacial layer may have a wafer contact angle (WCA) intermediate between a WCA of the hydrophobic dielectric and a WCA of the interlayer dielectric.