Bilayer Air-Gap Seal Material for Seam-Free Semiconductor Gaps
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Solution Overview
Problem
Existing semiconductor fabrication processes for forming air gaps in semiconductor devices often result in damaged seal materials due to seams, leading to defects and low device yield, particularly in finFET structures.
Innovation Solution
A bilayer seal material composed of silicon oxycarbide is deposited and treated to form seamless seal layers, using a first seal material on opposing sidewalls and a second seal material to enclose the air gap, with an anneal process in an oxygen ambient environment to remove seams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer seal material is used to form air gaps in semiconductor devices, then the manufacturing process is simpler, but seams form in the seal material causing damage to underlying structures and low device yield
Solution Approach 1:
The seal material is divided into two distinct layers: a first seal material layer deposited on opposing sidewalls, and a second seal material layer that encloses the air gap. This segmentation allows each layer to perform its function optimally without creating seams that would compromise device yield.
Solution Approach 2:
The invention uses a composite bilayer seal material structure where two different seal materials are combined. The first seal material (e.g., silicon nitride) and second seal material (e.g., silicon oxycarbide) work together to form a seamless enclosure, eliminating the seam-related defects that occur with single-layer structures.
2Reliability
If seam removal treatment is applied to seal materials, then defects are reduced and device yield improves, but the manufacturing process becomes more complex
Solution Approach 1:
The bilayer seal material structure is designed beforehand to prevent seam formation during the air gap enclosure process. By pre-configuring the two-layer structure with appropriate material properties and deposition sequences, the need for subsequent seam removal treatments is eliminated, simplifying the overall manufacturing process.
Solution Approach 2:
Instead of trying to remove harmful seams after they form, the invention converts the potential harm into a benefit by using the interface between the two seal material layers as a designed feature. The second seal material layer is specifically engineered to enclose the air gap seamlessly, turning what would be a defect-prone single-layer structure into a reliable bilayer system.
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 seamless seal layers prevent damage to underlying structures and improve device yield by reducing defects in air gaps, enhancing the reliability and performance of semiconductor devices.
Implementation Method 1
depositing a first seal material on opposing sidewalls and depositing a second seal material in the opening
Implementation Method 2
performing an anneal process on the deposited first and second seal materials
Implementation Method 3
the seamless seal layers prevent damage to underlying structures and improve device yield by reducing defects in air gaps
Data Source
AI summary
The present disclosure relates to a method for forming a semiconductor device includes forming an opening between first and second sidewalls of respective first and second terminals. The first and second sidewalls oppose each other. The method further includes depositing a first dielectric material at a first deposition rate on top portions of the opening and depositing a second dielectric material at a second deposition rate on the first dielectric material and on the first and second sidewalls. The second dielectric material and the first and second sidewalls entrap a pocket of air. The method also includes performing a treatment process on the second dielectric material.