Silicon Oxycarbide Hard Mask for Dielectric Plug Dishing
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Solution Overview
Problem
The semiconductor industry faces challenges in protecting dielectric plugs during the spacer etch back process, which can lead to dishing effects and defects in semiconductor devices, resulting in low yield and device failure.
Innovation Solution
A hard mask layer formed using silicon oxycarbide is applied to dielectric plugs to provide protection during fabrication steps, offering high etch selectivity against spacer materials, thereby preventing damage and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hard mask materials are used during spacer etch back process, then the etching process can be performed, but dishing effects occur on dielectric plugs causing defects and low yield
Solution Approach 1:
A silicon oxycarbide intermediate layer is deposited between the spacer material and the dielectric plug to act as a protective intermediary. This layer has high etch selectivity, allowing the spacer to be etched away while the dielectric plug remains protected from dishing effects and damage.
Solution Approach 2:
The invention changes the material composition parameter by using silicon oxycarbide (SiOC) with specific oxygen and carbon content ratios. This material has fundamentally different etch characteristics compared to conventional hard masks, providing both protection against dishing and high etch selectivity for the spacer removal process.
2Reliability
If a protective layer is added to prevent dishing effects, then dielectric plug integrity is improved, but process complexity increases
Solution Approach 1:
The silicon oxycarbide layer serves multiple functions simultaneously: it acts as a protective barrier against dishing effects, provides high etch selectivity for spacer removal, and maintains structural integrity during subsequent fabrication steps. This multi-functionality reduces the need for additional specialized process steps.
3Ease of manufacture
If conventional hard mask materials are used, then the process is simple, but etch selectivity against spacer materials is insufficient causing damage
Solution Approach 1:
By changing the material composition to silicon oxycarbide with controlled oxygen and carbon content, the etch selectivity parameter is fundamentally improved. This material exhibits significantly different etch rates compared to conventional hard masks, enabling precise spacer removal while protecting the dielectric plug without requiring complex process adjustments.
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 silicon oxycarbide hard mask effectively shields dielectric plugs from etching processes, reducing defects and enhancing device yield by maintaining the structural integrity of dielectric plugs during spacer etch back and subsequent fabrication steps.
Implementation Method 1
A hard mask layer formed using silicon oxycarbide is applied to dielectric plugs to provide protection during fabrication steps, offering high etch selectivity against spacer materials
Data Source
AI summary
The present disclosure relates to a semiconductor device that includes a first terminal formed on a fin region and having a first spacer. The semiconductor device further includes a second terminal having a hard mask and a second spacer opposing the first spacer. The hard mask and the second spacer are formed using different materials. The semiconductor device also includes a seal layer formed between first and second spacers of the first and second terminals, respectively. The semiconductor device further includes an air gap surrounded by the seal layer, the fin region, and the first and second spacers.