Semiconductor Air Gaps via Protruding Conductive Lines
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Solution Overview
Problem
The challenge in semiconductor device fabrication is reducing parasitic capacitance between conductive features while scaling down dimensions, which affects performance, yield, and complexity, and existing methods require additional masks and patterning processes, increasing fabrication costs.
Innovation Solution
The method involves forming protruding portions on conductive lines, creating voids between them, and expanding these voids into air gaps through an etch process, which alleviates parasitic capacitance without needing extra masks or patterning, using liner and protection layers to enhance the process, and sealing the air gaps with coverage layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional methods are used to reduce parasitic capacitance, then capacitance reduction is achieved, but additional masks and patterning processes are required, increasing fabrication complexity and cost
Solution Approach 1:
The method performs preliminary action by forming protruding portions on conductive lines before the main air gap formation process. These protruding portions are created in advance to define the future air gap locations, eliminating the need for separate masking and patterning steps that would otherwise be required to create air gaps between conductive features.
Solution Approach 2:
The protruding portions on adjacent conductive lines serve as self-aligned masks that automatically define the air gap positions. The conductive lines themselves provide the structural features needed to create the air gaps, eliminating the need for external masking materials and reducing fabrication complexity.
2Object-affected harmful factors
If air gaps are formed using additional masks and patterning, then parasitic capacitance is reduced, but fabrication cost and process time increase
Solution Approach 1:
The method merges the air gap formation process with the existing conductive line fabrication process. The protruding portions are formed as part of the conductive line structure itself, and the subsequent etching process that creates air gaps is integrated into the standard fabrication flow, eliminating separate time-consuming masking and patterning steps.
Solution Approach 2:
The protruding portions are formed in advance during the conductive line fabrication process, before the air gap creation step. This preliminary formation of structural features allows the air gaps to be created directly through etching without requiring additional time for mask application, alignment, and patterning.
3Ease of manufacture
If protruding portions are formed on conductive lines, then air gaps can be created without additional masks, but the conductive line structure becomes more complex
Solution Approach 1:
The method introduces a dimensional change by adding protruding portions that extend in the vertical dimension from the planar conductive lines. This vertical extension creates the necessary structural features for air gap formation while maintaining the overall simplicity of the fabrication process, as the protrusions are formed using standard deposition and etching techniques.
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
This approach effectively reduces parasitic capacitance between conductive features, improving semiconductor device performance and reducing fabrication costs by eliminating the need for additional masking and patterning steps.
Implementation Method 1
performing an etch process to expand the void into an air gap
Data Source
AI summary
The present application discloses a method for fabricating a semiconductor device with air gaps for reducing capacitive coupling between conductive features. The method includes the following operations: forming a first conductive line including a first protruding portion protruding from one side of the first conductive line, forming a second conductive line including a second protruding portion facing onto the first protruding portion and protruding from one side of the second conductive line, forming a void between the first protruding portion and the second protruding portion, and performing an etch process to expand the void into an air gap.