Air Spacer Ring Around Conductive Features for Lower Parasitic Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for forming air spacers between metal lines in integrated circuits require removing and refilling dielectric material, which is costly and time-consuming, and do not effectively reduce parasitic capacitance.
Innovation Solution
A method is developed to form air spacers by creating a sacrificial spacer around conductive features, which is then removed without the need for refilling or planarization processes, using a conformal deposition and selective etching to create uniform air spacers with low k-values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form air spacers by removing and refilling dielectric material, then air spacers can be formed between metal lines, but the process becomes costly and time-consuming due to multiple fabrication steps
Solution Approach 1:
The method performs preliminary actions by forming the air spacer structure through conformal deposition of sacrificial material and selective removal, rather than removing and refilling dielectric material. This preliminary structuring approach eliminates the need for subsequent planarization processes, thereby improving fabrication efficiency while maintaining air spacer formation precision
Solution Approach 2:
The invention extracts the essential function of air spacer formation from the complex process of dielectric removal and refilling. By using conformal deposition to create sacrificial spacers and then selectively removing them, the method isolates the critical air spacer creation step from unnecessary fabrication steps, reducing both cost and time while preserving the low-k value benefit
2Manufacturing precision
If conventional methods are used to form air spacers with dielectric material removal and refilling, then air spacers are created, but manufacturing costs increase due to costly planarization processes
Solution Approach 1:
The method employs sacrificial spacer material that is deposited conformally and then selectively removed to form the air spacer. This disposable sacrificial material approach replaces the costly planarization processes required in conventional methods, significantly reducing manufacturing costs while achieving the same air spacer formation precision
Solution Approach 2:
The invention changes the physical and chemical parameters of the spacer material through conformal deposition, creating a sacrificial layer with specific properties that enable selective removal. This parameter change allows the air spacer to be formed without requiring costly planarization steps, thereby reducing manufacturing costs while maintaining precision
3Object-affected harmful factors
If conventional air spacer formation methods are used, then dielectric material is removed and refilled, but parasitic capacitance is not effectively reduced
Solution Approach 1:
The method extracts the harmful dielectric material completely and replaces it with air (k=1.0) through the sacrificial spacer removal process. This complete extraction of the high-k dielectric material and replacement with air effectively reduces parasitic capacitance between conductive features, while the simplified process reduces device complexity
Solution Approach 2:
The invention changes the dielectric constant parameter from the original dielectric material (k>3.8) to air (k=1.0) through the conformal deposition and selective removal process. This parameter change effectively reduces parasitic capacitance, and the streamlined process reduces overall device complexity
4Manufacturing precision
If conventional methods with multiple fabrication steps are used, then air spacers can be formed, but fabrication time increases
Solution Approach 1:
The method performs preliminary conformal deposition of sacrificial spacer material and selective removal to form the air spacer structure in advance, eliminating the need for time-consuming subsequent planarization processes. This preliminary structuring reduces total fabrication time while maintaining air spacer formation precision
Solution Approach 2:
The invention skips the time-consuming steps of dielectric material removal and refilling by using conformal deposition followed by selective sacrificial material removal. This skipping of unnecessary fabrication steps significantly reduces fabrication time while achieving the same air spacer formation precision
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 method reduces parasitic capacitance between neighboring conductive features while eliminating the need for costly planarization processes, thereby reducing manufacturing costs and improving efficiency.
Implementation Method 1
a sacrificial spacer layer is deposited conformally over the conductive feature
Implementation Method 2
The sacrificial spacer layer is then removed to leave an air spacer surrounding the conductive feature
Data Source
AI summary
A method includes etching a dielectric layer to form an opening. A first conductive feature underlying the dielectric layer is exposed to the opening. A sacrificial spacer layer is deposited to extend into the opening. The sacrificial spacer layer is patterned. A bottom portion of the sacrificial spacer layer at a bottom of the opening is removed to reveal the first conductive feature, and a vertical portion of the sacrificial spacer layer in the opening and on sidewalls of the dielectric layer is left to form a ring. A second conductive feature is formed in the opening. The second conductive feature is encircled by the ring, and is over and electrically coupled to the first conductive feature. At least a portion of the ring is removed to form an air spacer.