Interconnect Structure Formation Using an sp2 Carbon Mask Layer
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Solution Overview
Problem
The reduction in size of semiconductor devices leads to nano-scale wiring, which poses challenges in alignment and overlay during the photolithography process, necessitating improved methods for forming interconnect structures.
Innovation Solution
A method involving the selective formation of a carbon layer with an sp2 bonding structure on a substrate, including a first metal layer and a first insulating layer, using chemical vapor deposition or plasma-enhanced CVD, where the carbon layer acts as a mask for depositing a second insulating layer and facilitates the formation of a second metal layer electrically connected to the first metal layer, utilizing a reactivity difference between the layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography process is used for nano-patterning, then wiring can be formed at nano-scale, but misalignment and overlay issues occur
Solution Approach 1:
A carbon layer with sp2 bonding structure is introduced as an intermediary mask layer between the photolithography pattern and the underlying metal layer. This carbon mask layer enables precise pattern transfer without direct photolithography on the metal, eliminating overlay issues while maintaining nano-scale wiring formation capability
2Area of stationary object
If carbon layer is formed to cover both metal layer and insulating layer, then complete coverage is achieved, but selective deposition on metal layer cannot be realized
Solution Approach 1:
The carbon layer is formed with different properties on different surfaces: on the metal layer, it forms an sp2 bonded graphitic structure with high carbon content and low reactivity, while on the insulating layer, it forms a different structure with lower carbon content. This local quality difference enables selective deposition and subsequent selective removal processes
3Ease of manufacture
If conventional carbon deposition is used, then carbon layer can be formed, but electromigration resistance is insufficient
Solution Approach 1:
The carbon layer is formed with controlled sp2 bonding content (50-99% of total carbon) through specific deposition parameters including temperature control (200-450°C), hydrogen gas addition (0.1% or more volume ratio), and deposition time control. This parameter optimization creates a carbon layer with enhanced electromigration resistance while maintaining ease of formation
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 enhances the precision and accuracy of interconnect structure formation by ensuring selective deposition of insulating layers and improving electromigration resistance through the use of carbon layers with sp2 bonding, thereby addressing alignment and overlay issues in nano-scale wiring.
Implementation Method 1
The selectively forming the carbon layer may include depositing the carbon layer on the first metal layer through a deposition process using chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD)
Implementation Method 2
The selectively forming the carbon layer may include depositing the carbon layer on the first metal layer through a deposition process using chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD)
Implementation Method 3
The selectively forming the second insulating layer may forming the second insulating layer on the first insulating layer due to a difference in surface energy between the first insulating layer and the carbon layer
Data Source
AI summary
Provided is a method of forming an interconnect structure. The method includes preparing a substrate including a first metal layer and a first insulating layer, selectively forming a carbon layer having an sp2 bonding structure on the first metal layer, selectively forming a second insulating layer on the first insulating layer, forming a third insulating layer to cover the second insulating layer, and forming a second metal layer electrically connected to the first metal layer.