Low-k Cu Barrier Etch Stop Layer for Interconnects
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Solution Overview
Problem
Current interconnect structures in integrated circuits face challenges in reducing parasitic capacitance and leakage due to the limitations in the dielectric constant of etch stop layers, which affects etching selectivity and increases leakage in interconnect structures.
Innovation Solution
The formation of an etch stop layer using a carbon-source gas and precursors like 1-methylsilane, 2-methylsilane, and 3-methylsilane, with a high carbon content, to achieve a low dielectric constant below 4.0, reducing leakage and improving etching selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the k value of etch stop layer is reduced to reduce parasitic capacitance, then parasitic capacitance is reduced, but etching selectivity is sacrificed and leakage increases
Solution Approach 1:
The patent changes the chemical composition parameters of the etch stop layer by using carbon-source gases (CH4, C2H6, C2H4) instead of traditional CO2, and by controlling the carbon content to be greater than 20 atomic percent. This parameter change enables achieving k < 4.0 while maintaining etching selectivity and reducing leakage, thereby resolving the contradiction between reducing parasitic capacitance and maintaining reliability
Solution Approach 2:
The patent creates a composite material structure by forming an etch stop layer with high carbon content embedded within the dielectric layer. This composite approach, combining carbon-rich materials with dielectric properties, achieves both low k value (reduced parasitic capacitance) and high etching selectivity with low leakage, resolving the technical contradiction
2Object-affected harmful factors
If the k value of etch stop layer is reduced, then parasitic capacitance is reduced, but leakage increases
Solution Approach 1:
By changing the carbon source from CO2 to hydrocarbon gases (CH4, C2H6, C2H4) and controlling carbon content > 20 atomic percent, the patent achieves a unique material composition that simultaneously reduces k value (lowering parasitic capacitance) and reduces leakage, breaking the traditional trade-off between these two parameters
3Object-affected harmful factors
If the k value of etch stop layer is reduced, then parasitic capacitance is reduced, but etching selectivity is sacrificed
Solution Approach 1:
The patent optimizes chemical composition parameters (carbon content > 20 atomic percent, specific carbon-source gases) to create an etch stop layer that maintains high etching selectivity despite having k < .0, thereby resolving the contradiction between reducing parasitic capacitance and maintaining manufacturing precision in the etching process
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 solution results in lower leakage and improved etching rates, leading to reduced parasitic capacitance and enhanced breakdown voltage and time-dependent dielectric breakdown behavior in interconnect structures.
Implementation Method 1
an etch stop layer is formed over the metal feature and the dielectric layer using a precursor and a carbon-source gas including carbon as precursors
Data Source
AI summary
In the formation of an interconnect structure, a metal feature is formed in a dielectric layer. An etch stop layer (ESL) is formed over the metal feature and the dielectric layer using a precursor and a carbon-source gas including carbon as precursors. The carbon-source gas is free from carbon dioxide (CO2). The precursor is selected from the group consisting essentially of 1-methylsilane (1MS), 2-methylsilane (2MS), 3-methylsilane (3MS), 4-methylsilane (4MS), and combinations thereof.