Semiconductor Interconnect Structure With Low-k Etch-Resistant Dielectric
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Solution Overview
Problem
As semiconductor devices continue to scale down, existing manufacturing processes are inadequate in ensuring reliable interconnect structures due to issues with over-etching and time-dependent dielectric breakdown, particularly in forming low k dielectric layers with high hardness and preventing metal diffusion.
Innovation Solution
A semiconductor structure is formed with a carbon-containing dielectric layer having a high hardness and low dielectric constant, an aluminum-containing layer for etch protection, and barrier layers to prevent metal diffusion, along with conductive vias and metal lines embedded in these layers to enhance reliability and reduce capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional dielectric layers are used in semiconductor interconnect structures, then the manufacturing process is simpler, but the structure suffers from over-etching and time-dependent dielectric breakdown due to insufficient hardness
Solution Approach 1:
The patent changes the physical and chemical parameters of the dielectric layer by incorporating carbon to achieve a specific hardness range (2-4 GPa). This parameter modification allows the dielectric layer to resist over-etching while maintaining low-k properties, directly resolving the contradiction between hardness and reliability
Solution Approach 2:
The patent creates a composite dielectric material containing carbon (10-30 atomic percent) combined with traditional dielectric components. This composite structure provides both the required hardness for etch resistance and the low-k properties for electrical performance, simultaneously addressing both requirements
2Reliability
If metal lines are formed in conventional dielectric layers, then the interconnect structure can be created, but metal diffusion occurs leading to device failure
Solution Approach 1:
The patent introduces barrier layers as intermediary structures between the metal lines and carbon-containing dielectric layer. These barrier layers (such as tantalum nitride or tungsten nitride) prevent direct contact and diffusion between metal and dielectric, while the carbon-containing dielectric provides additional diffusion protection, creating a multi-layer protection system
3Reliability
If the dielectric layer hardness is increased to prevent over-etching, then etch resistance improves, but the capacitance increases which reduces device performance
Solution Approach 1:
The patent optimizes the carbon content parameter (10-30 atomic percent) to achieve a balance between hardness and dielectric constant. At this specific composition range, the dielectric layer achieves sufficient hardness (2-4 GPa) for etch resistance while maintaining low-k properties (k<3.5), thus achieving both etch resistance and low capacitance simultaneously
Solution Approach 2:
The patent creates local quality variations by controlling carbon distribution and concentration within the dielectric layer. The carbon is distributed to provide localized hardness enhancement for etch resistance while maintaining overall low-k properties, allowing different regions of the dielectric to serve different functions
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 improves the reliability of interconnect structures by reducing capacitance, enhancing time-dependent dielectric breakdown resistance, and maintaining low resistance, thereby improving device performance and power efficiency.
Implementation Method 1
barrier layers to prevent metal diffusion
Implementation Method 2
an aluminum-containing layer for etch protection
Data Source
AI summary
A method for manufacturing a semiconductor structure is provided. The semiconductor structure includes an aluminum-containing layer and an etch stop layer formed over the aluminum-containing layer. The semiconductor structure further includes a carbon-containing dielectric layer formed over the etch stop layer. The semiconductor structure further includes a metal line formed in an upper portion of the carbon-containing dielectric layer. The semiconductor structure further includes a conductive via formed in a lower portion of the carbon-containing dielectric layer and through the etch stop layer and the aluminum-containing layer. The semiconductor structure further includes a barrier layer interposing the first sidewall of the metal line and carbon-containing dielectric layer and interposing the second sidewall of the conductive via and the carbon-containing dielectric layer.