Fluorocarbon Etch Stop Layer for Low-k Interconnect Uniformity
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Solution Overview
Problem
The use of porous ultra-low k materials in semiconductor interconnect structures results in poor uniformity of metal interconnects, leading to increased parasitic capacitance between metal interconnects.
Innovation Solution
A method involving the formation of a fluorocarbon layer as an etch stop mask to improve the uniformity of openings in the interconnect structure, which includes forming a patterned hardmask layer, etching the dielectric layers using the fluorocarbon layer, and filling the resulting trenches and through holes with a metal layer to reduce parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If porous ultra-low k materials are used as dielectric material, then the dielectric constant is reduced, but the uniformity of metal interconnects deteriorates
Solution Approach 1:
A fluorocarbon layer is introduced as an intermediary etch stop layer between the porous ultra-low k dielectric material and the etching process. This intermediate layer provides a well-defined etch stop that enables precise control of opening depth and shape, thereby improving metal interconnect uniformity while maintaining the low dielectric constant benefits of the porous material
Solution Approach 2:
The patent modifies the etching process parameters by introducing a fluorocarbon layer with specific etch selectivity characteristics. This allows for controlled etching depth and improved opening uniformity through parameter optimization, resolving the contradiction between using porous materials and achieving uniform metal interconnects
2Manufacturing precision
If a fluorocarbon layer is added as etch stop mask, then the uniformity of openings is improved, but the process complexity increases
Solution Approach 1:
The fluorocarbon layer serves multiple functions: it acts as an etch stop layer to define opening depth, provides a well-defined etch interface for uniform openings, and can be integrated with existing dielectric layers. This multi-functionality justifies the additional process step by delivering multiple benefits from a single layer
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 method enhances the uniformity of metal interconnects, thereby reducing parasitic capacitance between them, improving the performance of semiconductor devices.
Implementation Method 1
performing an etch process on the second dielectric layer using the fluorocarbon layer as an etch stop mask to form an opening
Data Source
AI summary
A method for manufacturing an interconnect structure includes providing a metal interconnect layer, forming a first dielectric layer on the metal interconnect layer, forming a fluorocarbon layer on the first dielectric layer, forming a second dielectric layer on the fluorocarbon layer, and performing an etch process on the second dielectric layer using the fluorocarbon layer as an etch stop mask to form an opening. The interconnect structure thus formed has an improved uniformity and reduced parasitic capacitance.