Stacked Hard Mask for Single-Step Semiconductor Opening Fabrication
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Solution Overview
Problem
The conventional damascene process for fabricating interconnect structures in semiconductor devices requires multiple etching steps, leading to longer cycle times and increased complexity.
Innovation Solution
A method that simplifies the process by using a stacked layer of a patterned metal hard mask, silicon oxynitride, and silicon oxide layers to perform a single etching step, exposing the dielectric layer and reducing the number of steps required to define the trench or opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple etching steps are performed to define the trench pattern in the hard mask layer, then the trench can be accurately formed, but the cycle time increases and process complexity increases
Solution Approach 1:
The patent combines multiple etching steps into a single etching process by using a composite hard mask layer structure. The first hard mask layer (titanium nitride) and second hard mask layer (PE-oxide) are etched simultaneously in one step, eliminating the need for sequential etching operations while maintaining the precision required for trench pattern definition.
Solution Approach 2:
The composite hard mask layer structure serves multiple functions: the titanium nitride layer provides both the primary hard mask function and acts as a barrier layer, while the PE-oxide layer provides additional mask protection. This multi-functional design allows a single etching step to achieve what previously required multiple specialized etching steps.
2Manufacturing precision
If multiple etching steps are performed to define the trench pattern, then the hard mask layer can be precisely patterned, but the process complexity increases
Solution Approach 1:
The patent merges the patterning of multiple hard mask layers into a single etching operation. By designing the hard mask structure with titanium nitride and PE-oxide layers that can be etched simultaneously, the process complexity is reduced while maintaining the precision needed for accurate trench pattern definition.
Solution Approach 2:
The patent performs preliminary actions by forming the composite hard mask layer structure before the final etching step. The titanium nitride and PE-oxide layers are deposited and patterned in advance, creating a ready-to-use multi-layer mask system that simplifies the subsequent etching process.
Data Source
AI summary
The present invention provides a fabrication method of an opening. The method includes providing a substrate having a conductive region therein. Thereafter, a dielectric layer is formed over the substrate and then a stacked layer is formed on the dielectric layer. The stacked layer includes a patterned metal hard mask layer, a patterned silicon oxynitride layer and a patterned silicon oxide layer on the dielectric layer in sequence. Afterward, a first portion of the dielectric layer is removed using the stacked layer as a first mask to form a first opening that exposes a surface of the conductive region.