Alternating Tantalum Etch Stop Stack for Semiconductor Inductors
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Solution Overview
Problem
Current semiconductor device fabrication processes face challenges in forming reliable inductors due to issues such as delamination and cracking of etch stop stacks, which affect the integrity and performance of magnetic layers and interconnect structures.
Innovation Solution
The formation of a semiconductor device involves a specific etch stop stack comprising alternately disposed tantalum and tantalum oxide layers, which protects the underlying dielectric layers during etching and ensures the magnetic layer's integrity, along with a dielectric layer encapsulating the magnetic layer and etch stop stack, enhancing structural reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional etch stop stacks are used in semiconductor device fabrication, then the etching process can proceed, but delamination and cracking occur affecting structural integrity
Solution Approach 1:
The patent employs a composite etch stop stack structure consisting of alternating tantalum (metal) and tantalum oxide (oxide) layers. This composite material approach combines materials with complementary properties: tantalum provides mechanical strength and adhesion, while tantalum oxide provides etch resistance. The composite structure prevents delamination and cracking by distributing stress across multiple layers with different mechanical and chemical properties, thereby resolving the technical contradiction between maintaining structural integrity and withstanding etching processes.
Solution Approach 2:
The etch stop function is segmented into multiple alternating layers of tantalum and tantalum oxide rather than using a single homogeneous layer. This segmentation allows each material to perform its optimal function: tantalum layers provide mechanical support and adhesion to prevent delamination, while tantalum oxide layers provide superior etch resistance. The segmented structure prevents crack propagation by creating barriers at each interface, thereby resolving the contradiction between structural integrity and resistance to harmful factors.
2Reliability
If magnetic layers are formed over dielectric layers, then inductor functionality is achieved, but the magnetic layer integrity is compromised during etching
Solution Approach 1:
The alternating tantalum and tantalum oxide layers serve as an intermediary protective barrier between the dielectric layer below and the magnetic layer above during the etching process. The tantalum oxide layers provide superior etch resistance, protecting the underlying dielectric and indirectly protecting the magnetic layer from etching damage. The tantalum layers provide mechanical support and stress distribution, further protecting the magnetic layer structure. This intermediary etch stop stack resolves the contradiction by shielding the magnetic layer from direct exposure to harsh etching conditions.
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 reduces delamination and cracking, improves the reliability of semiconductor devices by maintaining the structural integrity of the magnetic layer and dielectric layers, thereby enhancing the overall performance and yield of semiconductor devices.
Implementation Method 1
performing a plurality of cycles to form a plurality of tantalum layers and a plurality of tantalum oxide layers over the first dielectric layer, each cycle comprising depositing a tantalum layer and oxidizing the tantalum layer to form a tantalum oxide layer
Data Source
AI summary
Semiconductor devices and methods of forming the same are provided. One of the semiconductor devices comprises a conductive layer, a first dielectric layer disposed over the conductive layer, a magnetic layer disposed over the first dielectric layer, and a plurality of tantalum layers and a plurality of tantalum oxide layers alternately disposed between the magnetic layer and the first dielectric layer.