Silicon Oxide Embedded MIM Structure for Reliable Copper RDL
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Solution Overview
Problem
Existing semiconductor fabrication methods for copper redistribution layers (RDL) in metal-insulator-metal (MIM) structures result in subpar insulator layer characteristics, such as poor crystallinity and lower-than-desired dielectric constant, leading to degraded performance and reliability issues like time-dependent dielectric breakdown (TDDB).
Innovation Solution
Embedding the MIM structure in an oxide-based material, specifically silicon oxide, instead of nitride-based materials, to promote better formation of metal-containing layers and insulator layers, enhancing crystallinity and dielectric constant, and reducing TDDB failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitride-based materials are used to embed MIM structure, then the fabrication process is compatible with existing copper RDL schemes, but the insulator layers exhibit poor crystallinity and lower dielectric constant
Solution Approach 1:
The patent changes the material composition parameter of the embedding layer from nitride-based to oxide-based material. This parameter change fundamentally alters the interface properties, enabling better crystallinity and dielectric constant in the insulator layers while remaining compatible with existing copper RDL fabrication processes.
Solution Approach 2:
The patent employs a composite structure where oxide-based material is combined with metal-containing layers and insulator layers to form the MIM structure. The oxide-based embedding layer serves as a foundation that enhances the properties of subsequent layers, creating a composite system with superior overall performance.
2Reliability
If existing copper RDL fabrication methods are used, then the process is straightforward and compatible, but the insulator layers suffer from poor crystallinity leading to time-dependent dielectric breakdown
Solution Approach 1:
The patent applies preliminary action by preparing the oxide-based embedding layer before depositing the metal-containing and insulator layers. This pre-prepared foundation with optimal material properties enables the subsequent layers to achieve better crystallinity and resist TDDB failures, addressing the manufacturing precision issue before the problem manifests.
3Productivity
If MIM structure is formed with conventional embedding materials, then the device can be manufactured with current processes, but the insulator layers exhibit lower dielectric constant degrading performance
Solution Approach 1:
The patent changes the material parameter from nitride-based to oxide-based embedding material, which directly improves the dielectric constant of the insulator layers. This parameter change enhances the overall device performance while maintaining compatibility with existing manufacturing processes, resolving the contradiction between productivity and reliability.
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 improved copper RDL scheme achieves higher dielectric constant and reduced TDDB failures, enhancing device performance and reliability by forming metal-containing layers directly on silicon oxide, which improves the crystal lattice structure of insulator layers.
Implementation Method 1
Embedding the MIM structure in an oxide-based material, specifically silicon oxide, instead of nitride-based materials, to promote better formation of metal-containing layers and insulator layers, enhancing crystallinity
Data Source
AI summary
A device includes a first dielectric layer. A second dielectric layer is disposed over the first dielectric layer. The second dielectric layer and the first dielectric layer have different material compositions. A metal-insulator-metal (MIM) structure is embedded in the second dielectric layer. A third dielectric layer is disposed over the second dielectric layer. The third dielectric layer and the second dielectric layer have different material compositions. The first dielectric layer or the third dielectric layer may contain silicon nitride (SiN), the second dielectric layer may contain silicon oxide (SiO2).