Wafer Sidewall Barrier Layer for Moisture-Resistant Bonding
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Solution Overview
Problem
Existing wafer bonding processes face challenges in preventing detrimental chemicals and moisture from penetrating through the sidewalls, leading to degradation of low-k dielectric layers and metal features in the device wafer.
Innovation Solution
A high-density sidewall protection layer is formed using materials like silicon nitride or metal compounds to prevent chemical and moisture penetration, which is denser than silicon oxide, and is applied during the wafer bonding process to protect the device wafer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard silicon oxide sidewall protection layer is used, then the manufacturing process is simple and cost-effective, but the layer cannot effectively block detrimental chemicals and moisture from penetrating through, leading to degradation of low-k dielectric layers and metal features
Solution Approach 1:
The patent applies composite materials by forming a sidewall protection layer comprising multiple distinct layers: a first sidewall protection layer (silicon oxide) and a second sidewall protection layer (silicon nitride or metal compound). This composite structure combines the advantages of different materials - silicon oxide provides good adhesion and basic protection, while silicon nitride or metal compounds provide superior density and chemical/moisture barrier properties. The combination effectively blocks detrimental chemicals and moisture that would otherwise penetrate through a single silicon oxide layer, thereby resolving the contradiction between protection effectiveness and structural simplicity.
Solution Approach 2:
The patent applies parameter changes by modifying the density parameter of the sidewall protection layer. The second sidewall protection layer uses materials with higher density (silicon nitride or metal compounds) compared to the first layer (silicon oxide). This density enhancement is the key parameter change that enables the layer to effectively block chemical and moisture penetration. By changing the material density parameter, the patent achieves superior protection without significantly increasing process complexity, as these materials can be deposited using standard CVD or PECVD techniques.
2Object-affected harmful factors
If a high-density material is used for the sidewall protection layer, then the blocking ability against chemicals and moisture is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by first depositing the silicon oxide layer (first sidewall protection layer) before depositing the silicon nitride or metal compound layer (second sidewall protection layer). This sequential approach ensures that the foundational layer is in place to provide adhesion and basic protection, and then the high-density barrier layer is added on top to provide superior chemical and moisture blocking. This preliminary structuring simplifies the overall manufacturing process by breaking down the complex task of creating a high-performance barrier into manageable, sequential deposition steps using standard semiconductor fabrication equipment.
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 high-density sidewall protection layer effectively blocks oxygen and moisture, reducing degradation of low-k dielectric layers and metal features, thereby enhancing the integrity and performance of the device wafer.
Implementation Method 1
A sidewall protection layer is formed on the sidewall of the device wafer. The sidewall protection layer has a high density, which has a good blocking ability for preventing detrimental chemicals and moisture from penetrating through.
Data Source
AI summary
A method includes bonding a first wafer to a second wafer, performing a trimming process on the first wafer, and depositing a sidewall protection layer contacting a sidewall of the first wafer. The depositing the sidewall protection layer includes depositing a high-density material in contact with the sidewall of the first wafer. The sidewall protection layer has a density higher than a density of silicon oxide. The method further includes removing a horizontal portion of the sidewall protection layer that overlaps the first wafer, and forming an interconnect structure over the first wafer. The interconnect structure is electrically connected to integrated circuit devices in the first wafer.