Conductive Bonding Interface Structure for Gas-Tight Chip Sealing
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Solution Overview
Problem
Current adhesives used in semiconductor device fabrication and packaging are permeable to gases, leading to contamination and damage of sensitive integrated devices, and traditional solder adhesives pose long-term reliability issues, necessitating improved sealing methods.
Innovation Solution
The implementation of conductive and non-conductive interface features, such as copper and silicon oxide layers, that are directly bonded without adhesives to create a sealed structure, utilizing conductive features to prevent gas permeation and mitigate hillock formation during annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional adhesive materials are used to bond semiconductor elements, then the bonding process is simple and cost-effective, but the adhesive is permeable to gases causing contamination and device damage
Solution Approach 1:
The patent changes the material parameter from adhesive to direct metal bonding, fundamentally altering the bonding mechanism to achieve gas impermeability. This parameter change resolves the contradiction by eliminating the permeable adhesive layer while maintaining bonding functionality through direct metallurgical bonding of copper interfaces.
Solution Approach 2:
The patent employs composite material structures with copper layers and dielectric materials to create a bonded interface that provides both mechanical bonding and gas barrier functionality. The composite structure integrates multiple material properties to simultaneously achieve reliability and controlled complexity.
2Duration of action of stationary object
If solder adhesive is used for bonding, then initial bonding strength is achieved, but long-term reliability issues arise due to gas permeation and material degradation
Solution Approach 1:
The patent extracts and removes the harmful adhesive material from the bonding interface, replacing it with direct copper-to-copper bonding. This elimination of the permeable intermediate layer completely removes the gas permeation pathway, resolving the contradiction between initial bonding strength and long-term gas barrier performance.
Solution Approach 2:
The patent replaces the disposable adhesive material with a permanent metallurgical bond. The direct copper bonding creates an enduring connection that does not degrade over time like adhesive, providing lasting reliability without the need for replacement or maintenance.
3Reliability
If direct metal bonding is used to achieve gas-tight seal, then gas impermeability is improved, but the bonding process becomes more complex requiring precise interface control
Solution Approach 1:
The patent applies preliminary protective actions by forming copper layers with controlled properties and positioning them in advance before bonding. The copper layers are prepared with specific thicknesses and purities, and the bonding interfaces are pre-aligned, making the subsequent direct bonding process more manageable despite its inherent complexity.
Solution Approach 2:
The patent introduces copper layers as intermediary elements between the semiconductor elements to be bonded. These copper layers serve as both electrical interconnects and bonding interfaces, mediating the bonding process and providing a controlled, reproducible interface that simplifies the overall manufacturing while maintaining gas-tight seals.
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 provides a robust, gas-tight seal that reduces contamination and enhances the reliability of semiconductor devices by minimizing gas permeation and preventing damage from unwanted materials, while also addressing the issues associated with traditional adhesive methods.
Implementation Method 1
conductive features to prevent gas permeation
Implementation Method 2
mitigate hillock formation during annealing
Implementation Method 3
directly bonded without adhesives
Data Source
AI summary
A bonded structure is disclosed. The bonded structure includes a first element and a second element that is bonded to the first element along a bonding interface. The bonding interface has an elongate conductive interface feature and a nonconductive interface feature. The bonded structure also includes an integrated device that is coupled to or formed with the first element or the second element. The elongate conductive interface feature has a recess through a portion of a thickness of the elongate conductive interface feature. A portion of the nonconductive interface feature is disposed in the recess.