Sealed Bonded Structure With Closed Conductive Profile
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Solution Overview
Problem
Existing semiconductor device seals, such as those using adhesives like solder, are permeable to gases, which can damage sensitive integrated devices and affect performance, while alternative adhesives pose long-term reliability issues.
Innovation Solution
A bonded structure is formed with a conductive interface feature, such as a copper layer, and a nonconductive interface feature, such as silicon oxide, to create a sealed cavity that prevents gas permeation, using direct metal-to-metal bonding without adhesives, and a conductive structure extending around the integrated device to form an effectively closed profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive materials (such as solder) are used to seal the cavity, then the integrated device is sealed from the outside environs, but the adhesive is permeable to gases which can damage the device over time
Solution Approach 1:
The patent removes the adhesive material from the bonding interface, extracting the harmful element that causes gas permeation. Direct metal-to-metal bonding is used instead, eliminating the permeable adhesive layer while maintaining the sealing function through the metallurgical bond between cap and substrate.
Solution Approach 2:
The patent employs a composite bonding structure combining different metal layers with specific properties. The first and second metal layers form a metallurgical bond that provides both mechanical attachment and gas-tight sealing, leveraging the complementary properties of different materials to achieve hermetic sealing.
2Ease of manufacture
If wide metal lines are used for bonding, then direct metal-to-metal bonding is achieved, but dishing and inconsistent bonding occur
Solution Approach 1:
The patent applies different metal layers with specific local properties at the bonding interface. The first metal layer on the cap and second metal layer on the substrate are designed with particular compositions and thicknesses optimized for their respective roles, creating local quality variations that ensure consistent bonding across the interface without dishing.
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 structure effectively seals the integrated device from outside environs, reducing gas permeation and preventing damage, while avoiding issues like dishing and inconsistent bonding associated with wide metal lines.
Implementation Method 1
The first plurality of contact pads are directly bonded to the second plurality of contact pads along an interface structure without an intervening adhesive
Implementation Method 2
The elongate conductive structure can provide an effectively closed profile around the integrated device
Data Source
AI summary
A bonded structure is disclosed. The bonded structure includes a first element that has a front side and a back side that is opposite the front side. The first element has a first conductive pad and a first nonconductive field region at the front side of the first element. The bonded structure also includes a second element that has a second conductive pad and a second nonconductive field region at a front side of the second element. The second conductive pad is bonded to the first conductive pad along an interface structure. The bonded structure also includes an integrated device that is coupled to or formed with the first element or the second element. The bonded structure further includes an elongate conductive structure that extends from the back side of the first element to the interface structure. The elongate conductive structure provides an effectively closed profile around the integrated device.