Sealed Bonded Structure for Gas-Resistant IC Packaging
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Solution Overview
Problem
Existing adhesives used in semiconductor device fabrication and packaging are permeable to gases, which can damage sensitive integrated devices or affect device performance, and alternative adhesives like solder pose long-term reliability issues.
Innovation Solution
A bonded structure is formed using 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, utilizing a conductive structure to define an effectively annular or closed pattern around the integrated device, and embedding conductive features with non-conductive features to mitigate dishing during planarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesives are used to attach cap to substrate, then sealing is provided, but gases can permeate through the adhesive and into the cavity
Solution Approach 1:
The bonding interface is segmented into multiple discrete bonding regions (first, second, third, and fourth bonding regions) arranged in a pattern around the cavity. This segmentation creates multiple separate bonding points that collectively provide superior sealing compared to a continuous adhesive layer, preventing gas permeation while maintaining seal integrity.
Solution Approach 2:
A direct bond is formed between the cap and substrate at discrete bonding regions without using adhesive materials as intermediaries. This eliminates the adhesive layer that would otherwise allow gas permeation, while still providing the necessary sealing function through direct material-to-material bonding.
2Reliability
If solder is used to attach cap to substrate, then sealing is provided, but long-term reliability issues arise
Solution Approach 1:
The patent employs standard semiconductor materials (such as silicon, metal layers, and dielectric materials) that are already present in the device structure, eliminating the need for specialized solder materials. These materials provide reliable bonding without the long-term degradation issues associated with solder, leveraging existing device components for the bonding function.
3Reliability
If adhesive is used for bonding, then sealing is provided, but dishing and inconsistent bonding surfaces occur
Solution Approach 1:
The adhesive layer is completely removed from the bonding process. Instead of using adhesive that causes dishing and surface inconsistency, the patent achieves bonding through direct material-to-material contact at discrete regions, eliminating the source of the surface quality problems while maintaining sealing effectiveness.
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.