GaN Seal Ring Structure for Crack-Resistant 3D Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor structures with seal rings are prone to cracks during 2.5D or 3D IC packaging, leading to reduced reliability of GaN-based devices due to unprotected portions of the GaN layer, which can propagate and cause degradation.
Innovation Solution
Forming seal rings directly on the silicon substrate surrounding the III-V semiconductor layer, protecting compound semiconductor devices by isolating them from cracks, thereby enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal rings are formed during fabrication of multi-layer structure, then semiconductor devices are protected from moisture degradation and ionic contamination, but cracks can still propagate into unprotected portions of GaN layer causing device degradation
Solution Approach 1:
The patent applies preliminary action by forming the seal ring structure before the dicing and packaging processes. The seal ring is created during fabrication of the multi-layer structure, establishing protective barriers in advance that prevent crack propagation into the GaN layer during subsequent processing and operation. This proactive approach addresses crack propagation before it can occur during dicing or packaging.
Solution Approach 2:
The seal ring acts as an intermediary element between the GaN layer and external harmful factors. It is positioned at the periphery of the device structure, serving as a mediator that intercepts and contains cracks, preventing them from reaching the active GaN regions. The seal ring material composition and structural positioning enable it to absorb or deflect mechanical stress and crack propagation forces.
2Ease of manufacture
If existing seal ring structures are used, then basic protection is provided, but cracks during 2.5D or 3D IC packaging can propagate into unprotected GaN layer portions
Solution Approach 1:
The patent applies segmentation by dividing the protective function into distinct structural components: the seal ring structure formed during fabrication and the GaN layer with its active device regions. The seal ring is segmented to surround and protect specific portions of the GaN layer, creating isolated protected zones. This segmentation allows the structure to withstand packaging-induced stresses while maintaining device integrity.
Solution Approach 2:
The patent implements local quality by providing enhanced protection specifically at the periphery where cracks are most likely to initiate and propagate. The seal ring is positioned at the edges and corners of the device structure, concentrating protective measures where they are most needed. The GaN layer has different functional regions with varying protection requirements, and the seal ring provides localized reinforcement at critical stress points without affecting the entire device uniformly.
Data Source
AI summary
Semiconductor structures and methods are provided. An exemplary semiconductor structure according to the present disclosure includes a semiconductor substrate including a first region and a second region surrounding the first region, a III-V semiconductor layer disposed directly over the first region, a compound semiconductor device formed in and over the III-V semiconductor layer, a first plurality of conductive features disposed over and electrically coupled to a source contact of the compound semiconductor device, and a seal ring disposed directly over the second region and comprising a second plurality of conductive features, a top surface of a topmost conductive feature of the first plurality of conductive features is higher than a top surface of a topmost conductive feature of the second plurality of conductive features.