Semiconductor Seal Ring Structure for Adhesion and Dicing Stress
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Solution Overview
Problem
Existing semiconductor seal ring structures face challenges with adhesion between substrate and metal features, metal filling quality, and reliability due to poor adhesion, seams, or voids, which can lead to delamination defects or cracks during dicing and operational stress.
Innovation Solution
A seal ring structure with multi-step profile metal plugs and alternately arranged dummy gates, improving adhesion and filling quality, and incorporating multiple seal rings and trenches to enhance stress resistance and operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional seal ring structures are used, then fabrication is simpler, but adhesion between substrate and metal features deteriorates
Solution Approach 1:
The metal plug is divided into multiple sections (first section, second section, third section) with progressively increasing widths from bottom to top. This segmentation creates a multi-step profile that improves adhesion by increasing the contact area between the metal plug and surrounding materials, while maintaining structural integrity.
Solution Approach 2:
Different sections of the metal plug have different widths to optimize local properties. The narrower bottom section provides strong substrate attachment, while the wider upper sections provide better connection to overlying structures and improved stress distribution. This local variation in geometry enhances overall adhesion without requiring entirely different materials.
2Manufacturing precision
If conventional metal filling is used, then processing is faster, but filling quality deteriorates with seams or voids
Solution Approach 1:
The multi-step profile of the metal plug is formed before final metal filling, creating pre-formed cavities and adherence surfaces. This preliminary structuring ensures that subsequent metal filling processes can proceed efficiently while achieving void-free, seamless results, as the profile guides material flow and adhesion from the outset.
Solution Approach 2:
The multi-step metal plug structure acts as an intermediary form that mediates between the substrate and overlying structures. Its stepped geometry provides intermediate surfaces that facilitate uniform metal deposition and filling, preventing void formation by ensuring continuous material flow and adhesion across different height levels.
3Strength
If single seal ring structure is used, then device complexity is lower, but stress resistance during dicing deteriorates
Solution Approach 1:
The seal ring structure is segmented into multiple separate seal rings arranged in concentric or overlapping patterns. This segmentation allows each individual seal ring to be optimized for stress distribution, while the collective arrangement provides enhanced resistance to dicing forces. The multiple rings share the mechanical load, preventing catastrophic failure.
Solution Approach 2:
The multiple seal rings are positioned and sized to create overlapping or nested configurations that cushion against dicing stresses before they can propagate through the substrate. This prior cushioning arrangement absorbs and distributes mechanical energy from the dicing process, protecting the underlying circuitry.
4Reliability
If conventional seal ring structure is used, then fabrication is simpler, but operational reliability deteriorates due to delamination or cracks
Solution Approach 1:
The seal ring structure is merged with dummy gates in an alternating pattern, where seal rings and dummy gates are interspersed along the periphery of the circuit region. This merging serves multiple functions: it provides mechanical reinforcement against delamination and cracking, while the dummy gates also serve as structural elements that distribute stress. The combined structure achieves enhanced reliability without requiring entirely separate components.
Solution Approach 2:
The alternating seal ring and dummy gate structure serves multiple functions simultaneously: electrical isolation, mechanical reinforcement, stress distribution, and process compatibility. Each element in the alternating pattern contributes to both sealing and structural integrity, achieving universal functionality that improves reliability without proportionally increasing complexity.
Data Source
AI summary
A semiconductor structure includes a substrate having a seal ring region and a circuit region, a dielectric interlayer over the substrate, one or more dielectric layers disposed over the dielectric interlayer, a connection structure disposed in the one or more dielectric layers in the seal ring region, and a metal plug disposed below the connection structure and disposed at least partially in the dielectric interlayer in the seal ring region. The connection structure includes a stack of metal layers and metal vias connecting the stack of metal layers.