Semiconductor Seal Ring Structure for Adhesion and Dicing Reliability
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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, which improves adhesion and filling quality, and includes a connection structure with stacked metal layers and vias, and multiple nested seal rings to enhance operational reliability and withstand dicing stress.
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, leading to delamination defects
Solution Approach 1:
The seal ring structure is segmented into multiple functional layers including metal plugs, conductive barriers, and dielectric materials with distinct properties. Each layer serves a specific function: metal plugs provide mechanical anchoring, conductive barriers prevent diffusion, and dielectric layers provide electrical isolation. This segmentation allows optimization of adhesion at each interface independently.
Solution Approach 2:
The seal ring employs composite material structures combining multiple materials with complementary properties. Metal plugs are composed of copper or aluminum cores with tungsten or cobalt outer layers. Conductive barriers use titanium nitride or tantalum nitride. These composite structures enhance adhesion between substrate and metal features while preventing delamination defects.
2Manufacturing precision
If conventional metal filling is used, then processing is faster, but metal filling quality deteriorates, causing seams and voids
Solution Approach 1:
Conductive barrier layers are deposited on the substrate and within trench structures before metal plug formation. This preliminary action creates a foundation that guides subsequent metal filling, ensuring complete coverage and preventing void formation. The barrier layers are pre-configured to match the eventual metal plug geometry.
Solution Approach 2:
Copper or aluminum seed layers serve as intermediaries between the substrate/conductive barriers and the final tungsten or cobalt metal plugs. These intermediary layers facilitate controlled metal deposition, ensure uniform filling, and prevent direct contact between dissimilar materials that could cause seams or voids during the filling process.
3Reliability
If single-layer seal rings are used, then structure is simpler, but operational reliability deteriorates under dicing stress
Solution Approach 1:
The seal ring structure employs nested concentric rings with different materials and functions. An inner seal ring provides primary protection, while outer seal rings provide additional mechanical support and stress distribution. Each nested ring is anchored to the substrate through its own set of metal plugs, creating a hierarchical reinforcement structure that withstands dicing stress.
Solution Approach 2:
Dielectric layers with controlled mechanical properties are deposited between and around metal plugs in the seal ring structure. These dielectric layers act as cushioning elements that absorb and distribute stress during dicing operations. The dielectric materials are selected to have appropriate elasticity and bonding strength to prevent crack propagation while maintaining structural integrity.
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.