Hybrid Bond Semiconductor Structure for CMP Dishing Control
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes for semiconductor wafers often result in dishing and dielectric erosion, which hinder the formation of robust and electrically effective hybrid bonds between wafers, leading to poor structural and electrical connections.
Innovation Solution
The use of semiconductor processing tools to grow conductive materials and apply nitrogen plasma to fill voids, providing improved planarization and reducing dishing and dielectric erosion, along with the omission of post-bonding annealing to enhance bonding strength and surface purity through covalent bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CMP process is used to planarize wafer surface, then surface flatness is improved, but dishing and dielectric erosion occur
Solution Approach 1:
The patent applies nitrogen plasma treatment to the CMP-processed surface. The plasma reacts with the metal surface to form a protective nitride layer that prevents further dishing and dielectric erosion, converting the harmful CMP effects into beneficial protective features through chemical reaction.
Solution Approach 2:
The patent changes the physical and chemical state of the wafer surface by applying nitrogen plasma. This transforms the surface from a vulnerable metallic state to a stable nitride state, altering its mechanical and chemical properties to resist dishing and erosion while maintaining planarity.
2Strength
If post-bonding annealing is performed, then bonding strength is improved, but metal degradation and interdiffusion occur
Solution Approach 1:
The patent performs nitrogen plasma treatment on the metal surfaces before bonding occurs. This preliminary action creates a protective nitride layer that prevents metal degradation and interdiffusion during subsequent bonding processes, eliminating the need for post-bonding annealing that would otherwise cause harmful effects.
Solution Approach 2:
The nitrogen plasma acts as an intermediary substance between the metal surfaces. It forms a nitride layer that serves as a protective barrier, mediating the interaction between metal surfaces during bonding and preventing direct metal-to-metal contact that would cause degradation and interdiffusion.
3Strength
If conventional bonding is used, then wafer connection is achieved, but void formation reduces structural integrity
Solution Approach 1:
The patent uses nitrogen plasma to react with surface contaminants and organic residues, converting them into volatile compounds that are removed during the plasma process. This eliminates the source of void formation and creates a clean, reactive surface that promotes void-free bonding with improved structural integrity.
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
This approach results in a uniform bonding interface with increased mechanical strength, reduced void formation, and improved conductivity, enabling multi-wafer stacking and resistance to mechanical stress while avoiding metal degradation and interdiffusion.
Implementation Method 1
apply nitrogen plasma to fill voids
Implementation Method 2
growing a conductive material within the concave recessed portion
Implementation Method 3
enhance bonding strength and surface purity through covalent bonding
Data Source
AI summary
Some implementations described herein provide a semiconductor structure. The semiconductor structure includes a first conductive structure disposed within a first layer of the semiconductor structure. The semiconductor structure includes a dielectric structure disposed within a second layer of the semiconductor structure, with the second layer being disposed on the first layer. The semiconductor structure includes a second conductive structure disposed within a recessed portion of the dielectric structure that extends to the first conductive structure, with the second conductive structure having a concave recessed portion on a top surface of the second conductive structure. The semiconductor structure includes multiple layers of conductive material disposed within the concave recessed portion of the second conductive structure.