Conductive Pad Protrusion for Low-Resistance TSV Bonding
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing complex microelectronic components with smaller feature sizes, requiring improvements in integration density and packaging complexity, particularly in forming reliable connections between conductive pads and through silicon vias (TSVs) without increasing electrical resistance.
Innovation Solution
A semiconductor structure is developed with a protrusion between the conductive pad and the TSV, formed using deposition rather than electroplating, allowing for hybrid bonding at lower temperatures and maintaining low electrical resistance, and a method involving forming a first die with a conductive pad and via, and a second die with a bonded substrate and via, where the contact surface areas are optimized for efficient bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electroplating is used to form the connection between conductive pad and TSV, then the electrical resistance can be reduced, but the manufacturing process complexity and temperature requirements increase
Solution Approach 1:
The patent changes the deposition method from electroplating to physical vapor deposition (PVD), altering the process parameters to achieve low electrical resistance without requiring high temperatures or complex electroplating equipment. This parameter change resolves the contradiction by maintaining electrical performance while simplifying the manufacturing process
Solution Approach 2:
The patent replaces the electrochemical system (electroplating) with a physical deposition system (PVD). This substitution eliminates the need for electroplating baths, power supplies, and complex process control, thereby reducing manufacturing complexity while still achieving the required electrical conductivity through direct physical deposition of conductive material
2Productivity
If feature size is reduced to increase integration density, then more components can be integrated, but manufacturing precision requirements increase
Solution Approach 1:
The patent extracts the connection formation process from the broader lithography-etching-manufacturing sequence by using direct PVD deposition. This extraction allows the conductive material to be deposited precisely where needed without requiring the full lithography and etching sequence, thereby maintaining manufacturing precision while enabling smaller feature sizes and higher integration density
Solution Approach 2:
The patent performs preliminary deposition of conductive material on the conductive pad surface before TSV formation. This preliminary action ensures that when the TSV is later formed and contacted, the conductive interface is already prepared with precise material placement, reducing the precision burden on subsequent manufacturing steps and enabling smaller features
3Strength
If bonding temperature is increased to improve bonding strength, then hybrid bonding reliability improves, but the grain size of deposited material increases
Solution Approach 1:
The patent employs a two-stage bonding process with periodic heating: an initial low-temperature stage that forms fine-grained deposits, followed by a controlled second stage that enhances bonding strength without excessive grain growth. This periodic thermal action resolves the contradiction by achieving both strong bonding and fine grain structure through staged processing
Solution Approach 2:
The patent changes the bonding temperature parameter from high single-stage heating to controlled multi-stage heating with different temperature profiles. This parameter change allows the first stage to deposit fine grains at lower temperature, then the second stage to strengthen bonds without causing excessive grain growth, thereby resolving the contradiction between bonding strength and grain size
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 enhances the reliability and overall structure of semiconductor devices by allowing for smaller grain size deposition and lower temperature hybrid bonding, reducing electrical resistance and improving integration density without increasing complexity.
Implementation Method 1
the protrusion can be formed by deposition rather than an electroplating process
Implementation Method 2
the hybrid bonding between the first die and the second die can be annealed at a relatively lower temperature
Data Source
AI summary
The present application provides a semiconductor structure having a conductive pad with a protrusion, and a manufacturing method of the semiconductor structure. The semiconductor structure includes a first die including a first substrate, a first dielectric layer over the first substrate, a first conductive pad at least partially exposed through the first dielectric layer, a first bonding layer over the first dielectric layer, and a first via extending through the first bonding layer and coupled to the first conductive pad; and a second die including a second bonding layer bonded to the first bonding layer, a second substrate over the second bonding layer, and a second via extending through the second substrate and the second bonding layer, wherein a first contact surface area between the first bonding layer and the second via is substantially greater than a second contact surface area between the first via and the second via.