Semiconductor Package Hybrid Bonding with Segmented Copper Interfaces
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Solution Overview
Problem
In semiconductor package structures, the increasing demand for high I/O connections and smaller device geometries leads to challenges in contact resistance and alignment, particularly in hybrid bonding where metal-metal and dielectric-dielectric interfaces require precise planarization and alignment, which is complicated and difficult to control.
Innovation Solution
A semiconductor package structure with a copper-copper interface in narrower pitch regions and a copper-solder interface in wider pitch regions, allowing for relaxed planarization and alignment, with conductive pillars of different pitches and materials to facilitate self-assembly alignment and reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hybrid bonding with metal-metal and dielectric-dielectric interfaces is used to achieve high I/O connections, then connection density is improved, but planarization and alignment complexity increases
Solution Approach 1:
The bonding interface is segmented into two distinct regions: a first region with metal-to-metal bonding for high-density I/O connections and a second region with metal-to-solder bonding for lower-density connections. This segmentation allows each region to be optimized independently, simplifying the overall bonding process while maintaining high connection density.
Solution Approach 2:
Different bonding methods are applied to different regions of the bonding interface. The first region uses metal-to-metal bonding with specific planarization requirements, while the second region uses metal-to-solder bonding with relaxed planarization requirements. This local differentiation allows high-density connections where needed while reducing complexity in other areas.
2Reliability
If metal-to-metal bonding is used in all regions to achieve low contact resistance, then electrical performance is improved, but manufacturing complexity increases
Solution Approach 1:
Metal-to-metal bonding is applied specifically in the first region where low contact resistance is critical for high-density I/O connections, while metal-to-solder bonding is used in the second region where such stringent electrical performance requirements are not as critical. This localized application optimizes electrical performance where needed while simplifying manufacturing elsewhere.
Solution Approach 2:
The bonding structure is divided into two functional segments: a first segment with metal-to-metal bonding for critical low-resistance paths and a second segment with metal-to-solder bonding for less critical connections. This segmentation allows differential optimization of electrical performance and manufacturing ease in different parts of the package.
3Quantity of substance
If pitch between contact pads is reduced to increase I/O count, then connection density is improved, but alignment precision requirements increase
Solution Approach 1:
The contact pad array is segmented into a first region with narrow pitch for high I/O count and a second region with wider pitch. The metal-to-metal bonding in the first region provides robust alignment and low contact resistance, enabling the narrow pitch to be manufactured with acceptable precision while still achieving high I/O count.
Solution Approach 2:
The metal-to-metal bonding interface acts as an intermediary mechanism that facilitates alignment in the narrow pitch region. The direct metal contact provides self-alignment and tolerance compensation, enabling higher I/O counts at reduced pitches without proportionally increasing alignment precision requirements.
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 simplifies the bonding process by reducing the complexity of planarization and alignment, while maintaining lower contact resistance through the use of copper-copper interfaces in dense regions and copper-solder interfaces in less dense regions, enhancing the reliability and efficiency of the semiconductor package structure.
Implementation Method 1
a copper-copper interface
Implementation Method 2
a copper-solder interface
Data Source
AI summary
A semiconductor package structure includes a semiconductor die surface having a narrower pitch region and a wider pitch region adjacent to the narrower pitch region, a plurality of first type conductive pillars in the narrower pitch region, each of the first type conductive pillars having a copper-copper interface, and a plurality of second type conductive pillars in the wider pitch region, each of the second type conductive pillars having a copper-solder interface. A method for manufacturing the semiconductor package structure described herein is also disclosed.