Hybrid Bonding Pad Structure for Stacked Semiconductor Reliability
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Solution Overview
Problem
Current semiconductor package technologies face challenges in achieving high driving stability and improved electric characteristics, particularly in vertically stacked chip structures, where bonding between pads and insulating layers is critical for reliability and durability.
Innovation Solution
A semiconductor device is designed with a lower and upper structure, each having a substrate, circuit pattern, insulating layer, and pads, where the pads include a first and second portion of the same metallic material, allowing direct contact and bonding between the insulating layers to form a hybrid bonding structure, enhancing electrical connectivity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If vertically stacked chip structure is used to increase capacity and reduce size, then integration density is improved, but bonding reliability between pads and insulating layers deteriorates
Solution Approach 1:
The pad structure is segmented into multiple portions (first portion, second portion, third portion) with different materials and functions. The first portion provides mechanical support, the second portion enables direct bonding between insulating layers, and the third portion provides electrical connection, thereby resolving the bonding reliability issue while maintaining high integration density
Solution Approach 2:
The pad structure uses composite materials with different properties in different portions. The first portion uses a conductive material, the second portion uses a bonding material, and the third portion uses another conductive material, creating a multi-material composite structure that simultaneously achieves mechanical support, reliable bonding, and electrical connectivity
2Reliability
If direct bonding between insulating layers is implemented to improve reliability, then bonding strength is improved, but manufacturing complexity increases
Solution Approach 1:
The second portion of the pad is prepared in advance with a surface suitable for direct bonding before the bonding process. This preliminary preparation ensures that when the insulating layers are brought into contact, the bonding occurs reliably without requiring complex real-time processing or additional bonding steps
Solution Approach 2:
The direct bonding interface between the second portions of pads from opposite substrates enables the structure to bond itself when brought into contact. This self-bonding mechanism eliminates the need for external bonding equipment or complex bonding processes, thereby reducing manufacturing complexity while maintaining high bonding strength
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 configuration improves the electrical characteristics and driving stability of semiconductor devices by ensuring robust bonding between pads and insulating layers, preventing void formation and enhancing yield strength, thus improving the overall reliability and durability of the semiconductor package.
Implementation Method 1
performing a thermal treatment process to bond the first pad to the second pad
Data Source
AI summary
A semiconductor device may include a lower structure including a first substrate, a first pad on the first substrate, and a first insulating layer enclosing the first pad, and an upper structure including a second substrate, a second pad on the second substrate, and a second insulating layer enclosing the second pad. Each of the first and second pads may include a first portion and a second portion on the first portion. The second portion may include the same metallic material as the first portion. The second portion of the first pad may be in contact with the second portion of the second pad, and the first insulating layer may be in contact with the second insulating layer.