Hybrid Bonding Pads With Dual Diffusion Barriers for Leakage Control
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Solution Overview
Problem
Existing semiconductor packages face challenges in preventing metal diffusion from conductive pads into adjacent dielectric layers due to misalignment during bonding, leading to increased leakage current and reduced reliability.
Innovation Solution
Incorporating diffusion barriers with organic materials around conductive pads and silicon oxide layers to prevent metal diffusion, ensuring the semiconductor chips are bonded with a hybrid structure that includes a first diffusion barrier on the bottom surface and a second diffusion barrier on the lateral surface, both made of different materials to enhance adhesion and reduce copper diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding structures are used without diffusion barriers, then manufacturing process is simpler, but metal diffusion occurs from conductive pads into adjacent dielectric layers causing increased leakage current
Solution Approach 1:
The bonding structure is segmented into multiple functional layers: a first diffusion barrier layer contacts the bottom surface of the conductive pad, while a second diffusion barrier layer contacts the lateral surface. This segmentation allows each layer to specifically address diffusion from different surfaces, effectively preventing metal diffusion into dielectric layers without requiring a single complex barrier structure.
Solution Approach 2:
Different diffusion barrier materials are used at different locations: the first diffusion barrier layer uses a material optimized for bottom surface protection, while the second diffusion barrier layer uses a different material optimized for lateral surface protection. This local quality approach ensures optimal diffusion prevention at each location while managing overall structure complexity.
2Reliability
If diffusion barriers are added to prevent metal diffusion, then leakage current characteristics improve, but manufacturing precision requirements increase due to alignment constraints
Solution Approach 1:
The diffusion barrier layers are formed on the conductive pads before the bonding process. The first diffusion barrier layer is formed to contact the bottom surface, and the second diffusion barrier layer is formed to contact the lateral surface. This preliminary formation ensures that the barrier structure is already in place to prevent metal diffusion during bonding, reducing the need for high precision alignment during the bonding process itself.
Solution Approach 2:
The diffusion barrier layers act as intermediary structures between the conductive pads and the dielectric layers. By introducing these intermediate barrier layers, the patent creates a buffer zone that prevents direct contact and potential diffusion pathways, thereby reducing the stringency of alignment precision requirements during bonding.
3Reliability
If hybrid diffusion barrier structure with different materials is used, then adhesion and diffusion prevention are enhanced, but device complexity increases
Solution Approach 1:
The patent applies different materials for the first and second diffusion barrier layers based on their specific locations and functions. The first diffusion barrier layer material is selected for optimal adhesion to the bottom surface of the conductive pad, while the second diffusion barrier layer material is selected for optimal protection of the lateral surface. This local quality approach enhances overall reliability without requiring a single complex multi-material structure.
Solution Approach 2:
The bonding structure uses a composite approach with two different diffusion barrier materials in specific configurations. The first diffusion barrier layer and second diffusion barrier layer are made of different materials, creating a composite barrier system that leverages the advantages of each material for its specific location, thereby enhancing adhesion and diffusion prevention while managing structural complexity.
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
The solution effectively suppresses metal diffusion, thereby improving leakage current characteristics and enhancing the reliability and durability of semiconductor devices by maintaining structural integrity and electrical connectivity.
Implementation Method 1
a first diffusion barrier in contact with a bottom surface of the first conductive pad; and a second diffusion barrier in contact with a lateral surface of the first conductive pad
Data Source
AI summary
A semiconductor device includes a first semiconductor chip that includes a first conductive pad whose top surface is exposed; and a second semiconductor chip that includes a second conductive pad whose top surface is exposed and in contact with at least a portion of the top surface of the first conductive pad. The first semiconductor chip may include a first diffusion barrier in contact with a bottom surface of the first conductive pad, and a second diffusion barrier in contact with a lateral surface of the first conductive pad, and the first diffusion barrier and the second diffusion barrier may include different materials from each other.