Semiconductor Package Solder Bump Structure for Corrosion-Resistant Bonding
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Solution Overview
Problem
Conventional semiconductor packages face challenges in enhancing reliability and durability, and there is a need to improve production yield in the fabrication process.
Innovation Solution
The semiconductor package includes a semiconductor die with first and second redistribution insulating layers, first and second redistribution bonding pads, and solder bumps with specific shapes and configurations to enhance structural stability and adhesion, using a method that involves forming solder bumps with tapered shapes and a reflow process to improve bonding strength and prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bonding methods are used, then the fabrication process is simple, but the reliability and durability of the semiconductor package are insufficient
Solution Approach 1:
The patent applies preliminary action by forming a protective coating layer on the bonding pad before the reflow process. This coating layer is prepared in advance to prevent copper corrosion during subsequent processing steps, thereby improving reliability without significantly complicating the fabrication process
Solution Approach 2:
The patent uses composite materials by combining the bonding pad (copper), protective coating layer (oxide or other protective material), and solder bump (tin-based alloy). This composite structure provides both electrical connectivity and corrosion protection, enhancing durability while maintaining process feasibility
2Strength
If solder bumps are formed with conventional shapes, then the fabrication process is straightforward, but the adhesion and bonding strength are insufficient
Solution Approach 1:
The patent employs spheroidality by forming solder bumps with a spherical or hemispherical shape rather than a flat or irregular shape. This curved geometry increases the contact area between the solder bump and bonding pad, improving adhesion and bonding strength. The spherical shape is achieved through controlled reflow processing
Solution Approach 2:
The patent applies parameter changes by controlling the reflow process parameters (temperature, time, atmosphere) to achieve the desired solder bump morphology. By optimizing these parameters, the solder bump forms with enhanced wetting and adhesion properties, improving bonding strength while maintaining manufacturability
3Reliability
If copper bonding pads are used without protection, then the fabrication process is simple, but copper corrosion occurs reducing reliability
Solution Approach 1:
The patent applies preliminary anti-action by forming a protective coating layer on the copper bonding pad before the reflow process. This coating layer acts as a barrier to prevent copper corrosion during subsequent processing and operation, thereby improving reliability. The protective layer is integrated into the existing fabrication flow with minimal additional steps
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 enhances the reliability and durability of the semiconductor package by improving structural stability and adhesion, while increasing production yield and preventing copper corrosion, thereby addressing the challenges of conventional technologies.
Implementation Method 1
performing a reflow process while pressing the solder balls with the mold frame to form solder bumps bonded to the redistribution bonding pads
Data Source
AI summary
A semiconductor package may include a semiconductor die, first and second redistribution insulating layers sequentially stacked below the semiconductor die, first redistribution bonding pads disposed on a bottom surface of the second redistribution insulating layer, and first solder bumps bonded to the first redistribution bonding pads. The first solder bumps may cover and contact side surfaces of the first redistribution bonding pads.