Semiconductor Bump Structures with Varying Lateral Dimensions
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges in achieving precise control over bump structures to minimize gap variations and ensure uniformity in bump heights, leading to issues like bump bridging and cold joints during assembly, which affect the reliability and performance of electronic components.
Innovation Solution
The use of pillar bumps with varying lateral dimensions and controlled bump heights on different regions of a semiconductor chip, combined with under-bump metallization and lead-free solder capping layers, allows for precise positioning and bonding, minimizing gap variations and enhancing co-planarity, thereby reducing assembly risks and improving package structure quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If pillar bumps are used to achieve finer pitch, then bump pitch is reduced and capacitance load is reduced, but manufacturing precision control becomes more difficult
Solution Approach 1:
The patent applies parameter changes by varying the lateral dimensions of different regions on the semiconductor chip. Specifically, the chip surface is divided into multiple regions with different lateral dimensions, allowing each region to have optimized bump structures that account for variations in bump height and gap dimensions, thereby maintaining manufacturing precision even at finer pitches
Solution Approach 2:
The patent implements local quality by creating different lateral dimensions in different regions of the chip. Each region is tailored with specific dimensional characteristics to compensate for local variations in bump formation, ensuring uniform bump heights and gaps across the entire chip surface despite the finer overall pitch
2Adaptability or versatility
If bump structures are formed with varying gap dimensions, then positioning flexibility is improved, but gap variation control becomes more difficult leading to assembly issues
Solution Approach 1:
The patent applies local quality by dividing the chip into multiple regions with different lateral dimensions, where each region is optimized for its specific positioning requirements. This allows the structure to accommodate varying gap dimensions while maintaining controlled variations through region-specific dimensional tailoring
Solution Approach 2:
The patent utilizes parameter changes by systematically varying the lateral dimensions across different regions. This controlled parameter variation allows the bump structures to achieve positioning flexibility while maintaining uniform gap dimensions within each region, preventing assembly issues like bump bridging and cold joints
3Adaptability or versatility
If non-uniform bump heights are present, then positioning adaptability is improved, but co-planarity is reduced affecting assembly quality
Solution Approach 1:
The patent implements local quality by creating region-specific lateral dimensions that compensate for bump height variations. Each region is designed with tailored dimensions to ensure that bumps in that region achieve uniform co-planarity, while the overall structure maintains positioning adaptability across different areas of the chip
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 enables uniform standoff control and improved dispensing of underfill materials, reducing the risk of bump bridging and cold joints, and enhances the reliability and performance of semiconductor packages by ensuring consistent and efficient electrical connections.
Implementation Method 1
an under bump metallurgy (UBM) located between the bump and an I/O pad
Implementation Method 2
A solder alloy is still necessary for capping the bump structure and joining electronic components
Data Source
AI summary
A package structure includes a first substrate bonded to a second substrate by connecting metal pillars on the first substrate to connectors on the second substrate. A first metal pillar is formed overlying and electrically connected to a metal pad on a first region of the first substrate, and a second metal pillar is formed overlying a passivation layer in a second region of the first substrate. A first solder joint region is formed between metal pillar and the first connector, and a second solder joint region is formed between the second metal pillar and the second connector. The lateral dimension of the first metal pillar is greater than the lateral dimension of the second metal pillar.