Semiconductor Package Solder Pillar Distance Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In flip chip technology, managing the volume of solder bumps is crucial to prevent bridge and cold joint issues, which affect the yield and reliability of semiconductor packages, especially in fine-pitch applications where excessive solder volume can lead to electrical shorts.
Innovation Solution
A method involving the formation of an elongated conductive pillar with a controlled solder layer thickness, typically less than or equal to 16 μm, which is reflowed to form a bump structure that is then attached to a conductive trace, ensuring a controlled distance and preventing bridge issues by maintaining a solder joint region with precise dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder bump volume is increased to ensure reliable connections, then connection reliability improves, but bridge issues and electrical shorts occur in fine-pitch applications
Solution Approach 1:
The patent applies parameter changes by precisely controlling the solder layer thickness (≤16 μm) and the distance between conductive pillar and trace (≤16 μm), transforming the solder joint from a potential source of bridges to a controlled reliable connection that prevents both insufficient bonding and electrical shorts
Solution Approach 2:
The patent implements preliminary action by pre-forming the conductive pillar with controlled dimensions and pre-controlling the solder layer thickness before reflow, ensuring that the solder joint forms with precise dimensions that prevent bridge issues while maintaining connection reliability
2Object-affected harmful factors
If solder layer thickness is reduced to prevent bridge issues, then electrical short prevention improves, but connection reliability may be compromised
Solution Approach 1:
The patent applies parameter changes by establishing a specific solder layer thickness range (≤16 μm) that simultaneously achieves electrical short prevention and maintains connection reliability, resolving the trade-off between these two competing requirements
Solution Approach 2:
The patent implements preliminary action by pre-controlling the solder layer thickness before the reflow process, ensuring that the solder joint forms with precise dimensions that prevent bridges while maintaining adequate volume for reliable bonding
3Object-affected harmful factors
If distance between conductive pillar and conductive trace is reduced to control solder volume, then bridge prevention improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements preliminary action by pre-forming the conductive pillar with a controlled distance (≤16 μm) from the conductive trace before solder application, establishing the geometric constraints that enable subsequent precise solder joint formation and bridge prevention
Solution Approach 2:
The patent applies parameter changes by controlling both the distance between pillar and trace (≤16 μm) and the solder layer thickness (≤16 μm) as interconnected parameters, where the pre-established distance geometry enables precise solder volume control
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 effectively controls the solder volume, preventing electrical shorts and ensuring reliable connections by maintaining a controlled distance between the conductive pillar and the conductive trace, thus enhancing the yield and reliability of semiconductor packages.
Implementation Method 1
the solder is then reflowed between the flipped chip and the substrate supporting the external circuitry to complete the interconnection
Data Source
AI summary
A semiconductor package includes a workpiece with a conductive trace and a chip with a conductive pillar. The chip is attached to the workpiece and a solder joint region is formed between the conductive pillar and the conductive trace. The distance between the conductive pillar and the conductive trace is less than or equal to about 16 μm.