Packaging Substrate Bump Pad Layout for Controlled Solder Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor packaging processes face issues with solder bumps overflowing or being displaced during reflow, leading to electrical short circuits and empty soldering due to inadequate contact between solder bumps and electrical contact pads.
Innovation Solution
A packaging substrate with conductive bump pads made of nickel, embedded within copper electrical contact pads, and a routing structure with an insulating layer, where the bump pads guide solder flow during reflow, preventing short circuits and ensuring proper contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder bumps are used to connect electrical contact pads during reflow process, then electrical connection is achieved, but solder bumps may overflow to bridge adjacent pads causing electrical short circuit
Solution Approach 1:
The patent applies local quality by creating a conductive bump pad with different material composition and smaller dimensions than the surrounding electrical contact pad. The conductive bump pad region has localized enhanced properties (different material, reduced width) specifically at the solder bump contact area to control solder flow and prevent bridging to adjacent pads, while the rest of the electrical contact pad maintains its original function.
2Reliability
If solder bumps are used to connect electrical contact pads during reflow process, then electrical connection is achieved, but solder bumps may be displaced causing empty soldering
Solution Approach 1:
The conductive bump pad provides localized material properties and dimensional constraints that guide solder bump placement. The smaller width of the conductive bump pad compared to the electrical contact pad creates a localized region that confines and guides the solder bump to the correct position, improving positioning accuracy during the reflow process.
3Reliability
If conductive bump pad with different material is introduced, then solder flow control is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent segments the electrical contact pad structure into two distinct regions: the electrical contact pad itself and the conductive bump pad. This segmentation allows each region to have optimized properties for its specific function - the electrical contact pad for electrical connection and the conductive bump pad for solder flow control - while being manufactured as an integrated structure.
Solution Approach 2:
The patent employs composite materials by using different materials for the conductive bump pad compared to the electrical contact pad. This composite approach allows optimization of each region's material properties for its specific function, with the conductive bump pad material selected for solder flow control characteristics while the electrical contact pad material is optimized for electrical conductivity.
Data Source
AI summary
An electronic package, a packaging substrate and a fabricating method are provided, in which a conductive bump pad is formed on an electrical contact pad of the packaging substrate, so that when an electronic element is bonded to the packaging substrate via a solder material in a flip-chip process, the conductive bump pad can guide the flow of the solder material. Therefore, the problem of empty soldering caused by the solder material not effectively contacting with the electrical contact pad can be avoided.