Via-Wall Side-Wettable Package Structure for AOI-Visible Soldering
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Solution Overview
Problem
Conventional semiconductor packaging methods require complex manufacturing processes to form side-wettable structures, increasing costs and limiting the height of solder adhesion, which affects the stability and inspection capability of the package.
Innovation Solution
A package with a side-wettable structure formed on via walls, utilizing a composite substrate with conductive layers and conductive contacts, where the side-wettable structure is created during the singulation process, reducing process complexity and enhancing solder adhesion through an anti-oxidation conductive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the lead frame is pre-processed or cut multiple times during manufacturing to form the side-wettable structure, then the solder adhesion area is increased, but the manufacturing process complexity and cost increase
Solution Approach 1:
The side-wettable structure is formed during the singulation process itself, which is a preliminary action performed at the appropriate stage in the manufacturing flow. This eliminates the need for separate pre-processing steps or multiple cutting operations that would otherwise be required to create the same structure, thereby reducing overall process complexity while achieving the desired solder adhesion area
Solution Approach 2:
The formation of the side-wettable structure is merged with the singulation process. By combining these two functions into a single operational step, the patent eliminates redundant manufacturing steps and reduces process complexity while still achieving adequate solder adhesion area for stable package soldering
2Ease of manufacture
If the lead frame height is limited, then the manufacturing is simpler, but the solder adhesion capability is insufficient
Solution Approach 1:
Instead of increasing the vertical height of the lead frame to improve solder adhesion, the patent creates additional adhesion area by forming a side-wettable structure that extends laterally from the bond pad. This dimensional approach allows sufficient solder adhesion capability to be achieved without compromising manufacturing simplicity or requiring taller lead frames
3Manufacturing precision
If the side-wettable structure is formed by multiple cutting operations, then the solder creepage is improved, but the manufacturing time and cost increase
Solution Approach 1:
The patent merges the formation of the side-wettable structure with the singulation process into a single operation. This combined approach maintains the precision needed for proper solder creepage while eliminating multiple separate cutting operations, thereby improving manufacturing efficiency and reducing production time
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 simplifies manufacturing, increases solder adhesion area, and improves the stability and inspection capability of the package, ensuring stable soldering to circuit boards and effective Automated Optical Inspection.
Implementation Method 1
the anti-oxidation conductive layer can be plated on the cutting surface of each conductive contact to form the side-wettable structure
Implementation Method 2
The anti-oxidation conductive layer mounted on the surface of each conductive contact increases an area to which the solder adheres when the package of the present invention is soldered to another component
Data Source
AI summary
A package with a side-wettable structure formed on via walls has a composite substrate covered with a molding layer; an upper redistribution layer is formed on the molding layer, and an edge of the upper redistribution layer is uncovered with a solder mask to form at least one edge bonding surface; at least one conductive contact formed by cutting at least one conductive via is located adjacent to an edge of the composite substrate, and each edge bonding surface is connected with a cutting surface of each conductive contact; an anti-oxidation conductive layer is mounted on each cutting surface and a side wall of each conductive contact. The anti-oxidation conductive layer is adopted for a solder adsorption, so that an Automated Optical Inspection instrument can determine contacting situations between the package of the present invention and another component.