Lead Frame Through-Hole Roughening to Prevent Encapsulation Leakage
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Solution Overview
Problem
In the manufacturing of light-emitting diode devices, uncured encapsulation material often leaks into slits on the lead frame, leading to unstable attachment and reduced packaging reliability.
Innovation Solution
A method involving the formation of a multilayered structure with mask layers on a lead frame, followed by sandblasting to create a rough textured surface in through holes, which enhances the bonding of encapsulation material during a thermoforming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encapsulation material is filled into the lead frame area, then the cured encapsulation material can be firmly attached to the lead frame, but the uncured encapsulation material leaks into slits and overflows to the other side
Solution Approach 1:
The patent applies different surface qualities to different locations: the upper and lower surfaces of the lead frame remain smooth for brightness and solderability, while the inner surfaces of through-holes are roughened to enhance encapsulation material bonding. This local differentiation resolves the contradiction by providing anti-leakage functionality only where needed (at through-hole interfaces) without affecting the overall smoothness of the lead frame surfaces.
Solution Approach 2:
The patent performs preliminary surface treatment by forming rough textured surfaces in the through-holes before filling the encapsulation material. This advance preparation creates anchoring structures that prevent leakage during the subsequent encapsulation process, addressing the harmful effect before it occurs.
2Strength
If the lead frame surface is roughened to improve bonding, then the encapsulation material attachment strength increases, but the smoothness and brightness of the lead frame surface deteriorates
Solution Approach 1:
The patent selectively roughens only the inner surfaces of through-holes while maintaining the smoothness of the upper and lower lead frame surfaces. This localized approach allows the bonding strength to be enhanced at critical interfaces (through-hole walls) without compromising the overall surface quality needed for soldering and appearance.
Solution Approach 2:
The patent divides the lead frame surface into different functional zones: smooth zones (upper and lower surfaces) for soldering and appearance, and rough zones (through-hole inner surfaces) for enhanced bonding. This segmentation allows each zone to optimize its specific function without interfering with other requirements.
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 method improves the bonding strength between the encapsulation material and the lead frame, reduces leakage, and maintains the smoothness and brightness of the lead frame surfaces, thereby enhancing packaging reliability.
Implementation Method 1
A sandblasting process is performed in the through hole to form a rough textured surface in the through hole
Implementation Method 2
Dry air is blown out to the multilayered structure for taking away the sand grains from the first mask layer and the through hole of the multilayered structure
Implementation Method 3
a thermoforming process is performed to the lead frame so that a polymer material is encapsulated on the upper surface of the lead frame and filled into the through hole, and after the polymer material is cured, the polymer material is fixedly bonded on the rough textured surface in the through hole
Data Source
AI summary
A package structure and a method of manufacturing the same are provided. The method of manufacturing the package structure includes several steps as follows. A lead frame is provided. A first mask layer is formed on an upper surface of the lead frame and a second mask layer is formed on a lower surface of the lead frame, so that the first mask layer, the lead frame and the second mask layer are formed together to be a multilayered structure. A patterning process is performed on the multilayered structure, so a through hole penetrating through the multilayered structure is formed. A sandblasting process is performed in the through hole to form a rough textured surface in the through hole. After that, the first mask layer and the second mask layer are removed to expose the upper surface and the lower surface of the lead frame.