LED Package Through-Wiring Design for Bonding Strength
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Solution Overview
Problem
The existing LED mounting packages require multiple processes to form both LED and external connection pads on a substrate, leading to increased manufacturing costs and potential bonding strength issues due to the 'unsheathing' phenomenon where the LED connection pad and through-wiring detach from the substrate under pulling force.
Innovation Solution
A light emitting device mounting package design featuring a substrate with two through-wirings that have one end connected to the LED mounting part and the other end exposed, with a maximum part buried in the substrate having a larger plan-view shape than the wiring end, enhancing bonding strength and preventing unsheathing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the LED mounting package is manufactured without forming an external connection pad on the other surface of the substrate and instead use a part of the through-wiring exposed from the other surface of the substrate as the external connection pad, then the manufacturing cost is reduced, but the bonding strength between the through-wiring and the substrate is insufficient
Solution Approach 1:
The patent changes the geometric parameters of the through-wiring by forming a protruding part that extends beyond the through-hole in the substrate. This parameter change (increasing the length and surface area of the through-wiring) enhances the bonding strength between the through-wiring and substrate, preventing the unsheathing phenomenon while maintaining the cost-effective design of using exposed through-wiring as external connection pads
2Reliability
If a pulling force is applied in a direction separating the LED connection from the substrate, then the LED connection pad and through-wiring may fall off due to insufficient bonding, but forming both LED and external connection pads requires multiple processes increasing manufacturing cost
Solution Approach 1:
The patent modifies the dimensional parameters of the through-wiring by creating a protruding part that extends from the substrate surface. This geometric modification increases the bonding interface area and length, thereby enhancing reliability and preventing detachment under pulling forces, while avoiding the need for additional external connection pad formation processes
Solution Approach 2:
The through-wiring is segmented into different functional parts: an embedded portion within the substrate for bonding, a protruding part extending beyond the substrate surface for enhanced mechanical strength and electrical connection, and an exposed portion serving as the external connection pad. This segmentation allows each part to fulfill its specific function optimally
Data Source
AI summary
A package for mounting a light emitting device thereon. The package includes a substrate, a light emitting device mounting part including a wiring formed on one surface of the substrate, the wiring including two areas that are arranged facing each other and being separated a predetermined interval apart from each other in a plan view, first and second through-wirings that penetrate the substrate and are provided on the two areas, respectively, each of the first and second through-wirings including one end electrically connected to the light emitting device mounting part and another end exposed from another surface of the substrate. A part of each of the first and second through-wirings includes a maximum part having a plan-view shape that is larger than a plan-view shape of the one end of each of the first and second through-wirings.