LED Array Fabrication via Simultaneous Bonding and Conductive Interconnects
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Solution Overview
Problem
Traditional LED packaging methods are not cost-effective and face challenges with small form factor LEDs, as wire bonding becomes increasingly difficult and time-consuming, and can degrade electrical and optical characteristics.
Innovation Solution
A method of fabricating LED packages involves bonding LED arrays to a carrier substrate with conductive interconnects, allowing simultaneous bonding of multiple LED dies, which reduces manufacturing time and cost while maintaining robust electrical and optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is used for LED packaging, then electrical connections can be established, but manufacturing time increases and cost increases as LED die size decreases
Solution Approach 1:
The patent segments the LED die array into multiple individually addressable LED dies while maintaining a shared carrier substrate. This allows selective bonding and connection of specific LED dies to specific circuit board locations, enabling parallel processing and reducing overall manufacturing time while maintaining reliable electrical connections for each die.
Solution Approach 2:
The patent transitions from traditional one-to-one wire bonding to a many-to-many connection approach using conductive paste and printed circuit board traces. This dimensional change in the connection methodology allows multiple LED dies to be simultaneously connected to multiple circuit board locations, dramatically improving manufacturing efficiency.
2Reliability
If wire bonding is used for LED packaging, then electrical connections can be established, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple LED dies onto a single carrier substrate that can be simultaneously bonded to a printed circuit board. This consolidation reduces the number of separate bonding operations required, lowering manufacturing costs while maintaining reliable electrical connections through the conductive paste and PCB trace network.
Solution Approach 2:
The patent replaces the mechanical wire bonding process with a chemical/electrical connection method using conductive paste and PCB traces. This substitution eliminates the need for complex wire bonding equipment and operations, significantly reducing manufacturing costs while achieving reliable electrical connections.
3Reliability
If wire bonding is used for small form factor LEDs, then electrical connections can be made, but the process becomes increasingly difficult to apply
Solution Approach 1:
The patent segments the bonding process by allowing individual LED dies to be selectively bonded to specific PCB locations. This segmentation makes the process more manageable and easier to apply to small form factor LEDs, as it allows for flexible positioning and reduces the precision requirements compared to traditional wire bonding.
Solution Approach 2:
The patent introduces a conductive paste as an intermediary bonding material between the LED dies and the PCB. This intermediary simplifies the bonding process by providing a more forgiving and easier-to-apply alternative to direct wire bonding, especially for small form factor LEDs where precision is critical.
4Length of stationary object
If bonding wires are made longer to accommodate packaging, then electrical and optical characteristics of packaged LEDs are degraded
Solution Approach 1:
The patent extracts the bonding wires from the final packaged LED structure, replacing them with conductive paste and PCB traces. This elimination of long bonding wires prevents the degradation of electrical and optical characteristics while still achieving the necessary electrical connections through the alternative conduction path.
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 enables efficient electrical connections for LEDs with small form factors, reducing assembly time and maintaining high electrical and optical characteristics, thus addressing the limitations of traditional packaging methods.
Implementation Method 1
bonding LED arrays to a carrier substrate with conductive interconnects
Data Source
AI summary
An LED array comprises a growth substrate and at least two separated LED dies grown over the growth substrate. Each of LED dies sequentially comprise a first conductive type doped layer, a multiple quantum well layer and a second conductive type doped layer. The LED array is bonded to a carrier substrate. Each of separated LED dies on the LED array is simultaneously bonded to the carrier substrate. The second conductive type doped layer of each of separated LED dies is proximate to the carrier substrate. The first conductive type doped layer of each of LED dies is exposed. A patterned isolation layer is formed over each of LED dies and the carrier substrate. Conductive interconnects are formed over the patterned isolation layer to electrically connect the at least separated LED dies and each of LED dies to the carrier substrate.