Wafer-Level LED Packaging Separators for CTE-Matched Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED packaging is time-consuming and costly due to the need for precise handling of converter materials and encapsulants on singulated die, and it faces issues with heat management and thermal expansion, leading to potential delamination.
Innovation Solution
Wafer-level packaging where a metal support substrate with a coefficient of thermal expansion similar to the LED structure is used, incorporating discrete converter and cover elements, and separators to facilitate packaging and testing before dicing, reducing handling requirements and enhancing thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional LED packaging is used with singulated die, then individual LED devices can be manufactured, but the process is time-consuming and costly due to precise handling requirements
Solution Approach 1:
The patent performs packaging operations at the wafer level before dicing, rather than after. Converter materials and encapsulants are applied to entire wafers in bulk, and multiple wafers are stacked and packaged together before being cut into individual LED devices. This preliminary action eliminates the need for time-consuming individual handling of each singulated die.
Solution Approach 2:
The patent combines multiple LED devices into a single packaged unit by stacking multiple wafers together. Multiple converter materials and encapsulants are merged into a single integrated structure that encapsulates several LED devices simultaneously. This merging approach allows parallel processing and significantly increases packaging throughput.
2Ease of manufacture
If converter materials and encapsulants are formed on singulated LED die, then individual devices can be packaged, but precise handling is required which increases packaging costs
Solution Approach 1:
Converter materials and encapsulants are deposited onto entire wafers before dicing occurs. This preliminary formation of protective and functional layers eliminates the need for precise handling and deposition on individual singulated die, which would require complex positioning and alignment systems.
Solution Approach 2:
Multiple converter materials and encapsulants are combined into a single integrated packaging structure that covers multiple LED devices simultaneously. This merged approach allows standard deposition techniques to be used on large wafer surfaces rather than requiring precise material placement on each small individual die.
3Productivity
If LED die are mounted to separate support substrates, then individual devices can be supported, but the process is time-consuming and requires precise handling
Solution Approach 1:
Multiple LED wafers are stacked and mounted together as a single unit onto a support structure, rather than mounting each die individually. This merged mounting approach processes multiple devices in parallel, dramatically increasing mounting speed and eliminating the need for precise individual handling of each die.
Solution Approach 2:
The support substrate is prepared and positioned before the wafers are stacked onto it. This preliminary preparation allows the entire stack of multiple wafers to be mounted in a single operation rather than requiring sequential mounting of each individual die.
4Reliability
If conventional packaging is used, then LED devices can be encapsulated, but thermal expansion differences cause delamination between LED structure and support substrate
Solution Approach 1:
The patent selects a support substrate material whose coefficient of thermal expansion closely matches that of the LED structure. This matching of thermal expansion properties prevents differential expansion and contraction during temperature cycling, eliminating the thermal stresses that would otherwise cause delamination between the LED structure and support substrate.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers including the LED wafer, converter materials, encapsulants, and support substrate. This composite design allows optimization of each layer's material properties, including selecting the support substrate with matched thermal expansion characteristics to ensure overall structural reliability.
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 method allows for efficient, precise, and cost-effective packaging of LEDs at the wafer level, reducing manufacturing time and minimizing thermal-related damage, while enabling uniform color generation and improved thermal management.
Implementation Method 1
the LED structure 12 can emit a first emission (e.g., blue light) that stimulates the converter material 26 (e.g., phosphor) to emit a second emission (e.g., yellow light)
Implementation Method 2
a metal support substrate with a coefficient of thermal expansion similar to the LED structure is used
Data Source
AI summary
Wafer-level packaging of solid-state transducers (“SSTs”) is disclosed herein. A method in accordance with a particular embodiment includes forming a transducer structure having a first surface and a second surface opposite the first surface, and forming a plurality of separators that extend from at least the first surface of the transducer structure to beyond the second surface. The separators can demarcate lateral dimensions of individual SSTs. The method can further include forming a support substrate on the first surface of the transducer structure, and forming a plurality of discrete optical elements on the second surface of the transducer structure. The separators can form barriers between the discrete optical elements. The method can still further include dicing the SSTs along the separators. Associated SST devices and systems are also disclosed herein.