LED Submount with Integrated Bond Pads for Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional packaging techniques for semiconductor light emitting devices are costly, result in large and bulky packages, and have poor thermal resistance, making them unsuitable for miniaturized applications and limiting power levels and placement options.
Innovation Solution
A submount with a rectangular substrate featuring bond pads, solder pads, castellations, and thermal spreading layers, along with a method for forming packaged light emitting diodes using a sheet of ceramic material and encapsulant, to create a compact, thermally efficient, and cost-effective package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional packaging techniques are used, then the LED is protected from environmental harm and mechanical damage, but the package becomes large and bulky, increasing the volume and reducing suitability for miniaturized applications
Solution Approach 1:
The LED chip is mounted directly on the submount substrate, with the encapsulant material nested around the chip and bond wires, creating a compact integrated structure where components are nested within each other rather than arranged separately, significantly reducing overall package volume
Solution Approach 2:
The submount integrates multiple functions into a single component: the substrate serves as both mechanical support and thermal management path, bond pads provide both electrical connection and structural attachment points, and the encapsulant simultaneously provides environmental protection and optical function, eliminating the need for separate protective housings
2Ease of manufacture
If conventional packaging techniques are used, then the LED is protected, but the package structure becomes complex, increasing manufacturing cost and reducing ease of manufacture
Solution Approach 1:
The submount substrate performs multiple functions simultaneously: it provides mechanical support for the LED chip, conducts heat away from the device, provides electrical connection paths through integrated bond pads, and serves as a mounting platform for wirebond connections, eliminating the need for separate components for each function
Solution Approach 2:
The package structure merges the substrate, bonding infrastructure, and protective elements into an integrated assembly where the submount contains all necessary electrical and mechanical connection features, reducing the number of discrete parts and assembly steps required
3Power
If conventional packaging techniques are used, then the LED can be electrically connected to external circuits, but the thermal resistance is poor, limiting the power levels at which the LED chip may be driven
Solution Approach 1:
The submount substrate acts as an intermediary thermal management component between the LED chip and the external environment, providing a dedicated thermal conduction path that efficiently transfers heat away from the chip while maintaining electrical connection functionality
Solution Approach 2:
The substrate is designed with enhanced thermal conductivity properties specifically at the region underlying the LED chip, with thermal spreading layers and conductive pathways concentrated where heat generation is highest, optimizing heat removal efficiency at the critical location
4Ease of manufacture
If conventional packaging techniques are used, then the LED can be mounted and connected, but the package is costly, increasing the cost per lumen
Solution Approach 1:
The submount uses cost-effective materials and a simplified single-substrate architecture that reduces manufacturing complexity and material costs, making the package more economical while maintaining sufficient performance for the application
Solution Approach 2:
The integrated submount design performs multiple functions (mechanical support, thermal management, electrical connection) in a single component, reducing the total number of parts and assembly operations required, thereby lowering manufacturing costs while maintaining functional performance
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 enables the production of compact, thermally efficient, and cost-effective light emitting device packages suitable for miniaturized applications with improved thermal conductivity and luminous flux per unit area, suitable for applications like portable electronics and automotive lighting.
Implementation Method 1
a first thermal spreading layer over the first bond pad and configured to conduct heat away from the light emitting device
Implementation Method 2
An LED package also includes means, such as electrical leads, for electrically connecting the LED chip to an external circuit... to protect it from environmental harm and mechanical damage
Implementation Method 3
an LED 12 is mounted on a reflective cup 13 by means of a solder bond or epoxy
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 2D~3B
AI summary
A submount for a light emitting device package includes a rectangular substrate. A first bond pad and a second bond pad are on a first surface of the substrate. The first bond pad includes a die attach region offset toward a first end of the substrate and configured to receive a light emitting diode thereon. The second bond pad includes a bonding region between the first bond pad and the second end of the substrate and a second bond pad extension that extends from the bonding region along a side of the substrate toward a corner of the substrate at the first end of the substrate. First and second solder pads are a the second surface of the substrate. The first solder pad is adjacent the first end of the substrate and contacts the second bond pad. The second solder pad is adjacent the second end of the substrate and contacts the first bond pad. Related LED packages and methods of forming LED packages are disclosed.