Optoelectronic Submount With Wrap-Around Contacts
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Solution Overview
Problem
Conventional LED submounts lack versatility, leading to increased package size and cost, and are often incompatible with surface mount devices (SMDs), with solder reflow techniques potentially damaging circuitry, and there is no single design that can accommodate various LED chip designs.
Innovation Solution
A submount design featuring a substrate with top and bottom pads, wrap-around contacts, and feedthrough contacts that allow for electrical and thermal connectivity, enabling compatibility with SMDs and accommodating different LED chip designs, while incorporating circuitry for protection and reduced package size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LED submounts are used with various sizes and geometries, then different LED chip types can be accommodated, but package size and cost increase
Solution Approach 1:
The submount is designed with a standardized geometry and contact configuration that can accommodate multiple LED chip types and bonding methods (wire bonding, flip chip, solder bump). The standardized pad layout and contact positions enable a single submount design to serve universal functions across different LED chip designs, eliminating the need for multiple specialized submount variants.
2Adaptability or versatility
If conventional LED submounts are used, then electrical connection to LED chip is enabled, but compatibility with surface mount devices is lost
Solution Approach 1:
The submount design separates the electrical connection functions into distinct standardized contact pads that can interface with both LED chip bonding and surface mount device soldering. The contact pads are positioned and dimensioned to accommodate different bonding technologies independently, allowing the submount to segment its functionality to serve multiple purposes without increasing overall complexity.
3Adaptability or versatility
If solder reflow techniques are used for circuit integration, then circuitry can be incorporated into LED chip, but circuit damage occurs
Solution Approach 1:
The submount acts as an intermediary platform that provides mechanical support and electrical connection for the LED chip without requiring solder reflow on the LED chip itself. Circuit integration is achieved through the submount's contact pads and bonding structures, which are designed to accommodate various bonding methods that do not subject the LED chip to damaging solder reflow temperatures.
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 submount design enhances compatibility with SMDs, reduces package size, and allows for the integration of circuitry, such as electrostatic discharge protection, while maintaining electrical and thermal connectivity, enabling more efficient and compact optoelectronic device packaging.
Implementation Method 1
a first wrap-around contact in a sidewall recess of the substrate, in which the first wrap-around contact is coupled electrically to the first top pad and to the first bottom pad
Implementation Method 2
a thermally conductive contact pad on the bottom surface of the substrate
Data Source
AI summary
A submount for an optoelectronic device includes a substrate, a first top pad on a top surface of the substrate, a first bottom pad on a bottom surface of the substrate and a first wrap-around contact in a sidewall recess of the substrate, in which the first wrap-around contact is coupled electrically to the first top pad and to the first bottom pad. Alternatively, or in addition, the submount includes a device mounting pad on the top surface of the substrate, a wire-bond pad on the top surface of the substrate, a contact pad on the bottom surface of the substrate and a feedthrough contact which extends through the substrate and electrically couples the wire-bond pad to the contact pad.