Flexible Circuit Mounting With Blind Vias for Chip Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for mounting and cooling circuit components, such as VCSEL chips, face challenges with fragile ceramic circuit boards that can crack, leading to poor electrical connections and reduced thermal efficiency, and are not suitable for flexible circuit boards due to high-temperature sintering requirements.
Innovation Solution
A method using diffusion bonding or low-temperature sintering to connect flexible circuit boards with rigid substrates, forming blind vias by plating, and using a single solder joint to ensure reliable electrical and thermal pathways without the need for high-temperature sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic circuit boards are used for mounting VCSEL chips, then thermal conductivity and electrical insulation are improved, but mechanical fragility and crack resistance deteriorate
Solution Approach 1:
The patent employs a composite structure combining a flexible circuit board (polymer base with copper traces) and a rigid thermally conductive substrate (ceramic or metal). This composite approach allows the flexible board to provide electrical insulation and circuit routing, while the rigid substrate provides thermal conductivity and mechanical strength, thereby resolving the contradiction between thermal performance and mechanical fragility.
2Reliability
If high-temperature sintering is used to form vias in ceramic substrates, then electrical and thermal conductivity are improved, but compatibility with flexible circuit boards deteriorates
Solution Approach 1:
The patent changes the temperature parameter of the via formation process from high-temperature sintering (>700°C) to low-temperature electroplating (room temperature to moderate heating). This parameter change enables the formation of conductive vias through flexible polymer substrates without degrading the material, thereby achieving both electrical connectivity and material compatibility.
3Reliability
If multiple soldered connections are used in the current path, then electrical connectivity is achieved, but connection reliability and defect risk increase
Solution Approach 1:
The patent merges multiple separate connection functions into a single integrated structure. The conductive vias are formed by filling holes through the flexible circuit board with electroplated metal, creating a unified conductive pathway that combines electrical connection, mechanical anchoring, and thermal conduction in one element, thereby reducing the number of separate solder joints and improving 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 approach enhances the reliability and thermal efficiency of circuit component mounting by preventing cracks and reducing the risk of poor connections, while allowing the use of flexible circuit boards.
Implementation Method 1
A method using diffusion bonding or low-temperature sintering to connect flexible circuit boards with rigid substrates
Implementation Method 2
A method using diffusion bonding or low-temperature sintering to connect flexible circuit boards with rigid substrates
Implementation Method 3
forming blind vias by plating
Implementation Method 4
using a single solder joint to ensure reliable electrical and thermal pathways
Implementation Method 5
mounting and cooling a circuit component... mounted in good thermal contact with a heat sink
Data Source
Figure 1~2
Figure 3I~3VIII
AI summary
A method is disclosed for mounting and cooling a circuit component having a plurality of contacts. The method comprises mounting the circuit component on a rigid substrate of a thermally conductive and electrically insulating material with a circuit board arranged between the circuit component and the substrate. The circuit board, which has a flexible base and carries conductive traces that terminate in contact pads, is secured to the rigid substrate with at least some of the contact pads on the circuit board disposed on the side of the circuit board facing the rigid substrate, at least some of the latter contact pads being bonded to the substrate. To establish both an electrical and a thermal connection between the contacts of the circuit component and the contact pads bonded to the substrate, blind holes are formed in the flexible base of the circuit board, each hole terminating at a respective one of the contact pads bonded to the substrate. The side of the contact pads exposed by the holes is plated to form conductive vias that fill the holes and that are soldered to the contacts of the circuit component.