Hybrid Printed Circuit Boards (PCBs) use two different materials, which are usually made up of the flexible and rigid materials. The primary advantage to this combination is that helps to bolster the mechanical and electrical performance of the circuit board.
If you are looking to design your next consumer electronics with a hybrid PCB, this article will guide you on how to get started.
The Concept behind Hybrid PCB
When we talk about a circuit board being “hybrid,” it means that it uses two different properties or materials. These materials comprise the rigid PCB materials and the flexible circuit board materials.
With recent innovations, the options have been further extended. You can now use a wide range of materials sourced from any of the following to make the board:
- FR4 and Aluminum Base
- FR4 and Teflon
- FR4/Polyimide (PI)
- FR4 and Ceramic
It is also important to mention that hybrid PCBs are not always limited to two materials. It is also possible to use up to four (4) materials. For example, you can manufacture the board with varying materials, such as Copper, FR4/PTFE (Rogers), Ceramic and FR4 materials.
Hybrid PCB Material Composition and Bonding
There are two (2) major considerations to choosing a hybrid circuit board. These are the specific materials used for the design and the bonding capabilities. Getting this right could be the difference between integrating the components effectively and making a mess of the job.
Let us start by talking about the materials used in the stackup. A hybrid PCB usually requires a mixture or combination of high-frequency PTFE materials and the FR-4 materials. This ensures that the differences in the materials do not have an adverse effect on the physical properties.
The other aspect of hybrid PCB design is the bonding options. How do these materials bond or perform as expected, considering the differences in the materials and the physical properties?
The major bonding factor is the use of a method called phase-change. The change in the phase means that connection areas of the materials are subject to melting and curing, especially when subjected to higher operating temperatures.
A Breakdown of the Hybrid PCB Materials
Let us talk about some of the materials making up the hybrid circuit board. The understanding of how this works will help in knowing how these materials combine to deliver optimum performance of the circuit board.
Polyimide (PI) is one of the materials used when manufacturing a hybrid circuit board. It is commonly because of the excellent performance it delivers via the composition of the electrical and higher chemical resistance properties.
But the higher chemical resistance and improved electrical performance are only a few of the benefits. The others include the flexibility and lightweight, which increases movability.
This is a ceramic-based PCB material, used for fabricating both the hybrid and high-frequency circuit boards. It is commonly used with or combined with the FR-4 materials for designing the hybrid PCBs.
Worthy of mentioning is that the PTFE circuit board material is used for the following types of applications:
- High-speed applications
- Low signal loss applications and;
- Applications requiring an improved impedance control
These are one of the important materials used for hybrid PCB designs. It is common to use them alongside the PTFE materials for the job.
However, it can also be used with a variety of other materials, such as FR4/AIN, FR4/Polyimide (PI), FR4/Ceramic and FR4/Copper.
Despite the several combinations, the FR4 materials doesn’t lose the relevance of the flame retardant capabilities, as well as the low-cost.
You can rely on the FR4 materials to bolster the higher dielectric strength, higher temperature range resistance and electrical insulation of the circuit board.
Matching the Demand with Your Expectations
While the combination of the materials with high dielectric constants and high-frequency materials can make the difference in the hybrid PCB design, other design considerations must be made.
In terms of the market demand, there is an increasing requirement for the hybrid circuit boards due to the need to offer a balance between regular and high frequency in a Printed Circuit Board (PCB).
In terms of the specifications, it is usually up to the end-user or consumer to decide how best to factor-in the high-frequency and dielectric capabilities of these materials in one board.
Nevertheless, the considerations for a hybrid PCB should be prioritized, based on the aspects, such as:
- Mechanical properties
- Chemical properties
- Temperature ranges
- Thermal properties
- Required/targeted applications
- Estimated costs and;
- Types of frequencies
Advantages of the Hybrid PCBs
Working with hybrid Printed Circuit Boards (PCBs) comes with some benefits or upsides. Some of these include:
- Improved Signal Integrity: the higher the possibility of the signals to be transmitted, the higher the chances of making the most out of the PCB’s routing. This is the case with the hybrid PCB’s improved signal integrity that is deliverable via the increased numbers of layers used.
- Adjustability: the adjustable design of the hybrid PCB paves the way for customizations and further optimizations to the circuit board, following the enablement of new features to be added.
- Hybrid PCBs offer an increased thermal pathway.
- Miniaturization: You can count on these PCBs to cut down on the overall footprint of the consumer electronics’ package.
- Through the stackup, both the digital electronic designs and the RF designs can be combined/integrated into the same PCB footprint.
- Flexible Component Placement: components can be placed side-by-side inside the hybrid PCB, without having to compromise on the board’s heat regulation capabilities.
The Downsides to the Hybrid PCBs
Working with hybrid circuit boards offers a mix of smaller size, improved signal integrity, improved electrical performance and greater circuit density.
Likewise, it comes with some potential downsides, including differences in the materials’ CTE value, requirements for additional components and varying adhesive system.
Working with hybrid PCBs opens up the opportunity to be creative with circuit board designs, while integrating the relevant materials and components needed to make a good job out of it.
This type of PCB is best handled by specialists, of which we are one of the best hands you can find out there. Through our versatile experience, the quality of our PCB designs and the excellence of the equipment used, you can be sure that we will design the PCBs that match your bespoke requirements.