When you get a PCB manufactured, it becomes important to laminate it with a layer of strong laminate. Doing so will keep your PCB safe from spillage, wear and tear, and many other types of damages. This article will walk you through an engineering study on PCB laminate in a user-friendly manner.
What’s a PCB stackup?
When a manufacturer manufactures PCB, they create several thin layers and stack them on top of each other according to the design. The concept of stacking all the layers of a PCB to make one final PCB product is called PCB stackup. The stacked layers are stuck together using an adhesive and baked at a high temperature so that the adhesive becomes a permanent bond.
What’s a PCB laminate?
Once the manufacturer stacks up and bakes all the layers using adhesive, they apply a layer of lamination. The lamination material can be of different types. Just like we laminate important documents to protect it from weather, moisture, water, etc., the PCB manufacturers laminate a PCB to keep it protected from outside interference.
What are the types of PCB laminate?
1.Polyimide
Many makers use polyamide for its strong thermal stability and its ability to resist high temperatures. If high-quality laminate is your preference, then you can go with polyamide lamination on your PCB. PCBs used in aerospace, automotives, etc., often use polyamide lamination.
Also read: What is polyimide PCB? – a comprehensive guideline – material, types, advantages
2.Ceramic
As the name suggests, a ceramic laminate has a ceramic base that can include but is not limited to alumina, etc. PCB makers use this type of laminate when they need resistance to high temperature, thermal conductivity, and strong dimensional stability.
Also read: Ceramic PCB – what is it, why we should use and how to manufacture
3.FR-4 (Flame Retardant 4)
If you want a highly economic laminate, then FR-4 is the way to go. It’s the most common type of PCB laminate that’s used and trusted by millions of PCB makers globally. This type of laminate is easily available in the market and has strong resistance to fire and high temperature. On top of that, it has incredible electrical insulation and other features.
Also read: FR4 PCB – The design and how it can be used for multiple applications
What are the properties of PCB laminate?
1.Thermal Properties
Thermal property of a PCB is responsible for throwing away all the heat that is generated in a PCB because of all the components on it. Components can get overheated and it’s the responsibility of a PCB laminate to get rid of all the excess heat and aid heatsink attached to the PCB (if any). High-Tg, FR-4, ceramic, etc., are some laminates with fantastic thermal properties.
2.Electrical Properties
Electrical property of a PCB laminate helps it keep the PCB safe from electrical interference and give a good electrical insulation. This helps in avoiding any short circuit occurring due to moisture or water spillage on the PCB. It’s just like a plastic coating on a wire that creates insulation.
3.Chemical Properties
Once the PCB is manufactured and the lamination is done, it’s time for PCB assembly. That’s a stage where a lot of chemicals will be poured on the PCB and the PCB will go through a lot of chemical reactions. Therefore, it’s important for a PCB laminate to have high chemical properties that can protect it from chemicals like solder mask, flux, solvents, etc.
4.Mechanical Properties
It’s very important for a PCB laminate to have high strength. It’s not at all feasible for a PCB laminate to be weak that can easily break, tear down, or chip off the PCB. during PCBA and fabrication, the PCB laminate shouldn’t wear off. That’s called the mechanical property of a PCB laminate.
PCB Laminate VS PCB Prepreg
Comparison Basis | PC Laminate | PCB Prepreg |
Definition | Strong, rigid, and cured material | Pre-impregnated, partially cured, and acts as a middle layer in the PCB |
Function | To offer rigidness and structural integrity to the PCB | To act as an adhesive bond in the PCB stackup |
Properties | Electrical insulation, mechanical strength, chemical resistance, temperature resistance, etc. | Flexibility, electrical strength, and mechanical toughness. |
Thickness | At least 0.1mm and can be up to several mm | Less than 1mm to several mm |
Applications | Most probably applied on both the sides of the PCB | Applied between the layers of a PCB, preferably between core laminates and copper foils |
What is PCB lamination process?
1.Material selection: The most relevant PCB laminate material is chosen based on the application and requirement of the PCB.
2.Prepreg manufacturing: Resin binder and fiberglass cloth are processed to make prepreg.
3.Core laminate manufacturing: Once the resin binder and fiberglass cloth are pre-impregnated, they’re applied between the layers of the PCB during PCB stackup. The number of layers are subject to the overall design of the PCB. Once the layers are stacked up and the prepreg is between the layers, a high pressure and heat is applied to the stackup, so that the adhesive cures.
4.Drilling: Vias and holes are drilled as per the PCB design and requirements. Drilling ain’t directly related to lamination, but is important during the lamination process.
Also read: PCB Drilling – What is it and how to minimize its cost during assembling
5.Lamination: The PCB makers might use additional prepreg to bond the laminate layer with the PCB layers. Once again, heat and pressure is used to bond the prepreg, so that the lamination layer and PCB layers get stuck well.
6.Surface treatment: The outermost surface may be roughened a little bit, and/or a layer of copper or aluminum may be embedded on the PCB, completing the lamination process.
Also read: What’s the type of PCB surface treatment?
How to choose a PCB lamination material?
1.Look for electrical requirements in your PCB and choose a material that can offer required electrical insulation.
2.Thermal conduction is also important to look for. If you need high resistance to temperatures, go for FR-4 or FR-4 Tg versions. Or go for Roger, etc., if you have low thermal conduction requirements.
Also read: How does Rogers PCB outperform FR4 PCB?
3.Frequency and signal integrity of a laminate is vital if you need low dielectric loss, low insertion loss, etc.
Conclusion
Now that you’ve got a great idea on PCB laminates, here’s what you can do- go with IBE Electronics, who’ll take care of using the right PCB laminate according to your project. You don’t have to mention the laminate type explicitly, as IBE Electronics’ experts will figure out the most suitable PCB laminate and will take care of the entire lamination process smoothly for you.
- Polyimide
- Ceramic
- FR-4 (Flame Retardant 4)
- Material selection
- Prepreg manufacturing
- Core laminate manufacturing
- Drilling
- Lamination
- Surface treatment
1.Look for electrical requirements in your PCB and choose a material that can offer required electrical insulation.
2.Thermal conduction is also important to look for.
3.Frequency and signal integrity of a laminate is vital if you need low dielectric loss, low insertion loss, etc.
