What makes FR-4 the most commonly used laminate is how it performs across all characteristics. This material has a good strength-to-weight ratio, is flame resistant, which improves its reliability, and when there is an increased temperature, the material’s mechanical, electrical, and physical properties stay maintained.
You would use a high-performance FR-4 laminate when dealing with multi-layered PCBs. It has a high-reliability level due to the increased TG and is more suitable for high-frequency circuits because of its low dielectric properties.
High Tg Epoxy
For multilayer PCBs, the High Tg Epoxy is most suitable. The Tg is the vitrification temperature, similar to the melting point. The higher the number, the more rigid the board will be. A material with a high TG (over 170o C) has better heat, moisture, and chemical resistance, as well as better stability.
Most suitable for lead-free PCBs, the BT Epoxy laminate is known for having outstanding thermal, mechanical, and electrical properties. This laminate is commonly used for multilayer PCBs. It will also maintain bond strength at high temperatures.
This type of laminate produces extreme environmental stability. You would use the Polyimide laminate when working with high-density, flexible, rigid-flex circuit boards, and multilayer PCBs. It also produces high levels of thermal, chemical, and mechanical properties. A polyimide laminate is ideal for advanced applications, including military, aerospace, automotive, and consumer electronics.
Copper Clad (CCL)
The Copper Clad laminate is made up of a glass fiber or wood pulp paper as the reinforcing material. You would typically use a CCL laminate for high-voltage circuits based on specific aspects, including appearance, size, electrical, physical, chemical, and environmental performance.
The most commonly used material in high frequency applications. Teflon materials come in many different options, the easier materials to use in manufacturing are teflons with woven glass. There are several challenges with manufacturing teflon PCBs that causes issues with a conventional board shop.