- Electrical characteristics of insulation resistance, resistance to the electric field strength (voltage resistance), the dielectric properties (dielectric constant, dielectric loss factor Wei, etc.), ion migration resistance, resistance to leakage and trace quality copper resistance.
- The physical characteristics of thermal expansion coefficient (CTE), flammability (flame retardant), a base that is generally warped by the degree of flatness (bow and twist), moisture absorption.
- Chemical properties. Heat resistance, breaking glass transition temperature (Tg), weldability, resistance to chemicals capacity (acid, alkali and solvent resistance) and the like.
- Environmental resistance. Fungus resistance, moisture resistance, cooking, resistance to thermal shock properties.
- Green living substrates suitable for RoHS Directive inauspicious lead and other harmful substances halogen chapter though – .. Some high reliability requirements of the product is not currently required · main lead solder must be used, but from the perspective of environmental protection jealous consideration. When conditions are ripe to make the use of non-polluting or less polluting materials.
What are the properties of PCB substrate?
This material allows a minimum amount of electricity from the circuit. Because there exists an insulating layer between two conducting layers. For example, FR-4 is the most common sort of dielectric substantial. You must consider its properties before choosing it for your circuit board.
Here are the 4 most important properties of dielectric material:
Let’s consider the thermal properties of the substrate material:
A temperature range in which a glassy or rigid state of the PCB substrate becomes a softened or deformable state. The properties of the material return its original states after cooling down. You can express this temperature range in the Tg unit. And, you need to measure this temperature in degrees Celsius.
Relative Permittivity of Dielectric Constant (Dk or Er)
It is very important to consider the dielectric constant of material for checking impedance considerations and signal integrity. Both are remarkable factors of high-frequency electrical performance. The range of Er is between 2.5 and 4.5 in most PCB substrate material.
Flammability Specs – UL94
It is a plastics flammability standard for classifying plastic from the lowest flame-retardant to the highest one. So it is very helpful for plastic material appliances testing. Underwriters Laboratories (UL) defines this standard. Here are some essential requirements of this standard:
- Mechanical Properties
- Peel Strength