CID PCB Materials & Manufacturing Processes

Question 1

What is the primary function of the substrate in a PCB?

Accepted Answer

To provide mechanical support and insulation

Answer

The substrate in a Printed Circuit Board (PCB) is the non-conductive material, typically fiberglass, that forms the base of the board. Its primary function is to provide rigid mechanical support for all components and copper traces. Additionally, it electrically insulates these conductive elements from each other, preventing short circuits and ensuring proper circuit function.

Question 2

Which material is commonly used as a substrate in rigid PCBs?

Accepted Answer

FR-4

Answer

FR-4 is the most widely used and cost-effective material for rigid PCB substrates. It is a glass-reinforced epoxy laminate that provides an excellent balance of electrical insulation, mechanical strength, and thermal stability. This makes it suitable for a vast range of electronic applications, from consumer electronics to industrial equipment.

Question 3

What is the purpose of solder mask on a PCB?

Accepted Answer

To protect copper traces and prevent solder bridging

Answer

Solder mask is a protective polymer layer applied over the copper traces of a PCB. Its primary purpose is to insulate the traces, preventing accidental short circuits (solder bridging) during the soldering process. It also protects the copper from oxidation, moisture, and contaminants, ensuring long-term reliability of the board.

Question 4

Which manufacturing process is used to create PCB copper traces?

Accepted Answer

Etching

Answer

Etching is the chemical process fundamental to creating PCB copper traces. After a photoresist layer defines the desired circuit pattern, the board is exposed to an etchant solution. This solution selectively dissolves the unprotected copper, leaving behind the intricate network of conductive traces and pads that form the circuit.

Question 5

What is the main benefit of using a via in PCB design?

Accepted Answer

To connect multiple layers electrically

Answer

Vias are plated-through holes in a PCB that serve as essential electrical connections between different layers of the board. They allow signals and power to transition vertically through the substrate, enabling the creation of complex multi-layer designs and compact component placement. This is crucial for modern high-density electronics.

(CID) Certified Interconnect Designer Practice Test

(CID) Certified Interconnect Designer Practice Test

CID PCB Materials & Manufacturing Processes