Manufacturing of PCBs (printed circuit board) is a complex process and the first step of electronics manufacturing services.

1. An overview of the method used for
manufacturing PCBs
Manufacturing of PCBs (printed circuit board) is a complex
process and the first step of electronics manufacturing services.
There are three types of circuit boards; single sided, double sided
and multi-layered. Complexity, density and the spatial
requirements are the deciding factor of which type of circuit to
be used.

2. Method of PCB manufacturing
Usually nonconductive materials are used for the backing of boards.
Conductive materials are used for the coating of circuit boards such
as aluminum, nickel and copper. Here’s a brief look at the method of
PCB manufacturing:
Drilling & scrubbing the boards:Once the backing has been plated
with conductive material, holes are drilled to allow other electronic
components to be mounted over it. After drilling the holes, boards
are scrubbed to remove tiny conductor particles. Electrically
conductive materials like copper are recycled and recovered from
the water waste with the help of filtration process or via centrifuge.

3. Etching process:In this process, the boards are first cleaned. After that,
they are etched for better adhesion in the following steps. Next step
involves adding another conducting layer. Since the holes that were drilled
in the earlier stage are not electrically conducive, hence for the purpose of
coating the holes with a conductive material, a process like electrolysis
copper plating is employed.
Getting final thickness:Photo imaging is used for making the final design
of circuit. Electroplating copper is used for obtaining the final thickness of
printed board. A very thin layer of lead or tin solder resist is applied for
protecting final circuit in next stage of etching. The plating is then removed
in the next stage to expose the copper which will not be a part of the final
circuit. Hydrogen-peroxide or sulfuric acid is used to remove unwanted
copper material.

4. Alternative resists:Volatile compounds or photosensitive materials can
also be used as other types of resists. They can be applied either dry or
wet. These photosensitive compounds get hard when they are exposed to
UV light. Various techniques are used for applying liquid resists such as
roller, squeegee, spray or silk screen. The liquid may be applied on either
both sides or on a particular surface area.
Multi-layered PCB panels:These panels are made by assembling inner
layers. These panels are then assembled as alternate epoxy sheet layers
and copper foil layers. This book-like structure is then placed for
lamination under high pressure. This results in melting of epoxy layers,
and release of adhesive bond. This is followed by drilling of necessary
holes.
This was an overview of a conventionally used method for producing PCB
boards by electronics manufacturing company.