How Are Printed Circuit Boards Manufactured - Miracle Electronics

1
Printed Circuit Boards (PCBs) are self-contained
modules of interconnected electronic components
found in a variety of electronic devices. The
circuits are formed by a thin layer of
conducting material deposited or printed on the
surface of an insulating board that is called
the substrate after which a number of tiny
electronic components are placed on the surface
and soldered to the interconnecting circuits.

• PCBs could be single-sided, double-sided, or
  multi-layered. Clearly as the names suggest,
  single-sided boards have components on one side
  of the substrate double-sided boards have
  components on both sides of the substrate and
  multi- layered boards have a substrate made up
  of layers of printed circuits separated by
  layers of insulation. With these basics known,
  now let us get into the details of how a Printed
  Circuit Board is manufactured.
• First of all, the environment in which the PCB is
  to be manufactured should be cleaned thoroughly
  such that there is no contamination of any kind,
  and the air and components can be kept safe.
• Next, the substrate is prepared by unwinding
  woven glass fiber from a roll
• and feeding it through a process station, where
  it is impregnated with epoxy resin. This is then
  passed through rollers that roll the material to
  the desired thickness, while removing excess
  amounts of resin. This substrate is then passed
  through an oven to be semi-cured, after which is
  cut into large panels. These panels are stacked
  in layers, with alternating layers of

2

• adhesive-backed copper foil inserted in between,
  which are then placed in a press that subjects
  them to high temperatures and pressures for hours
  together to fully cure the resin and make a
  tight bond.
• Once the substrates are manufactured, several
  panels are stacked and
• pinned together to keep them from moving. They
  are then placed in a CNC machine where holes are
  drilled, and then de-burred to remove any excess
  material clinging to the edges of the holes.
  These holes are then plated with copper.
• Next, a printed circuit pattern is created on the
  substrate. For this, the
• surface is degreased, after which the panels pass
  through a vacuum chamber, where a positive
  photoresist material is pressed firmly onto the
  surface. After this, the printed circuit pattern
  mask is laid on top of the photoresist, and the
  panels are exposed to intense UV light. The mask
  is then removed and the surface of the panels is
  sprayed with alkaline developer, and then
  electroplated with copper. Next, another
  protective coating is placed on top to prevent
  the copper from oxidizing. The photoresist is
  then stripped off and the boards are sprayed with
  an acid solution.
• Contact fingers are then attached to the edge of
  the substrate to connect with the printed
  circuit, but they are masked off from the rest of
  the board and then plated with tin-lead, nickel,
  and gold. To prevent oxidization, the panels are
  passed through a reflow oven or hot oil bath that
  causes the tin- lead to melt into a shiny
  surface. Each panel is then sealed with epoxy and
• the panels are cut into individual boards.
• Finally, all the tiny electronic components are
  placed on the board with the help of several
  machines. With the surface mount technology, the
  board passes through an automatic solder paster,
  which places solder paste at each component
  contact point. Then, the components are placed
  where they need to be with the help of a chip
  shooter or robotic placer, or may be placed
  manually if they are big enough. All these
  components are then soldered to the circuits.
  Finally, all the residue is cleaned with water or
  solvents, as appropriate, to make the PCB ready
  to use.
• Miracle Electronics is a leading manufacturer of
  the finest quality PCB assembly from Germany
  that provides end-to-end turnkey solutions using
  not only surface mount technologies, but also
  plated-through-holes technologies if required.
  All the procedures are standardized, making all
  the products of the highest quality!