Estimated reading time: 7 minutes
Electronic components are based on printed circuit boards, or PCBs. It connects and holds every part. The process of creating a PCB is time-consuming and meticulous. There are numerous steps. Every step of the PCB manufacturing process is explained in this guide. We’ll walk through the entire PCB manufacturing process.
Prepare the design and files
The circuit board layout is first created by a designer. For this, they employ specialized software. They can place all the parts and draw all the lines with the aid of the software. The designer forwards the files to the factory once the design is complete. The Gerber file is the most crucial one. A Gerber file is more than just a picture. It’s a data file. It instructs the machines on where to place each line, hole, and component.
The files are received and examined by the factory. We refer to this check as CAM engineering. The engineers check the design for errors. They ensure that the design can be turned into an actual board. They resolve minor problems. This step is crucial because it ensures that everything will proceed as planned.
Making and Imaging Film
The factory then produces a movie. The film functions similarly to a stencil. Every layer of the circuit board’s design is included. The design is laser-drawn on the film by a specialized machine. The locations of the copper lines are depicted in the movie. On the film, the copper lines are visible. Everywhere else is black. The next step uses this film.
A worker then takes a sheet of material. This substance contains copper. We refer to it as copper-clad laminate. The worker does a great job cleaning the sheet. On the sheet, they applied a unique light-sensitive ink. Photoresist is the name of this ink. The employee covers the sheet with the film. They then expose it to intense UV light. In some areas, the light hardens the ink. Under the black portions of the film, the ink remains soft. The design is displayed on the board through this process.
Inspection and Etching of the Inner Layer
The inner layers of multi-layer boards are where the process begins. The soft ink is removed following the imaging process. The copper underneath is visible here. After that, the board is placed inside an etching machine. The device makes use of a unique chemical. All of the exposed copper is eliminated by this chemical. The hard ink protects the copper underneath. It isn’t taken out. This creates the circuit’s copper lines.
The boards are examined once the etching is complete. The board is examined by an automated machine. The board and the design file are compared. It searches for any short circuits or broken lines. This is a crucial check. Issues on the inner layer cannot be fixed later.
Lamination and Layering
The inner layers are stacked once they are prepared. Only multi-layer boards should use this step. The factory stacks new copper sheets, some sticky sheets, and the inner layers on top of one another. Prepreg is the term for the sticky sheets. The prepreg is similar to glue.
The stack of layers was then placed inside a large machine. High pressure and high heat are used by the machine. The prepreg melts in the heat. All of the layers adhere to one another quite effectively due to the pressure. The prepreg then becomes hard once more. All of the layers are now one sturdy board.
Plating and Drilling
The board requires holes once it is a single, solid piece. Thousands of holes are drilled into the board by a machine. The holes are for components. Additionally, they link various layers. The drill bit used by the machine is extremely accurate. The drill file from the design is followed by the machine.
The interior of the holes is not coated in copper after they are drilled. However, current must flow to other layers through the holes. The board is thus placed in a unique chemical bath. A very thin layer of copper is applied to the hole walls by this bath. We refer to this procedure as copper plating. It creates a channel for electricity to move between layers.
Imaging and Etching of the Outer Layer
Next, the board’s outer layers are processed. The top and bottom of the board are the outer layers. First, more copper is applied to the board’s surface and holes. The copper becomes thicker as a result. The imaging procedure from Step 2 is then applied. The outer layer design is transferred to the board through this process.
The board then passes through another etching machine. All of the copper that the design does not cover is eliminated by the chemical. The last lines and pads on the board’s exterior are produced in this way. The components that are visible on the board are formed in this step.
Silkscreen and Solder Mask
The board needs to be protected now. The board is covered with a layer of special paint. Solder mask is the name of this paint. Although solder masks can be any color, they are typically green. The copper lines are hidden by the solder mask. It prevents damage to the lines. Additionally, it aids in preventing short circuits during soldering. The only pads that are left open are those to which parts will be attached.
Once the solder mask is in place, the silkscreen is applied. The silkscreen is the white text on the board. It shows where the parts are located. Additionally shown are the values and part names. It is advantageous to whoever is putting the parts on the board. It is an essential part of the board.
Shaping and Surface Finish
One final layer of protection is required for the exposed copper pads. We refer to this layer as the surface finish. It prevents rusting of the copper. Additionally, it improves the solder’s adhesion. Surface finishes come in a wide variety. ENIG is one popular kind. It covers the copper with a layer of gold.
The boards are then cut. A large piece of board is placed on a machine. Every board is cut out by the machine. The boards are cut into the desired shape. This keeps each board apart from the big panel on which it was created.
Quality Check and Electrical Test
Each and every board is tested at the end. A test machine touches the board with tiny probes. It verifies that each line is intact. It looks for short circuits as well. This test ensures that each board functions. The customer only receives boards that pass this test.
Employees visually inspect the boards in addition to performing the electrical test. The gaps are examined. They gauge the thickness. They guarantee that the board is built properly. This final inspection guarantees the final product’s quality.
In conclusion
Despite being a tiny component of an electronic device, a PCB’s manufacturing process is intricate. From design to final testing, there are numerous steps involved. To create a good, functional board, each step is crucial. You can gain a solid understanding of how contemporary electronics are constructed by comprehending the PCB production flow.
FAQ
The Gerber file is the most crucial one. The manufacturing machines use this standard data file to determine where to make each line, pad, and hole on the board. The factory cannot begin production without a precise Gerber file.
Different layers on PCBs enable more intricate and condensed circuits. Traces and components are on one side of a single-layer board. Multiple circuit layers are stacked on top of one another on a multi-layer printed circuit board (PCB), with insulation between them. Because of this, designers can make dense boards with a lot more connections without physically expanding the board.
The copper traces on the PCB are covered by a protective layer of polymer called the solder mask, which is usually green. Its primary functions include shielding the copper from oxidation and damage over time and preventing short circuits between neighboring traces during the soldering process.
