The Process a Printed Circuit Board Manufacturer Uses to Produce PCBs
PCBs are in everything from smartphones to appliances, making them a highly demanded component. However, their design and fabrication are complex. This article will cover the process a printed circuit board manufacturer uses to produce these crucial components.
The first step is to review and prepare the designs for manufacturing. At Bay Area Circuits this is performed by a Planner who creates a set of instructions known as a Process Card.
Layout
A printed circuit board (abbreviated as PCB or PWB) is a rugged nonconductive substrate that houses many active and passive components that connect to each other using the surface-mount mounting technique. PCBs are used in a wide range of electronic devices from computers to industrial equipment.
During the design phase, designers build schematics to determine how everything will be positioned and connected on a PCB. The resulting layout is then refined using iterative design cycles to achieve the intended functionalities and performance requirements of the finished product.
After the final confirmation printed circuit board manufacturer of the initial layout, PCB fabrication begins. A prototype PCB is then made to test and verify the design under indigenous usage conditions, allowing for a quick correction or update if necessary before the full production run.
The bare substrate of the PCB is then plated with copper to help send signals from one layer to another. Depending on the complexity of the circuit, holes may also be drilled or lasered in to form vias. The exact method of drilling or lasering will depend on the substrate material; glass fiber FR-4 is a common choice due to its ability to conduct electrical currents and resist corrosion.
The component pin pads are then mapped and laid out on the board using a PCB designer software. The layout is then converted into a photomask that can be replicated on the blank copper-clad substrate by photolithography. The resulting mask can be applied in a number of colors, although manufacturers tend to use green because it makes it easier to inspect for defects during the manufacturing process.
Etching
A PCB manufacturer uses a technique called deep reactive ion etching (DRIE) to create the copper planes that are the foundation of the board. The process involves exposing the substrate to a gas composition that combines with an atomic oxygen ion that etches the surface of the substrate. This allows for etch depths of hundreds of microns and vertical sidewalls, which are necessary to route the circuits.
After the copper planes have been pre-bonded to the laminate, workers wash off the rest of the resist that didn’t harden during the printing process. This cleaning removes areas that covered non-conductive portions of the copper, allowing the copper to glisten with conductivity. This step also cleans any copper solvent residue off the surface of the inner layer.
The next step is a chemical bath that dissolves any bubbles that may form on the plate. To prevent acid from etching into unprotected parts of the metal, the printmaker may wave away the bubbles using a feather or similar item. He or she may also lift the plate from the acid, allowing it to air-dry.
After the inner and outer layers have been cleaned, the technician places them into a machine that uses registration holes to align the two. The machine also performs an automatic optical inspection to check that the layers are completely free of defects.
Lamination
Lamination is the process of bonding a plastic film to printed materials, enclosing them in a protective sheath. This allows for better protection from regular handling, moisture, and damage while also adding luster, strength, readability, and durability. It can be used on documents, photos, art projects, and even credit cards to protect them from dirt, smudges, stains, or tears. Lamination is a practical and cost-effective solution for protecting items that require durability and readability.
PCBs are rugged nonconductive circuit boards that provide electrical connections Printed Circuit Board Manufacturer Supplier and mechanical support for electronic components. They are prevalent in most electronic devices and can be either single- or double-sided. The manufacturing process of a PCB is known as fabrication and consists of two main steps: the manufacture of the insulating base and the electrical and mechanical connection of the component parts to the board.
Some printed circuit boards are made using additive methods, while others use subtractive methods. Additive boards start with a bare laminate panel which is covered by a photo-sensitive film that prints the design. The exposed areas of the board are then sensitized with a chemical bath that makes them capable of bonding metal ions. The area is then plated with copper (which can be any weight).
Companies that offer custom printed circuit board fabrication include Howman Engineering, Cir-Q-Tek, and Ark Electronics. They also provide engineering, designing, testing, and retrofitting services. Founded in 1987, Howman Engineering is located in Whitehouse, NJ. Cir-Q-Tek is based in Bristol, PA and was established in 2000. Ark Electronics is headquartered in Irvine, CA and was established in 2011.
Microsectioning
During micro-sectioning, the bare PCB is cut into two-dimensional slices. These are then examined using a microscope to find the source of the defect. This is an important part of the failure analysis process because it provides an objective factual basis for discovering and solving problems. It also helps ensure that the quality of products is maintained, and that processes can be corrected to prevent future defects.
Several different inspection processes can be used to check the quality of a PCB, including burn-in testing and X-ray inspection. In addition, the board can undergo a peel test to determine how much strength is required to pull off the surface of the laminate, and a solder float test to see whether the holes can handle thermal stress.
A metallographic cross section is another inspection technique that can help you get to the root of a problem. This involves a series of steps that include sawing, grinding, and polishing the specimen to reveal the plane of interest. A metallographic sample can then be etched and stained to reveal the internal structure of the material. Depending on the type of defect, a metallographic sample can be prepared to measure the thickness of the plated copper or to identify the presence of other defects.
To determine the wall plating thickness of a through-hole, manufacturers make multiple non-destructive measurements on each hole and then average those readings to calculate the total wall plating thickness for the entire hole. This helps them maintain the quality of their products by finding potential flaws before they can cause costly failures.