• Rana Udayveer Singh

Printed Circuit Boards (PCB)

A Printed Circuit Board (PCB) is an essential part of all major electronics. PCB acts as a mechanical support and connects electric components using conductive tracks, pads, and other features etched from one or more sheet layers of copper laminated onto sheet layers of a non-conductive substrate. The copper routes determine the unique role of each piece of the PCB circuit board. In short, PCBs define the pathway of the electricity in devices to maintain their operational effectiveness. PCBs are used in each and every electronic device such as laptops, cameras, calculators, etc. and are also used in some electrical products, such as passive switch boxes.

Different Layers of PCB

When it comes to printed circuit boards, there is a wide range of boards you can choose, from single-sided boards to multi-layer or even flexible PCBs. Each of these circuit boards has a different number of layers that define their functionality, making them optimum for specific tasks. The number of layers refers to the number of separate conductor patterns. It is usually even and includes the two outer layers. Most boards have between 4 and 8 layers, but PCBs with almost 100 layers can also be made. The four layers present in most of the PCBs are explained below:

1. Substrate Layer - This layer is made up of fiberglass, which gives the board a rigid form. The majority of boards have this material as their substrate, except flexible PCBs, which are built on flexible plastic such as Kapton. Substrate PCB layers can be made using other materials such as epoxies, however they lack the durability that is found in fiberglass, required for a high quality board.

2. Copper Layer - A thin layer of copper foil is laminated to the board using heat. When we speak of different layered PCBs, we are referring to how many copper layers they consist of. If we are creating a single-sided PCB, the circuit board has one layer of conducting material on one side of the board and the other side is used for incorporating different electronic components whereas double-sided PCBs can mount the conductive copper and components on both sides of the board. This proves to be very useful in many electronic products as the circuits on one side of the board can be connected to the other with the help of holes drilled into it. The thickness of the copper layer on the PCB will depend on the power the PCB needs to withstand. PCBs that need to handle very high power throughout, usually have a thick copper layer.

3. Solder Mask layer - Once the copper layer has been applied, the solder mask layer is placed on top. This gives the PCB its green colour and is used to insulate the copper layer to avoid any contact with any other metal or elements of the board that could disrupt the copper traces.

4. Silkscreen layer - The silkscreen mainly serves the purpose of helping humans better understand the board and the functionality of different pins or LEDs, by adding letters, numbers and symbols to the board.

Market Insights

Consumer electronics, medical instruments and surveillance technology have all seen the need for PCB in their development. The small size of the components guarantees their inclusion in various items, from laptops to minimally invasive medical equipment. The printed circuit board (PCB) market is expected to show a growth of USD 10.85 billion during 2020-2024, and it is expected to register a Compound Annual Growth Rate (CAGR) of 1.53%, during 2021-2026. The PCB market which was valued at USD 58.91 billion in 2020, is projected to be worth USD 75.72 billion by 2026. In 2020, 93% of growth was contributed by APAC and the largest marketplace is North America. The rapid growth of the market in the last few years is due to the increasing usage of consumer electronics devices and PCBs in all electronics and electrical equipment.

What is the Future?

The ever-evolving tech industry makes sure that the future for PCBs is growing with it, which is also evident from their increased use in wearable electronics, flexible displays, medical and other applications. Flexible PCB technology is pushing the industry increasingly toward flexible and rigid-flex PCBs.

1. Flexible PCBs - Derive their name for their ability to enable the circuitry to be designed to fit the electronic device or product, as opposed to building the device to conform to the circuit board. They consist of a thin insulating polymer film having conductive circuit patterns affixed and supplied with a thin polymer coating to protect the conductor circuits.

In many cases, flex circuits are made of polyimide or a similar polymer. This material dissipates heat better than most rigid circuit board materials. For this reason, flexible circuits can be placed in inconvenient locations where heat would impact the performance of a rigid circuit board. Flexible circuit boards can be designed to withstand extreme temperatures – between -200° C and 400° C – which makes them the most suitable choice for operations in the oil and gas industry and they are also the first choice for engineering design in most industrial sensor technologies. High-temperature resistance usually comes with good chemical resistance and excellent resistance to radiation and UV exposure as well. Combined with the ability to control impedances in high-density circuit board designs, flexible circuit designs offer a wide range of benefits to manufacturers.

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  1. https://en.wikipedia.org/

  2. https://www.ablcircuits.co.uk/pcb-layers-explained/

  3. https://www.pcbcart.com/article/content/PCB-manufacturing-process.html

  4. https://www.pcbway.com/pcb_prototype/What_is_Flexible_PCB.html

  5. https://www.candorind.com/pcb-manufacturing-process/

  6. https://www.mclpcb.com/pcb-manufacturing-process/

  7. https://www.businesswire.com/news/home/20210203005607/en/10.85-Billion-Growth-in-Global-Printed-Circuit-Board-PCB-Market-2020-2024-Key-Vendor-Insights-and-Market-Forecasts-for-New-Normal-Technavio

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