The Printed Circuit Board Industry

The Printed Circuit Board (PCB) is a required component of all the electronic devices we depend on every day. The purpose of the PCB is to connect all the distinct elements of electronic devices. Taking the smartphone, for example, it has a display, a battery, memory, storage, modems, camera module, and various sensors. All these components cannot work independently but have to be connected to processor units, including a multiple-core CPU and the GPU. These components are connected or mounted onto the PCB, which provides the electrical connection between these components for them to work together.

As devices become smaller while their functions get more powerful, the circuits need to get smaller and more compact. For each generation in the evolution of the PCB, new challenges need to be overcome to improve the yield rate of the products. Below are some general challenges in PCB production. We will update this page as new information becomes available.

The Evolution of the Printed Circuit Board

Here is a simplified overview of the evolution of the PCB. Traditional PCBs include single-sided boards, double-sided boards, and multi-layer boards. We use these for simple electronics such as calculators and computer motherboards. Next are more complex high-density interconnect (HDI) boards, which have an increasing number of layers stacked into smaller and smaller sizes. Rigid-flex boards use a flexible PCB to connect two or more pieces of HDI boards. This allows the PCBs to be installed in a device at different angles to take advantage of 3-dimensional space. Any layer HDI is an advancement over HDI technology with an even higher circuit density, allowing for further reduction in the PCB's size. While HDI connects all layers by a conductive hole that passes through all the layers, any layer HDI builds connections between any of the layers of the circuit, allowing a more flexible and compact design of the circuits. Other key developments in the industry include Substrate-Like PCB, a hybrid between PCB technology and IC packaging technology.

The PCB Production Process

With each generation of PCB products, the size of the PCB decreases while the complexity and the amount of circuits increases. The line width and the line spacing keeps getting smaller and smaller, requiring advanced and highly fine-tuned process control. With each PCB layer requiring the same production processes but may require different process parameters (e.g. flow rate and spray pressure), the equipment needs to be flexible enough to cater to a wide range of production parameters. For the processes to be reliable and repeatable, we control the pumps using a variable frequency drives (VFD) and we monitor and fine tune the process parameters to maintain process stability.

Advanced Production Controls

Advanced PCB products require advanced production process controls. With many parameters going into each step of the production process, there is a need to fully automate the production to eliminate errors. With thousands of moving parts working together, it is insufficient to just have the process automated. It is also crucial to have continuous feedback from the process back to the control system to detect divergence. For example, if one of the spray nozzles breaks or comes loose, the spray pressure will change, potentially affecting the quality of the product. A feedback loop will notify the control center or an on-site operator of the error to determine the best cause of action to minimize production losses.

Production Environment

The traditional PCB factory uses open plating tanks, often resulting in exposing corrosive fumes in the work environment. As technology improved, most of the processes now take place in enclosed equipment or environmentally controlled enclosures, further improving the workspace. As production technology advances, and line width and line space get smaller, there is a need to minimize dust particles in the work environment. A climate-controlled clean environment is becoming the norm for new production facilities. Besides dust control, we need to limit on-site personnel which is a source of dust and heat. The process equipment needs to have the highest level of reliability and must be leak-free to minimize the need for maintenance and repairs, and to avoid contaminating the work environment. There is a shift towards equipment that is designed for clean-room environments that not only fit the above criteria but also offer additional services such as on-site monitoring that tracks equipment health for preventive maintenance.

Staying Cost Competitive

The PCB industry is a highly competitive market. The only way to stay competitive is to achieve a high product yield rate and minimize costs. So far we have looked at some factors that help manufacturers maintain production competitiveness through process control. There are other strategies that manufacturers can employ to further reduce their operating costs.

1. Use high-efficiency equipment. Energy efficiency has long been one of the key areas of improvement. However, since the production line comprises various pieces of technologies, such as the pump, the heat exchanger, the conveyor system, etc. Each component has its area of expertise and it is up to the PCB manufacturer to discuss with the production system designer what is available to reduce overall energy use. It is often necessary to involve the component manufacturers to understand the options available.

2. Look at the Life-Cycle Costs (LCC). The LCC of the equipment is the lifetime costs of the equipment, from initial purchase, installation, training, operation, production downtime, maintenance, repairs, to its decommissioning. Taking the chemical pump, for example, operation costs is usually the largest part of the LCC, followed by the maintenance and repair costs. Production downtime could be a very significant cost for products that are unreliable and unpredictable.

3. Durability of your equipment. The typical PCB process equipment has an average lifecycle of about eight years before it becomes obsolete and requires replacement or repurposing. The durability of the components is also an important factor. Taking the chemical pump, for example, if the pump can last through the entire lifecycle of the process equipment, it is more cost-effective than a pump that has a shorter useful life. This is important because just looking at the LCC of the pump itself may not reveal the true cost of the pump over the lifecycle of the process equipment.